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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file SemanticInformation.h
* @author Christian <c@ethdev.com>
* @date 2015
* Helper to provide semantic information about assembly items.
*/
#pragma once
#include <libevmasm/Instruction.h>
namespace dev
{
namespace eth
{
class AssemblyItem;
/**
* Helper functions to provide context-independent information about assembly items.
*/
struct SemanticInformation
{
/// @returns true if the given items starts a new block for common subexpression analysis.
/// @param _msizeImportant if false, consider an operation non-breaking if its only side-effect is that it modifies msize.
static bool breaksCSEAnalysisBlock(AssemblyItem const& _item, bool _msizeImportant);
/// @returns true if the item is a two-argument operation whose value does not depend on the
/// order of its arguments.
static bool isCommutativeOperation(AssemblyItem const& _item);
static bool isDupInstruction(AssemblyItem const& _item);
static bool isSwapInstruction(AssemblyItem const& _item);
static bool isJumpInstruction(AssemblyItem const& _item);
static bool altersControlFlow(AssemblyItem const& _item);
/// @returns false if the value put on the stack by _item depends on anything else than
/// the information in the current block header, memory, storage or stack.
static bool isDeterministic(AssemblyItem const& _item);
/// @returns true if the instruction can be moved or copied (together with its arguments)
/// without altering the semantics. This means it cannot depend on storage or memory,
/// cannot have any side-effects, but it can depend on a call-constant state of the blockchain.
static bool movable(solidity::Instruction _instruction);
/// @returns true if the given instruction modifies memory.
static bool invalidatesMemory(solidity::Instruction _instruction);
/// @returns true if the given instruction modifies storage (even indirectly).
static bool invalidatesStorage(solidity::Instruction _instruction);
static bool invalidInPureFunctions(solidity::Instruction _instruction);
static bool invalidInViewFunctions(solidity::Instruction _instruction);
};
}
}
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