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/*
* 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 <wtf/Platform.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
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