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      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 ir_variable_refcount_entry::ir_variable_refcount_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 ir_variable_refcount_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       ir_variable_refcount_entry *entry = (ir_variable_refcount_entry *)iter.get();
     55       if (entry->var == var)
     56 	 return entry;
     57    }
     58 
     59    ir_variable_refcount_entry *entry = new(mem_ctx) ir_variable_refcount_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    ir_variable_refcount_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    ir_variable_refcount_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    ir_variable_refcount_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 }
    114