src/glsl/ir_variable_refcount.cpp

   1 /*
   2  * Copyright © 2010 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * \file ir_variable_refcount.cpp
  26  *
  27  * Provides a visitor which produces a list of variables referenced,
  28  * how many times they were referenced and assigned, and whether they
  29  * were defined in the scope.
  30  */
  31
  32 #include "ir.h"
  33 #include "ir_visitor.h"
  34 #include "ir_variable_refcount.h"
  35 #include "glsl_types.h"
  36
  37
  38 // constructor
  39 variable_entry::variable_entry(ir_variable *var)
  40 {
  41    this->var = var;
  42    assign = NULL;
  43    assigned_count = 0;
  44    declaration = false;
  45    referenced_count = 0;
  46 }
  47
  48
  49 variable_entry *
  50 ir_variable_refcount_visitor::get_variable_entry(ir_variable *var)
  51 {
  52    assert(var);
  53    foreach_iter(exec_list_iterator, iter, this->variable_list) {
  54       variable_entry *entry = (variable_entry *)iter.get();
  55       if (entry->var == var)
  56          return entry;
  57    }
  58
  59    variable_entry *entry = new(mem_ctx) variable_entry(var);
  60    assert(entry->referenced_count == 0);
  61    this->variable_list.push_tail(entry);
  62    return entry;
  63 }
  64
  65
  66 ir_visitor_status
  67 ir_variable_refcount_visitor::visit(ir_variable *ir)
  68 {
  69    variable_entry *entry = this->get_variable_entry(ir);
  70    if (entry)
  71       entry->declaration = true;
  72
  73    return visit_continue;
  74 }
  75
  76
  77 ir_visitor_status
  78 ir_variable_refcount_visitor::visit(ir_dereference_variable *ir)
  79 {
  80    ir_variable *const var = ir->variable_referenced();
  81    variable_entry *entry = this->get_variable_entry(var);
  82
  83    if (entry)
  84       entry->referenced_count++;
  85
  86    return visit_continue;
  87 }
  88
  89
  90 ir_visitor_status
  91 ir_variable_refcount_visitor::visit_enter(ir_function_signature *ir)
  92 {
  93    /* We don't want to descend into the function parameters and
  94     * dead-code eliminate them, so just accept the body here.
  95     */
  96    visit_list_elements(this, &ir->body);
  97    return visit_continue_with_parent;
  98 }
  99
 100
 101 ir_visitor_status
 102 ir_variable_refcount_visitor::visit_leave(ir_assignment *ir)
 103 {
 104    variable_entry *entry;
 105    entry = this->get_variable_entry(ir->lhs->variable_referenced());
 106    if (entry) {
 107       entry->assigned_count++;
 108       if (entry->assign == NULL)
 109          entry->assign = ir;
 110    }
 111
 112    return visit_continue;
 113 }