This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: [PATCHv2] gdb/mi: New commands to catch C++ exceptions
On 16-06-19 17:29, Andrew Burgess wrote:
> * Tom de Vries <tdevries@suse.de> [2019-06-16 15:14:06 +0200]:
>
>> On 16-06-19 00:34, Andrew Burgess wrote:
>>> * Andrew Burgess <andrew.burgess@embecosm.com> [2019-05-12 00:46:46 +0100]:
>>>
>>>> Eli,
>>>>
>>>> This iteration includes updated documentation that fixes almost all of
>>>> the issues you raised. The only thing I haven't done is collapse all
>>>> of the command sub-sections into a single sub-section. I looked
>>>> through most of the existing MI commands and they all seem to be one
>>>> command per sub-section, so I wasn't entirely sure how to layout a
>>>> merged entry, nor if a merged entry was inline with the style for MI
>>>> commands.
>>>>
>>>> ---
>>>>
>>>> I have also tweaked the code a little in this version, the changes
>>>> around how a catchpoint is reported when it is initially setup has
>>>> changed, the output is not more inline with other breakpoints. See
>>>> the changes in print_mention_exception_catchpoint, and the new
>>>> scoped_restore restore_breakpoint_reporting in
>>>> mi_cmd_catch_exception_event. Otherwise the code is unchanged.
>>>>
>>>> Thanks,
>>>> Andrew
>>>>
>>>> ---
>>>>
>>>> Adds some MI commands to catch C++ exceptions. The new commands are
>>>> -catch-throw, -catch-rethrow, and -catch-catch, these all correspond
>>>> to the CLI commands 'catch throw', 'catch rethrow', and 'catch catch'.
>>>>
>>>> Each MI command takes two optional arguments, '-t' has the effect of
>>>> calling 'tcatch' instead of 'catch', for example:
>>>>
>>>> (gdb)
>>>> -catch-throw -t
>>>>
>>>> Is the same as:
>>>>
>>>> (gdb) tcatch throw
>>>>
>>>> There is also a '-r REGEXP' argument that can supply a regexp to match
>>>> against the exception type, so:
>>>>
>>>> (gdb)
>>>> -catch-catch -r PATTERN
>>>>
>>>> Is the same as:
>>>>
>>>> (gdb) catch catch PATTERN
>>>>
>>>> The change in print_mention_exception_catchpoint might seem a little
>>>> strange; changing the output from using ui_out::field_int and
>>>> ui_out::text to using ui_out::message.
>>>>
>>>> The print_mention_exception_catchpoint is used as the 'print_mention'
>>>> method for the exception catchpoint breakpoint object. Most of the
>>>> other 'print_mention' methods (see breakpoint.c) use either
>>>> printf_filtered, of ui_out::message. Using field_int was causing an
>>>> unexpected field to be added to the MI output. Here's the output
>>>> without the change in print_mention_exception_catchpoint:
>>>>
>>>> (gdb)
>>>> -catch-throw
>>>> ^done,bkptno="1",bkpt={number="1",type="breakpoint",disp="keep",
>>>> enabled="y",addr="0x00000000004006c0",
>>>> what="exception throw",catch-type="throw",
>>>> thread-groups=["i1"],times="0"}
>>>>
>>>> Notice the breakpoint number appears in both the 'bkptno' field, and
>>>> the 'number' field within the 'bkpt' tuple. Here's the output with
>>>> the change in print_mention_exception_catchpoint:
>>>>
>>>> (gdb)
>>>> -catch-throw
>>>> ^done,bkpt={number="1",type="breakpoint",disp="keep",
>>>> enabled="y",addr="0x00000000004006c0",
>>>> what="exception throw",catch-type="throw",
>>>> thread-groups=["i1"],times="0"}
>>>>
>>>> gdb/ChangeLog:
>>>>
>>>> * NEWS: Mention new MI commands.
>>>> * break-catch-throw.c (enum exception_event_kind): Move to
>>>> breakpoint.h.
>>>> (print_mention_exception_catchpoint): Output text as a single
>>>> message.
>>>> (catch_exception_command_1): Rename to...
>>>> (catch_exception_event): ...this, make non-static, update header
>>>> command, and change some parameter types.
>>>> (catch_catch_command): Update for changes to
>>>> catch_exception_command_1.
>>>> (catch_throw_command): Likewise.
>>>> (catch_rethrow_command): Likewise.
>>>> * breakpoint.c (enum exception_event_kind): Delete.
>>>> * breakpoint.h (enum exception_event_kind): Moved here from
>>>> break-catch-throw.c.
>>>> (catch_exception_event): Declare.
>>>> * mi/mi-cmd-catch.c (mi_cmd_catch_exception_event): New function.
>>>> (mi_cmd_catch_throw): New function.
>>>> (mi_cmd_catch_rethrow): New function.
>>>> (mi_cmd_catch_catch): New function.
>>>> * mi/mi-cmds.c (mi_cmds): Add 'catch-throw', 'catch-rethrow', and
>>>> 'catch-catch' entries.
>>>> * mi/mi-cmds.h (mi_cmd_catch_throw): Declare.
>>>> (mi_cmd_catch_rethrow): Declare.
>>>> (mi_cmd_catch_catch): Declare.
>>>>
>>>> gdb/doc/ChangeLog:
>>>>
>>>> * gdb.texinfo (GDB/MI Catchpoint Commands): Add menu entry to new
>>>> node.
>>>> (C++ Exception GDB/MI Catchpoint Commands): New node to describe
>>>> new MI commands.
>>>>
>>>> gdb/testsuite/ChangeLog:
>>>>
>>>> * gdb.mi/mi-catch-cpp-exceptions.cc: New file.
>>>> * gdb.mi/mi-catch-cpp-exceptions.exp: New file.
>>>> * lib/mi-support.exp (mi_expect_stop): Handle 'exception-caught'
>>>> as a stop reason.
>>>
>>> I've now pushed this patch with the doc fixes that Eli suggested.
>>>
>>
>> I've filed PR24686 - "FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with
>> invalid regexp: run until breakpoint in main (timeout)"
>
> Thanks for reporting this.
>
> I have pushed the patch below which I believe should change the FAIL
> you are seeing into a KFAIL.
>
> Let me know if this helps.
>
Hi,
that works, I see a KFAIL now.
Thanks,
- Tom
> Thanks,
> Andrew
>
> --
>
> commit 93cb9841d68263174a600dc70af742a8e2eabfc6
> Author: Andrew Burgess <andrew.burgess@embecosm.com>
> Date: Sun Jun 16 16:17:59 2019 +0100
>
> gdb/testsuite: Improve detection of bug gdb/24541
>
> In bug gdb/24686 a testsuite failure was reported, this failure was
> actually just another instance of bug gdb/24541, however, due to the
> non-deterministic nature of bug gdb/24541 the testsuite pattern that
> was intended to catch this bug failed.
>
> This commit adds a second pattern to help detect gdb/24541, which
> should change the FAIL reported in gdb/24686 into a KFAIL.
>
> gdb/testsuite/ChangeLog:
>
> PR gdb/24686
> * gdb.mi/mi-catch-cpp-exceptions.exp: Add an extra pattern to
> improve detection of bug gdb/24541.
>
> diff --git a/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.exp b/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.exp
> index b5dfbe68c1a..fa5b11e3e58 100644
> --- a/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.exp
> +++ b/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.exp
> @@ -141,6 +141,9 @@ with_test_prefix "all with invalid regexp" {
> -re "could not find minimal symbol for typeinfo address.*$mi_gdb_prompt$" {
> kfail "gdb/24541" "${testname}"
> }
> + -re "\\*stopped,bkptno=\"$decimal\",reason=\"breakpoint-hit\",disp=\"keep\".*func=\"__cxa_throw\".*$mi_gdb_prompt$" {
> + kfail "gdb/24541" "${testname}"
> + }
> -re "\\*stopped,reason=\"breakpoint-hit\".*func=\"main\".*line=\"${main_lineno}\".*$mi_gdb_prompt$" {
> pass "${testname}"
> }
>