[Mesa-dev] [RFCv3 08/11] gallium/auxiliary: introduce nir_emulate

Connor Abbott cwabbott0 at gmail.com
Mon Feb 1 16:42:31 UTC 2016


This doesn't really seem to be following NIR's convention/style of
having separate passes/files for each thing that needs to be lowered.
This might've made sense for TGSI, where there was a lot of
boilerplate that each thing needed since TGSI isn't designed for doing
transforms on it, but with NIR it doesn't. Also, this isn't really any
more TGSI-specific than the other stuff that you've already put in
src/compiler/nir. So instead, in src/compiler/nir you would have
something like:

- nir_lower_passthrough_edgeflags
- nir_lower_clamp_color_outputs
- nir_force_persample_interp

Unfortunately, it doesn't quite fit with the whole "nir_lower_noun"
convention, but oh well...


On Sun, Jan 31, 2016 at 3:16 PM, Rob Clark <robdclark at gmail.com> wrote:
> From: Rob Clark <robclark at freedesktop.org>
>
> NIR equivalent of tgsi_emulate
>
> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
>  src/gallium/auxiliary/Makefile.sources  |   2 +
>  src/gallium/auxiliary/nir/nir_emulate.c | 177 ++++++++++++++++++++++++++++++++
>  src/gallium/auxiliary/nir/nir_emulate.h |  34 ++++++
>  3 files changed, 213 insertions(+)
>  create mode 100644 src/gallium/auxiliary/nir/nir_emulate.c
>  create mode 100644 src/gallium/auxiliary/nir/nir_emulate.h
>
> diff --git a/src/gallium/auxiliary/Makefile.sources b/src/gallium/auxiliary/Makefile.sources
> index 6f50f71..c32cfdf 100644
> --- a/src/gallium/auxiliary/Makefile.sources
> +++ b/src/gallium/auxiliary/Makefile.sources
> @@ -311,6 +311,8 @@ C_SOURCES := \
>         util/u_video.h
>
>  NIR_SOURCES := \
> +       nir/nir_emulate.c \
> +       nir/nir_emulate.h \
>         nir/tgsi_to_nir.c \
>         nir/tgsi_to_nir.h
>
> diff --git a/src/gallium/auxiliary/nir/nir_emulate.c b/src/gallium/auxiliary/nir/nir_emulate.c
> new file mode 100644
> index 0000000..af1d3bc
> --- /dev/null
> +++ b/src/gallium/auxiliary/nir/nir_emulate.c
> @@ -0,0 +1,177 @@
> +/*
> + * 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/nir_emulate.h"
> +
> +#include "compiler/nir/nir_builder.h"
> +
> +typedef struct {
> +   nir_shader *shader;
> +   nir_builder b;
> +   unsigned flags;
> +   /* for TGSI_EMU_PASSTHROUGH_EDGEFLAG: */
> +   struct {
> +      bool emitted;
> +      nir_variable *in, *out;
> +   } edgeflag;
> +} emu_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
> +is_color_output(emu_state *state, nir_variable *out)
> +{
> +   switch (state->shader->stage) {
> +   case MESA_SHADER_VERTEX:
> +   case MESA_SHADER_GEOMETRY:
> +      switch (out->data.location) {
> +      case VARYING_SLOT_COL0:
> +      case VARYING_SLOT_COL1:
> +      case VARYING_SLOT_BFC0:
> +      case VARYING_SLOT_BFC1:
> +         return true;
> +      default:
> +         return false;
> +      }
> +      break;
> +   case MESA_SHADER_FRAGMENT:
> +      switch (out->data.location) {
> +      case FRAG_RESULT_COLOR:
> +         return true;
> +      default:
> +         return false;
> +      }
> +      break;
> +   default:
> +      return false;
> +   }
> +}
> +
> +static void
> +emu_intrinsic(emu_state *state, nir_intrinsic_instr *intr)
> +{
> +   nir_variable *out;
> +   nir_builder *b = &state->b;
> +   nir_ssa_def *s;
> +
> +   assert(state->flags & TGSI_EMU_CLAMP_COLOR_OUTPUTS);
> +
> +   if (intr->intrinsic != nir_intrinsic_store_var)
> +      return;
> +
> +   out = intr->variables[0]->var;
> +
> +   if (out->data.mode != nir_var_shader_out)
> +      return;
> +
> +   /* NOTE: 'out' can be null for types larger than vec4,
> +    * but these will never be color out's so we can ignore
> +    */
> +
> +   if (out && is_color_output(state, out)) {
> +      b->cursor = nir_before_instr(&intr->instr);
> +      s = nir_ssa_for_src(b, intr->src[0], intr->num_components);
> +      s = nir_fsat(b, s);
> +      nir_instr_rewrite_src(&intr->instr, &intr->src[0], nir_src_for_ssa(s));
> +   }
> +}
> +
> +static void
> +passthrough_edgeflags(emu_state *state, nir_block *block)
> +{
> +   nir_builder *b = &state->b;
> +   nir_ssa_def *def;
> +
> +   if (!state->edgeflag.in)
> +      state->edgeflag.in = create_edgeflag_var(state->shader, false);
> +
> +   if (!state->edgeflag.out)
> +      state->edgeflag.out = create_edgeflag_var(state->shader, true);
> +
> +   b->cursor = nir_before_block(block);
> +
> +   def = nir_load_var(b, state->edgeflag.in);
> +   nir_store_var(b, state->edgeflag.out, def, 0xf);
> +}
> +
> +static bool
> +emu_block(nir_block *block, void *_state)
> +{
> +   emu_state *state = _state;
> +
> +   /* we should hit the first block first.. */
> +   if ((state->flags & TGSI_EMU_PASSTHROUGH_EDGEFLAG) &&
> +       !state->edgeflag.emitted) {
> +      passthrough_edgeflags(state, block);
> +      state->edgeflag.emitted = true;
> +   }
> +
> +   /* early return if we don't need per-instruction lowering: */
> +   if (!(state->flags & TGSI_EMU_CLAMP_COLOR_OUTPUTS))
> +      return false;
> +
> +   nir_foreach_instr_safe(block, instr) {
> +      if (instr->type == nir_instr_type_intrinsic)
> +         emu_intrinsic(state, nir_instr_as_intrinsic(instr));
> +   }
> +
> +   return true;
> +}
> +static void
> +emu_impl(emu_state *state, nir_function_impl *impl)
> +{
> +   nir_builder_init(&state->b, impl);
> +
> +   nir_foreach_block(impl, emu_block, state);
> +   nir_metadata_preserve(impl, nir_metadata_block_index |
> +                               nir_metadata_dominance);
> +}
> +
> +void nir_emulate(nir_shader *shader, unsigned flags)
> +{
> +   emu_state state = {
> +      .shader = shader,
> +      .flags = flags,
> +   };
> +
> +   assert(flags != 0);
> +
> +   if (flags & TGSI_EMU_FORCE_PERSAMPLE_INTERP) {
> +      nir_foreach_variable(var, &shader->inputs) {
> +         var->data.sample = true;
> +      }
> +   }
> +
> +   nir_foreach_function(shader, function) {
> +      if (function->impl)
> +         emu_impl(&state, function->impl);
> +   }
> +}
> diff --git a/src/gallium/auxiliary/nir/nir_emulate.h b/src/gallium/auxiliary/nir/nir_emulate.h
> new file mode 100644
> index 0000000..9f56620
> --- /dev/null
> +++ b/src/gallium/auxiliary/nir/nir_emulate.h
> @@ -0,0 +1,34 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef _NIR_EMULATE_H_
> +#define _NIR_EMULATE_H_
> +
> +#include "tgsi/tgsi_emulate.h"  /* for now share TGSI_EMU_x flags */
> +
> +#include "compiler/nir/nir.h"
> +
> +
> +void nir_emulate(nir_shader *shader, unsigned flags);
> +
> +#endif /* _NIR_EMULATE_H_ */
> --
> 2.5.0
>


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