[lldb-dev] break on exceptions/windows

[Zachary Turner via lldb-dev]

Calling everything "catch" is a bit too much of a catch-all though (excuse
the pun).

I like the idea of every command being able to have a platform specific sub
command, similar to gregs suggested "platform break set".

But I think you need a way to make commands themselves platform specific so
that entire commands or subcommands could exist only for certain platforms.
There's plenty of commands i want to implement on Windows that have no
analogue anywhere else, so at some level i still think we need a way to
have dynamic commands and options that only show up for a given platform
On Mon, Apr 4, 2016 at 2:40 PM Jim Ingham <jingham at apple.com> wrote:

> If we're going this far, then we should just add a "catch" command, and
> have the platforms be able to add "catchable" things.  For instance, you
> could catch shared library loads, you could catch fork & exec, maybe IPC
> message sends and Windows exceptions.  Seems like they fit better in this
> model than as breakpoints.
>
> Jim
>
>
> > On Apr 4, 2016, at 2:28 PM, Greg Clayton <gclayton at apple.com> wrote:
> >
> > We could add a "platform breakpoint set" command as a new stand alone
> breakpoint mechanism and avoid messing with the "breakpoint set" command at
> all.
> >
> > (lldb) platform breakpoint set ...
> >
> > This would be passed to the current lldb_private::Platform plug-in for
> it to parse as needed. Each platform can have their own options that are
> completely custom.
> >
> >
> >
> >> On Apr 4, 2016, at 1:27 PM, Zachary Turner <zturner at google.com> wrote:
> >>
> >> Another option would be to have sub-sub commands.  Already when you mix
> so many options together, lots of the options don't make sense with each
> other.  What about
> >>
> >> break set windows --exc-code=0xC0000005
> >>
> >> This way all the windows specific stuff is wrapped up behind another
> subcommand, and you don't have to worry about consistency with other
> platforms' interfaces.
> >>
> >> On Mon, Apr 4, 2016 at 1:18 PM Greg Clayton <gclayton at apple.com> wrote:
> >> I really would rather avoid the key/value thing. I prefer the
> --exception-name and --exception-code and have the platform handle it.
> Seems cleaner.
> >>
> >> Greg
> >>
> >>> On Apr 4, 2016, at 11:41 AM, Jim Ingham <jingham at apple.com> wrote:
> >>>
> >>> Yes, that's why I prefer a more abstract command interface than trying
> to be too specific about some abstract breakpoint.  So you'd just have:
> >>>
> >>> Error
> >>> Platform::SetPlatformBreakpoint(lldb_private::Target *target, const
> char *data);
> >>>
> >>> Then this can have any meaning that it needs to.  The other way to
> structure this is:
> >>>
> >>> break set -P -key "KEY" -value "VALUE"
> >>>
> >>> Jim
> >>>
> >>>
> >>>
> >>>> On Apr 4, 2016, at 11:36 AM, Carlo Kok <ck at remobjects.com> wrote:
> >>>>
> >>>>
> >>>>
> >>>> Op 2016-04-04 om 20:30 schreef Greg Clayton:
> >>>>>
> >>>>>> On Apr 4, 2016, at 11:24 AM, Zachary Turner <zturner at google.com>
> wrote:
> >>>>>>
> >>>>>> It seems like we already have some precedent for conditional
> command arguments.  For example:
> >>>>>>
> >>>>>> (lldb) help platform process list
> >>>>>> ...
> >>>>>>      -u <unsigned-integer> ( --uid <unsigned-integer> )
> >>>>>>           [POSIX] Find processes that have a matching user ID.
> >>>>>>
> >>>>>> So on Windows this argument doesn't make sense.  Could we make an
> argument that is conditional on the *target* rather than the host?  Then,
> for example, you could have something like this:
> >>>>>>
> >>>>>> (lldb) help break set
> >>>>>> ...
> >>>>>>      --code <hex-integer> ( --code <hex-integer> )
> >>>>>>           [Windows Target] Break when the exception with code
> <code> is raised.
> >>>>>>
> >>>>>> How to plumb this to the ProcessWindows plugin is an open question,
> but should be mostly mechanical.
> >>>>>
> >>>>> This is like my suggestion of:
> >>>>>
> >>>>> (lldb) breakpoint set --exception-code 0x40010005
> >>>>>
> >>>>> The code can be passed to the current Platform along with the
> current target:
> >>>>>
> >>>>> Error Platform::SetExceptionBreakpointWithExceptionCode
> (lldb_private::Target *target, uint64_t exception_code);
> >>>>>
> >>>>> The process can be extracted from the target when the breakpoint
> needs to be resolved.
> >>>>>
> >>>>>
> >>>>
> >>>> There should be a way then to do a "break on every exception",
> instead of just 1 specific code.
> >>>>
> >>>> and some way for the api to get the payload (which can have a
> variable number of parameters)
> >>>>
> >>>> --
> >>>> Carlo Kok
> >>>> RemObjects Software
> >>>
> >>
> >
>
>
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