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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 20B0A3858D39 for ; Mon, 27 Feb 2023 19:45:57 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 20B0A3858D39 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=1677527156; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=L/3y/48+L0SfR0LCTC7SfCfGYCYrmR68I/Q0JrQPmhc=; b=dIvLl6K8R0J3b4FGSBh6z+SOj2VM5oKnrC06nvOP6OW4yRyflPau35GXCVu6cSz7w/f2jn DEcDOevjxD2pBQY/zD0dzu5NVMEvNLHG5hQihE3ZV4e+yQo0eFR/nCR1ktxxim7vwf1Ril AsyP1QVH0eSnQtPAf9DzUTen6cKADmI= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-455-kroy0AqAOYmxh3PUZi8hTA-1; Mon, 27 Feb 2023 14:45:55 -0500 X-MC-Unique: kroy0AqAOYmxh3PUZi8hTA-1 Received: by mail-wm1-f70.google.com with SMTP id l20-20020a05600c1d1400b003e10d3e1c23so5812163wms.1 for ; Mon, 27 Feb 2023 11:45:51 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677527150; h=mime-version:message-id:date:references:in-reply-to:subject:to:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=L/3y/48+L0SfR0LCTC7SfCfGYCYrmR68I/Q0JrQPmhc=; b=k99SdRJ/zhcgEjI8oSWduG8qESvAPFthioCH/BKQ6ANLV+b4SzzrGG/jt1GMAlW6Sm IfAPWtGKgBT0U+0WdO33JRSV82btI1CQzYL6ccCYJ+fS/O1FfuVsJQkTBQqm13QnEAIv 1PW3yooa8lxy7CNMKnYze13rMmjWbdXAZ9qB6YwwHNy+0lGWoZD+D7mfb05f4ECO2Wx8 MKJui6KU3ihmic0/UgEXctF6lpK3C+5RnFrQfACdSaKZoMct5Oyvwpb6Vr3EpqwskoNK 5RoLTUC0DXpeT2/Urca9H61meVC56PKihaKpbodOXNTRNohKHjo87DlnKE5qNPN9C8Et eJJQ== X-Gm-Message-State: AO0yUKV9MUxBDkDb3q/AlibsuVymPiBK6iaP1eKmoBnYVybMyamk7ji8 m4c0Bgjv/wrh33SoZizn7IohD1x22zcldiI4gx27dVe5g7jZbq18xbGKM96YCsHPuw3D2ngb3Y0 4RNg3iOUQvT+1ji71WljDE3qTihQ= X-Received: by 2002:a5d:6187:0:b0:2ca:e8c2:6d25 with SMTP id j7-20020a5d6187000000b002cae8c26d25mr258429wru.60.1677527150343; Mon, 27 Feb 2023 11:45:50 -0800 (PST) X-Google-Smtp-Source: AK7set9cKA/CIk7pvxvuD3u8dj8hgYMjgukC8SGzMA8wIb5sTOElpO4uRI4RRh1XKkPZxk446erkdw== X-Received: by 2002:a5d:6187:0:b0:2ca:e8c2:6d25 with SMTP id j7-20020a5d6187000000b002cae8c26d25mr258418wru.60.1677527150001; Mon, 27 Feb 2023 11:45:50 -0800 (PST) Received: from localhost (95.72.115.87.dyn.plus.net. [87.115.72.95]) by smtp.gmail.com with ESMTPSA id n3-20020a5d4203000000b002c57384dfe0sm7719317wrq.113.2023.02.27.11.45.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Feb 2023 11:45:49 -0800 (PST) From: Andrew Burgess To: Pedro Alves , gdb-patches@sourceware.org Subject: Re: [PATCH 3/3] gdb: don't use the global thread-id in the saved breakpoints file In-Reply-To: <00607ab6-b94c-869c-5d1a-7528cf4dd85f@palves.net> References: <22df7afc-cf88-d260-516d-7b9a45e2ad78@palves.net> <87pmahuxzu.fsf@redhat.com> <00607ab6-b94c-869c-5d1a-7528cf4dd85f@palves.net> Date: Mon, 27 Feb 2023 19:45:48 +0000 Message-ID: <87o7pej3ir.fsf@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-11.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,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: Pedro Alves writes: > Hi! > > On 2023-02-10 7:22 p.m., Andrew Burgess wrote: >> Pedro Alves writes: >> >>> On 2023-02-08 3:23 p.m., Andrew Burgess via Gdb-patches wrote: >>> >>>> breakpoint::print_recreate_thread (struct ui_file *fp) const >>>> { >>>> if (thread != -1) >>>> - gdb_printf (fp, " thread %d", thread); >>>> + { >>>> + struct thread_info *thr = find_thread_global_id (thread); >>>> + gdb_printf (fp, " thread %s", print_thread_id (thr)); >>> >>> print_thread_id only prints the inferior-qualified thread id if >>> there are multiple inferiors. I am wondering whether the save breakpoints >>> file should _always_ end up with inferior-qualified thread ids, so that >>> reloading the saved file works the same if you meanwhile add another >>> inferior. >> >> As a counter argument; if the user has a single inferior and places >> breakpoints on a particular thread, we'll have a save like: >> >> break foo thread 2 >> >> Then if the user sets up two inferiors, they can select which inferior >> the breakpoints should apply to - source the saves from inferior 2, and >> the b/p will apply to inferior 2 threads, source from inferior 1, and >> the b/p will apply to inferior 1 threads. >> >> If the user has changed the inferior setup when sourcing the breakpoint >> save file, I think they have to take some responsibility for knowing >> what they want ... maybe? >> >> If you feel strongly then it's easy enough to print the qualified >> thread-id, just let me know and I'll get it done. >> > > My thinking is that internally, the thread is really inferior-qualified. > It is just a presentation detail in the CLI that we don't print the > inferior when there's only one inferior, for backwards compatibility. > That may even change in the future. An MI frontend / GUI may be presenting > the qualified ID, for instance. > > It seems to be that there are two valid approaches: > > #1 - we consider what the user typed when the breakpoint was created as canonical, > and thus we save the breakpoint using the same breakpoint spec string that > user typed originally, meaning, if the user typed: > > "break foo thread 1" > > then that's what we'd save, even if the user added a second > inferior after creating the breakpoint. > > Of course, it follows then that if the breakpoint is created with > > "break foo thread 1.1" > > then that's what we save. So the user would have the option. > > I'm really not sure whether this is an option that we should be giving > users, though. What if the breakpoint was created via Python, or via the > MI with --thread ? Then the concept of original "thread" may not even exists, > even though we save such a breakpoint too. > > #2 - we consider that the thread that the breakpoint ended up bound to is what > is canonical and thus we always print the qualified id to the file. > > The approach in your patch is neither of the above -- it prints the qualified > or non-qualified thread id depending on a CLI presentation detail, which seems > brittle to me. > > Option #2 seems the simplest to explain, document, and implement, to me, > but I could be convinced to go with #1 too. Thanks for the explanation. I've implemented #2 in the patch below, what are your thoughts? Thanks, Andrew --- commit 868a074345bb6d20d9a64470936d699c8a123894 Author: Andrew Burgess Date: Wed Feb 8 13:56:22 2023 +0000 gdb: don't use the global thread-id in the saved breakpoints file I noticed that breakpoint::print_recreate_thread was printing the global thread-id. This function is used to implement the 'save breakpoints' command, and should be writing out suitable CLI commands for recreating the current breakpoints. The CLI does not use global thread-ids, but instead uses the inferior specific thread-ids, e.g. "2.1". After some discussion on the mailing list it was suggested that the most consistent solution would be for the saved breakpoints file to always contain the inferior-qualified thread-id, so the file would include "thread 1.1" instead of just "thread 1", even when there is only a single inferior. So, this commit adds print_full_thread_id, which is just like the existing print_thread_id, only it always prints the inferior-qualified thread-id. I then update the existing print_thread_id to make use of this new function, and finally, I update breakpoint::print_recreate_thread to also use this new function. There's a multi-inferior test that confirms the saved breakpoints file correctly includes the fully-qualified thread-id, and I've also updated the single inferior test gdb.base/save-bp.exp to have it validate that the saved breakpoints file includes the inferior-qualified thread-id, even for this single inferior case. diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index 0db3adaf916..6b616be547a 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -14141,7 +14141,10 @@ void breakpoint::print_recreate_thread (struct ui_file *fp) const { if (thread != -1) - gdb_printf (fp, " thread %d", thread); + { + struct thread_info *thr = find_thread_global_id (thread); + gdb_printf (fp, " thread %s", print_full_thread_id (thr)); + } if (task != -1) gdb_printf (fp, " task %d", task); diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h index c0f27a8a66e..848daa94410 100644 --- a/gdb/gdbthread.h +++ b/gdb/gdbthread.h @@ -661,6 +661,10 @@ extern int show_inferior_qualified_tids (void); circular static buffer, NUMCELLS deep. */ const char *print_thread_id (struct thread_info *thr); +/* Like print_thread_id, but always prints the inferior-qualified form, + even when there is only a single inferior. */ +const char *print_full_thread_id (struct thread_info *thr); + /* Boolean test for an already-known ptid. */ extern bool in_thread_list (process_stratum_target *targ, ptid_t ptid); diff --git a/gdb/testsuite/gdb.base/save-bp.exp b/gdb/testsuite/gdb.base/save-bp.exp index 41d71837fb6..68933d36427 100644 --- a/gdb/testsuite/gdb.base/save-bp.exp +++ b/gdb/testsuite/gdb.base/save-bp.exp @@ -89,3 +89,19 @@ gdb_test_sequence "info break" "info break" [list \ "\[\r\n\]+\[ \t\]+printf" \ "\[\r\n\]+$disabled_row_start main at \[^\r\n\]*$srcfile:$loc_bp8" \ ] + +# Copy the saved breakpoints file to the local machine (if necessary), +# and then check its contents. +if {[is_remote host]} { + set bps [remote_upload host bps [standard_output_file bps]] +} +set fh [open $bps] +set lines [split [read $fh] "\n"] +close $fh + +with_test_prefix "in bps file" { + gdb_assert {[lsearch -regexp $lines "break ${srcfile}:${loc_bp2}$"] != -1} \ + "check for general breakpoint" + gdb_assert {[lsearch -regexp $lines "break ${srcfile}:${loc_bp3} thread 1\\.1"] != -1} \ + "check for thread-specific breakpoint" +} diff --git a/gdb/testsuite/gdb.multi/bp-thread-specific.exp b/gdb/testsuite/gdb.multi/bp-thread-specific.exp index 777fcf85ab0..85c08f44a2c 100644 --- a/gdb/testsuite/gdb.multi/bp-thread-specific.exp +++ b/gdb/testsuite/gdb.multi/bp-thread-specific.exp @@ -15,6 +15,9 @@ # Check that GDB uses the correct thread-id when describing multiple # thread specific breakpoints at the same location. +# +# Also check that the correct thread-ids are used in the saved +# breakpoints file. # The plain remote target can't do multiple inferiors. require !use_gdb_stub @@ -59,3 +62,46 @@ gdb_test "break foo thread 1.1" \ "Note: breakpoint $bpnum \\(thread 2.1\\) also set at pc $hex\\." \ "Note: breakpoint $bpnum \\(thread 2.1\\) also set at pc $hex\\." \ "Breakpoint $decimal at $hex: foo\\. \\(2 locations\\)"] + +# Save the breakpoints into a file. +if {[is_remote host]} { + set bps bps +} else { + set bps [standard_output_file bps] +} + +remote_file host delete "$bps" +gdb_test "save breakpoints $bps" "" "save breakpoint to bps" + +if {[is_remote host]} { + set bps [remote_upload host bps [standard_output_file bps]] +} + +# Now dig through the saved breakpoints file and check that the +# thread-ids were written out correctly. First open the saved +# breakpoints and read them into a list. +set fh [open $bps] +set lines [split [read $fh] "\n"] +close $fh + +# Except the list created from the saved breakpoints file will have a +# blank line entry at the end, so remove it now. +gdb_assert {[string equal [lindex $lines end] ""]} \ + "check last item was an empty line" +set lines [lrange $lines 0 end-1] + +# These are the lines we expect in the saved breakpoints file, in the +# order that we expect them. These are strings, not regexps. +set expected_results \ + [list \ + "break -qualified main" \ + "break foo thread 2.1" \ + "break foo thread 1.1"] + +# Now check that the files contents (in LINES) matches the +# EXPECTED_RESULTS. +gdb_assert {[llength $lines] == [llength $expected_results]} \ + "correct number of lines in saved breakpoints file" +foreach a $lines b $expected_results { + gdb_assert {[string equal $a $b]} "line '$b'" +} diff --git a/gdb/thread.c b/gdb/thread.c index 1a852f70206..9ba383d9bee 100644 --- a/gdb/thread.c +++ b/gdb/thread.c @@ -1431,12 +1431,22 @@ show_inferior_qualified_tids (void) const char * print_thread_id (struct thread_info *thr) { + if (show_inferior_qualified_tids ()) + return print_full_thread_id (thr); + char *s = get_print_cell (); + xsnprintf (s, PRINT_CELL_SIZE, "%d", thr->per_inf_num); + return s; +} - if (show_inferior_qualified_tids ()) - xsnprintf (s, PRINT_CELL_SIZE, "%d.%d", thr->inf->num, thr->per_inf_num); - else - xsnprintf (s, PRINT_CELL_SIZE, "%d", thr->per_inf_num); +/* See gdbthread.h. */ + +const char * +print_full_thread_id (struct thread_info *thr) +{ + char *s = get_print_cell (); + + xsnprintf (s, PRINT_CELL_SIZE, "%d.%d", thr->inf->num, thr->per_inf_num); return s; }