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
38class ir_function_can_inline_visitor : public ir_hierarchical_visitor {
39public:
40   ir_function_can_inline_visitor()
41   {
42      this->num_returns = 0;
43   }
44
45   virtual ir_visitor_status visit_enter(ir_return *);
46
47   int num_returns;
48};
49
50ir_visitor_status
51ir_function_can_inline_visitor::visit_enter(ir_return *ir)
52{
53   (void) ir;
54   this->num_returns++;
55   return visit_continue;
56}
57
58bool
59can_inline(ir_call *call)
60{
61   ir_function_can_inline_visitor v;
62   const ir_function_signature *callee = call->callee;
63   if (!callee->is_defined)
64      return false;
65
66   v.run((exec_list *) &callee->body);
67
68   /* If the function is empty (no last instruction) or does not end with a
69    * return statement, we need to count the implicit return.
70    */
71   ir_instruction *last = (ir_instruction *)callee->body.get_tail();
72   if (last == NULL || !last->as_return())
73      v.num_returns++;
74
75   return v.num_returns == 1;
76}
77