--- /dev/null
+/*
+ * Copyright © 2019 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 "nir.h"
+#include "nir_builder.h"
+#include "nir_deref.h"
+
+/** @file nir_lower_io_to_vector.c
+ *
+ * Merges compatible input/output variables residing in different components
+ * of the same location. It's expected that further passes such as
+ * nir_lower_io_to_temporaries will combine loads and stores of the merged
+ * variables, producing vector nir_load_input/nir_store_output instructions
+ * when all is said and done.
+ */
+
+static const struct glsl_type *
+resize_array_vec_type(const struct glsl_type *type, unsigned num_components)
+{
+ if (glsl_type_is_array(type)) {
+ const struct glsl_type *arr_elem =
+ resize_array_vec_type(glsl_get_array_element(type), num_components);
+ return glsl_array_type(arr_elem, glsl_get_length(type), 0);
+ } else {
+ assert(glsl_type_is_vector_or_scalar(type));
+ return glsl_vector_type(glsl_get_base_type(type), num_components);
+ }
+}
+
+static bool
+variable_can_rewrite(const nir_variable *var)
+{
+ /* Only touch user defined varyings as these are the only ones we split */
+ if (var->data.location < VARYING_SLOT_VAR0)
+ return false;
+
+ /* Skip complex types we don't split in the first place */
+ if (!glsl_type_is_vector_or_scalar(glsl_without_array(var->type)))
+ return false;
+
+ /* TODO: add 64/16bit support ? */
+ if (glsl_get_bit_size(glsl_without_array(var->type)) != 32)
+ return false;
+
+ return true;
+}
+
+static bool
+variables_can_merge(nir_shader *shader,
+ const nir_variable *a, const nir_variable *b)
+{
+ const struct glsl_type *a_type_tail = a->type;
+ const struct glsl_type *b_type_tail = b->type;
+
+ /* They must have the same array structure */
+ while (glsl_type_is_array(a_type_tail)) {
+ if (!glsl_type_is_array(b_type_tail))
+ return false;
+
+ if (glsl_get_length(a_type_tail) != glsl_get_length(b_type_tail))
+ return false;
+
+ a_type_tail = glsl_get_array_element(a_type_tail);
+ b_type_tail = glsl_get_array_element(b_type_tail);
+ }
+
+ if (!glsl_type_is_vector_or_scalar(a_type_tail) ||
+ !glsl_type_is_vector_or_scalar(b_type_tail))
+ return false;
+
+ if (glsl_get_base_type(a->type) != glsl_get_base_type(b->type))
+ return false;
+
+ assert(a->data.mode == b->data.mode);
+ if (shader->info.stage == MESA_SHADER_FRAGMENT &&
+ a->data.mode == nir_var_shader_in &&
+ a->data.interpolation != b->data.interpolation)
+ return false;
+
+ return true;
+}
+
+static bool
+create_new_io_vars(nir_shader *shader, struct exec_list *io_list,
+ nir_variable *old_vars[MAX_VARYINGS_INCL_PATCH][4],
+ nir_variable *new_vars[MAX_VARYINGS_INCL_PATCH][4])
+{
+ if (exec_list_is_empty(io_list))
+ return false;
+
+ nir_foreach_variable(var, io_list) {
+ if (variable_can_rewrite(var)) {
+ unsigned loc = var->data.location - VARYING_SLOT_VAR0;
+ unsigned frac = var->data.location_frac;
+ old_vars[loc][frac] = var;
+ }
+ }
+
+ bool merged_any_vars = false;
+
+ /* We don't handle combining vars of different type e.g. different array
+ * lengths.
+ */
+ for (unsigned loc = 0; loc < MAX_VARYINGS_INCL_PATCH; loc++) {
+ unsigned frac = 0;
+ while (frac < 4) {
+ nir_variable *first_var = old_vars[loc][frac];
+ if (!first_var) {
+ frac++;
+ continue;
+ }
+
+ int first = frac;
+ bool found_merge = false;
+
+ while (frac < 4) {
+ nir_variable *var = old_vars[loc][frac];
+ if (!var)
+ break;
+
+ if (var != first_var) {
+ if (!variables_can_merge(shader, first_var, var))
+ break;
+
+ found_merge = true;
+ }
+
+ const unsigned num_components =
+ glsl_get_components(glsl_without_array(var->type));
+
+ /* We had better not have any overlapping vars */
+ for (unsigned i = 1; i < num_components; i++)
+ assert(old_vars[loc][frac + i] == NULL);
+
+ frac += num_components;
+ }
+
+ if (!found_merge)
+ continue;
+
+ merged_any_vars = true;
+
+ nir_variable *var = nir_variable_clone(old_vars[loc][first], shader);
+ var->data.location_frac = first;
+ var->type = resize_array_vec_type(var->type, frac - first);
+
+ nir_shader_add_variable(shader, var);
+ for (unsigned i = first; i < frac; i++)
+ new_vars[loc][i] = var;
+ }
+ }
+
+ return merged_any_vars;
+}
+
+static nir_deref_instr *
+build_array_deref_of_new_var(nir_builder *b, nir_variable *new_var,
+ nir_deref_instr *leader)
+{
+ if (leader->deref_type == nir_deref_type_var)
+ return nir_build_deref_var(b, new_var);
+
+ nir_deref_instr *parent =
+ build_array_deref_of_new_var(b, new_var, nir_deref_instr_parent(leader));
+
+ return nir_build_deref_follower(b, parent, leader);
+}
+
+static bool
+nir_lower_io_to_vector_impl(nir_function_impl *impl, nir_variable_mode modes)
+{
+ assert(!(modes & ~(nir_var_shader_in | nir_var_shader_out)));
+
+ nir_builder b;
+ nir_builder_init(&b, impl);
+
+ nir_metadata_require(impl, nir_metadata_dominance);
+
+ nir_shader *shader = impl->function->shader;
+ nir_variable *old_inputs[MAX_VARYINGS_INCL_PATCH][4] = {0};
+ nir_variable *new_inputs[MAX_VARYINGS_INCL_PATCH][4] = {0};
+ nir_variable *old_outputs[MAX_VARYINGS_INCL_PATCH][4] = {0};
+ nir_variable *new_outputs[MAX_VARYINGS_INCL_PATCH][4] = {0};
+
+ if (modes & nir_var_shader_in) {
+ /* Vertex shaders support overlapping inputs. We don't do those */
+ assert(b.shader->info.stage != MESA_SHADER_VERTEX);
+
+ /* If we don't actually merge any variables, remove that bit from modes
+ * so we don't bother doing extra non-work.
+ */
+ if (!create_new_io_vars(shader, &shader->inputs,
+ old_inputs, new_inputs))
+ modes &= ~nir_var_shader_in;
+ }
+
+ if (modes & nir_var_shader_out) {
+ /* Fragment shader outputs are always vec4. You shouldn't have
+ * scalarized them and it doesn't make sense to vectorize them.
+ */
+ assert(b.shader->info.stage != MESA_SHADER_FRAGMENT);
+
+ /* If we don't actually merge any variables, remove that bit from modes
+ * so we don't bother doing extra non-work.
+ */
+ if (!create_new_io_vars(shader, &shader->outputs,
+ old_outputs, new_outputs))
+ modes &= ~nir_var_shader_out;
+ }
+
+ if (!modes)
+ return false;
+
+ bool progress = false;
+
+ /* Actually lower all the IO load/store intrinsics. Load instructions are
+ * lowered to a vector load and an ALU instruction to grab the channels we
+ * want. Outputs are lowered to a write-masked store of the vector output.
+ * For non-TCS outputs, we then run nir_lower_io_to_temporaries at the end
+ * to clean up the partial writes.
+ */
+ nir_foreach_block(block, impl) {
+ nir_foreach_instr_safe(instr, block) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+
+ switch (intrin->intrinsic) {
+ case nir_intrinsic_load_deref:
+ case nir_intrinsic_interp_deref_at_centroid:
+ case nir_intrinsic_interp_deref_at_sample:
+ case nir_intrinsic_interp_deref_at_offset: {
+ nir_deref_instr *old_deref = nir_src_as_deref(intrin->src[0]);
+ if (!(old_deref->mode & modes))
+ break;
+
+ if (old_deref->mode == nir_var_shader_out)
+ assert(b.shader->info.stage == MESA_SHADER_TESS_CTRL);
+
+ nir_variable *old_var = nir_deref_instr_get_variable(old_deref);
+ if (old_var->data.location < VARYING_SLOT_VAR0)
+ break;
+
+ const unsigned loc = old_var->data.location - VARYING_SLOT_VAR0;
+ const unsigned old_frac = old_var->data.location_frac;
+ nir_variable *new_var = old_deref->mode == nir_var_shader_in ?
+ new_inputs[loc][old_frac] :
+ new_outputs[loc][old_frac];
+ if (!new_var)
+ break;
+
+ assert(new_var->data.location == VARYING_SLOT_VAR0 + loc);
+ const unsigned new_frac = new_var->data.location_frac;
+
+ nir_component_mask_t vec4_comp_mask =
+ ((1 << intrin->num_components) - 1) << old_frac;
+
+ b.cursor = nir_before_instr(&intrin->instr);
+
+ /* Rewrite the load to use the new variable and only select a
+ * portion of the result.
+ */
+ nir_deref_instr *new_deref =
+ build_array_deref_of_new_var(&b, new_var, old_deref);
+ assert(glsl_type_is_vector(new_deref->type));
+ nir_instr_rewrite_src(&intrin->instr, &intrin->src[0],
+ nir_src_for_ssa(&new_deref->dest.ssa));
+
+ intrin->num_components =
+ glsl_get_components(new_deref->type);
+ intrin->dest.ssa.num_components = intrin->num_components;
+
+ b.cursor = nir_after_instr(&intrin->instr);
+
+ nir_ssa_def *new_vec = nir_channels(&b, &intrin->dest.ssa,
+ vec4_comp_mask >> new_frac);
+ nir_ssa_def_rewrite_uses_after(&intrin->dest.ssa,
+ nir_src_for_ssa(new_vec),
+ new_vec->parent_instr);
+
+ progress = true;
+ break;
+ }
+
+ case nir_intrinsic_store_deref: {
+ nir_deref_instr *old_deref = nir_src_as_deref(intrin->src[0]);
+ if (old_deref->mode != nir_var_shader_out)
+ break;
+
+ nir_variable *old_var = nir_deref_instr_get_variable(old_deref);
+ if (old_var->data.location < VARYING_SLOT_VAR0)
+ break;
+
+ const unsigned loc = old_var->data.location - VARYING_SLOT_VAR0;
+ const unsigned old_frac = old_var->data.location_frac;
+ nir_variable *new_var = new_outputs[loc][old_frac];
+ if (!new_var)
+ break;
+
+ assert(new_var->data.location == VARYING_SLOT_VAR0 + loc);
+ const unsigned new_frac = new_var->data.location_frac;
+
+ b.cursor = nir_before_instr(&intrin->instr);
+
+ /* Rewrite the store to be a masked store to the new variable */
+ nir_deref_instr *new_deref =
+ build_array_deref_of_new_var(&b, new_var, old_deref);
+ assert(glsl_type_is_vector(new_deref->type));
+ nir_instr_rewrite_src(&intrin->instr, &intrin->src[0],
+ nir_src_for_ssa(&new_deref->dest.ssa));
+
+ intrin->num_components =
+ glsl_get_components(new_deref->type);
+
+ nir_component_mask_t old_wrmask = nir_intrinsic_write_mask(intrin);
+
+ assert(intrin->src[1].is_ssa);
+ nir_ssa_def *old_value = intrin->src[1].ssa;
+ nir_ssa_def *comps[4];
+ for (unsigned c = 0; c < intrin->num_components; c++) {
+ if (new_frac + c >= old_frac &&
+ (old_wrmask & 1 << (new_frac + c - old_frac))) {
+ comps[c] = nir_channel(&b, old_value,
+ new_frac + c - old_frac);
+ } else {
+ comps[c] = nir_ssa_undef(&b, old_value->num_components,
+ old_value->bit_size);
+ }
+ }
+ nir_ssa_def *new_value = nir_vec(&b, comps, intrin->num_components);
+ nir_instr_rewrite_src(&intrin->instr, &intrin->src[1],
+ nir_src_for_ssa(new_value));
+
+ nir_intrinsic_set_write_mask(intrin,
+ old_wrmask << (old_frac - new_frac));
+
+ progress = true;
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+ }
+
+ if (progress) {
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+ }
+
+ return progress;
+}
+
+bool
+nir_lower_io_to_vector(nir_shader *shader, nir_variable_mode modes)
+{
+ bool progress = false;
+
+ nir_foreach_function(function, shader) {
+ if (function->impl)
+ progress |= nir_lower_io_to_vector_impl(function->impl, modes);
+ }
+
+ return progress;
+}
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