From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2926 invoked by alias); 30 Jan 2012 06:57:58 -0000 Received: (qmail 2912 invoked by uid 22791); 30 Jan 2012 06:57:57 -0000 X-SWARE-Spam-Status: No, hits=-1.3 required=5.0 tests=AWL,BAYES_00,KAM_STOCKGEN,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from rock.gnat.com (HELO rock.gnat.com) (205.232.38.15) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 30 Jan 2012 06:57:31 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id CEC5D2BB126; Mon, 30 Jan 2012 01:57:30 -0500 (EST) Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id vp7ncWfvIKrU; Mon, 30 Jan 2012 01:57:30 -0500 (EST) Received: from joel.gnat.com (localhost.localdomain [127.0.0.1]) by rock.gnat.com (Postfix) with ESMTP id F39782BB125; Mon, 30 Jan 2012 01:57:29 -0500 (EST) Received: by joel.gnat.com (Postfix, from userid 1000) id 54994145615; Mon, 30 Jan 2012 10:57:17 +0400 (RET) From: Joel Brobecker To: gdb-patches@sourceware.org Cc: Joel Brobecker Subject: [PATCH] GDB/MI: crash printing "_task" (Ada) argument Date: Mon, 30 Jan 2012 07:01:00 -0000 Message-Id: <1327906636-20099-1-git-send-email-brobecker@adacore.com> Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-01/txt/msg00979.txt.bz2 Hello, In GDB/MI mode, trying to print the arguments of the frame corresponding to the body of a task ("-stack-list-arguments 1") causes the debugger to crash. This is because the compiler adds an implicit argument to that task body called "_task". mi/mi-cmd-stack.c:list_args_or_locals, which is responsible for printing the value of our arguments, finds that our "_task" symbol is an argument, and thus tries to fing the non-argument equivalent: if (SYMBOL_IS_ARGUMENT (sym)) sym2 = lookup_symbol (SYMBOL_NATURAL_NAME (sym), block, VAR_DOMAIN, (int *) NULL); Unfortunately, it tries using the natural name instead of the search name when doing the lookup. The correct name to use for symbol lookups is the search name. In C/C++, it's the same, but not in Ada. In Ada, "_task"'s natural name is "<_task>", and that symbol does not exist, so sym2 is NULL, thus causing the crash a little later on when trying to dereference it. gdb/ChangeLog: * mi/mi-cmd-stack.c (list_args_or_locals): For argument symbols, use SYMBOL_SEARCH_NAME to find the corresponding non-argument symbol. Add assertion that sym2 is never NULL. gdb/testsuite/ChangeLog: gdb.ada/mi_task_arg: New testcase. Tested on x86_64-linux, no regression. I will commit in a few days unless there are objections. For the record, I also audited the rest of the code, searching for lookups obviously using SYMBOL_NATURAL_NAME, but did not find any. Thanks, -- Joel --- gdb/mi/mi-cmd-stack.c | 3 +- gdb/testsuite/gdb.ada/mi_task_arg.exp | 51 +++++++++++++++ gdb/testsuite/gdb.ada/mi_task_arg/task_switch.adb | 70 +++++++++++++++++++++ 3 files changed, 123 insertions(+), 1 deletions(-) create mode 100644 gdb/testsuite/gdb.ada/mi_task_arg.exp create mode 100644 gdb/testsuite/gdb.ada/mi_task_arg/task_switch.adb diff --git a/gdb/mi/mi-cmd-stack.c b/gdb/mi/mi-cmd-stack.c index c0c17bc..b414844 100644 --- a/gdb/mi/mi-cmd-stack.c +++ b/gdb/mi/mi-cmd-stack.c @@ -389,11 +389,12 @@ list_args_or_locals (enum what_to_list what, enum print_values values, struct frame_arg arg, entryarg; if (SYMBOL_IS_ARGUMENT (sym)) - sym2 = lookup_symbol (SYMBOL_NATURAL_NAME (sym), + sym2 = lookup_symbol (SYMBOL_SEARCH_NAME (sym), block, VAR_DOMAIN, (int *) NULL); else sym2 = sym; + gdb_assert (sym2 != NULL); memset (&arg, 0, sizeof (arg)); arg.sym = sym2; diff --git a/gdb/testsuite/gdb.ada/mi_task_arg.exp b/gdb/testsuite/gdb.ada/mi_task_arg.exp new file mode 100644 index 0000000..a8cc59b --- /dev/null +++ b/gdb/testsuite/gdb.ada/mi_task_arg.exp @@ -0,0 +1,51 @@ +# Copyright 2011-2012 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 . + +load_lib "ada.exp" + +set testdir "mi_task_arg" +set testfile "${testdir}/task_switch" +set srcfile ${srcdir}/${subdir}/${testfile}.adb +set binfile ${objdir}/${subdir}/${testfile} + +file mkdir ${objdir}/${subdir}/${testdir} +if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug additional_flags=-gnata ]] != "" } { + return -1 +} + +load_lib mi-support.exp +set MIFLAGS "-i=mi" + +gdb_exit +if [mi_gdb_start] { + continue +} + +mi_delete_breakpoints +mi_gdb_reinitialize_dir $srcdir/$subdir +mi_gdb_load ${binfile} + +if ![mi_runto "task_switch.break_me"] then { + fail "Cannot run to main, testcase aborted" + return 0 +} + +# Verify that "-stack-list-arguments" does not cause the debugger to +# crash when printing the arguments of frame 1 (due to the internally- +# generated argument "_task"). +mi_gdb_test "-stack-list-arguments 1" \ + "\\^done,stack-args=\\\[frame=\{level=\"0\",args=\\\[\\\]\},frame=\{level=\"1\",args=\\\[\{name=\"<_task>\",value=\"$hex\"\}\\\]\},frame=\{level=\"2\",args=\\\[\\\]\}.*" \ + "-stack-list-arguments 1" + diff --git a/gdb/testsuite/gdb.ada/mi_task_arg/task_switch.adb b/gdb/testsuite/gdb.ada/mi_task_arg/task_switch.adb new file mode 100644 index 0000000..8ee1a2d --- /dev/null +++ b/gdb/testsuite/gdb.ada/mi_task_arg/task_switch.adb @@ -0,0 +1,70 @@ +-- Copyright 2011-2012 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 . + +procedure Task_Switch is + + ------------------- + -- Declaractions -- + ------------------- + + task type Callee is + entry Finito; + end Callee; + type Callee_Ptr is access Callee; + + task type Caller is + end Caller; + type Caller_Ptr is access Caller; + + procedure Break_Me; + + My_Caller : Caller_Ptr; + My_Callee : Callee_Ptr; + + ------------ + -- Bodies -- + ------------ + + task body Callee is + begin + -- Just wait until we are told to terminate this task. + -- This is just to maintain this task alive. + accept Finito do + null; + end Finito; + end Callee; + + task body Caller is + begin + Break_Me; + My_Callee.Finito; + end Caller; + + procedure Break_Me is + begin + null; + end Break_Me; + +begin + + -- Make sure to create the Callee task first... And then give it + -- enough time to complete its activation phase before we start + -- the Caller task. + My_Callee := new Callee; + delay 0.1; + + My_Caller := new Caller; + +end Task_Switch; -- 1.7.1