From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 4E7C83858C50 for ; Sun, 24 Sep 2023 13:02:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 4E7C83858C50 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695560554; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gPM6jaZEOSxAYDyLTN+xaDJJeTq2+PIWWRTvM0wRRoA=; b=dUEET0MfadcuQeXY1IlyaYhs2yF+ICddaDZ5R6kEpTeniP6aDAWA2P6W09VSQcnGXMyQLl PUKBx2K+YNrz4+SbMOoDdWhseF+zPyLLcBrUJ/3yWYxZR784371Ck/mvGSOyGCJgJnK9xY o4IgO3lj4pIAF+7kvkitUVdttPET8p4= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-90-XsklGRdjNrOwwSWbeeZ40g-1; Sun, 24 Sep 2023 09:02:32 -0400 X-MC-Unique: XsklGRdjNrOwwSWbeeZ40g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 324CF29AA2C5 for ; Sun, 24 Sep 2023 13:02:32 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.42.28.5]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A8660140E950; Sun, 24 Sep 2023 13:02:31 +0000 (UTC) From: Guinevere Larsen To: gdb-patches@sourceware.org Cc: kevinb@redhat.com, Guinevere Larsen Subject: [PATCH v2 1/2] gdb/record: print frame information when exiting a recursive call Date: Sun, 24 Sep 2023 14:58:55 +0200 Message-ID: <20230924125855.983839-3-blarsen@redhat.com> In-Reply-To: <20230923103457.29768-2-blarsen@redhat.com> References: <20230923103457.29768-2-blarsen@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII"; x-default=true X-Spam-Status: No, score=-10.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_SHORT,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Currently, when GDB is reverse stepping out of a function into the same function due to a recursive call, it doesn't print frame information, as reported by PR record/29178. This happens because when the inferior leaves the current frame, GDB decides to refresh the step information, clobbering the original step_frame_id, making it impossible to figure out later on that the frame has been changed. This commit changes GDB so that, if we notice we're in this exact situation, we won't refresh the step information. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29178 --- gdb/infrun.c | 18 +++++++++ gdb/testsuite/gdb.reverse/recursion.c | 44 ++++++++++++++++++++++ gdb/testsuite/gdb.reverse/recursion.exp | 49 +++++++++++++++++++++++++ 3 files changed, 111 insertions(+) create mode 100644 gdb/testsuite/gdb.reverse/recursion.c create mode 100644 gdb/testsuite/gdb.reverse/recursion.exp diff --git a/gdb/infrun.c b/gdb/infrun.c index 4730d290442..3491327422d 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -6923,6 +6923,11 @@ process_event_stop_test (struct execution_control_state *ecs) frame = get_current_frame (); gdbarch = get_frame_arch (frame); + /* Shorthand to make if statements smaller. */ + struct frame_id original_frame_id + = ecs->event_thread->control.step_frame_id; + struct frame_id curr_frame_id = get_frame_id (get_current_frame ()); + switch (what.main_action) { case BPSTAT_WHAT_SET_LONGJMP_RESUME: @@ -7722,6 +7727,19 @@ process_event_stop_test (struct execution_control_state *ecs) "it's not the start of a statement"); } } + else if (execution_direction == EXEC_REVERSE + && curr_frame_id != original_frame_id + && original_frame_id.code_addr_p && curr_frame_id.code_addr_p + && original_frame_id.code_addr == curr_frame_id.code_addr) + { + /* If we enter here, we're leaving a recursive function call. In this + situation, we shouldn't refresh the step information, because if we + do, we'll lose the frame_id of when we started stepping, and this + will make GDB not know we need to print frame information. */ + refresh_step_info = false; + infrun_debug_printf ("reverse stepping, left a recursive call, don't " + "update step info so we remember we left a frame"); + } /* We aren't done stepping. diff --git a/gdb/testsuite/gdb.reverse/recursion.c b/gdb/testsuite/gdb.reverse/recursion.c new file mode 100644 index 00000000000..480362dd9ad --- /dev/null +++ b/gdb/testsuite/gdb.reverse/recursion.c @@ -0,0 +1,44 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 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 . */ + +/* Test GDB's ability to handle recursive functions when executing + in reverse. */ + +/* The recursive foo call must be the first line of the recursive + function, to test that we're not stepping too much and skipping + multiple calls when we should skip only one. */ +int +foo (int x) +{ + if (x) return foo(x-1); + return 0; +} + +int +bar (int x) +{ + int r = foo(x); + return 2*r; +} + +int +main () +{ + int i = bar(5); + int j = foo(5); + return 0; /* END OF MAIN */ +} diff --git a/gdb/testsuite/gdb.reverse/recursion.exp b/gdb/testsuite/gdb.reverse/recursion.exp new file mode 100644 index 00000000000..331113bee0a --- /dev/null +++ b/gdb/testsuite/gdb.reverse/recursion.exp @@ -0,0 +1,49 @@ +# Copyright 2008-2023 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 . */ + +# This file is part of the GDB testsuite. It tests reverse stepping. +# Lots of code borrowed from "step-test.exp". + +# +# Test step and next in reverse +# + +require supports_reverse + +standard_testfile + +if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } { + return -1 +} + +runto_main + +if [supports_process_record] { + # Activate process record/replay + gdb_test_no_output "record" "turn on process record" +} + +set end_of_program [gdb_get_line_number "END OF MAIN" "$srcfile"] +gdb_breakpoint $end_of_program +gdb_continue_to_breakpoint ".*$srcfile/$end_of_program.*" + +## test if GDB can reverse over a recursive program +gdb_test "reverse-next" ".*int j = foo.*" "Skipping recursion from outside" +## setup and next over a recursion for inside a recursive call +repeat_cmd_until "reverse-step" ".*" ".*foo .x=4.*" +gdb_test "reverse-next" ".*return foo.*" "Skipping recursion from inside" +gdb_test "reverse-next" ".*foo .x=5.*" "print frame when stepping out" +gdb_test "reverse-next" ".*bar .x=5.*" "stepping into a different function" +gdb_test "reverse-next" "main .. at .*" "stepping back to main" -- 2.41.0