JavaScriptCore-7601.1.46.3.tar.gz

[apple/javascriptcore.git] / runtime / VarOffset.h

diff --git a/runtime/VarOffset.h b/runtime/VarOffset.h
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+/*
+ * Copyright (C) 2015 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. 
+ */
+
+#ifndef VarOffset_h
+#define VarOffset_h
+
+#include "DirectArgumentsOffset.h"
+#include "ScopeOffset.h"
+#include "VirtualRegister.h"
+#include <wtf/HashMap.h>
+
+namespace JSC {
+
+enum class VarKind : uint8_t {
+    Invalid,
+    Scope,
+    Stack,
+    DirectArgument
+};
+
+class VarOffset {
+public:
+    VarOffset()
+        : m_kind(VarKind::Invalid)
+        , m_offset(UINT_MAX)
+    {
+    }
+    
+    VarOffset(WTF::HashTableDeletedValueType)
+        : m_kind(VarKind::Invalid)
+        , m_offset(0)
+    {
+    }
+    
+    explicit VarOffset(VirtualRegister stackOffset)
+    {
+        if (!stackOffset.isValid()) {
+            m_kind = VarKind::Invalid;
+            m_offset = UINT_MAX;
+        } else {
+            m_kind = VarKind::Stack;
+            m_offset = stackOffset.offset();
+        }
+    }
+    
+    explicit VarOffset(ScopeOffset scopeOffset)
+    {
+        if (!scopeOffset) {
+            m_kind = VarKind::Invalid;
+            m_offset = UINT_MAX;
+        } else {
+            m_kind = VarKind::Scope;
+            m_offset = scopeOffset.offset();
+        }
+    }
+    
+    explicit VarOffset(DirectArgumentsOffset capturedArgumentsOffset)
+    {
+        if (!capturedArgumentsOffset) {
+            m_kind = VarKind::Invalid;
+            m_offset = UINT_MAX;
+        } else {
+            m_kind = VarKind::DirectArgument;
+            m_offset = capturedArgumentsOffset.offset();
+        }
+    }
+    
+    static VarOffset assemble(VarKind kind, unsigned offset)
+    {
+        VarOffset result;
+        result.m_kind = kind;
+        result.m_offset = offset;
+        result.checkSanity();
+        return result;
+    }
+    
+    bool isValid() const
+    {
+        return m_kind != VarKind::Invalid;
+    }
+    
+    bool operator!() const
+    {
+        return !isValid();
+    }
+    
+    VarKind kind() const { return m_kind; }
+    
+    bool isStack() const
+    {
+        return m_kind == VarKind::Stack;
+    }
+    
+    bool isScope() const
+    {
+        return m_kind == VarKind::Scope;
+    }
+    
+    bool isDirectArgument() const
+    {
+        return m_kind == VarKind::DirectArgument;
+    }
+    
+    VirtualRegister stackOffsetUnchecked() const
+    {
+        if (!isStack())
+            return VirtualRegister();
+        return VirtualRegister(m_offset);
+    }
+    
+    ScopeOffset scopeOffsetUnchecked() const
+    {
+        if (!isScope())
+            return ScopeOffset();
+        return ScopeOffset(m_offset);
+    }
+    
+    DirectArgumentsOffset capturedArgumentsOffsetUnchecked() const
+    {
+        if (!isDirectArgument())
+            return DirectArgumentsOffset();
+        return DirectArgumentsOffset(m_offset);
+    }
+    
+    VirtualRegister stackOffset() const
+    {
+        ASSERT(isStack());
+        return VirtualRegister(m_offset);
+    }
+    
+    ScopeOffset scopeOffset() const
+    {
+        ASSERT(isScope());
+        return ScopeOffset(m_offset);
+    }
+    
+    DirectArgumentsOffset capturedArgumentsOffset() const
+    {
+        ASSERT(isDirectArgument());
+        return DirectArgumentsOffset(m_offset);
+    }
+    
+    unsigned rawOffset() const
+    {
+        ASSERT(isValid());
+        return m_offset;
+    }
+    
+    void checkSanity() const
+    {
+        if (ASSERT_DISABLED)
+            return;
+        
+        switch (m_kind) {
+        case VarKind::Invalid:
+            ASSERT(m_offset == UINT_MAX);
+            return;
+        case VarKind::Scope:
+            ASSERT(scopeOffset());
+            return;
+        case VarKind::Stack:
+            ASSERT(stackOffset().isValid());
+            return;
+        case VarKind::DirectArgument:
+            ASSERT(capturedArgumentsOffset());
+            return;
+        }
+        
+        ASSERT_NOT_REACHED();
+    }
+    
+    bool operator==(const VarOffset& other) const
+    {
+        return m_kind == other.m_kind
+            && m_offset == other.m_offset;
+    }
+    
+    bool operator!=(const VarOffset& other) const
+    {
+        return !(*this == other);
+    }
+    
+    unsigned hash() const
+    {
+        return WTF::IntHash<unsigned>::hash((static_cast<unsigned>(m_kind) << 20) + m_offset);
+    }
+    
+    bool isHashTableDeletedValue() const
+    {
+        return m_kind == VarKind::Invalid && !m_offset;
+    }
+    
+    void dump(PrintStream&) const;
+    
+private:
+    VarKind m_kind;
+    unsigned m_offset;
+};
+
+struct VarOffsetHash {
+    static unsigned hash(const VarOffset& key) { return key.hash(); }
+    static bool equal(const VarOffset& a, const VarOffset& b) { return a == b; }
+    static const bool safeToCompareToEmptyOrDeleted = true;
+};
+
+} // namespace JSC
+
+namespace WTF {
+
+void printInternal(PrintStream&, JSC::VarKind);
+
+template<typename T> struct DefaultHash;
+template<> struct DefaultHash<JSC::VarOffset> {
+    typedef JSC::VarOffsetHash Hash;
+};
+
+template<typename T> struct HashTraits;
+template<> struct HashTraits<JSC::VarOffset> : SimpleClassHashTraits<JSC::VarOffset> {
+    static const bool emptyValueIsZero = false;
+};
+
+} // namespace WTF
+
+#endif // VarOffset_h
+