VTIL-Core/VTIL-Architecture/symex/memory.hpp
2020-08-21 00:55:43 +02:00

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// Copyright (c) 2020 Can Boluk and contributors of the VTIL Project
// 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.
// 3. Neither the name of VTIL Project nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER 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.
//
#pragma once
#include <vtil/utility>
#include <list>
#include "pointer.hpp"
#include "variable.hpp"
#include "../arch/register_desc.hpp"
namespace vtil::symbolic
{
struct memory
{
// Common typedefs.
//
using store_entry = std::pair<pointer, expression::reference>;
using store_type = std::list<store_entry>;
using fn_calc_distance = function_view<uncertain<bitcnt_t>( const pointer&, const pointer& )>;
static uncertain<bitcnt_t> bit_distance( const pointer& p1, const pointer& p2 )
{
// If pointer cannot overlap lookup, skip.
//
if ( !p1.can_overlap( p2 ) )
return uncertain_t::null;
// Calculate displacement and return.
//
std::optional byte_distance = p1 - p2;
return byte_distance ? uncertain{ math::narrow_cast<bitcnt_t>( *byte_distance * 8 ) } : uncertain_t::unknown;
}
// The memory state.
//
bool relaxed_aliasing;
store_type value_map;
// Default constructor, optionally takes a boolean to indicate relaxed aliasing.
//
memory( bool relaxed_aliasing = false )
: relaxed_aliasing( relaxed_aliasing ) {}
// Default copy/move.
//
memory( memory&& ) = default;
memory( const memory& ) = default;
memory& operator=( memory&& ) = default;
memory& operator=( const memory& ) = default;
// Wrap around the store type.
//
auto begin() { return value_map.begin(); }
auto end() { return value_map.end(); }
auto begin() const { return value_map.cbegin(); }
auto end() const { return value_map.cend(); }
size_t size() const { return value_map.size(); }
void reset() { value_map.clear(); }
// Returns the mask of known/unknown bits of the given region, if alias failure occurs returns nullopt.
//
std::optional<uint64_t> known_mask( const pointer& ptr, bitcnt_t size, fn_calc_distance distance = bit_distance ) const;
std::optional<uint64_t> unknown_mask( const pointer& ptr, bitcnt_t size, fn_calc_distance distance = bit_distance ) const;
// Reads N bits from the given pointer, returns null reference if alias failure occurs.
// - Will output the mask of bits contained in the state into contains if it does not fail.
//
expression::reference read( const pointer& ptr, bitcnt_t size, const il_const_iterator& reference_iterator = symbolic::free_form_iterator, uint64_t* contains = nullptr, fn_calc_distance distance = bit_distance ) const;
// Writes the given value to the pointer, returns null reference if alias failure occurs.
//
optional_reference<expression::reference> write( const pointer& ptr, deferred_value<expression::reference> value, bitcnt_t size, fn_calc_distance distance = bit_distance );
optional_reference<expression::reference> write( const pointer& ptr, expression::reference value, fn_calc_distance distance = bit_distance ) { return write( ptr, value, value.size(), std::move( distance ) ); }
};
};