Imported WebKit commit 8ff1f22783a32de82fee915abd55bd1b298f2644 (http://svn.webkit.org/repository/webkit/trunk@122325)

New snapshot that should work with the latest Qt build system changes

1 files changed, 161 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/jit/JITStubRoutine.h b/Source/JavaScriptCore/jit/JITStubRoutine.h
new file mode 100644
index 000000000..4400589ff
--- /dev/null
+++ b/Source/JavaScriptCore/jit/JITStubRoutine.h
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+/*
+ * Copyright (C) 2012 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 JITStubRoutine_h
+#define JITStubRoutine_h
+
+#include <wtf/Platform.h>
+
+#if ENABLE(JIT)
+
+#include "ExecutableAllocator.h"
+#include "MacroAssemblerCodeRef.h"
+#include <wtf/RefCounted.h>
+#include <wtf/Vector.h>
+
+namespace JSC {
+
+class JITStubRoutineSet;
+
+// This is a base-class for JIT stub routines, and also the class you want
+// to instantiate directly if you have a routine that does not need any
+// help from the GC. If in doubt, use one of the other stub routines. But
+// if you know for sure that the stub routine cannot be on the stack while
+// someone triggers a stub routine reset, then using this will speed up
+// memory reclamation. One case where a stub routine satisfies this
+// condition is if it doesn't make any calls, to either C++ or JS code. In
+// such a routine you know that it cannot be on the stack when anything
+// interesting happens.
+// See GCAwareJITStubRoutine.h for the other stub routines.
+class JITStubRoutine {
+    WTF_MAKE_NONCOPYABLE(JITStubRoutine);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    JITStubRoutine(const MacroAssemblerCodeRef& code)
+        : m_code(code)
+        , m_refCount(1)
+    {
+    }
+    
+    // Use this if you want to pass a CodePtr to someone who insists on taking
+    // a RefPtr<JITStubRoutine>.
+    static PassRefPtr<JITStubRoutine> createSelfManagedRoutine(
+        MacroAssemblerCodePtr rawCodePointer)
+    {
+        return adoptRef(new JITStubRoutine(MacroAssemblerCodeRef::createSelfManagedCodeRef(rawCodePointer)));
+    }
+    
+    virtual ~JITStubRoutine();
+    
+    // MacroAssemblerCodeRef is copyable, but at the cost of reference
+    // counting churn. Returning a reference is a good way of reducing
+    // the churn.
+    const MacroAssemblerCodeRef& code() const { return m_code; }
+    
+    static MacroAssemblerCodePtr asCodePtr(PassRefPtr<JITStubRoutine> stubRoutine)
+    {
+        if (!stubRoutine)
+            return MacroAssemblerCodePtr();
+        
+        MacroAssemblerCodePtr result = stubRoutine->code().code();
+        ASSERT(!!result);
+        return result;
+    }
+    
+    void ref()
+    {
+        m_refCount++;
+    }
+    
+    void deref()
+    {
+        if (--m_refCount)
+            return;
+        observeZeroRefCount();
+    }
+    
+    // Helpers for the GC to determine how to deal with marking JIT stub
+    // routines.
+    uintptr_t startAddress() const { return m_code.executableMemory()->startAsInteger(); }
+    uintptr_t endAddress() const { return m_code.executableMemory()->endAsInteger(); }
+    static uintptr_t addressStep() { return jitAllocationGranule; }
+    
+    static bool canPerformRangeFilter()
+    {
+#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
+        return true;
+#else
+        return false;
+#endif
+    }
+    static uintptr_t filteringStartAddress()
+    {
+#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
+        return startOfFixedExecutableMemoryPool;
+#else
+        UNREACHABLE_FOR_PLATFORM();
+        return 0;
+#endif
+    }
+    static size_t filteringExtentSize()
+    {
+#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
+        return fixedExecutableMemoryPoolSize;
+#else
+        UNREACHABLE_FOR_PLATFORM();
+        return 0;
+#endif
+    }
+    static bool passesFilter(uintptr_t address)
+    {
+        if (!canPerformRangeFilter()) {
+            // Just check that the address doesn't use any special values that would make
+            // our hashtables upset.
+            return address >= jitAllocationGranule && address != std::numeric_limits<uintptr_t>::max();
+        }
+        
+        if (address - filteringStartAddress() >= filteringExtentSize())
+            return false;
+        
+        return true;
+    }
+
+protected:
+    virtual void observeZeroRefCount();
+
+    MacroAssemblerCodeRef m_code;
+    unsigned m_refCount;
+};
+
+// Helper for the creation of simple stub routines that need no help from the GC.
+#define FINALIZE_CODE_FOR_STUB(patchBuffer, dataLogArguments) \
+    (adoptRef(new JITStubRoutine(FINALIZE_CODE((patchBuffer), dataLogArguments))))
+
+} // namespace JSC
+
+#endif // ENABLE(JIT)
+
+#endif // JITStubRoutine_h
+