webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

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diff --git a/Source/JavaScriptCore/domjit/DOMJITReg.h b/Source/JavaScriptCore/domjit/DOMJITReg.h
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+++ b/Source/JavaScriptCore/domjit/DOMJITReg.h
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+/*
+ * Copyright (C) 2016 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. ``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
+ * 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.
+ */
+
+#pragma once
+
+#include "Reg.h"
+#include <wtf/Variant.h>
+
+#if ENABLE(JIT)
+
+namespace JSC { namespace DOMJIT {
+
+// It is quite unfortunate that 32 bit environment exists on DFG! This means that JSValueRegs contains 2 registers
+// in such an environment. If we use GPRReg and FPRReg in DOMJITPatchpointParams, DOMJITPatchpointParams may contain
+// different number of registers in 32bit and 64bit environments when we pass JSValueRegs, it is confusing.
+// Therefore, we introduce an abstraction that DOMJIT::Reg, which is a polymorphic register class. It can refer FPRReg,
+// GPRReg, and "JSValueRegs". Note that isGPR() will return false if the target Reg is "JSValueRegs" even if the
+// environment is 64bit.
+//
+// FIXME: Eventually we should move this class into JSC and make is available for other JIT code.
+// https://bugs.webkit.org/show_bug.cgi?id=162990
+class Reg {
+public:
+    enum class Type : uint8_t {
+        GPR = 0,
+        FPR = 1,
+        JSValue = 2,
+    };
+
+    Reg(GPRReg reg)
+        : m_variant(reg)
+    {
+    }
+
+    Reg(FPRReg reg)
+        : m_variant(reg)
+    {
+    }
+
+    Reg(JSValueRegs regs)
+        : m_variant(regs)
+    {
+    }
+
+    bool isGPR() const { return m_variant.index() == static_cast<unsigned>(Type::GPR); }
+    bool isFPR() const { return m_variant.index() == static_cast<unsigned>(Type::FPR); }
+    bool isJSValueRegs() const { return m_variant.index() == static_cast<unsigned>(Type::JSValue); }
+
+    GPRReg gpr() const
+    {
+        ASSERT(isGPR());
+        return WTF::get<GPRReg>(m_variant);
+    }
+    FPRReg fpr() const
+    {
+        ASSERT(isFPR());
+        return WTF::get<FPRReg>(m_variant);
+    }
+    JSValueRegs jsValueRegs() const
+    {
+        ASSERT(isJSValueRegs());
+        return WTF::get<JSValueRegs>(m_variant);
+    }
+
+private:
+    Variant<GPRReg, FPRReg, JSValueRegs> m_variant;
+};
+
+} }
+
+#endif