diff options
| -rw-r--r-- | src/glsl/Makefile.sources | 1 | ||||
| -rw-r--r-- | src/glsl/nir/nir.h | 2 | ||||
| -rw-r--r-- | src/glsl/nir/nir_lower_outputs_to_temporaries.c | 127 |
3 files changed, 130 insertions, 0 deletions
diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources index 8f468e10ee3..da7fdf95902 100644 --- a/src/glsl/Makefile.sources +++ b/src/glsl/Makefile.sources @@ -40,6 +40,7 @@ NIR_FILES = \ nir/nir_lower_locals_to_regs.c \ nir/nir_lower_idiv.c \ nir/nir_lower_io.c \ + nir/nir_lower_outputs_to_temporaries.c \ nir/nir_lower_phis_to_scalar.c \ nir/nir_lower_samplers.cpp \ nir/nir_lower_system_values.c \ diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h index 2bcd18aabe5..2ba7731c1ff 100644 --- a/src/glsl/nir/nir.h +++ b/src/glsl/nir/nir.h @@ -1786,6 +1786,8 @@ void nir_lower_global_vars_to_local(nir_shader *shader); void nir_lower_locals_to_regs(nir_shader *shader); +void nir_lower_outputs_to_temporaries(nir_shader *shader); + void nir_assign_var_locations(struct exec_list *var_list, unsigned *size, int (*type_size)(const struct glsl_type *)); diff --git a/src/glsl/nir/nir_lower_outputs_to_temporaries.c b/src/glsl/nir/nir_lower_outputs_to_temporaries.c new file mode 100644 index 00000000000..b730cad0020 --- /dev/null +++ b/src/glsl/nir/nir_lower_outputs_to_temporaries.c @@ -0,0 +1,127 @@ +/* + * 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 variables to a temporary plus an + * output variable with a single copy at each exit point of the shader. + * This way the output variable is only ever written. + * + * Because valid NIR requires that output variables are never read, this + * pass is more of a helper for NIR producers and must be run before the + * shader is ever validated. + */ + +#include "nir.h" + +struct lower_outputs_state { + nir_shader *shader; + struct exec_list old_outputs; +}; + +static void +emit_output_copies(nir_cursor cursor, struct lower_outputs_state *state) +{ + assert(exec_list_length(&state->shader->outputs) == + exec_list_length(&state->old_outputs)); + + foreach_two_lists(out_node, &state->shader->outputs, + temp_node, &state->old_outputs) { + nir_variable *output = exec_node_data(nir_variable, out_node, node); + nir_variable *temp = exec_node_data(nir_variable, temp_node, node); + + nir_intrinsic_instr *copy = + nir_intrinsic_instr_create(state->shader, nir_intrinsic_copy_var); + copy->variables[0] = nir_deref_var_create(copy, output); + copy->variables[1] = nir_deref_var_create(copy, temp); + + nir_instr_insert(cursor, ©->instr); + } +} + +static bool +emit_output_copies_block(nir_block *block, void *state) +{ + nir_foreach_instr(block, instr) { + if (instr->type != nir_instr_type_intrinsic) + continue; + + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); + if (intrin->intrinsic == nir_intrinsic_emit_vertex) + emit_output_copies(nir_before_instr(&intrin->instr), state); + } + + return true; +} + +void +nir_lower_outputs_to_temporaries(nir_shader *shader) +{ + struct lower_outputs_state state; + + state.shader = shader; + exec_list_move_nodes_to(&shader->outputs, &state.old_outputs); + + /* Walk over all of the outputs turn each output into a temporary and + * make a new variable for the actual output. + */ + foreach_list_typed(nir_variable, var, node, &state.old_outputs) { + nir_variable *output = ralloc(shader, nir_variable); + memcpy(output, var, sizeof *output); + + /* The orignal is now the temporary */ + nir_variable *temp = var; + + /* Give the output a new name with @out-temp appended */ + temp->name = ralloc_asprintf(var, "%s@out-temp", output->name); + temp->data.mode = nir_var_global; + temp->constant_initializer = NULL; + + exec_list_push_tail(&shader->outputs, &output->node); + } + + nir_foreach_overload(shader, overload) { + if (overload->impl == NULL) + continue; + + if (shader->stage == MESA_SHADER_GEOMETRY) { + /* For geometry shaders, we have to emit the output copies right + * before each EmitVertex call. + */ + nir_foreach_block(overload->impl, emit_output_copies_block, &state); + } else if (strcmp(overload->function->name, "main") == 0) { + /* 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(overload->impl->end_block->predecessors, block_entry) { + struct nir_block *block = (void *)block_entry->key; + emit_output_copies(nir_after_block_before_jump(block), &state); + } + } + + nir_metadata_preserve(overload->impl, nir_metadata_block_index | + nir_metadata_dominance); + } + + exec_list_append(&shader->globals, &state.old_outputs); +} |