From: Andrew Burgess via Gdb-patches <gdb-patches@sourceware.org>
To: Tom de Vries <tdevries@suse.de>, Simon Marchi <simark@simark.ca>,
gdb-patches@sourceware.org
Subject: Re: [PATCH 2/3] gdb: improve disassembler styling when Pygments raises an exception
Date: Mon, 10 Oct 2022 15:04:42 +0100 [thread overview]
Message-ID: <87fsfvepvp.fsf@redhat.com> (raw)
In-Reply-To: <f25cb8df-2a1d-3dd0-f6f3-590b47cf5473@suse.de>
Tom de Vries <tdevries@suse.de> writes:
> On 10/10/22 13:16, Andrew Burgess wrote:
>> Tom de Vries <tdevries@suse.de> writes:
>>
>>> On 10/10/22 11:32, Andrew Burgess via Gdb-patches wrote:
>>>> Simon Marchi <simark@simark.ca> writes:
>>>>
>>>>> On 2022-10-08 12:00, Andrew Burgess wrote:
>>>>>> Simon Marchi <simark@simark.ca> writes:
>>>>>>
>>>>>>>> +# Check that, if the user is using Python Pygments for disassembler
>>>>>>>> +# styling, then the styling correctly switches off when an error is
>>>>>>>> +# detected in the Python code.
>>>>>>>> +proc test_disassembler_error_handling { } {
>>>>>>>> +
>>>>>>>> + # This test requires the Python Pygments module to be installed
>>>>>>>> + # and used by GDB.
>>>>>>>> + if { !$::python_disassembly_styling } {
>>>>>>>> + return
>>>>>>>> + }
>>>>>>>> +
>>>>>>>> + save_vars { env(TERM) } {
>>>>>>>> + # We need an ANSI-capable terminal to get the output.
>>>>>>>> + setenv TERM ansi
>>>>>>>> +
>>>>>>>> + # Restart GDB with the correct TERM variable setting, this
>>>>>>>> + # means that GDB will enable styling.
>>>>>>>> + clean_restart_and_disable "restart 4" $::binfile
>>>>>>>> +
>>>>>>>> + # Disable use of libopcodes for styling. As this function is
>>>>>>>> + # only called when Python Pygments module is available, we
>>>>>>>> + # should now be using that module to style the disassembler
>>>>>>>> + # output.
>>>>>>>> + gdb_test_no_output "maint set libopcodes-styling enabled off"
>>>>>>>> +
>>>>>>>> + # Disassemble a single instruction and ensure that the output
>>>>>>>> + # has styling markers in it.
>>>>>>>> + set insn_before [get_single_disassembled_insn]
>>>>>>>> + gdb_assert { [regexp "\033" $insn_before] } \
>>>>>>>> + "have style markers when Pygments is working fine"
>>>>>>>> +
>>>>>>>> + # Now replace the standard function that colorizes the
>>>>>>>> + # disassembler output, with a new function that always returns
>>>>>>>> + # None, this should cause GDB to stop using the Pygments
>>>>>>>> + # module for disassembler styling.
>>>>>>>> + gdb_py_test_silent_cmd \
>>>>>>>> + [multi_line_input \
>>>>>>>> + "python" \
>>>>>>>> + "def replacement_colorize_disasm(content,gdbarch):" \
>>>>>>>> + " return None" \
>>>>>>>> + "gdb.styling.colorize_disasm = replacement_colorize_disasm" \
>>>>>>>> + "\004"] \
>>>>>>>
>>>>>>> Any reason you are using \004 here, instead of end? I don't quite
>>>>>>> understand why, but it seems to cause some random failures. Running the
>>>>>>> test under `taskset -c 2` makes it fail most of the time. Running it
>>>>>>> with check-read1 makes it fail consistently:
>>>>>>>
>>>>>>> FAIL: gdb.base/style.exp: capture_command_output for x/1i *main
>>>>>>>
>>>>>>> When changing \004 for end, it passes. I don't have an explanation why
>>>>>>> though.
>>>>>>
>>>>>> It'll be a copy&paste. There's a couple of other places in the
>>>>>> testsuite where this pattern is used.
>>>>>>
>>>>>> The patch below changes all three to use 'end'. How's this?
>>>>>>
>>>>>> Thanks,
>>>>>> Andrew
>>>>>
>>>>> This is fine with me, but again, I didn't dig into it so I don't really
>>>>> know what sending a \004 was causing,
>>>>
>>>> Hi,
>>>>
>>>> Given you were seeing problems with the use of \004, and the tests
>>>> definitely were not about whether \004 could be used or not, I've pushed
>>>> the patch I proposed (exact version is below).
>>>>
>>>
>>> I found this independently and filed a PR (
>>> https://sourceware.org/bugzilla/show_bug.cgi?id=29664 ) and wrote the
>>> same fix (in the same three test-cases), and was about to commit ...
>>>
>>> The FAIL is caused by using gdb_py_test_silent_cmd, which adds a "\n" at
>>> the end of the command in combination with "\004", causing a stray "\n"
>>> that generates an extra prompt, which makes the prompt matching
>>> unpredictable.
>>
>> Apologies for the duplicated effort. Also, thanks for the explanation,
>> which, if I'd spotted sooner would have saved me investigating the
>> problem.
>>
>> Again, thanks for picking up after me, and apologies for wasting your
>> time.
>>
>
> Hi Andrew,
>
> thanks for following up.
>
> Luckily most of my time went to investigating the root cause (which had
> me puzzled for quite a bit), so that's not effort wasted.
>
> Also, I forgot to check the mailing list to see if the FAIL was already
> noted there, so that's on me.
>
> Anyway, I propose to error out in gdb_test_multiple on this specific
> pattern. Dealing with ^C / ^D for now.
>
> Not tested yet (I'll start testing in now in combination with the
> proposed patch to fix the build).
>
> WDYT?
This seems like a sensible precaution, I like it.
Patch looks good.
Thanks,
Andrew
>
> Thanks,
> - Tom
> [gdb/testsuite] Detect trailing ^C/^D in command
>
> Detect a trailing ^C/^D in the command argument of gdb_test, and error out.
>
> Tested on x86_64-linux.
>
> ---
> gdb/testsuite/gdb.testsuite/gdb-test.exp | 34 ++++++++++++++++++++++++++------
> gdb/testsuite/lib/gdb.exp | 4 ++++
> 2 files changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/gdb/testsuite/gdb.testsuite/gdb-test.exp b/gdb/testsuite/gdb.testsuite/gdb-test.exp
> index 2ce8eb31d73..e891f81e7b0 100644
> --- a/gdb/testsuite/gdb.testsuite/gdb-test.exp
> +++ b/gdb/testsuite/gdb.testsuite/gdb-test.exp
> @@ -19,10 +19,32 @@ clean_restart
>
> # Check that a command with trailing newline triggers an error.
>
> -set results [catch {
> - gdb_test "pwd\n" ".*" "cmd with trailing newline"
> -} output]
> +with_test_prefix "cmd with trailing newline" {
> + set results [catch {
> + gdb_test "pwd\n" ".*" "pwd"
> + } output]
>
> -gdb_assert { $results == 1 }
> -set expected_error_msg "Invalid trailing newline in \"pwd\n\" command"
> -gdb_assert { [string equal $output $expected_error_msg] }
> + gdb_assert { $results == 1 }
> + set expected_error_msg "Invalid trailing newline in \"pwd\n\" command"
> + gdb_assert { [string equal $output $expected_error_msg] }
> +}
> +
> +with_test_prefix "cmd with trailing control code" {
> + foreach_with_prefix control_code {^C ^D} {
> + switch $control_code {
> + ^C {
> + set cmd "\003"
> + }
> + ^D {
> + set cmd "\004"
> + }
> + }
> + set results [catch {
> + gdb_test $cmd ".*" "control code"
> + } output]
> +
> + gdb_assert { $results == 1 }
> + set expected_error_msg "Invalid trailing control code in \"$cmd\" command"
> + gdb_assert { [string equal $output $expected_error_msg] }
> + }
> +}
> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
> index 5f0acfaa530..ac28ede1b08 100644
> --- a/gdb/testsuite/lib/gdb.exp
> +++ b/gdb/testsuite/lib/gdb.exp
> @@ -1003,6 +1003,10 @@ proc gdb_test_multiple { command message args } {
> error "Invalid trailing newline in \"$command\" command"
> }
>
> + if [string match "*\[\003\004\]" $command] {
> + error "Invalid trailing control code in \"$command\" command"
> + }
> +
> if [string match "*\[\r\n\]*" $message] {
> error "Invalid newline in \"$message\" test"
> }
next prev parent reply other threads:[~2022-10-10 14:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-30 14:16 [PATCH 0/3] Improvements for Pygments based disassembly styling Andrew Burgess via Gdb-patches
2022-08-30 14:16 ` [PATCH 1/3] gdb/testsuite: extend styling test for libopcodes styling Andrew Burgess via Gdb-patches
2022-08-30 14:16 ` [PATCH 2/3] gdb: improve disassembler styling when Pygments raises an exception Andrew Burgess via Gdb-patches
2022-10-08 2:25 ` Simon Marchi via Gdb-patches
2022-10-08 16:00 ` Andrew Burgess via Gdb-patches
2022-10-08 16:01 ` Simon Marchi via Gdb-patches
2022-10-10 9:32 ` Andrew Burgess via Gdb-patches
2022-10-10 10:31 ` Tom de Vries via Gdb-patches
2022-10-10 11:16 ` Andrew Burgess via Gdb-patches
2022-10-10 13:22 ` Tom de Vries via Gdb-patches
2022-10-10 14:04 ` Andrew Burgess via Gdb-patches [this message]
2022-10-10 11:03 ` Andrew Burgess via Gdb-patches
2022-08-30 14:16 ` [PATCH 3/3] gdb/disasm: better intel flavour disassembly styling with Pygments Andrew Burgess via Gdb-patches
2022-10-02 16:38 ` [PATCH 0/3] Improvements for Pygments based disassembly styling Andrew Burgess via Gdb-patches
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