+++ /dev/null
-/*
- * Copyright © 2010 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.
- */
-
-/**
- * \file opt_constant_variable.cpp
- *
- * Marks variables assigned a single constant value over the course
- * of the program as constant.
- *
- * The goal here is to trigger further constant folding and then dead
- * code elimination. This is common with vector/matrix constructors
- * and calls to builtin functions.
- */
-
-#include "ir.h"
-#include "ir_visitor.h"
-#include "ir_optimization.h"
-#include "compiler/glsl_types.h"
-#include "util/hash_table.h"
-
-namespace {
-
-struct assignment_entry {
- int assignment_count;
- ir_variable *var;
- ir_constant *constval;
- bool our_scope;
-};
-
-class ir_constant_variable_visitor : public ir_hierarchical_visitor {
-public:
- using ir_hierarchical_visitor::visit;
- using ir_hierarchical_visitor::visit_enter;
-
- virtual ir_visitor_status visit_enter(ir_dereference_variable *);
- virtual ir_visitor_status visit(ir_variable *);
- virtual ir_visitor_status visit_enter(ir_assignment *);
- virtual ir_visitor_status visit_enter(ir_call *);
-
- struct hash_table *ht;
-};
-
-} /* unnamed namespace */
-
-static struct assignment_entry *
-get_assignment_entry(ir_variable *var, struct hash_table *ht)
-{
- struct hash_entry *hte = _mesa_hash_table_search(ht, var);
- struct assignment_entry *entry;
-
- if (hte) {
- entry = (struct assignment_entry *) hte->data;
- } else {
- entry = (struct assignment_entry *) calloc(1, sizeof(*entry));
- entry->var = var;
- _mesa_hash_table_insert(ht, var, entry);
- }
-
- return entry;
-}
-
-ir_visitor_status
-ir_constant_variable_visitor::visit(ir_variable *ir)
-{
- struct assignment_entry *entry = get_assignment_entry(ir, this->ht);
- entry->our_scope = true;
- return visit_continue;
-}
-
-/* Skip derefs of variables so that we can detect declarations. */
-ir_visitor_status
-ir_constant_variable_visitor::visit_enter(ir_dereference_variable *ir)
-{
- (void)ir;
- return visit_continue_with_parent;
-}
-
-ir_visitor_status
-ir_constant_variable_visitor::visit_enter(ir_assignment *ir)
-{
- ir_constant *constval;
- struct assignment_entry *entry;
-
- entry = get_assignment_entry(ir->lhs->variable_referenced(), this->ht);
- assert(entry);
- entry->assignment_count++;
-
- /* If there's more than one assignment, don't bother - we won't do anything
- * with this variable anyway, and continuing just wastes memory cloning
- * constant expressions.
- */
- if (entry->assignment_count > 1)
- return visit_continue;
-
- /* If it's already constant, don't do the work. */
- if (entry->var->constant_value)
- return visit_continue;
-
- ir_variable *var = ir->whole_variable_written();
- if (!var)
- return visit_continue;
-
- /* Ignore buffer variables, since the underlying storage is shared
- * and we can't be sure that this variable won't be written by another
- * thread.
- */
- if (var->data.mode == ir_var_shader_storage ||
- var->data.mode == ir_var_shader_shared)
- return visit_continue;
-
- constval = ir->rhs->constant_expression_value(ralloc_parent(ir));
- if (!constval)
- return visit_continue;
-
- /* Mark this entry as having a constant assignment (if the
- * assignment count doesn't go >1). do_constant_variable will fix
- * up the variable with the constant value later.
- */
- entry->constval = constval;
-
- return visit_continue;
-}
-
-ir_visitor_status
-ir_constant_variable_visitor::visit_enter(ir_call *ir)
-{
- /* Mark any out parameters as assigned to */
- foreach_two_lists(formal_node, &ir->callee->parameters,
- actual_node, &ir->actual_parameters) {
- ir_rvalue *param_rval = (ir_rvalue *) actual_node;
- ir_variable *param = (ir_variable *) formal_node;
-
- if (param->data.mode == ir_var_function_out ||
- param->data.mode == ir_var_function_inout) {
- ir_variable *var = param_rval->variable_referenced();
- struct assignment_entry *entry;
-
- assert(var);
- entry = get_assignment_entry(var, this->ht);
- entry->assignment_count++;
- }
-
- /* We don't know if the variable passed to this function has been
- * assigned a value or if it is undefined, so for now we always assume
- * it has been assigned a value. Once functions have been inlined any
- * further potential optimisations will be taken care of.
- */
- struct assignment_entry *entry;
- entry = get_assignment_entry(param, this->ht);
- entry->assignment_count++;
- }
-
- /* Mark the return storage as having been assigned to */
- if (ir->return_deref != NULL) {
- ir_variable *var = ir->return_deref->variable_referenced();
- struct assignment_entry *entry;
-
- assert(var);
- entry = get_assignment_entry(var, this->ht);
- entry->assignment_count++;
- }
-
- return visit_continue;
-}
-
-/**
- * Does a copy propagation pass on the code present in the instruction stream.
- */
-bool
-do_constant_variable(exec_list *instructions)
-{
- bool progress = false;
- ir_constant_variable_visitor v;
-
- v.ht = _mesa_pointer_hash_table_create(NULL);
- v.run(instructions);
-
- hash_table_foreach(v.ht, hte) {
- struct assignment_entry *entry = (struct assignment_entry *) hte->data;
-
- if (entry->assignment_count == 1 && entry->constval && entry->our_scope) {
- entry->var->constant_value = entry->constval;
- progress = true;
- }
- hte->data = NULL;
- free(entry);
- }
- _mesa_hash_table_destroy(v.ht, NULL);
-
- return progress;
-}
-
-bool
-do_constant_variable_unlinked(exec_list *instructions)
-{
- bool progress = false;
-
- foreach_in_list(ir_instruction, ir, instructions) {
- ir_function *f = ir->as_function();
- if (f) {
- foreach_in_list(ir_function_signature, sig, &f->signatures) {
- if (do_constant_variable(&sig->body))
- progress = true;
- }
- }
- }
-
- return progress;
-}
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