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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
*
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* Copyright (C) 2009 Apple Inc. All rights reserved.
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#ifndef assembler_assembler_MacroAssemblerCodeRef_h
#define assembler_assembler_MacroAssemblerCodeRef_h
#include "assembler/wtf/Assertions.h"
#include "assembler/wtf/Platform.h"
#include "assembler/jit/ExecutableAllocator.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 WTF_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 WTF_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 WTF_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 WTF_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!() const
{
return !m_value;
}
ptrdiff_t operator -(const MacroAssemblerCodePtr &other) const
{
JS_ASSERT(m_value);
return reinterpret_cast<uint8_t *>(m_value) -
reinterpret_cast<uint8_t *>(other.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_executablePool(NULL),
m_size(0)
{
}
MacroAssemblerCodeRef(void* code, ExecutablePool* executablePool, size_t size)
: m_code(code)
, m_executablePool(executablePool)
, m_size(size)
{
}
// Release the code memory in this code ref.
void release()
{
if (!m_executablePool)
return;
#if defined DEBUG && (defined WTF_CPU_X86 || defined WTF_CPU_X86_64)
void *addr = m_code.executableAddress();
memset(addr, 0xcc, m_size);
#endif
m_executablePool->release();
m_executablePool = NULL;
}
MacroAssemblerCodePtr code() const {
return m_code;
}
size_t size() const {
return m_size;
}
MacroAssemblerCodePtr m_code;
ExecutablePool* m_executablePool;
size_t m_size;
};
} // namespace JSC
#endif // ENABLE(ASSEMBLER)
#endif /* assembler_assembler_MacroAssemblerCodeRef_h */