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
37class ir_function_can_inline_visitor : public ir_hierarchical_visitor {
38public:
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
49ir_visitor_status
50ir_function_can_inline_visitor::visit_enter(ir_return *ir)
51{
52   (void) ir;
53   this->num_returns++;
54   return visit_continue;
55}
56
57bool
58can_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