mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
91 lines
3.9 KiB
C++
91 lines
3.9 KiB
C++
/*
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This file is part of solidity.
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solidity is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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solidity is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with solidity. If not, see <http://www.gnu.org/licenses/>.
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*/
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// SPDX-License-Identifier: GPL-3.0
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/**
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* @file SemanticInformation.h
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* @author Christian <c@ethdev.com>
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* @date 2015
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* Helper to provide semantic information about assembly items.
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*/
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#pragma once
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#include <libevmasm/Instruction.h>
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namespace solidity::evmasm
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{
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class AssemblyItem;
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/**
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* Helper functions to provide context-independent information about assembly items.
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*/
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struct SemanticInformation
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{
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/// Corresponds to the effect that a YUL-builtin has on a generic data location (storage, memory
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/// and other blockchain state).
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enum Effect
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{
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None,
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Read,
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Write
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};
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/// @returns true if the given items starts a new block for common subexpression analysis.
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/// @param _msizeImportant if false, consider an operation non-breaking if its only side-effect is that it modifies msize.
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static bool breaksCSEAnalysisBlock(AssemblyItem const& _item, bool _msizeImportant);
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/// @returns true if the item is a two-argument operation whose value does not depend on the
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/// order of its arguments.
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static bool isCommutativeOperation(AssemblyItem const& _item);
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static bool isDupInstruction(AssemblyItem const& _item);
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static bool isSwapInstruction(AssemblyItem const& _item);
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static bool isJumpInstruction(AssemblyItem const& _item);
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static bool altersControlFlow(AssemblyItem const& _item);
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static bool terminatesControlFlow(AssemblyItem const& _item);
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static bool terminatesControlFlow(Instruction _instruction);
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static bool reverts(AssemblyItem const& _item);
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static bool reverts(Instruction _instruction);
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/// @returns false if the value put on the stack by _item depends on anything else than
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/// the information in the current block header, memory, storage or stack.
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static bool isDeterministic(AssemblyItem const& _item);
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/// @returns true if the instruction can be moved or copied (together with its arguments)
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/// without altering the semantics. This means it cannot depend on storage or memory,
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/// cannot have any side-effects, but it can depend on a call-constant state of the blockchain.
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static bool movable(Instruction _instruction);
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/// If true, the expressions in this code can be moved or copied (together with their arguments)
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/// across control flow branches and instructions as long as these instructions' 'effects' do
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/// not influence the 'effects' of the aforementioned expressions.
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static bool movableApartFromEffects(Instruction _instruction);
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/// @returns true if the instruction can be removed without changing the semantics.
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/// This does not mean that it has to be deterministic or retrieve information from
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/// somewhere else than purely the values of its arguments.
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static bool canBeRemoved(Instruction _instruction);
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/// @returns true if the instruction can be removed without changing the semantics.
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/// This does not mean that it has to be deterministic or retrieve information from
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/// somewhere else than purely the values of its arguments.
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/// If true, the instruction is still allowed to influence the value returned by the
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/// msize instruction.
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static bool canBeRemovedIfNoMSize(Instruction _instruction);
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static Effect memory(Instruction _instruction);
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static Effect storage(Instruction _instruction);
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static Effect otherState(Instruction _instruction);
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static bool invalidInPureFunctions(Instruction _instruction);
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static bool invalidInViewFunctions(Instruction _instruction);
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};
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}
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