mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
401 lines
10 KiB
C++
401 lines
10 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.cpp
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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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#include <libevmasm/SemanticInformation.h>
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#include <libevmasm/AssemblyItem.h>
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using namespace std;
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using namespace solidity;
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using namespace solidity::evmasm;
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bool SemanticInformation::breaksCSEAnalysisBlock(AssemblyItem const& _item, bool _msizeImportant)
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{
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switch (_item.type())
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{
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default:
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case UndefinedItem:
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case Tag:
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case PushDeployTimeAddress:
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case AssignImmutable:
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case VerbatimBytecode:
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return true;
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case Push:
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case PushString:
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case PushTag:
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case PushSub:
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case PushSubSize:
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case PushProgramSize:
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case PushData:
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case PushLibraryAddress:
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case PushImmutable:
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return false;
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case Operation:
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{
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if (isSwapInstruction(_item) || isDupInstruction(_item))
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return false;
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if (_item.instruction() == Instruction::GAS || _item.instruction() == Instruction::PC)
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return true; // GAS and PC assume a specific order of opcodes
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if (_item.instruction() == Instruction::MSIZE)
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return true; // msize is modified already by memory access, avoid that for now
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InstructionInfo info = instructionInfo(_item.instruction());
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if (_item.instruction() == Instruction::SSTORE)
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return false;
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if (_item.instruction() == Instruction::MSTORE)
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return false;
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if (!_msizeImportant && (
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_item.instruction() == Instruction::MLOAD ||
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_item.instruction() == Instruction::KECCAK256
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))
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return false;
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//@todo: We do not handle the following memory instructions for now:
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// calldatacopy, codecopy, extcodecopy, mstore8,
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// msize (note that msize also depends on memory read access)
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// the second requirement will be lifted once it is implemented
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return info.sideEffects || info.args > 2;
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}
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}
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}
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bool SemanticInformation::isCommutativeOperation(AssemblyItem const& _item)
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{
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if (_item.type() != Operation)
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return false;
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switch (_item.instruction())
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{
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case Instruction::ADD:
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case Instruction::MUL:
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case Instruction::EQ:
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case Instruction::AND:
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case Instruction::OR:
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case Instruction::XOR:
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return true;
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default:
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return false;
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}
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}
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bool SemanticInformation::isDupInstruction(AssemblyItem const& _item)
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{
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if (_item.type() != Operation)
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return false;
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return evmasm::isDupInstruction(_item.instruction());
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}
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bool SemanticInformation::isSwapInstruction(AssemblyItem const& _item)
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{
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if (_item.type() != Operation)
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return false;
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return evmasm::isSwapInstruction(_item.instruction());
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}
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bool SemanticInformation::isJumpInstruction(AssemblyItem const& _item)
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{
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return _item == Instruction::JUMP || _item == Instruction::JUMPI;
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}
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bool SemanticInformation::altersControlFlow(AssemblyItem const& _item)
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{
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if (_item.type() != Operation)
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return false;
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switch (_item.instruction())
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{
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// note that CALL, CALLCODE and CREATE do not really alter the control flow, because we
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// continue on the next instruction
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case Instruction::JUMP:
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case Instruction::JUMPI:
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case Instruction::RETURN:
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case Instruction::SELFDESTRUCT:
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case Instruction::STOP:
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case Instruction::INVALID:
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case Instruction::REVERT:
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return true;
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default:
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return false;
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}
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}
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bool SemanticInformation::terminatesControlFlow(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::RETURN:
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case Instruction::SELFDESTRUCT:
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case Instruction::STOP:
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case Instruction::INVALID:
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case Instruction::REVERT:
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return true;
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default:
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return false;
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}
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}
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bool SemanticInformation::reverts(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::INVALID:
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case Instruction::REVERT:
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return true;
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default:
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return false;
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}
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}
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bool SemanticInformation::isDeterministic(AssemblyItem const& _item)
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{
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assertThrow(_item.type() != VerbatimBytecode, AssemblyException, "");
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if (_item.type() != Operation)
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return true;
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switch (_item.instruction())
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{
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case Instruction::CALL:
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case Instruction::CALLCODE:
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case Instruction::DELEGATECALL:
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case Instruction::STATICCALL:
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case Instruction::CREATE:
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case Instruction::CREATE2:
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case Instruction::GAS:
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case Instruction::PC:
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case Instruction::MSIZE: // depends on previous writes and reads, not only on content
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case Instruction::BALANCE: // depends on previous calls
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case Instruction::SELFBALANCE: // depends on previous calls
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case Instruction::EXTCODESIZE:
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case Instruction::EXTCODEHASH:
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case Instruction::RETURNDATACOPY: // depends on previous calls
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case Instruction::RETURNDATASIZE:
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return false;
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default:
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return true;
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}
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}
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bool SemanticInformation::movable(Instruction _instruction)
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{
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// These are not really functional.
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if (isDupInstruction(_instruction) || isSwapInstruction(_instruction))
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return false;
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InstructionInfo info = instructionInfo(_instruction);
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if (info.sideEffects)
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return false;
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switch (_instruction)
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{
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case Instruction::KECCAK256:
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case Instruction::BALANCE:
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case Instruction::SELFBALANCE:
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case Instruction::EXTCODESIZE:
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case Instruction::EXTCODEHASH:
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case Instruction::RETURNDATASIZE:
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case Instruction::SLOAD:
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case Instruction::PC:
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case Instruction::MSIZE:
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case Instruction::GAS:
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return false;
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default:
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return true;
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}
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return true;
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}
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bool SemanticInformation::canBeRemoved(Instruction _instruction)
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{
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// These are not really functional.
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assertThrow(!isDupInstruction(_instruction) && !isSwapInstruction(_instruction), AssemblyException, "");
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return !instructionInfo(_instruction).sideEffects;
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}
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bool SemanticInformation::canBeRemovedIfNoMSize(Instruction _instruction)
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{
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if (_instruction == Instruction::KECCAK256 || _instruction == Instruction::MLOAD)
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return true;
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else
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return canBeRemoved(_instruction);
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}
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SemanticInformation::Effect SemanticInformation::memory(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::CALLDATACOPY:
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case Instruction::CODECOPY:
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case Instruction::EXTCODECOPY:
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case Instruction::RETURNDATACOPY:
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case Instruction::MSTORE:
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case Instruction::MSTORE8:
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case Instruction::CALL:
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case Instruction::CALLCODE:
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case Instruction::DELEGATECALL:
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case Instruction::STATICCALL:
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return SemanticInformation::Write;
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case Instruction::CREATE:
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case Instruction::CREATE2:
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case Instruction::KECCAK256:
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case Instruction::MLOAD:
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case Instruction::MSIZE:
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case Instruction::RETURN:
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case Instruction::REVERT:
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case Instruction::LOG0:
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case Instruction::LOG1:
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case Instruction::LOG2:
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case Instruction::LOG3:
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case Instruction::LOG4:
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return SemanticInformation::Read;
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default:
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return SemanticInformation::None;
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}
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}
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bool SemanticInformation::movableApartFromEffects(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::EXTCODEHASH:
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case Instruction::EXTCODESIZE:
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case Instruction::RETURNDATASIZE:
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case Instruction::BALANCE:
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case Instruction::SELFBALANCE:
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case Instruction::SLOAD:
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case Instruction::KECCAK256:
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case Instruction::MLOAD:
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return true;
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default:
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return movable(_instruction);
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}
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}
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SemanticInformation::Effect SemanticInformation::storage(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::CALL:
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case Instruction::CALLCODE:
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case Instruction::DELEGATECALL:
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case Instruction::CREATE:
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case Instruction::CREATE2:
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case Instruction::SSTORE:
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return SemanticInformation::Write;
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case Instruction::SLOAD:
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case Instruction::STATICCALL:
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return SemanticInformation::Read;
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default:
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return SemanticInformation::None;
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}
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}
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SemanticInformation::Effect SemanticInformation::otherState(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::CALL:
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case Instruction::CALLCODE:
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case Instruction::DELEGATECALL:
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case Instruction::CREATE:
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case Instruction::CREATE2:
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case Instruction::SELFDESTRUCT:
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case Instruction::STATICCALL: // because it can affect returndatasize
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// Strictly speaking, log0, .., log4 writes to the state, but the EVM cannot read it, so they
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// are just marked as having 'other side effects.'
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return SemanticInformation::Write;
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case Instruction::EXTCODESIZE:
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case Instruction::EXTCODEHASH:
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case Instruction::RETURNDATASIZE:
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case Instruction::BALANCE:
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case Instruction::SELFBALANCE:
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case Instruction::RETURNDATACOPY:
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case Instruction::EXTCODECOPY:
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// PC and GAS are specifically excluded here. Instructions such as CALLER, CALLVALUE,
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// ADDRESS are excluded because they cannot change during execution.
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return SemanticInformation::Read;
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default:
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return SemanticInformation::None;
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}
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}
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bool SemanticInformation::invalidInPureFunctions(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::ADDRESS:
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case Instruction::SELFBALANCE:
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case Instruction::BALANCE:
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case Instruction::ORIGIN:
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case Instruction::CALLER:
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case Instruction::CALLVALUE:
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case Instruction::CHAINID:
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case Instruction::BASEFEE:
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case Instruction::GAS:
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case Instruction::GASPRICE:
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case Instruction::EXTCODESIZE:
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case Instruction::EXTCODECOPY:
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case Instruction::EXTCODEHASH:
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case Instruction::BLOCKHASH:
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case Instruction::COINBASE:
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case Instruction::TIMESTAMP:
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case Instruction::NUMBER:
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case Instruction::DIFFICULTY:
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case Instruction::GASLIMIT:
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case Instruction::STATICCALL:
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case Instruction::SLOAD:
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return true;
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default:
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break;
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}
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return invalidInViewFunctions(_instruction);
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}
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bool SemanticInformation::invalidInViewFunctions(Instruction _instruction)
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{
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switch (_instruction)
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{
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case Instruction::SSTORE:
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case Instruction::JUMP:
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case Instruction::JUMPI:
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case Instruction::LOG0:
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case Instruction::LOG1:
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case Instruction::LOG2:
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case Instruction::LOG3:
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case Instruction::LOG4:
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case Instruction::CREATE:
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case Instruction::CALL:
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case Instruction::CALLCODE:
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case Instruction::DELEGATECALL:
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case Instruction::CREATE2:
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case Instruction::SELFDESTRUCT:
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return true;
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default:
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break;
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}
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return false;
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}
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