Re: [PATCH 0/3] Compile-time gimple checking, without typedefs

[David Malcolm <dmalcolm at redhat dot com>]

On Mon, 2014-05-05 at 21:53 +0200, Jakub Jelinek wrote:
> On Mon, May 05, 2014 at 01:44:06PM -0600, Jeff Law wrote:
> > On 05/05/14 11:37, Richard Biener wrote:
> > >
> > >Well, I hope that Andrew doesn't do without a namespace (and I still
> > >don't believe in what he tries to achieve without laying proper ground-work
> > >throughout the compiler).  With a namespace gimple we can use
> > >gimple::stmt.
> > namespaces, while nice, aren't going to solve all these issues.
> > While I think we can get a good separation between gimple and the
> > rest of the world, I suspect namespaces aren't going to help much
> > with the statement vs expression vs type issues.
> > 
> > Ultimately I suspect we're not going to have too many places where
> > we can stick a "using namespace gimple-whatever", but time will
> > tell.
> > 
> > >Agreed on that, btw.  But switch_ can't be the answer either.  Maybe
> > >swidch (similar do klass) or swjdch.  Or swtch.  I like swtch the best
> > >(similar to stmt).
> > As David pointed out there's several others that map to keywords.
> > I'd rather set a standard here across the project so that we don't
> > have folks using gto for goto, others using goto_, _goto, whatever.
> > While swtch works well, I don't think the other examples work nearly
> > as well.  Thus some kind of prefix/suffix seems better to me (though
> > I'm sure my eyes will bleed as a result of looking at those
> > objects).
> 
> But the prefix can be as short as e.g. "g" (for gimple), so gtry, ggoto,
> gassign, gcall.

FWIW, I like this: I think it's clear and concise, and I think it avoids
the need for namespaces. (I'd prefer not to have a namespace, due to
gengtype).

Given Richi's preference for the base class being "gimple", that could
give:

Existing           New
--------           ---
gimple             gimple *


gimple             gswitch *
  a GIMPLE_SWITCH


gimple             gcall *
  a GIMPLE_CALL

etc

with the various
  gimple_statement_with_FOO
becoming just
  gimple_with_FOO
e.g. "gimple_with_memory_ops"

How would you want subclasses for the OpenMP statements to be named?
e.g. replace "gimple_statement_omp" with gomp_" for e.g.
"gomp_for *"

or to "gimple_omp_", giving e.g. "gimple_omp_for *"

with the former (less verbose) approach giving the following names, I
think (showing the class hierarchy):

   gimple
     |    layout: GSS_BASE
     |    used for 4 codes: GIMPLE_ERROR_MARK
     |                      GIMPLE_NOP
     |                      GIMPLE_OMP_SECTIONS_SWITCH
     |                      GIMPLE_PREDICT
     |
     + gimple_with_ops_base
     |   |    (no GSS layout)
     |   |
     |   + gimple_with_ops
     |   |   |    layout: GSS_WITH_OPS
     |   |   |
     |   |   + gcond
     |   |   |     code: GIMPLE_COND
     |   |   |
     |   |   + gdebug
     |   |   |     code: GIMPLE_DEBUG
     |   |   |
     |   |   + ggoto
     |   |   |     code: GIMPLE_GOTO
     |   |   |
     |   |   + glabel
     |   |   |     code: GIMPLE_LABEL
     |   |   |
     |   |   + gswitch
     |   |         code: GIMPLE_SWITCH
     |   |
     |   + gimple_with_memory_ops_base
     |       |    layout: GSS_WITH_MEM_OPS_BASE
     |       |
     |       + gimple_with_memory_ops
     |       |   |    layout: GSS_WITH_MEM_OPS
     |       |   |
     |       |   + gassign
     |       |   |    code GIMPLE_ASSIGN
     |       |   |
     |       |   + greturn
     |       |        code GIMPLE_RETURN
     |       |
     |       + gcall
     |       |        layout: GSS_CALL, code: GIMPLE_CALL
     |       |
     |       + gasm
     |       |        layout: GSS_ASM, code: GIMPLE_ASM
     |       |
     |       + gtransaction
     |                layout: GSS_TRANSACTION, code: GIMPLE_TRANSACTION
     |
     + gomp
     |   |    layout: GSS_OMP.  Used for code GIMPLE_OMP_SECTION
     |   |
     |   + gomp_critical
     |   |        layout: GSS_OMP_CRITICAL, code: GIMPLE_OMP_CRITICAL
     |   |
     |   + gomp_for
     |   |        layout: GSS_OMP_FOR, code: GIMPLE_OMP_FOR
     |   |
     |   + gomp_parallel_layout
     |   |   |    layout: GSS_OMP_PARALLEL_LAYOUT
     |   |   |
     |   |   + gomp_taskreg
     |   |   |   |
     |   |   |   + gomp_parallel
     |   |   |   |        code: GIMPLE_OMP_PARALLEL
     |   |   |   |
     |   |   |   + gomp_task
     |   |   |            code: GIMPLE_OMP_TASK
     |   |   |
     |   |   + gomp_target
     |   |            code: GIMPLE_OMP_TARGET
     |   |
     |   + gomp_sections
     |   |        layout: GSS_OMP_SECTIONS, code: GIMPLE_OMP_SECTIONS
     |   |
     |   + gomp_single_layout
     |       |    layout: GSS_OMP_SINGLE_LAYOUT
     |       |
     |       + gomp_single
     |       |        code: GIMPLE_OMP_SINGLE
     |       |
     |       + gomp_teams
     |                code: GIMPLE_OMP_TEAMS
     |
     + gbind
     |        layout: GSS_BIND, code: GIMPLE_BIND
     |
     + gcatch
     |        layout: GSS_CATCH, code: GIMPLE_CATCH
     |
     + geh_filter
     |        layout: GSS_EH_FILTER, code: GIMPLE_EH_FILTER
     |
     + geh_else
     |        layout: GSS_EH_ELSE, code: GIMPLE_EH_ELSE
     |
     + geh_mnt
     |        layout: GSS_EH_MNT, code: GIMPLE_EH_MUST_NOT_THROW
     |
     + gphi
     |        layout: GSS_PHI, code: GIMPLE_PHI
     |
     + geh_ctrl
     |   |    layout: GSS_EH_CTRL
     |   |
     |   + gresx
     |   |        code: GIMPLE_RESX
     |   |
     |   + geh_dispatch
     |            code: GIMPLE_EH_DISPATCH
     |
     + gtry
     |        layout: GSS_TRY, code: GIMPLE_TRY
     |
     + gwce
     |        layout: GSS_WCE, code: GIMPLE_WITH_CLEANUP_EXPR
     |
     + gomp_continue
     |        layout: GSS_OMP_CONTINUE, code: GIMPLE_OMP_CONTINUE
     |
     + gomp_atomic_load
     |        layout: GSS_OMP_ATOMIC_LOAD, code: GIMPLE_OMP_ATOMIC_LOAD
     |
     + gomp_atomic_store_layout
         |    layout: GSS_OMP_ATOMIC_STORE_LAYOUT,
         |    code: GIMPLE_OMP_ATOMIC_STORE
         |
         + gomp_atomic_store
         |        code: GIMPLE_OMP_ATOMIC_STORE
         |
         + gomp_return
                  code: GIMPLE_OMP_RETURN





Dave