Re: [PATCHv2] gdb/mi: New commands to catch C++ exceptions

[Tom de Vries <tdevries@suse.de>]

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,
- Tom