1/*
2 * Copyright (C) 2016 Apple Inc. All rights reserved.
3 * Copyright (C) 2017 Yusuke Suzuki <[email protected]>.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include "Reg.h"
30#include <wtf/Variant.h>
31
32#if ENABLE(JIT)
33
34namespace JSC {
35
36// It is quite unfortunate that 32 bit environment exists on DFG! This means that JSValueRegs contains 2 registers
37// in such an environment. If we use GPRReg and FPRReg in SnippetParams, SnippetParams may contain
38// different number of registers in 32bit and 64bit environments when we pass JSValueRegs, it is confusing.
39// Therefore, we introduce an abstraction that SnippetReg, which is a polymorphic register class. It can refer FPRReg,
40// GPRReg, and "JSValueRegs". Note that isGPR() will return false if the target Reg is "JSValueRegs" even if the
41// environment is 64bit.
42//
43// FIXME: Eventually we should move this class into JSC and make is available for other JIT code.
44// https://bugs.webkit.org/show_bug.cgi?id=162990
45class SnippetReg {
46public:
47 enum class Type : uint8_t {
48 GPR = 0,
49 FPR = 1,
50 JSValue = 2,
51 };
52
53 SnippetReg(GPRReg reg)
54 : m_variant(reg)
55 {
56 }
57
58 SnippetReg(FPRReg reg)
59 : m_variant(reg)
60 {
61 }
62
63 SnippetReg(JSValueRegs regs)
64 : m_variant(regs)
65 {
66 }
67
68 bool isGPR() const { return m_variant.index() == static_cast<unsigned>(Type::GPR); }
69 bool isFPR() const { return m_variant.index() == static_cast<unsigned>(Type::FPR); }
70 bool isJSValueRegs() const { return m_variant.index() == static_cast<unsigned>(Type::JSValue); }
71
72 GPRReg gpr() const
73 {
74 ASSERT(isGPR());
75 return WTF::get<GPRReg>(m_variant);
76 }
77 FPRReg fpr() const
78 {
79 ASSERT(isFPR());
80 return WTF::get<FPRReg>(m_variant);
81 }
82 JSValueRegs jsValueRegs() const
83 {
84 ASSERT(isJSValueRegs());
85 return WTF::get<JSValueRegs>(m_variant);
86 }
87
88private:
89 Variant<GPRReg, FPRReg, JSValueRegs> m_variant;
90};
91
92}
93
94#endif
95