Merge WebKit at r82507: Initial merge by git

Change-Id: I60ce9d780725b58b45e54165733a8ffee23b683e

1 files changed, 249 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGGenerationInfo.h b/Source/JavaScriptCore/dfg/DFGGenerationInfo.h
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+++ b/Source/JavaScriptCore/dfg/DFGGenerationInfo.h
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+/*
+ * 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. ``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 DFGGenerationInfo_h
+#define DFGGenerationInfo_h
+
+#if ENABLE(DFG_JIT)
+
+#include <dfg/DFGJITCompiler.h>
+
+namespace JSC { namespace DFG {
+
+// === DataFormat ===
+//
+// This enum tracks the current representation in which a value is being held.
+// Values may be unboxed primitives (int32, double, or cell), or boxed as a JSValue.
+// For boxed values, we may know the type of boxing that has taken place.
+// (May also need bool, array, object, string types!)
+enum DataFormat {
+    DataFormatNone = 0,
+    DataFormatInteger = 1,
+    DataFormatDouble = 2,
+    DataFormatCell = 3,
+    DataFormatJS = 8,
+    DataFormatJSInteger = DataFormatJS | DataFormatInteger,
+    DataFormatJSDouble = DataFormatJS | DataFormatDouble,
+    DataFormatJSCell = DataFormatJS | DataFormatCell,
+};
+
+// === GenerationInfo ===
+//
+// This class is used to track the current status of a live values during code generation.
+// Can provide information as to whether a value is in machine registers, and if so which,
+// whether a value has been spilled to the RegsiterFile, and if so may be able to provide
+// details of the format in memory (all values are spilled in a boxed form, but we may be
+// able to track the type of box), and tracks how many outstanding uses of a value remain,
+// so that we know when the value is dead and the machine registers associated with it
+// may be released.
+class GenerationInfo {
+public:
+    GenerationInfo()
+        : m_nodeIndex(NoNode)
+        , m_useCount(0)
+        , m_registerFormat(DataFormatNone)
+        , m_spillFormat(DataFormatNone)
+        , m_canFill(false)
+    {
+    }
+
+    // Used to set the generation info according the the result
+    // of various operations.
+    void initArgument(NodeIndex nodeIndex, uint32_t useCount)
+    {
+        m_nodeIndex = nodeIndex;
+        m_useCount = useCount;
+        m_registerFormat = DataFormatNone;
+        m_spillFormat = DataFormatNone;
+        m_canFill = true;
+    }
+    void initConstant(NodeIndex nodeIndex, uint32_t useCount)
+    {
+        m_nodeIndex = nodeIndex;
+        m_useCount = useCount;
+        m_registerFormat = DataFormatNone;
+        m_spillFormat = DataFormatNone;
+        m_canFill = true;
+    }
+    void initInteger(NodeIndex nodeIndex, uint32_t useCount, GPRReg gpr)
+    {
+        m_nodeIndex = nodeIndex;
+        m_useCount = useCount;
+        m_registerFormat = DataFormatInteger;
+        m_spillFormat = DataFormatNone;
+        m_canFill = false;
+        u.gpr = gpr;
+    }
+    void initJSValue(NodeIndex nodeIndex, uint32_t useCount, GPRReg gpr, DataFormat format = DataFormatJS)
+    {
+        ASSERT(format & DataFormatJS);
+
+        m_nodeIndex = nodeIndex;
+        m_useCount = useCount;
+        m_registerFormat = format;
+        m_spillFormat = DataFormatNone;
+        m_canFill = false;
+        u.gpr = gpr;
+    }
+    void initCell(NodeIndex nodeIndex, uint32_t useCount, GPRReg gpr)
+    {
+        m_nodeIndex = nodeIndex;
+        m_useCount = useCount;
+        m_registerFormat = DataFormatCell;
+        m_spillFormat = DataFormatNone;
+        m_canFill = false;
+        u.gpr = gpr;
+    }
+    void initDouble(NodeIndex nodeIndex, uint32_t useCount, FPRReg fpr)
+    {
+        m_nodeIndex = nodeIndex;
+        m_useCount = useCount;
+        m_registerFormat = DataFormatDouble;
+        m_spillFormat = DataFormatNone;
+        m_canFill = false;
+        u.fpr = fpr;
+    }
+    void initNone(NodeIndex nodeIndex, uint32_t useCount)
+    {
+        m_nodeIndex = nodeIndex;
+        m_useCount = useCount;
+        m_registerFormat = DataFormatNone;
+        m_spillFormat = DataFormatNone;
+        m_canFill = false;
+    }
+
+    // Get the index of the node that produced this value.
+    NodeIndex nodeIndex() { return m_nodeIndex; }
+
+    // Mark the value as having been used (decrement the useCount).
+    // Returns true if this was the last use of the value, and any
+    // associated machine registers may be freed.
+    bool use()
+    {
+        return !--m_useCount;
+    }
+
+    // Used to check the operands of operations to see if they are on
+    // their last use; in some cases it may be safe to reuse the same
+    // machine register for the result of the operation.
+    bool canReuse()
+    {
+        ASSERT(m_useCount);
+        return m_useCount == 1;
+    }
+
+    // Get the format of the value in machine registers (or 'none').
+    DataFormat registerFormat() { return m_registerFormat; }
+    // Get the format of the value as it is spilled in the RegisterFile (or 'none').
+    DataFormat spillFormat() { return m_spillFormat; }
+
+    // Get the machine resister currently holding the value.
+    GPRReg gpr() { ASSERT(m_registerFormat && m_registerFormat != DataFormatDouble); return u.gpr; }
+    FPRReg fpr() { ASSERT(m_registerFormat == DataFormatDouble); return u.fpr; }
+
+    // Check whether a value needs spilling in order to free up any associated machine registers.
+    bool needsSpill()
+    {
+        // This should only be called on values that are currently in a register.
+        ASSERT(m_registerFormat != DataFormatNone);
+        // Constants and arguments do not need spilling, nor do values
+        // that have already been spilled to the RegisterFile.
+        return !m_canFill;
+    }
+
+    // Called when a VirtualRegister is being spilled †o the RegisterFile for the first time.
+    void spill(DataFormat spillFormat)
+    {
+        // We shouldn't be spill values that don't need spilling.
+        ASSERT(!m_canFill);
+        ASSERT(m_spillFormat == DataFormatNone);
+        // We should only be spilling values that are currently in machine registers.
+        ASSERT(m_registerFormat != DataFormatNone);
+        // We only spill values that have been boxed as a JSValue; otherwise the GC
+        // would need a way to distinguish cell pointers from numeric primitives.
+        ASSERT(spillFormat & DataFormatJS);
+
+        m_registerFormat = DataFormatNone;
+        m_spillFormat = spillFormat;
+        m_canFill = true;
+    }
+
+    // Called on values that don't need spilling (constants, arguments,
+    // values that have already been spilled), to mark them as no longer
+    // being in machine registers.
+    void setSpilled()
+    {
+        // Should only be called on values that don't need spilling, and are currently in registers.
+        ASSERT(m_canFill && m_registerFormat != DataFormatNone);
+        m_registerFormat = DataFormatNone;
+    }
+
+    // Record that this value is filled into machine registers,
+    // tracking which registers, and what format the value has.
+    void fillJSValue(GPRReg gpr, DataFormat format = DataFormatJS)
+    {
+        ASSERT(format & DataFormatJS);
+        m_registerFormat = format;
+        u.gpr = gpr;
+    }
+    void fillInteger(GPRReg gpr)
+    {
+        m_registerFormat = DataFormatInteger;
+        u.gpr = gpr;
+    }
+    void fillDouble(FPRReg fpr)
+    {
+        m_registerFormat = DataFormatDouble;
+        u.fpr = fpr;
+    }
+
+#ifndef NDEBUG
+    bool alive()
+    {
+        return m_useCount;
+    }
+#endif
+
+private:
+    // The index of the node whose result is stored in this virtual register.
+    // FIXME: Can we remove this? - this is currently only used when collecting
+    // snapshots of the RegisterBank for SpeculationCheck/EntryLocation. Could
+    // investigate storing NodeIndex as the name in RegsiterBank, instead of
+    // VirtualRegister.
+    NodeIndex m_nodeIndex;
+    uint32_t m_useCount;
+    DataFormat m_registerFormat;
+    DataFormat m_spillFormat;
+    bool m_canFill;
+    union {
+        GPRReg gpr;
+        FPRReg fpr;
+    } u;
+};
+
+} } // namespace JSC::DFG
+
+#endif
+#endif