| /* |
| * Copyright © 2015 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. |
| */ |
| |
| /* |
| * Implements a pass that lowers output and/or input variables to a |
| * temporary plus an output variable with a single copy at each exit |
| * point of the shader and/or an input variable with a single copy |
| * at the entrance point of the shader. This way the output variable |
| * is only ever written once and/or input is only read once, and there |
| * are no indirect outut/input accesses. |
| */ |
| |
| #include "nir.h" |
| |
| struct lower_io_state { |
| nir_shader *shader; |
| nir_function *entrypoint; |
| struct exec_list old_outputs; |
| struct exec_list old_inputs; |
| }; |
| |
| static void |
| emit_copies(nir_cursor cursor, nir_shader *shader, struct exec_list *new_vars, |
| struct exec_list *old_vars) |
| { |
| assert(exec_list_length(new_vars) == exec_list_length(old_vars)); |
| |
| foreach_two_lists(new_node, new_vars, old_node, old_vars) { |
| nir_variable *newv = exec_node_data(nir_variable, new_node, node); |
| nir_variable *temp = exec_node_data(nir_variable, old_node, node); |
| |
| nir_intrinsic_instr *copy = |
| nir_intrinsic_instr_create(shader, nir_intrinsic_copy_var); |
| copy->variables[0] = nir_deref_var_create(copy, newv); |
| copy->variables[1] = nir_deref_var_create(copy, temp); |
| |
| nir_instr_insert(cursor, ©->instr); |
| } |
| } |
| |
| static void |
| emit_output_copies_impl(struct lower_io_state *state, nir_function_impl *impl) |
| { |
| if (state->shader->stage == MESA_SHADER_GEOMETRY) { |
| /* For geometry shaders, we have to emit the output copies right |
| * before each EmitVertex call. |
| */ |
| nir_foreach_block(block, impl) { |
| nir_foreach_instr(instr, block) { |
| if (instr->type != nir_instr_type_intrinsic) |
| continue; |
| |
| nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); |
| if (intrin->intrinsic == nir_intrinsic_emit_vertex) { |
| nir_cursor cursor = nir_before_instr(&intrin->instr); |
| emit_copies(cursor, state->shader, &state->shader->outputs, |
| &state->old_outputs); |
| } |
| } |
| } |
| } else if (impl->function == state->entrypoint) { |
| /* For all other shader types, we need to do the copies right before |
| * the jumps to the end block. |
| */ |
| struct set_entry *block_entry; |
| set_foreach(impl->end_block->predecessors, block_entry) { |
| struct nir_block *block = (void *)block_entry->key; |
| nir_cursor cursor = nir_after_block_before_jump(block); |
| emit_copies(cursor, state->shader, &state->shader->outputs, |
| &state->old_outputs); |
| } |
| } |
| } |
| |
| static void |
| emit_input_copies_impl(struct lower_io_state *state, nir_function_impl *impl) |
| { |
| if (impl->function == state->entrypoint) { |
| nir_cursor cursor = nir_before_block(nir_start_block(impl)); |
| emit_copies(cursor, state->shader, &state->old_inputs, |
| &state->shader->inputs); |
| } |
| } |
| |
| static nir_variable * |
| create_shadow_temp(struct lower_io_state *state, nir_variable *var) |
| { |
| nir_variable *nvar = ralloc(state->shader, nir_variable); |
| memcpy(nvar, var, sizeof *nvar); |
| |
| /* The original is now the temporary */ |
| nir_variable *temp = var; |
| |
| /* Reparent the name to the new variable */ |
| ralloc_steal(nvar, nvar->name); |
| |
| /* Reparent the constant initializer (if any) */ |
| ralloc_steal(nvar, nvar->constant_initializer); |
| |
| /* Give the original a new name with @<mode>-temp appended */ |
| const char *mode = (temp->data.mode == nir_var_shader_in) ? "in" : "out"; |
| temp->name = ralloc_asprintf(var, "%s@%s-temp", mode, nvar->name); |
| temp->data.mode = nir_var_global; |
| temp->constant_initializer = NULL; |
| |
| return nvar; |
| } |
| |
| void |
| nir_lower_io_to_temporaries(nir_shader *shader, nir_function *entrypoint, |
| bool outputs, bool inputs) |
| { |
| struct lower_io_state state; |
| |
| if (shader->stage == MESA_SHADER_TESS_CTRL) |
| return; |
| |
| state.shader = shader; |
| state.entrypoint = entrypoint; |
| |
| if (inputs) |
| exec_list_move_nodes_to(&shader->inputs, &state.old_inputs); |
| else |
| exec_list_make_empty(&state.old_inputs); |
| |
| if (outputs) |
| exec_list_move_nodes_to(&shader->outputs, &state.old_outputs); |
| else |
| exec_list_make_empty(&state.old_outputs); |
| |
| /* Walk over all of the outputs turn each output into a temporary and |
| * make a new variable for the actual output. |
| */ |
| nir_foreach_variable(var, &state.old_outputs) { |
| nir_variable *output = create_shadow_temp(&state, var); |
| exec_list_push_tail(&shader->outputs, &output->node); |
| } |
| |
| /* and same for inputs: */ |
| nir_foreach_variable(var, &state.old_inputs) { |
| nir_variable *input = create_shadow_temp(&state, var); |
| exec_list_push_tail(&shader->inputs, &input->node); |
| } |
| |
| nir_foreach_function(function, shader) { |
| if (function->impl == NULL) |
| continue; |
| |
| if (inputs) |
| emit_input_copies_impl(&state, function->impl); |
| |
| if (outputs) |
| emit_output_copies_impl(&state, function->impl); |
| |
| nir_metadata_preserve(function->impl, nir_metadata_block_index | |
| nir_metadata_dominance); |
| } |
| |
| exec_list_append(&shader->globals, &state.old_inputs); |
| exec_list_append(&shader->globals, &state.old_outputs); |
| } |