[Mesa-dev] [PATCH 4/5] i965/fs: Make get_timestamp() pass back the MOV rather than emitting it.

[Pohjolainen, Topi]

On Mon, Mar 09, 2015 at 11:40:19AM -0700, Matt Turner wrote:
> On Sun, Mar 8, 2015 at 1:08 AM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> > This makes another part of the INTEL_DEBUG=shader_time code emittable
> > at arbitrary locations, rather than just at the end of the instruction
> > stream.
> >
> > v2: Don't lose smear!  Caught by Topi Pohjolainen.
> > v3: Don't set smear on the destination of the MOV.  Thanks Topi!
> >
> > Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> > ---
> >  src/mesa/drivers/dri/i965/brw_fs.cpp | 19 +++++++++++++++----
> >  src/mesa/drivers/dri/i965/brw_fs.h   |  2 +-
> >  2 files changed, 16 insertions(+), 5 deletions(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
> > index 682841b..8f11600 100644
> > --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> > +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> > @@ -677,8 +677,14 @@ fs_visitor::type_size(const struct glsl_type *type)
> >     return 0;
> >  }
> >
> > +/**
> > + * Create a MOV to read the timestamp register.
> > + *
> > + * The caller is responsible for emitting the MOV.  The return value is
> > + * the destination of the MOV, with extra parameters set.
> > + */
> >  fs_reg
> > -fs_visitor::get_timestamp()
> > +fs_visitor::get_timestamp(fs_inst **out_mov)
> >  {
> >     assert(brw->gen >= 7);
> >
> > @@ -689,7 +695,7 @@ fs_visitor::get_timestamp()
> >
> >     fs_reg dst = fs_reg(GRF, alloc.allocate(1), BRW_REGISTER_TYPE_UD, 4);
> >
> > -   fs_inst *mov = emit(MOV(dst, ts));
> > +   fs_inst *mov = MOV(dst, ts);
> >     /* We want to read the 3 fields we care about even if it's not enabled in
> >      * the dispatch.
> >      */
> > @@ -707,6 +713,7 @@ fs_visitor::get_timestamp()
> >      */
> >     dst.set_smear(0);
> >
> > +   *out_mov = mov;
> >     return dst;
> >  }
> >
> > @@ -714,7 +721,9 @@ void
> >  fs_visitor::emit_shader_time_begin()
> >  {
> >     current_annotation = "shader time start";
> > -   shader_start_time = get_timestamp();
> > +   fs_inst *mov;
> > +   shader_start_time = get_timestamp(&mov);
> > +   emit(mov);
> 
> What do you think about returning the mov instruction from
> get_timestamp, and then just doing shader_start_time = mov->dst?

Then each caller would need to additionally set the smear:

shader_start_time.set_smear(0);