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
  30  * other than as the last instruction.  We could potentially work
  31  * around this for some constructs by flattening control flow and
  32  * moving the return to the end, or by using breaks from a do {} while
  33  * (0) loop surrounding the function body.
  34  */
  35
  36 #include "ir.h"
  37
  38 class ir_function_can_inline_visitor : public ir_hierarchical_visitor {
  39 public:
  40    ir_function_can_inline_visitor()
  41    {
  42       this->can_inline = true;
  43       this->num_returns = 0;
  44    }
  45
  46    virtual ir_visitor_status visit_enter(ir_loop *);
  47    virtual ir_visitor_status visit_enter(ir_return *);
  48    virtual ir_visitor_status visit_enter(ir_if *);
  49
  50    bool can_inline;
  51    int num_returns;
  52 };
  53
  54 ir_visitor_status
  55 ir_function_can_inline_visitor::visit_enter(ir_loop *ir)
  56 {
  57    /* FINISHME: Implement loop cloning in ir_function_inlining.cpp */
  58    (void) ir;
  59    this->can_inline = false;
  60    return visit_stop;
  61 }
  62
  63
  64 ir_visitor_status
  65 ir_function_can_inline_visitor::visit_enter(ir_return *ir)
  66 {
  67    (void) ir;
  68    this->num_returns++;
  69    return visit_continue;
  70 }
  71
  72
  73 ir_visitor_status
  74 ir_function_can_inline_visitor::visit_enter(ir_if *ir)
  75 {
  76    /* FINISHME: Implement if cloning in ir_function_inlining.cpp. */
  77    (void) ir;
  78    this->can_inline = false;
  79    return visit_stop;
  80 }
  81
  82 bool
  83 can_inline(ir_call *call)
  84 {
  85    ir_function_can_inline_visitor v;
  86    const ir_function_signature *callee = call->get_callee();
  87
  88    v.run((exec_list *) &callee->body);
  89
  90    ir_instruction *last = (ir_instruction *)callee->body.get_tail();
  91    if (last && !last->as_return())
  92       v.num_returns++;
  93
  94    return v.can_inline && v.num_returns == 1;
  95 }