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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_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. }
  76.