[Mesa-dev] [PATCH 08b/11] nir: passthrough-edgeflags support

[Connor Abbott]

On Tue, Feb 2, 2016 at 1:07 PM, Rob Clark <robdclark at gmail.com> wrote:
> From: Rob Clark <robclark at freedesktop.org>
>
> Handled by tgsi_emulate for glsl->tgsi case.
>
> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
>  src/compiler/Makefile.sources                      |  1 +
>  src/compiler/nir/nir.h                             |  2 +
>  src/compiler/nir/nir_lower_passthrough_edgeflags.c | 86 ++++++++++++++++++++++
>  3 files changed, 89 insertions(+)
>  create mode 100644 src/compiler/nir/nir_lower_passthrough_edgeflags.c
>
> diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
> index e85cde5..e493ab0 100644
> --- a/src/compiler/Makefile.sources
> +++ b/src/compiler/Makefile.sources
> @@ -194,6 +194,7 @@ NIR_FILES = \
>         nir/nir_lower_idiv.c \
>         nir/nir_lower_io.c \
>         nir/nir_lower_outputs_to_temporaries.c \
> +       nir/nir_lower_passthrough_edgeflags.c \
>         nir/nir_lower_phis_to_scalar.c \
>         nir/nir_lower_samplers.c \
>         nir/nir_lower_system_values.c \
> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> index dc31a67..6601346 100644
> --- a/src/compiler/nir/nir.h
> +++ b/src/compiler/nir/nir.h
> @@ -2121,6 +2121,8 @@ void nir_lower_two_sided_color(nir_shader *shader);
>
>  void nir_lower_clamp_color_outputs(nir_shader *shader);
>
> +void nir_lower_passthrough_edgeflags(nir_shader *shader);
> +
>  typedef struct nir_lower_wpos_ytransform_options {
>     int state_tokens[5];
>     bool fs_coord_origin_upper_left :1;
> diff --git a/src/compiler/nir/nir_lower_passthrough_edgeflags.c b/src/compiler/nir/nir_lower_passthrough_edgeflags.c
> new file mode 100644
> index 0000000..6476c80
> --- /dev/null
> +++ b/src/compiler/nir/nir_lower_passthrough_edgeflags.c
> @@ -0,0 +1,86 @@
> +/*
> + * Copyright © 2015 Red Hat
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
> + * SOFTWARE.
> + */
> +
> +#include "nir.h"
> +#include "nir_builder.h"
> +
> +typedef struct {
> +   nir_shader *shader;
> +   nir_builder b;
> +   bool emitted;
> +   nir_variable *in, *out;
> +} lower_state;
> +
> +static nir_variable *
> +create_edgeflag_var(nir_shader *shader, bool output)
> +{
> +   nir_variable_mode mode = output ? nir_var_shader_out : nir_var_shader_in;
> +   nir_variable *var = nir_variable_create(shader, mode, glsl_vec4_type(),
> +                                           output ? "edgeflag_out" : "edgeflag_in");
> +   var->data.location = output ? VARYING_SLOT_EDGE : VERT_ATTRIB_EDGEFLAG;
> +   return var;
> +}
> +
> +static bool
> +lower_block(nir_block *block, void *_state)
> +{
> +   lower_state *state = _state;
> +   nir_builder *b = &state->b;
> +   nir_ssa_def *def;
> +
> +   if (!state->in)
> +      state->in = create_edgeflag_var(state->shader, false);
> +
> +   if (!state->out)
> +      state->out = create_edgeflag_var(state->shader, true);

You know that this code is going to be run exactly once, so why not do
it in nir_lower_passthrough_edgeflags()? Also, once you do that, you
can probably just inline create_edgeflag_var(), since splitting it
into a separate function probably doesn't help you much.

> +
> +   b->cursor = nir_before_block(block);
> +
> +   def = nir_load_var(b, state->in);
> +   nir_store_var(b, state->out, def, 0xf);
> +
> +   /* only do this for first block: */
> +   return false;
> +}
> +
> +static void
> +lower_impl(lower_state *state, nir_function_impl *impl)
> +{
> +   nir_builder_init(&state->b, impl);
> +
> +   nir_foreach_block(impl, lower_block, state);
> +   nir_metadata_preserve(impl, nir_metadata_block_index |
> +                               nir_metadata_dominance);
> +}
> +
> +void nir_lower_passthrough_edgeflags(nir_shader *shader)
> +{
> +   lower_state state = {
> +      .shader = shader,
> +   };
> +
> +   nir_foreach_function(shader, function) {
> +      if (function->impl)

Just to future proof this a little bit and make it more obvious that
this only applies to entrypoints, can you do "strcmp(function->name,
"main") == 0 && function->impl" here? In the future, we're going to
need better handling of entrypoints (including multiple entrypoints
per shader) in NIR for SPIR-V, but this can do for now. With those
comments addressed, this is

Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>

> +         lower_impl(&state, function->impl);
> +   }
> +}
> --
> 2.5.0
>