From: Andrew Burgess via Gdb-patches <gdb-patches@sourceware.org>
To: gdb-patches@sourceware.org
Cc: Andrew Burgess <aburgess@redhat.com>
Subject: [PATCH] gdb: new 'maint print frame-id' command
Date: Tue, 16 Aug 2022 18:18:22 +0100 [thread overview]
Message-ID: <20220816171822.3315660-1-aburgess@redhat.com> (raw)
When debugging a certain class of GDB bug, I often end up wanting to
know what GDB thinks the frame-id is in a particular frame. It's
not too hard to pull this from some debug output, but I thought it
might be nice if there was a maintenance command that could tell us.
This commit adds 'maint print frame-id' which prints the frame-id of
the currently selected frame. You can also pass a frame level number
to find the frame-id for a specific frame.
There's a new test too.
---
gdb/NEWS | 4 ++
gdb/doc/gdb.texinfo | 17 +++++
gdb/frame.c | 28 ++++++++
gdb/testsuite/gdb.base/maint-print-frame-id.c | 40 +++++++++++
.../gdb.base/maint-print-frame-id.exp | 68 +++++++++++++++++++
5 files changed, 157 insertions(+)
create mode 100644 gdb/testsuite/gdb.base/maint-print-frame-id.c
create mode 100644 gdb/testsuite/gdb.base/maint-print-frame-id.exp
diff --git a/gdb/NEWS b/gdb/NEWS
index f2040e26c0c..49ac714efda 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -91,6 +91,10 @@ show style disassembler symbol
The 'disassembler address' and 'disassembler symbol' styles are
aliases for the 'address' and 'function' styles respectively.
+maintenance print frame-id [ LEVEL ]
+ Print GDB's internal frame-id for the frame at LEVEL. If LEVEL is
+ not given, then print the frame-id for the currently selected frame.
+
* Changed commands
maintenance info line-table
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 82cb1c8d668..ca958173b57 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -40142,6 +40142,23 @@
Takes an optional file parameter.
+@kindex maint print frame-id
+@item maint print frame-id
+@itemx maint print frame-id @var{level}
+Print @value{GDBN}'s internal frame-id for the frame at relative
+@var{level}, or for the currently selected frame when @var{level} is
+not given.
+
+If used, @var{level} should be an integer, as displayed in the
+@command{backtrace} output.
+
+@smallexample
+(@value{GDBP}) maint print frame-id
+frame-id for frame #0: {stack=0x7fffffffac70,code=0x0000000000401106,!special}
+(@value{GDBP}) maint print frame-id 2
+frame-id for frame #2: {stack=0x7fffffffac90,code=0x000000000040111c,!special}
+@end smallexample
+
@kindex maint print registers
@kindex maint print raw-registers
@kindex maint print cooked-registers
diff --git a/gdb/frame.c b/gdb/frame.c
index ae45e22d613..e6bebf575ca 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -3116,6 +3116,30 @@ the rest of the stack trace."),
},
};
+/* Implement the 'maintenance print frame-id' command. */
+
+static void
+maintenance_print_frame_id (const char *args, int from_tty)
+{
+ struct frame_info *frame;
+
+ /* Use the currently selected frame, or select a frame based on the level
+ number passed by the user. */
+ if (args == nullptr)
+ frame = get_selected_frame ("No frame selected");
+ else
+ {
+ int level = value_as_long (parse_and_eval (args));
+ frame = find_relative_frame (get_current_frame (), &level);
+ }
+
+ /* Print the frame-id. */
+ gdb_assert (frame != nullptr);
+ gdb_printf ("frame-id for frame #%d: %s\n",
+ frame_relative_level (frame),
+ get_frame_id (frame).to_string ().c_str ());
+}
+
void _initialize_frame ();
void
_initialize_frame ()
@@ -3160,4 +3184,8 @@ When non-zero, frame specific internal debugging is enabled."),
NULL,
show_frame_debug,
&setdebuglist, &showdebuglist);
+
+ add_cmd ("frame-id", class_maintenance, maintenance_print_frame_id,
+ _("Print the current frame-id."),
+ &maintenanceprintlist);
}
diff --git a/gdb/testsuite/gdb.base/maint-print-frame-id.c b/gdb/testsuite/gdb.base/maint-print-frame-id.c
new file mode 100644
index 00000000000..bc9eb3000e7
--- /dev/null
+++ b/gdb/testsuite/gdb.base/maint-print-frame-id.c
@@ -0,0 +1,40 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2022 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/>. */
+
+int
+foo (void)
+{
+ return 0;
+}
+
+int
+bar (void)
+{
+ return foo ();
+}
+
+int
+baz (void)
+{
+ return bar ();
+}
+
+int
+main (void)
+{
+ return baz ();
+}
diff --git a/gdb/testsuite/gdb.base/maint-print-frame-id.exp b/gdb/testsuite/gdb.base/maint-print-frame-id.exp
new file mode 100644
index 00000000000..395927a22c4
--- /dev/null
+++ b/gdb/testsuite/gdb.base/maint-print-frame-id.exp
@@ -0,0 +1,68 @@
+# Copyright 2022 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/>.
+
+# Test the 'maint print frame-id' command.
+
+standard_testfile
+
+if {[prepare_for_testing "failed to prepare" $testfile \
+ $srcfile {debug}]} {
+ return -1
+}
+
+if ![runto_main] then {
+ return -1
+}
+
+gdb_breakpoint foo
+gdb_continue_to_breakpoint "run to foo"
+
+proc get_frame_id { level } {
+ set id "**unknown**"
+
+ gdb_test_multiple "maint print frame-id ${level}" "" {
+ -re "^maint print frame-id\[^\r\n\]+\r\n" {
+ exp_continue
+ }
+
+ -wrap -re "^frame-id for frame #\[0-9\]+: (\[^\r\n\]+)" {
+ set id $expect_out(1,string)
+ pass $gdb_test_name
+ }
+ }
+
+ return $id
+}
+
+# Get the frame-id for each frame using the frame level.
+array set ids {}
+with_test_prefix "get id by level" {
+ for { set i 0 } { $i < 4 } { incr i } {
+ set ids($i) [get_frame_id $i]
+ }
+}
+
+# Now get the frame-id of the currently selected frame, and check it
+# matches the frame-id we got earlier. Then move up the stack,
+# selecting a new frame.
+for { set i 0 } { $i < 4 } { incr i } {
+ with_test_prefix "frame $i is current" {
+ set id [get_frame_id ""]
+ gdb_assert { [string equal $id $ids($i)] } \
+ "check frame-id matches"
+ }
+ gdb_test "up" ".*" \
+ "move up from frame $i"
+}
--
2.25.4
next reply other threads:[~2022-08-16 17:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-16 17:18 Andrew Burgess via Gdb-patches [this message]
2022-08-17 9:21 ` Bruno Larsen via Gdb-patches
2022-08-17 13:20 ` Andrew Burgess via Gdb-patches
2022-08-17 11:07 ` Eli Zaretskii via Gdb-patches
2022-08-17 14:11 ` Luis Machado via Gdb-patches
2022-08-24 13:45 ` Andrew Burgess via Gdb-patches
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