1/*
2 * Copyright (C) 2015 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#if ENABLE(JIT)
29
30#include "ValueRecovery.h"
31#include "VirtualRegister.h"
32#include <wtf/Vector.h>
33
34namespace JSC {
35
36// A CachedRecovery is a wrapper around a ValueRecovery that records where said
37// value should go on the stack and/or in registers. Whenever we perform an
38// operation changing the ValueRecovery, we update the CachedRecovery's member
39// in place.
40class CachedRecovery {
41public:
42 CachedRecovery(ValueRecovery recovery)
43 : m_recovery { recovery }
44 {
45 }
46
47 CachedRecovery(CachedRecovery&) = delete;
48 CachedRecovery(CachedRecovery&&) = delete;
49 CachedRecovery& operator=(CachedRecovery&) = delete;
50 CachedRecovery& operator=(CachedRecovery&&) = delete;
51
52 const Vector<VirtualRegister, 1>& targets() const { return m_targets; }
53
54 void addTarget(VirtualRegister reg)
55 {
56 ASSERT(m_targets.isEmpty() || m_targets.last() < reg);
57 m_targets.append(reg);
58 }
59
60 void removeTarget(VirtualRegister reg)
61 {
62 ASSERT_UNUSED(reg, m_targets.last() == reg);
63 m_targets.shrink(m_targets.size() - 1);
64 }
65
66 void clearTargets()
67 {
68 m_targets.clear();
69 }
70
71 void setWantedJSValueRegs(JSValueRegs jsValueRegs)
72 {
73 ASSERT(m_wantedFPR == InvalidFPRReg);
74 m_wantedJSValueRegs = jsValueRegs;
75 }
76
77 void setWantedFPR(FPRReg fpr)
78 {
79 ASSERT(!m_wantedJSValueRegs);
80 m_wantedFPR = fpr;
81 }
82
83 // Determine whether converting this recovery into a JSValue will
84 // require additional GPRs and/or FPRs.
85 // This is guaranteed to only depend on the DataFormat, and the
86 // result of these calls will stay valid after loads and/or stores.
87 bool boxingRequiresGPR() const
88 {
89#if USE(JSVALUE64)
90 return recovery().dataFormat() == DataFormatDouble;
91#else
92 return false;
93#endif
94 }
95 bool boxingRequiresFPR() const
96 {
97#if USE(JSVALUE64)
98 switch (recovery().dataFormat()) {
99 case DataFormatInt52:
100 case DataFormatStrictInt52:
101 return true;
102
103 default:
104 return false;
105 }
106#else
107 return false;
108#endif
109 }
110
111 // This is used to determine what kind of register we need to be
112 // able to load a recovery. We only use it when a direct load is
113 // currently impossible, to determine whether we should spill a
114 // GPR or an FPR for loading this value.
115 bool loadsIntoGPR() const;
116 bool loadsIntoFPR() const;
117
118 ValueRecovery recovery() const { return m_recovery; }
119
120 void setRecovery(ValueRecovery recovery) { m_recovery = recovery; }
121
122 JSValueRegs wantedJSValueRegs() const { return m_wantedJSValueRegs; }
123
124 FPRReg wantedFPR() const { return m_wantedFPR; }
125private:
126 Vector<VirtualRegister, 1> m_targets;
127 ValueRecovery m_recovery;
128 JSValueRegs m_wantedJSValueRegs;
129 FPRReg m_wantedFPR { InvalidFPRReg };
130};
131
132} // namespace JSC
133
134#endif // ENABLE(JIT)
135