workbench/libs/mesa/src/glsl/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 #include "ir.h"
  37 #include "ir_visitor.h"
  38 #include "ir_rvalue_visitor.h"
  39 #include "ir_expression_flattening.h"
  40 #include "glsl_types.h"
  41
  42 class ir_expression_flattening_visitor : public ir_rvalue_visitor {
  43 public:
  44    ir_expression_flattening_visitor(bool (*predicate)(ir_instruction *ir))
  45    {
  46       this->predicate = predicate;
  47    }
  48
  49    virtual ~ir_expression_flattening_visitor()
  50    {
  51       /* empty */
  52    }
  53
  54    void handle_rvalue(ir_rvalue **rvalue);
  55    bool (*predicate)(ir_instruction *ir);
  56 };
  57
  58 void
  59 do_expression_flattening(exec_list *instructions,
  60                          bool (*predicate)(ir_instruction *ir))
  61 {
  62    ir_expression_flattening_visitor v(predicate);
  63
  64    foreach_iter(exec_list_iterator, iter, *instructions) {
  65       ir_instruction *ir = (ir_instruction *)iter.get();
  66
  67       ir->accept(&v);
  68    }
  69 }
  70
  71 void
  72 ir_expression_flattening_visitor::handle_rvalue(ir_rvalue **rvalue)
  73 {
  74    ir_variable *var;
  75    ir_assignment *assign;
  76    ir_rvalue *ir = *rvalue;
  77
  78    if (!ir || !this->predicate(ir))
  79       return;
  80
  81    void *ctx = ralloc_parent(ir);
  82
  83    var = new(ctx) ir_variable(ir->type, "flattening_tmp", ir_var_temporary);
  84    base_ir->insert_before(var);
  85
  86    assign = new(ctx) ir_assignment(new(ctx) ir_dereference_variable(var),
  87                                    ir,
  88                                    NULL);
  89    base_ir->insert_before(assign);
  90
  91    *rvalue = new(ctx) ir_dereference_variable(var);
  92 }