From 70175292616118bad315296ba6180f375326bb6c Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Tue, 16 Aug 2022 16:48:01 +0100 Subject: [PATCH] gdb: new 'maint print frame-id' command 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 c2a5e6723d3..25b771b84f2 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -93,6 +93,10 @@ 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..33a56e0ead5 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -40142,6 +40142,23 @@ The program being debugged stopped while in a function called from GDB. 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 . */ + +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 . + +# 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" +} -- 2.30.2