mesa/st: add nir pass to lower tex_src_plane

Signed-off-by: Rob Clark <[email protected]>

3 files changed, 124 insertions, 0 deletions

diff --git a/src/mesa/Makefile.sources b/src/mesa/Makefile.sources
index c04e0f96469..fbe58610582 100644
--- a/src/mesa/Makefile.sources
+++ b/src/mesa/Makefile.sources
@@ -505,6 +505,7 @@ STATETRACKER_FILES = \
 	state_tracker/st_mesa_to_tgsi.h \
 	state_tracker/st_nir.h \
 	state_tracker/st_nir_lower_builtin.c \
+	state_tracker/st_nir_lower_tex_src_plane.c \
 	state_tracker/st_pbo.c \
 	state_tracker/st_pbo.h \
 	state_tracker/st_program.c \
diff --git a/src/mesa/state_tracker/st_nir.h b/src/mesa/state_tracker/st_nir.h
index 523a274bb13..28d375c6fd1 100644
--- a/src/mesa/state_tracker/st_nir.h
+++ b/src/mesa/state_tracker/st_nir.h
@@ -34,6 +34,9 @@ extern "C" {
 struct nir_shader;
 
 void st_nir_lower_builtin(struct nir_shader *shader);
+void st_nir_lower_tex_src_plane(struct nir_shader *shader, unsigned free_slots,
+                                unsigned lower_2plane, unsigned lower_3plane);
+
 struct nir_shader * st_glsl_to_nir(struct st_context *st, struct gl_program *prog,
                                    struct gl_shader_program *shader_program,
                                    gl_shader_stage stage);
diff --git a/src/mesa/state_tracker/st_nir_lower_tex_src_plane.c b/src/mesa/state_tracker/st_nir_lower_tex_src_plane.c
new file mode 100644
index 00000000000..1dcaa315124
--- /dev/null
+++ b/src/mesa/state_tracker/st_nir_lower_tex_src_plane.c
@@ -0,0 +1,120 @@
+/*
+ * Copyright © 2016 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.
+ */
+
+/* Lowers the additional tex_src_plane src, generated by nir_lower_tex
+ * for planar YUV textures, into separate samplers, matching the logic
+ * that mesa/st uses to insert additional sampler view/state (since both
+ * sides need to agree).
+ *
+ * This should run after nir_lower_samplers.
+ */
+
+#include "compiler/nir/nir.h"
+#include "st_nir.h"
+
+typedef struct {
+   unsigned lower_2plane;
+   unsigned lower_3plane;
+
+   /* Maps a primary sampler (used for Y) to the U or UV sampler.  In
+    * case of 3-plane YUV format, the V plane is next sampler after U.
+    */
+   unsigned char sampler_map[PIPE_MAX_SAMPLERS][2];
+} lower_tex_src_state;
+
+static void
+assign_extra_samplers(lower_tex_src_state *state, unsigned free_slots)
+{
+   unsigned mask = state->lower_2plane | state->lower_3plane;
+
+   while (mask) {
+      unsigned extra, y_samp = u_bit_scan(&mask);
+
+      extra = u_bit_scan(&free_slots);
+      state->sampler_map[y_samp][0] = extra;
+
+      if (state->lower_3plane & (1 << y_samp)) {
+         extra = u_bit_scan(&free_slots);
+         state->sampler_map[y_samp][1] = extra;
+      }
+   }
+}
+
+static void
+lower_tex_src_plane_block(lower_tex_src_state *state, nir_block *block)
+{
+   nir_foreach_instr(instr, block) {
+      if (instr->type != nir_instr_type_tex)
+         continue;
+
+      nir_tex_instr *tex = nir_instr_as_tex(instr);
+      int plane_index = nir_tex_instr_src_index(tex, nir_tex_src_plane);
+
+      if (plane_index < 0)
+         continue;
+
+      nir_const_value *plane = nir_src_as_const_value(tex->src[plane_index].src);
+      assume(plane);
+
+      if (plane->i32[0] > 0) {
+         unsigned y_samp = tex->texture_index;
+
+         assume(tex->texture_index == tex->sampler_index);
+         assume(((state->lower_3plane & (1 << y_samp)) && plane->i32[0] < 3) ||
+               (plane->i32[0] < 2));
+
+         tex->texture_index = tex->sampler_index =
+               state->sampler_map[y_samp][plane->i32[0] - 1];
+      }
+
+      nir_tex_instr_remove_src(tex, plane_index);
+   }
+}
+
+static void
+lower_tex_src_plane_impl(lower_tex_src_state *state, nir_function_impl *impl)
+{
+   nir_foreach_block(block, impl) {
+      lower_tex_src_plane_block(state, block);
+   }
+
+   nir_metadata_preserve(impl, nir_metadata_block_index |
+                               nir_metadata_dominance);
+}
+
+void
+st_nir_lower_tex_src_plane(struct nir_shader *shader, unsigned free_slots,
+                           unsigned lower_2plane, unsigned lower_3plane)
+{
+   lower_tex_src_state state = {0};
+
+   state.lower_2plane = lower_2plane;
+   state.lower_3plane = lower_3plane;
+
+   assign_extra_samplers(&state, free_slots);
+
+   nir_foreach_function(function, shader) {
+      if (function->impl)
+         lower_tex_src_plane_impl(&state, function->impl);
+   }
+}