720d6bbcd8
c24f918e5 oaknut: 1.1.6 3a70cd40a oaknut: Run clang-format dc54784b8 oaknut: Add support for iOS memory protection. 14207278a oaknut: 1.1.5 841f9b693 oaknut: throw OaknutException instead of plain C string git-subtree-dir: externals/oaknut git-subtree-split: c24f918e52e629fc315c6e4bca4ea62def8b55e8
132 lines
3.9 KiB
C++
132 lines
3.9 KiB
C++
// SPDX-FileCopyrightText: Copyright (c) 2022 merryhime <https://mary.rs>
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// SPDX-License-Identifier: MIT
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#pragma once
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#include <cstddef>
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#include <cstdint>
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#include <variant>
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#include "oaknut/oaknut_exception.hpp"
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namespace oaknut {
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struct Label;
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namespace detail {
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constexpr std::uint64_t inverse_mask_from_size(std::size_t size)
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{
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return (~std::uint64_t{0}) << size;
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}
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constexpr std::uint64_t mask_from_size(std::size_t size)
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{
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return (~std::uint64_t{0}) >> (64 - size);
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}
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template<std::size_t bit_count>
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constexpr std::uint64_t sign_extend(std::uint64_t value)
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{
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static_assert(bit_count != 0, "cannot sign-extend zero-sized value");
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constexpr size_t shift_amount = 64 - bit_count;
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return static_cast<std::uint64_t>(static_cast<std::int64_t>(value << shift_amount) >> shift_amount);
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}
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} // namespace detail
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template<std::size_t bitsize, std::size_t alignment>
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struct AddrOffset {
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AddrOffset(std::ptrdiff_t diff)
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: m_payload(encode(diff))
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{}
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AddrOffset(Label& label)
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: m_payload(&label)
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{}
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AddrOffset(void* ptr)
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: m_payload(ptr)
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{}
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static std::uint32_t encode(std::ptrdiff_t diff)
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{
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const std::uint64_t diff_u64 = static_cast<std::uint64_t>(diff);
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if (detail::sign_extend<bitsize>(diff_u64) != diff_u64)
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throw OaknutException{ExceptionType::OffsetOutOfRange};
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if (diff_u64 != (diff_u64 & detail::inverse_mask_from_size(alignment)))
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throw OaknutException{ExceptionType::OffsetMisaligned};
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return static_cast<std::uint32_t>((diff_u64 & detail::mask_from_size(bitsize)) >> alignment);
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}
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private:
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template<typename Policy>
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friend class BasicCodeGenerator;
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std::variant<std::uint32_t, Label*, void*> m_payload;
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};
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template<std::size_t bitsize, std::size_t shift_amount>
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struct PageOffset {
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PageOffset(const void* ptr)
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: m_payload(ptr)
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{}
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PageOffset(Label& label)
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: m_payload(&label)
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{}
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static std::uint32_t encode(std::uintptr_t current_addr, std::uintptr_t target)
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{
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std::uint64_t diff = (static_cast<std::uint64_t>(target) >> shift_amount) - (static_cast<std::uint64_t>(current_addr) >> shift_amount);
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if (detail::sign_extend<bitsize>(diff) != diff)
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throw OaknutException{ExceptionType::OffsetOutOfRange};
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diff &= detail::mask_from_size(bitsize);
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return static_cast<std::uint32_t>(((diff & 3) << (bitsize - 2)) | (diff >> 2));
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}
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private:
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template<typename Policy>
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friend class BasicCodeGenerator;
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std::variant<Label*, const void*> m_payload;
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};
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template<std::size_t bitsize, std::size_t alignment>
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struct SOffset {
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SOffset(std::int64_t offset)
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{
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const std::uint64_t diff_u64 = static_cast<std::uint64_t>(offset);
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if (detail::sign_extend<bitsize>(diff_u64) != diff_u64)
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throw OaknutException{ExceptionType::OffsetOutOfRange};
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if (diff_u64 != (diff_u64 & detail::inverse_mask_from_size(alignment)))
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throw OaknutException{ExceptionType::OffsetMisaligned};
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m_encoded = static_cast<std::uint32_t>((diff_u64 & detail::mask_from_size(bitsize)) >> alignment);
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}
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private:
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template<typename Policy>
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friend class BasicCodeGenerator;
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std::uint32_t m_encoded;
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};
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template<std::size_t bitsize, std::size_t alignment>
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struct POffset {
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POffset(std::int64_t offset)
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{
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const std::uint64_t diff_u64 = static_cast<std::uint64_t>(offset);
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if (diff_u64 > detail::mask_from_size(bitsize))
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throw OaknutException{ExceptionType::OffsetOutOfRange};
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if (diff_u64 != (diff_u64 & detail::inverse_mask_from_size(alignment)))
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throw OaknutException{ExceptionType::OffsetMisaligned};
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m_encoded = static_cast<std::uint32_t>((diff_u64 & detail::mask_from_size(bitsize)) >> alignment);
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}
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private:
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template<typename Policy>
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friend class BasicCodeGenerator;
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std::uint32_t m_encoded;
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};
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} // namespace oaknut
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