webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

1 files changed, 134 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/jit/CachedRecovery.h b/Source/JavaScriptCore/jit/CachedRecovery.h
new file mode 100644
index 000000000..f627ac901
--- /dev/null
+++ b/Source/JavaScriptCore/jit/CachedRecovery.h
@@ -0,0 +1,134 @@
+/*
+ * 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. 
+ */
+
+#pragma once
+
+#if ENABLE(JIT)
+
+#include "ValueRecovery.h"
+#include "VirtualRegister.h"
+#include <wtf/Vector.h>
+
+namespace JSC {
+
+// A CachedRecovery is a wrapper around a ValueRecovery that records where said
+// value should go on the stack and/or in registers. Whenever we perform an
+// operation changing the ValueRecovery, we update the CachedRecovery's member
+// in place.
+class CachedRecovery {
+public:
+    CachedRecovery(ValueRecovery recovery)
+        : m_recovery { recovery }
+    {
+    }
+
+    CachedRecovery(CachedRecovery&) = delete;
+    CachedRecovery(CachedRecovery&&) = delete;
+    CachedRecovery& operator=(CachedRecovery&) = delete;
+    CachedRecovery& operator=(CachedRecovery&&) = delete;
+
+    const Vector<VirtualRegister, 1>& targets() const { return m_targets; }
+
+    void addTarget(VirtualRegister reg)
+    {
+        ASSERT(m_targets.isEmpty() || m_targets.last() < reg);
+        m_targets.append(reg);
+    }
+
+    void removeTarget(VirtualRegister reg)
+    {
+        ASSERT_UNUSED(reg, m_targets.last() == reg);
+        m_targets.shrink(m_targets.size() - 1);
+    }
+
+    void clearTargets()
+    {
+        m_targets.clear();
+    }
+
+    void setWantedJSValueRegs(JSValueRegs jsValueRegs)
+    {
+        ASSERT(m_wantedFPR == InvalidFPRReg);
+        m_wantedJSValueRegs = jsValueRegs;
+    }
+
+    void setWantedFPR(FPRReg fpr)
+    {
+        ASSERT(!m_wantedJSValueRegs);
+        m_wantedFPR = fpr;
+    }
+
+    // Determine whether converting this recovery into a JSValue will
+    // require additional GPRs and/or FPRs.
+    // This is guaranteed to only depend on the DataFormat, and the
+    // result of these calls will stay valid after loads and/or stores.
+    bool boxingRequiresGPR() const
+    {
+#if USE(JSVALUE64)
+        return recovery().dataFormat() == DataFormatDouble;
+#else
+        return false;
+#endif
+    }
+    bool boxingRequiresFPR() const
+    {
+#if USE(JSVALUE64)
+        switch (recovery().dataFormat()) {
+        case DataFormatInt52:
+        case DataFormatStrictInt52:
+            return true;
+
+        default:
+            return false;
+        }
+#else
+        return false;
+#endif
+    }
+    
+    // This is used to determine what kind of register we need to be
+    // able to load a recovery. We only use it when a direct load is
+    // currently impossible, to determine whether we should spill a
+    // GPR or an FPR for loading this value.
+    bool loadsIntoGPR() const;
+    bool loadsIntoFPR() const;
+
+    ValueRecovery recovery() const { return m_recovery; }
+
+    void setRecovery(ValueRecovery recovery) { m_recovery = recovery; }
+
+    JSValueRegs wantedJSValueRegs() const { return m_wantedJSValueRegs; }
+
+    FPRReg wantedFPR() const { return m_wantedFPR; }
+private:
+    ValueRecovery m_recovery;
+    JSValueRegs m_wantedJSValueRegs;
+    FPRReg m_wantedFPR { InvalidFPRReg };
+    Vector<VirtualRegister, 1> m_targets;
+};
+
+} // namespace JSC
+
+#endif // ENABLE(JIT)