src/compiler/glsl/ir_function_can_inline.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_function_can_inline.cpp
  26  *
  27  * Determines if we can inline a function call using ir_function_inlining.cpp.
  28  *
  29  * The primary restriction is that we can't return from the function other
  30  * than as the last instruction.  In lower_jumps.cpp, we can lower return
  31  * statements not at the end of the function to other control flow in order to
  32  * deal with this restriction.
  33  */
  34
  35 #include "ir.h"
  36
  37 class ir_function_can_inline_visitor : public ir_hierarchical_visitor {
  38 public:
  39    ir_function_can_inline_visitor()
  40    {
  41       this->num_returns = 0;
  42    }
  43
  44    virtual ir_visitor_status visit_enter(ir_return *);
  45
  46    int num_returns;
  47 };
  48
  49 ir_visitor_status
  50 ir_function_can_inline_visitor::visit_enter(ir_return *ir)
  51 {
  52    (void) ir;
  53    this->num_returns++;
  54    return visit_continue;
  55 }
  56
  57 bool
  58 can_inline(ir_call *call)
  59 {
  60    ir_function_can_inline_visitor v;
  61    const ir_function_signature *callee = call->callee;
  62    if (!callee->is_defined)
  63       return false;
  64
  65    v.run((exec_list *) &callee->body);
  66
  67    /* If the function is empty (no last instruction) or does not end with a
  68     * return statement, we need to count the implicit return.
  69     */
  70    ir_instruction *last = (ir_instruction *)callee->body.get_tail();
  71    if (last == NULL || !last->as_return())
  72       v.num_returns++;
  73
  74    return v.num_returns == 1;
  75 }