154 lines
4.6 KiB
C++
154 lines
4.6 KiB
C++
/*
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* Copyright © 2010 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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/**
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* \file ir_variable_refcount.cpp
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*
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* Provides a visitor which produces a list of variables referenced,
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* how many times they were referenced and assigned, and whether they
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* were defined in the scope.
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*/
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#include "ir.h"
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#include "ir_visitor.h"
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#include "ir_variable_refcount.h"
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#include "glsl_types.h"
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#include "util/hash_table.h"
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ir_variable_refcount_visitor::ir_variable_refcount_visitor()
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{
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this->mem_ctx = ralloc_context(NULL);
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this->ht = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
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_mesa_key_pointer_equal);
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}
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static void
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free_entry(struct hash_entry *entry)
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{
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ir_variable_refcount_entry *ivre = (ir_variable_refcount_entry *) entry->data;
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/* Free assignment list */
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exec_node *n;
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while ((n = ivre->assign_list.pop_head()) != NULL) {
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struct assignment_entry *assignment_entry =
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exec_node_data(struct assignment_entry, n, link);
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free(assignment_entry);
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}
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delete ivre;
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}
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ir_variable_refcount_visitor::~ir_variable_refcount_visitor()
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{
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ralloc_free(this->mem_ctx);
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_mesa_hash_table_destroy(this->ht, free_entry);
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}
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// constructor
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ir_variable_refcount_entry::ir_variable_refcount_entry(ir_variable *var)
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{
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this->var = var;
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assigned_count = 0;
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declaration = false;
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referenced_count = 0;
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}
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ir_variable_refcount_entry *
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ir_variable_refcount_visitor::get_variable_entry(ir_variable *var)
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{
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assert(var);
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struct hash_entry *e = _mesa_hash_table_search(this->ht, var);
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if (e)
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return (ir_variable_refcount_entry *)e->data;
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ir_variable_refcount_entry *entry = new ir_variable_refcount_entry(var);
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assert(entry->referenced_count == 0);
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_mesa_hash_table_insert(this->ht, var, entry);
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return entry;
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}
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ir_visitor_status
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ir_variable_refcount_visitor::visit(ir_variable *ir)
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{
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ir_variable_refcount_entry *entry = this->get_variable_entry(ir);
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if (entry)
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entry->declaration = true;
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return visit_continue;
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}
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ir_visitor_status
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ir_variable_refcount_visitor::visit(ir_dereference_variable *ir)
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{
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ir_variable *const var = ir->variable_referenced();
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ir_variable_refcount_entry *entry = this->get_variable_entry(var);
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if (entry)
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entry->referenced_count++;
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return visit_continue;
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}
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ir_visitor_status
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ir_variable_refcount_visitor::visit_enter(ir_function_signature *ir)
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{
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/* We don't want to descend into the function parameters and
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* dead-code eliminate them, so just accept the body here.
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*/
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visit_list_elements(this, &ir->body);
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return visit_continue_with_parent;
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}
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ir_visitor_status
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ir_variable_refcount_visitor::visit_leave(ir_assignment *ir)
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{
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ir_variable_refcount_entry *entry;
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entry = this->get_variable_entry(ir->lhs->variable_referenced());
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if (entry) {
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entry->assigned_count++;
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/* Build a list for dead code optimisation. Don't add assignment if it
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* was declared out of scope (outside the instruction stream). Also don't
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* bother adding any more to the list if there are more references than
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* assignments as this means the variable is used and won't be optimised
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* out.
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*/
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assert(entry->referenced_count >= entry->assigned_count);
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if (entry->referenced_count == entry->assigned_count) {
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struct assignment_entry *assignment_entry =
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(struct assignment_entry *)calloc(1, sizeof(*assignment_entry));
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assignment_entry->assign = ir;
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entry->assign_list.push_head(&assignment_entry->link);
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}
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}
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return visit_continue;
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}
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