anv: Add an input attachment lowering pass

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

src/intel/vulkan/Makefile.sources

@@ -34,6 +34,7 @@ VULKAN_FILES := \
 	anv_nir.h \
 	anv_nir_apply_dynamic_offsets.c \
 	anv_nir_apply_pipeline_layout.c \
+	anv_nir_lower_input_attachments.c \
 	anv_nir_lower_push_constants.c \
 	anv_pass.c \
 	anv_pipeline.c \

src/intel/vulkan/anv_nir.h

@@ -31,6 +31,8 @@
 extern "C" {
 #endif
 
+void anv_nir_lower_input_attachments(nir_shader *shader);
+
 void anv_nir_lower_push_constants(nir_shader *shader);
 
 void anv_nir_apply_dynamic_offsets(struct anv_pipeline *pipeline,

src/intel/vulkan/anv_nir_lower_input_attachments.c

@@ -0,0 +1,141 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * 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 "anv_nir.h"
+#include "nir/nir_builder.h"
+
+static nir_ssa_def *
+load_frag_coord(nir_builder *b)
+{
+   nir_foreach_variable(var, &b->shader->inputs) {
+      if (var->data.location == VARYING_SLOT_POS)
+         return nir_load_var(b, var);
+   }
+
+   nir_variable *pos = nir_variable_create(b->shader, nir_var_shader_in,
+                                           glsl_vec4_type(), NULL);
+   pos->data.location = VARYING_SLOT_POS;
+   pos->data.origin_upper_left = true;
+
+   return nir_load_var(b, pos);
+}
+
+static void
+try_lower_input_load(nir_function_impl *impl, nir_intrinsic_instr *load)
+{
+
+   const struct glsl_type *image_type =
+      glsl_without_array(load->variables[0]->var->type);
+   enum glsl_sampler_dim image_dim = glsl_get_sampler_dim(image_type);
+   if (image_dim != GLSL_SAMPLER_DIM_SUBPASS &&
+       image_dim != GLSL_SAMPLER_DIM_SUBPASS_MS)
+      return;
+
+   const bool multisampled = (image_dim == GLSL_SAMPLER_DIM_SUBPASS_MS);
+
+   nir_builder b;
+   nir_builder_init(&b, impl);
+   b.cursor = nir_before_instr(&load->instr);
+
+   nir_ssa_def *frag_coord = nir_f2i(&b, load_frag_coord(&b));
+   nir_ssa_def *offset = nir_ssa_for_src(&b, load->src[0], 2);
+   nir_ssa_def *pos = nir_iadd(&b, frag_coord, offset);
+
+   nir_ssa_def *layer =
+      nir_load_system_value(&b, nir_intrinsic_load_layer_id, 0);
+   nir_ssa_def *coord =
+      nir_vec3(&b, nir_channel(&b, pos, 0), nir_channel(&b, pos, 1), layer);
+
+   nir_tex_instr *tex = nir_tex_instr_create(b.shader, 2 + multisampled);
+
+   tex->op = nir_texop_txf;
+
+   switch (glsl_get_sampler_result_type(image_type)) {
+   case GLSL_TYPE_FLOAT:
+      tex->dest_type = nir_type_float;
+      break;
+   case GLSL_TYPE_INT:
+      tex->dest_type = nir_type_int;
+      break;
+   case GLSL_TYPE_UINT:
+      tex->dest_type = nir_type_uint;
+      break;
+   default:
+      unreachable("Invalid image type");
+   }
+   tex->is_array = true;
+   tex->is_shadow = false;
+
+   tex->texture =
+      nir_deref_as_var(nir_copy_deref(tex, &load->variables[0]->deref));
+   tex->sampler = NULL;
+   tex->texture_index = 0;
+   tex->sampler_index = 0;
+
+   tex->src[0].src_type = nir_tex_src_coord;
+   tex->src[0].src = nir_src_for_ssa(coord);
+   tex->coord_components = 3;
+
+   tex->src[1].src_type = nir_tex_src_lod;
+   tex->src[1].src = nir_src_for_ssa(nir_imm_int(&b, 0));
+
+   if (image_dim == GLSL_SAMPLER_DIM_SUBPASS_MS) {
+      tex->op = nir_texop_txf_ms;
+
+      nir_ssa_def *sample_id =
+         nir_load_system_value(&b, nir_intrinsic_load_sample_id, 0);
+      tex->src[2].src_type = nir_tex_src_ms_index;
+      tex->src[2].src = nir_src_for_ssa(sample_id);
+   }
+
+   nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
+   nir_builder_instr_insert(&b, &tex->instr);
+
+   nir_ssa_def_rewrite_uses(&load->dest.ssa,
+                            nir_src_for_ssa(&tex->dest.ssa));
+}
+
+void
+anv_nir_lower_input_attachments(nir_shader *shader)
+{
+   assert(shader->stage == MESA_SHADER_FRAGMENT);
+
+   nir_foreach_function(function, shader) {
+      if (!function->impl)
+         continue;
+
+      nir_foreach_block(block, function->impl) {
+         nir_foreach_instr(instr, block) {
+            if (instr->type != nir_instr_type_intrinsic)
+               continue;
+
+            nir_intrinsic_instr *load = nir_instr_as_intrinsic(instr);
+
+            if (load->intrinsic != nir_intrinsic_image_load)
+               continue;
+
+            try_lower_input_load(function->impl, load);
+         }
+      }
+   }
+}

src/intel/vulkan/anv_pipeline.c

@@ -172,6 +172,9 @@ anv_shader_compile_to_nir(struct anv_device *device,
    nir_lower_clip_cull_distance_arrays(nir);
    nir_validate_shader(nir);
 
+   if (stage == MESA_SHADER_FRAGMENT)
+      anv_nir_lower_input_attachments(nir);
+
    nir_shader_gather_info(nir, entry_point->impl);
 
    nir_variable_mode indirect_mask = 0;