ir_expression_flattening.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_expression_flattening.cpp
  26  *
  27  * Takes the leaves of expression trees and makes them dereferences of
  28  * assignments of the leaves to temporaries, according to a predicate.
  29  *
  30  * This is used for automatic function inlining, where we want to take
  31  * an expression containing a call and move the call out to its own
  32  * assignment so that we can inline it at the appropriate place in the
  33  * instruction stream.
  34  */
  35
  36 #define NULL 0
  37 #include "ir.h"
  38 #include "ir_visitor.h"
  39 #include "ir_expression_flattening.h"
  40 #include "glsl_types.h"
  41
  42 class ir_expression_flattening_visitor : public ir_visitor {
  43 public:
  44    ir_expression_flattening_visitor(ir_instruction *base_ir,
  45                                     bool (*predicate)(ir_instruction *ir))
  46    {
  47       this->base_ir = base_ir;
  48       this->predicate = predicate;
  49
  50       /* empty */
  51    }
  52
  53    virtual ~ir_expression_flattening_visitor()
  54    {
  55       /* empty */
  56    }
  57
  58    /**
  59     * \name Visit methods
  60     *
  61     * As typical for the visitor pattern, there must be one \c visit method for
  62     * each concrete subclass of \c ir_instruction.  Virtual base classes within
  63     * the hierarchy should not have \c visit methods.
  64     */
  65    /*@{*/
  66    virtual void visit(ir_variable *);
  67    virtual void visit(ir_loop *);
  68    virtual void visit(ir_loop_jump *);
  69    virtual void visit(ir_function_signature *);
  70    virtual void visit(ir_function *);
  71    virtual void visit(ir_expression *);
  72    virtual void visit(ir_swizzle *);
  73    virtual void visit(ir_dereference *);
  74    virtual void visit(ir_assignment *);
  75    virtual void visit(ir_constant *);
  76    virtual void visit(ir_call *);
  77    virtual void visit(ir_return *);
  78    virtual void visit(ir_if *);
  79    /*@}*/
  80
  81    bool (*predicate)(ir_instruction *ir);
  82    ir_instruction *base_ir;
  83 };
  84
  85 void
  86 do_expression_flattening(exec_list *instructions,
  87                          bool (*predicate)(ir_instruction *ir))
  88 {
  89    foreach_iter(exec_list_iterator, iter, *instructions) {
  90       ir_instruction *ir = (ir_instruction *)iter.get();
  91
  92       ir_expression_flattening_visitor v(ir, predicate);
  93       ir->accept(&v);
  94    }
  95 }
  96
  97 void
  98 ir_expression_flattening_visitor::visit(ir_variable *ir)
  99 {
 100    (void) ir;
 101 }
 102
 103 void
 104 ir_expression_flattening_visitor::visit(ir_loop *ir)
 105 {
 106    do_expression_flattening(&ir->body_instructions, this->predicate);
 107 }
 108
 109 void
 110 ir_expression_flattening_visitor::visit(ir_loop_jump *ir)
 111 {
 112    (void) ir;
 113 }
 114
 115
 116 void
 117 ir_expression_flattening_visitor::visit(ir_function_signature *ir)
 118 {
 119    do_expression_flattening(&ir->body, this->predicate);
 120 }
 121
 122 void
 123 ir_expression_flattening_visitor::visit(ir_function *ir)
 124 {
 125    (void) ir;
 126 }
 127
 128 void
 129 ir_expression_flattening_visitor::visit(ir_expression *ir)
 130 {
 131    unsigned int operand;
 132
 133    for (operand = 0; operand < ir->get_num_operands(); operand++) {
 134       ir->operands[operand]->accept(this);
 135
 136       /* If the operand matches the predicate, then we'll assign its
 137        * value to a temporary and deref the temporary as the operand.
 138        */
 139       if (this->predicate(ir->operands[operand])) {
 140          ir_variable *var;
 141          ir_assignment *assign;
 142
 143          var = new ir_variable(ir->operands[operand]->type, "flattening_tmp");
 144          this->base_ir->insert_before(var);
 145
 146          assign = new ir_assignment(new ir_dereference(var),
 147                                     ir->operands[operand],
 148                                     NULL);
 149          this->base_ir->insert_before(assign);
 150
 151          ir->operands[operand] = new ir_dereference(var);
 152       }
 153    }
 154 }
 155
 156
 157 void
 158 ir_expression_flattening_visitor::visit(ir_swizzle *ir)
 159 {
 160    ir->val->accept(this);
 161 }
 162
 163
 164 void
 165 ir_expression_flattening_visitor::visit(ir_dereference *ir)
 166 {
 167    if (ir->mode == ir_dereference::ir_reference_array) {
 168       ir->selector.array_index->accept(this);
 169    }
 170    ir->var->accept(this);
 171 }
 172
 173 void
 174 ir_expression_flattening_visitor::visit(ir_assignment *ir)
 175 {
 176    ir->rhs->accept(this);
 177 }
 178
 179
 180 void
 181 ir_expression_flattening_visitor::visit(ir_constant *ir)
 182 {
 183    (void) ir;
 184 }
 185
 186
 187 void
 188 ir_expression_flattening_visitor::visit(ir_call *ir)
 189 {
 190    (void) ir;
 191 }
 192
 193
 194 void
 195 ir_expression_flattening_visitor::visit(ir_return *ir)
 196 {
 197    (void) ir;
 198 }
 199
 200
 201 void
 202 ir_expression_flattening_visitor::visit(ir_if *ir)
 203 {
 204    ir->condition->accept(this);
 205
 206    do_expression_flattening(&ir->then_instructions, this->predicate);
 207    do_expression_flattening(&ir->else_instructions, this->predicate);
 208 }