st/nir/radeonsi: move nir_lower_uniforms_to_ubo() to the state tracker

This will only ever be used by gallium drivers so it probably doesn't
belong in the nir toolkit. Also we want to pass it some non NIR
things in the following patch.

To avoid regressions we wrap the lowering calls that have been moved
to st_glsl_to_nir with a quick hack so that they are only called for
radeonsi, we will replace the hack with a check for uniform packing
in a following patch.

Reviewed-by: Marek Olšák <[email protected]>

3 files changed, 112 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_glsl_to_nir.cpp b/src/mesa/state_tracker/st_glsl_to_nir.cpp
index 1fd553fdf8b..2ca64231e0d 100644
--- a/src/mesa/state_tracker/st_glsl_to_nir.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_nir.cpp
@@ -37,6 +37,7 @@
 #include "main/uniforms.h"
 
 #include "st_context.h"
+#include "st_glsl_types.h"
 #include "st_program.h"
 
 #include "compiler/nir/nir.h"
@@ -752,6 +753,18 @@ st_finalize_nir(struct st_context *st, struct gl_program *prog,
    st_nir_assign_uniform_locations(st->ctx, prog, shader_program,
                                    &nir->uniforms, &nir->num_uniforms);
 
+   /* Below is a quick hack so that uniform lowering only runs on radeonsi
+    * (the only NIR backend that currently supports tess) once we enable
+    * uniform packing support we will just use
+    * ctx->Const.PackedDriverUniformStorage for this check.
+    */
+   if (screen->get_shader_param(screen, PIPE_SHADER_TESS_CTRL,
+                                PIPE_SHADER_CAP_MAX_INSTRUCTIONS) > 0) {
+      NIR_PASS_V(nir, nir_lower_io, nir_var_uniform, type_size,
+                 (nir_lower_io_options)0);
+      NIR_PASS_V(nir, st_nir_lower_uniforms_to_ubo);
+   }
+
    if (screen->get_param(screen, PIPE_CAP_NIR_SAMPLERS_AS_DEREF))
       NIR_PASS_V(nir, nir_lower_samplers_as_deref, shader_program);
    else
diff --git a/src/mesa/state_tracker/st_nir.h b/src/mesa/state_tracker/st_nir.h
index 8c81c3f2d86..1c2e32a5e6f 100644
--- a/src/mesa/state_tracker/st_nir.h
+++ b/src/mesa/state_tracker/st_nir.h
@@ -36,6 +36,7 @@ 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);
+bool st_nir_lower_uniforms_to_ubo(struct nir_shader *shader);
 
 void st_finalize_nir(struct st_context *st, struct gl_program *prog,
                      struct gl_shader_program *shader_program,
diff --git a/src/mesa/state_tracker/st_nir_lower_uniforms_to_ubo.c b/src/mesa/state_tracker/st_nir_lower_uniforms_to_ubo.c
new file mode 100644
index 00000000000..1d2cca065b8
--- /dev/null
+++ b/src/mesa/state_tracker/st_nir_lower_uniforms_to_ubo.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright 2017 Advanced Micro Devices, Inc.
+ *
+ * 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
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHOR(S) AND/OR THEIR SUPPLIERS 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.
+ */
+
+/*
+ * Remap load_uniform intrinsics to UBO accesses of UBO binding point 0. Both
+ * the base and the offset are interpreted as 16-byte units.
+ *
+ * Simultaneously, remap existing UBO accesses by increasing their binding
+ * point by 1.
+ */
+
+#include "nir.h"
+#include "nir_builder.h"
+#include "st_nir.h"
+
+static bool
+lower_instr(nir_intrinsic_instr *instr, nir_builder *b)
+{
+   b->cursor = nir_before_instr(&instr->instr);
+
+   if (instr->intrinsic == nir_intrinsic_load_ubo) {
+      nir_ssa_def *old_idx = nir_ssa_for_src(b, instr->src[0], 1);
+      nir_ssa_def *new_idx = nir_iadd(b, old_idx, nir_imm_int(b, 1));
+      nir_instr_rewrite_src(&instr->instr, &instr->src[0],
+                            nir_src_for_ssa(new_idx));
+      return true;
+   }
+
+   if (instr->intrinsic == nir_intrinsic_load_uniform) {
+      nir_ssa_def *ubo_idx = nir_imm_int(b, 0);
+      nir_ssa_def *ubo_offset =
+         nir_imul(b, nir_imm_int(b, 16),
+                  nir_iadd(b, nir_imm_int(b, nir_intrinsic_base(instr)),
+                           nir_ssa_for_src(b, instr->src[0], 1)));
+
+      nir_intrinsic_instr *load =
+         nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_ubo);
+      load->num_components = instr->num_components;
+      load->src[0] = nir_src_for_ssa(ubo_idx);
+      load->src[1] = nir_src_for_ssa(ubo_offset);
+      nir_ssa_dest_init(&load->instr, &load->dest,
+                        load->num_components, instr->dest.ssa.bit_size,
+                        instr->dest.ssa.name);
+      nir_builder_instr_insert(b, &load->instr);
+      nir_ssa_def_rewrite_uses(&instr->dest.ssa, nir_src_for_ssa(&load->dest.ssa));
+
+      nir_instr_remove(&instr->instr);
+      return true;
+   }
+
+   return false;
+}
+
+bool
+st_nir_lower_uniforms_to_ubo(nir_shader *shader)
+{
+   bool progress = false;
+
+   nir_foreach_function(function, shader) {
+      if (function->impl) {
+         nir_builder builder;
+         nir_builder_init(&builder, function->impl);
+         nir_foreach_block(block, function->impl) {
+            nir_foreach_instr_safe(instr, block) {
+               if (instr->type == nir_instr_type_intrinsic)
+                  progress |= lower_instr(nir_instr_as_intrinsic(instr),
+                                          &builder);
+            }
+         }
+
+         nir_metadata_preserve(function->impl, nir_metadata_block_index |
+                                               nir_metadata_dominance);
+      }
+   }
+
+   return progress;
+}
+