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 4AD2D3858296 for ; Wed, 18 Jan 2023 16:18:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 4AD2D3858296 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=1674058713; 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=V+ErLct8LXX4NVV5I/yZP8O52bnCZHA/CjCAswlA+dM=; b=YWmQk2c0g1McSqM0RzPiyzFXSCwCBxFoYfnoUZrtwXgxB5c0oGHVSCYsZcV+ybcHTXtgNV ShLj57dBELiEjaI1EXj8W0Z5BWZsWactVHycxRiG9zOo0pDRZqgRH4bTxwFIrIZ5v5+0HJ jFGjKtT+59xB5T/Ojqdd6xgcmcGcbFQ= Received: from mail-qv1-f69.google.com (mail-qv1-f69.google.com [209.85.219.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-46-0bk8oeb9PSWq4C6DZpUX6A-1; Wed, 18 Jan 2023 11:18:30 -0500 X-MC-Unique: 0bk8oeb9PSWq4C6DZpUX6A-1 Received: by mail-qv1-f69.google.com with SMTP id pm24-20020ad446d8000000b0053233e46a00so12938865qvb.23 for ; Wed, 18 Jan 2023 08:18:30 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=V+ErLct8LXX4NVV5I/yZP8O52bnCZHA/CjCAswlA+dM=; b=z6ZGWBniCu4WpDWhkcetwMK/tErjBtct3i4DJ/XOF1KpYE+nibB9B7IdVeJ1iHfLfc 1o62kYMxqBBGoOxRoXIWD0pTqxLV02zVjVYqL32ZWNoZ9eCEucGzORLqdE2FVupt+HE5 7gUPUAyQnYpHZoS+BSkQcS+QB5aFPe0uJ5CoJTq9gdxaUe7DNLdr4CSVDuZWm9MytPTI IOS1uG/NLYrdo3482gBMclyIDrL+yIWOWR+RSSsC/YVOouF3fnh+TtqtTUoJQVlqPYJ3 vEgWu89bueZbC3rubzgbfLo592opgDhjrwHn2+i+my0LmrI8ha1uaHtYRfbYIQMvi7hk yEAw== X-Gm-Message-State: AFqh2kqG3537MjWRrZqUL3GLShroX5VvJsXXHXnE3PRkI4p4iQGaWcf0 3v5mSN2DTO9PdOWcFqSTdaOB8d5liDhgNf++ZiADkQgxg1xz2/ffo9YC4zYJJNWd7TbnD69tcfq iAK+KY5YLjjUHtPi/m+qdmgEP3tqf8Mj3DRE9sYFARHDuvhwnbUSQTE1ndfnkHpnv7PJnOK9Dpw == X-Received: by 2002:a0c:8dc9:0:b0:534:fe24:db68 with SMTP id u9-20020a0c8dc9000000b00534fe24db68mr10638783qvb.4.1674058709343; Wed, 18 Jan 2023 08:18:29 -0800 (PST) X-Google-Smtp-Source: AMrXdXszW8zHszm98cr+CLiLHqY/OBj5+ExptudKvk3AgP6x7Fd4j3g1kRdpvdnAsjVLNQ2iaHkizw== X-Received: by 2002:a0c:8dc9:0:b0:534:fe24:db68 with SMTP id u9-20020a0c8dc9000000b00534fe24db68mr10638749qvb.4.1674058708942; Wed, 18 Jan 2023 08:18:28 -0800 (PST) Received: from localhost (95.72.115.87.dyn.plus.net. [87.115.72.95]) by smtp.gmail.com with ESMTPSA id q44-20020a05620a2a6c00b006fc9fe67e34sm8407593qkp.81.2023.01.18.08.18.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Jan 2023 08:18:28 -0800 (PST) From: Andrew Burgess To: gdb-patches@sourceware.org Cc: Andrew Burgess Subject: [PATCHv2 07/13] gdb: don't always print breakpoint location after failed condition check Date: Wed, 18 Jan 2023 16:18:03 +0000 Message-Id: <6f9398a42867d24757af1a0b74623f24fb1cd606.1674058360.git.aburgess@redhat.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: References: MIME-Version: 1.0 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=-11.8 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: Consider the following session: (gdb) list some_func 1 int 2 some_func () 3 { 4 int *p = 0; 5 return *p; 6 } 7 8 void 9 foo () 10 { (gdb) break foo if (some_func ()) Breakpoint 1 at 0x40111e: file bpcond.c, line 11. (gdb) r Starting program: /tmp/bpcond Program received signal SIGSEGV, Segmentation fault. 0x0000000000401116 in some_func () at bpcond.c:5 5 return *p; Error in testing condition for breakpoint 1: The program being debugged stopped while in a function called from GDB. Evaluation of the expression containing the function (some_func) will be abandoned. When the function is done executing, GDB will silently stop. Breakpoint 1, 0x0000000000401116 in some_func () at bpcond.c:5 5 return *p; (gdb) What happens here is the breakpoint condition includes a call to an inferior function, and the inferior function segfaults. We can see that GDB reports the segfault, and then gives an error message that indicates that an inferior function call was interrupted. After this GDB appears to report that it is stopped at Breakpoint 1, inside some_func. I find this second stop report a little confusing. Yes, GDB has stopped as a result of hitting breakpoint 1, but, I think the message as it currently is might give the impression that the thread is actually stopped at a location of breakpoint 1, which is not the case. Also, I find the second stop message draws attention away from the "Program received signal SIGSEGV, Segmentation fault" stop message, and this second stop might be thought of as replacing in someway the earlier message. In short, I think that the in the situation above, I think things would be clearer if the second stop message were not reported at all, so the output should (I think) look like this: (gdb) list some_func 1 int 2 some_func () 3 { 4 int *p = 0; 5 return *p; 6 } 7 8 void 9 foo () 10 { (gdb) break foo if (some_func ()) Breakpoint 1 at 0x40111e: file bpcond.c, line 11. (gdb) r Starting program: /tmp/bpcond Program received signal SIGSEGV, Segmentation fault. 0x0000000000401116 in some_func () at bpcond.c:5 5 return *p; Error in testing condition for breakpoint 1: The program being debugged stopped while in a function called from GDB. Evaluation of the expression containing the function (some_func) will be abandoned. When the function is done executing, GDB will silently stop. (gdb) The user can still find the number of the breakpoint that triggered the initial stop in this line: Error in testing condition for breakpoint 1: But there's now only one stop reason reported, the SIGSEGV, which I think is much clearer. To achieve this change I set the bpstat::print field when: (a) a breakpoint condition evaluation failed, and (b) the $pc of the thread changed during condition evaluation. I've updated the existing tests that checked the error message printed when a breakpoint condition evaluation failed. --- gdb/breakpoint.c | 12 ++++++++++++ gdb/testsuite/gdb.base/infcall-failure.exp | 18 ++++++++---------- 2 files changed, 20 insertions(+), 10 deletions(-) diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index eecaeefed3e..c4fec7e8e55 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -5533,6 +5533,7 @@ bpstat_check_breakpoint_conditions (bpstat *bs, thread_info *thread) else within_current_scope = false; } + CORE_ADDR pc_before_check = get_frame_pc (get_selected_frame (nullptr)); if (within_current_scope) { try @@ -5544,6 +5545,17 @@ bpstat_check_breakpoint_conditions (bpstat *bs, thread_info *thread) exception_fprintf (gdb_stderr, ex, "Error in testing condition for breakpoint %d:\n", b->number); + + /* If the pc value changed as a result of evaluating the + condition then we probably stopped within an inferior + function call due to some unexpected stop, e.g. the thread + hit another breakpoint, or the thread received an + unexpected signal. In this case we don't want to also + print the information about this breakpoint. */ + CORE_ADDR pc_after_check + = get_frame_pc (get_selected_frame (nullptr)); + if (pc_before_check != pc_after_check) + bs->print = 0; } } else diff --git a/gdb/testsuite/gdb.base/infcall-failure.exp b/gdb/testsuite/gdb.base/infcall-failure.exp index 2dcdda34b4d..8fa2c407fc5 100644 --- a/gdb/testsuite/gdb.base/infcall-failure.exp +++ b/gdb/testsuite/gdb.base/infcall-failure.exp @@ -79,10 +79,7 @@ proc_with_prefix run_cond_hits_breakpoint_test { async_p non_stop_p } { "The program being debugged stopped while in a function called from GDB\\." \ "Evaluation of the expression containing the function" \ "\\(func_bp\\) will be abandoned\\." \ - "When the function is done executing, GDB will silently stop\\." \ - "" \ - "Breakpoint ${bp_1_num}, \[^\r\n\]+" \ - "${::decimal}\\s+\[^\r\n\]+Second breakpoint\[^\r\n\]+"] + "When the function is done executing, GDB will silently stop\\."] } # Start GDB according to ASYNC_P and NON_STOP_P, then call an inferior @@ -138,13 +135,12 @@ proc_with_prefix run_cond_hits_segfault_test { async_p non_stop_p } { "${::hex} in func_segfault \\(\\) at \[^\r\n\]+:${::segv_line}" \ "${::decimal}\\s+\[^\r\n\]+Segfault here\[^\r\n\]+" \ "Error in testing condition for breakpoint ${bp_1_num}:" \ - "The program being debugged stopped while in a function called from GDB\\." \ + "The program being debugged was signaled while in a function called from GDB\\." \ + "GDB remains in the frame where the signal was received\\." \ + "To change this behavior use \"set unwindonsignal on\"\\." \ "Evaluation of the expression containing the function" \ "\\(func_segfault\\) will be abandoned\\." \ - "When the function is done executing, GDB will silently stop\\." \ - "" \ - "Breakpoint ${bp_1_num}, \[^\r\n\]+" \ - "${::decimal}\\s+\[^\r\n\]+Segfault here\[^\r\n\]+"] + "When the function is done executing, GDB will silently stop\\."] } # Start GDB according to ASYNC_P and NON_STOP_P, then call an inferior @@ -167,7 +163,9 @@ proc_with_prefix run_call_hits_segfault_test { async_p non_stop_p } { "Program received signal SIGSEGV, Segmentation fault\\." \ "${::hex} in func_segfault \\(\\) at \[^\r\n\]+:${::segv_line}" \ "${::decimal}\\s+\[^\r\n\]+Segfault here\[^\r\n\]+" \ - "The program being debugged stopped while in a function called from GDB\\." \ + "The program being debugged was signaled while in a function called from GDB\\." \ + "GDB remains in the frame where the signal was received\\." \ + "To change this behavior use \"set unwindonsignal on\"\\." \ "Evaluation of the expression containing the function" \ "\\(func_segfault\\) will be abandoned\\." \ "When the function is done executing, GDB will silently stop\\."] -- 2.25.4