JavaScriptCore/assembler/MacroAssemblerCodeRef.h
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/assembler/MacroAssemblerCodeRef.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) 2009 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 MacroAssemblerCodeRef_h
+#define MacroAssemblerCodeRef_h
+
+#include "ExecutableAllocator.h"
+#include "PassRefPtr.h"
+#include "RefPtr.h"
+#include "UnusedParam.h"
+
+#if ENABLE(ASSEMBLER)
+
+// ASSERT_VALID_CODE_POINTER checks that ptr is a non-null pointer, and that it is a valid
+// instruction address on the platform (for example, check any alignment requirements).
+#if CPU(ARM_THUMB2)
+// ARM/thumb instructions must be 16-bit aligned, but all code pointers to be loaded
+// into the processor are decorated with the bottom bit set, indicating that this is
+// thumb code (as oposed to 32-bit traditional ARM).  The first test checks for both
+// decorated and undectorated null, and the second test ensures that the pointer is
+// decorated.
+#define ASSERT_VALID_CODE_POINTER(ptr) \
+    ASSERT(reinterpret_cast<intptr_t>(ptr) & ~1); \
+    ASSERT(reinterpret_cast<intptr_t>(ptr) & 1)
+#define ASSERT_VALID_CODE_OFFSET(offset) \
+    ASSERT(!(offset & 1)) // Must be multiple of 2.
+#else
+#define ASSERT_VALID_CODE_POINTER(ptr) \
+    ASSERT(ptr)
+#define ASSERT_VALID_CODE_OFFSET(offset) // Anything goes!
+#endif
+
+namespace JSC {
+
+// FunctionPtr:
+//
+// FunctionPtr should be used to wrap pointers to C/C++ functions in JSC
+// (particularly, the stub functions).
+class FunctionPtr {
+public:
+    FunctionPtr()
+        : m_value(0)
+    {
+    }
+
+    template<typename FunctionType>
+    explicit FunctionPtr(FunctionType* value)
+#if COMPILER(RVCT)
+     // RVTC compiler needs C-style cast as it fails with the following error
+     // Error:  #694: reinterpret_cast cannot cast away const or other type qualifiers
+        : m_value((void*)(value))
+#else
+        : m_value(reinterpret_cast<void*>(value))
+#endif
+    {
+        ASSERT_VALID_CODE_POINTER(m_value);
+    }
+
+    void* value() const { return m_value; }
+    void* executableAddress() const { return m_value; }
+
+
+private:
+    void* m_value;
+};
+
+// ReturnAddressPtr:
+//
+// ReturnAddressPtr should be used to wrap return addresses generated by processor
+// 'call' instructions exectued in JIT code.  We use return addresses to look up
+// exception and optimization information, and to repatch the call instruction
+// that is the source of the return address.
+class ReturnAddressPtr {
+public:
+    ReturnAddressPtr()
+        : m_value(0)
+    {
+    }
+
+    explicit ReturnAddressPtr(void* value)
+        : m_value(value)
+    {
+        ASSERT_VALID_CODE_POINTER(m_value);
+    }
+
+    explicit ReturnAddressPtr(FunctionPtr function)
+        : m_value(function.value())
+    {
+        ASSERT_VALID_CODE_POINTER(m_value);
+    }
+
+    void* value() const { return m_value; }
+
+private:
+    void* m_value;
+};
+
+// MacroAssemblerCodePtr:
+//
+// MacroAssemblerCodePtr should be used to wrap pointers to JIT generated code.
+class MacroAssemblerCodePtr {
+public:
+    MacroAssemblerCodePtr()
+        : m_value(0)
+    {
+    }
+
+    explicit MacroAssemblerCodePtr(void* value)
+#if CPU(ARM_THUMB2)
+        // Decorate the pointer as a thumb code pointer.
+        : m_value(reinterpret_cast<char*>(value) + 1)
+#else
+        : m_value(value)
+#endif
+    {
+        ASSERT_VALID_CODE_POINTER(m_value);
+    }
+
+    explicit MacroAssemblerCodePtr(ReturnAddressPtr ra)
+        : m_value(ra.value())
+    {
+        ASSERT_VALID_CODE_POINTER(m_value);
+    }
+
+    void* executableAddress() const { return m_value; }
+#if CPU(ARM_THUMB2)
+    // To use this pointer as a data address remove the decoration.
+    void* dataLocation() const { ASSERT_VALID_CODE_POINTER(m_value); return reinterpret_cast<char*>(m_value) - 1; }
+#else
+    void* dataLocation() const { ASSERT_VALID_CODE_POINTER(m_value); return m_value; }
+#endif
+
+    bool operator!()
+    {
+        return !m_value;
+    }
+
+private:
+    void* m_value;
+};
+
+// MacroAssemblerCodeRef:
+//
+// A reference to a section of JIT generated code.  A CodeRef consists of a
+// pointer to the code, and a ref pointer to the pool from within which it
+// was allocated.
+class MacroAssemblerCodeRef {
+public:
+    MacroAssemblerCodeRef()
+        : m_size(0)
+    {
+    }
+
+    MacroAssemblerCodeRef(void* code, PassRefPtr<ExecutablePool> executablePool, size_t size)
+        : m_code(code)
+        , m_executablePool(executablePool)
+        , m_size(size)
+    {
+    }
+
+    MacroAssemblerCodePtr m_code;
+    RefPtr<ExecutablePool> m_executablePool;
+    size_t m_size;
+};
+
+} // namespace JSC
+
+#endif // ENABLE(ASSEMBLER)
+
+#endif // MacroAssemblerCodeRef_h