Files
dynarmic/src/dynarmic/backend/x64/devirtualize.h
2022-04-19 18:05:04 +01:00

82 lines
2.4 KiB
C++

/* This file is part of the dynarmic project.
* Copyright (c) 2018 MerryMage
* SPDX-License-Identifier: 0BSD
*/
#pragma once
#include <cstring>
#include <utility>
#include <mcl/bit_cast.hpp>
#include <mcl/stdint.hpp>
#include <mcl/type_traits/function_info.hpp>
#include "dynarmic/backend/x64/callback.h"
namespace Dynarmic {
namespace Backend::X64 {
namespace impl {
template<typename FunctionType, FunctionType mfp>
struct ThunkBuilder;
template<typename C, typename R, typename... Args, R (C::*mfp)(Args...)>
struct ThunkBuilder<R (C::*)(Args...), mfp> {
static R Thunk(C* this_, Args... args) {
return (this_->*mfp)(std::forward<Args>(args)...);
}
};
} // namespace impl
template<auto mfp>
ArgCallback DevirtualizeGeneric(mcl::class_type<decltype(mfp)>* this_) {
return ArgCallback{&impl::ThunkBuilder<decltype(mfp), mfp>::Thunk, reinterpret_cast<u64>(this_)};
}
template<auto mfp>
ArgCallback DevirtualizeWindows(mcl::class_type<decltype(mfp)>* this_) {
static_assert(sizeof(mfp) == 8);
return ArgCallback{mcl::bit_cast<u64>(mfp), reinterpret_cast<u64>(this_)};
}
template<auto mfp>
ArgCallback DevirtualizeItanium(mcl::class_type<decltype(mfp)>* this_) {
struct MemberFunctionPointer {
/// For a non-virtual function, this is a simple function pointer.
/// For a virtual function, it is (1 + virtual table offset in bytes).
u64 ptr;
/// The required adjustment to `this`, prior to the call.
u64 adj;
} mfp_struct = mcl::bit_cast<MemberFunctionPointer>(mfp);
static_assert(sizeof(MemberFunctionPointer) == 16);
static_assert(sizeof(MemberFunctionPointer) == sizeof(mfp));
u64 fn_ptr = mfp_struct.ptr;
u64 this_ptr = reinterpret_cast<u64>(this_) + mfp_struct.adj;
if (mfp_struct.ptr & 1) {
u64 vtable = mcl::bit_cast_pointee<u64>(this_ptr);
fn_ptr = mcl::bit_cast_pointee<u64>(vtable + fn_ptr - 1);
}
return ArgCallback{fn_ptr, this_ptr};
}
template<auto mfp>
ArgCallback Devirtualize(mcl::class_type<decltype(mfp)>* this_) {
#if defined(__APPLE__) || defined(linux) || defined(__linux) || defined(__linux__)
return DevirtualizeItanium<mfp>(this_);
#elif defined(__MINGW64__)
return DevirtualizeItanium<mfp>(this_);
#elif defined(_WIN32)
return DevirtualizeWindows<mfp>(this_);
#else
return DevirtualizeGeneric<mfp>(this_);
#endif
}
} // namespace Backend::X64
} // namespace Dynarmic