1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
# Copyright (C) 2011 Apple Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
# THE POSSIBILITY OF SUCH DAMAGE.
require "config"
require "ast"
#
# "Optimization" passes. These are used to lower the representation for
# backends that cannot handle some of our higher-level instructions.
#
#
# A temporary - a variable that will be allocated to a register after we're
# done.
#
class Node
def replaceTemporariesWithRegisters(kind)
mapChildren {
| node |
node.replaceTemporariesWithRegisters(kind)
}
end
end
class Tmp < NoChildren
attr_reader :firstMention, :lastMention
attr_reader :kind
attr_accessor :register
def initialize(codeOrigin, kind)
super(codeOrigin)
@kind = kind
end
def dump
"$tmp#{object_id}"
end
def mention!(position)
if not @firstMention or position < @firstMention
@firstMention = position
end
if not @lastMention or position > @lastMention
@lastMention = position
end
end
def replaceTemporariesWithRegisters(kind)
if @kind == kind
raise "Did not allocate register to temporary at #{codeOriginString}" unless @register
@register
else
self
end
end
def address?
false
end
def label?
false
end
def immediate?
false
end
def register?
true
end
end
# Assign registers to temporaries, by finding which temporaries interfere
# with each other. Note that this relies on temporary live ranges not crossing
# basic block boundaries.
def assignRegistersToTemporaries(list, kind, registers)
list.each_with_index {
| node, index |
node.filter(Tmp).uniq.each {
| tmp |
if tmp.kind == kind
tmp.mention! index
end
}
}
freeRegisters = registers.dup
list.each_with_index {
| node, index |
tmpList = node.filter(Tmp).uniq
tmpList.each {
| tmp |
if tmp.kind == kind and tmp.firstMention == index
raise "Could not allocate register to temporary at #{node.codeOriginString}" if freeRegisters.empty?
tmp.register = freeRegisters.pop
end
}
tmpList.each {
| tmp |
if tmp.kind == kind and tmp.lastMention == index
freeRegisters.push tmp.register
raise "Register allocation inconsistency at #{node.codeOriginString}" if freeRegisters.size > registers.size
end
}
}
list.map {
| node |
node.replaceTemporariesWithRegisters(kind)
}
end
|
