diff options
Diffstat (limited to 'libevmasm/PeepholeOptimiser.cpp')
| -rw-r--r-- | libevmasm/PeepholeOptimiser.cpp | 201 |
1 files changed, 149 insertions, 52 deletions
diff --git a/libevmasm/PeepholeOptimiser.cpp b/libevmasm/PeepholeOptimiser.cpp index f42dba48..b96b0295 100644 --- a/libevmasm/PeepholeOptimiser.cpp +++ b/libevmasm/PeepholeOptimiser.cpp @@ -1,21 +1,21 @@ /* - This file is part of cpp-ethereum. + This file is part of solidity. - cpp-ethereum is free software: you can redistribute it and/or modify + 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. - cpp-ethereum is distributed in the hope that it will be useful, + 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>. + along with solidity. If not, see <http://www.gnu.org/licenses/>. */ /** - * @file PeepholeOptimiser.h + * @file PeepholeOptimiser.cpp * Performs local optimising code changes to assembly. */ @@ -30,60 +30,131 @@ using namespace dev; // TODO: Extend this to use the tools from ExpressionClasses.cpp -struct Identity +struct OptimiserState +{ + AssemblyItems const& items; + size_t i; + std::back_insert_iterator<AssemblyItems> out; +}; + +template <class Method, size_t Arguments> +struct ApplyRule +{ +}; +template <class Method> +struct ApplyRule<Method, 3> { - static size_t windowSize() { return 1; } - static bool apply(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out) + static bool applyRule(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out) { - *_out = *_in; - return true; + return Method::applySimple(_in[0], _in[1], _in[2], _out); + } +}; +template <class Method> +struct ApplyRule<Method, 2> +{ + static bool applyRule(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out) + { + return Method::applySimple(_in[0], _in[1], _out); + } +}; +template <class Method> +struct ApplyRule<Method, 1> +{ + static bool applyRule(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out) + { + return Method::applySimple(_in[0], _out); } }; -struct PushPop +template <class Method, size_t WindowSize> +struct SimplePeepholeOptimizerMethod { - static size_t windowSize() { return 2; } - static bool apply(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems>) + static bool apply(OptimiserState& _state) { - auto t = _in[0].type(); - if (_in[1] == Instruction::POP && ( - SemanticInformation::isDupInstruction(_in[0]) || - t == Push || t == PushString || t == PushTag || t == PushSub || - t == PushSubSize || t == PushProgramSize || t == PushData || t == PushLibraryAddress - )) + if ( + _state.i + WindowSize <= _state.items.size() && + ApplyRule<Method, WindowSize>::applyRule(_state.items.begin() + _state.i, _state.out) + ) + { + _state.i += WindowSize; return true; + } else return false; } }; -struct DoubleSwap +struct Identity: SimplePeepholeOptimizerMethod<Identity, 1> { - static size_t windowSize() { return 2; } - static bool apply(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems>) + static bool applySimple(AssemblyItem const& _item, std::back_insert_iterator<AssemblyItems> _out) { - if (_in[0] == _in[1] && SemanticInformation::isSwapInstruction(_in[0])) - return true; - else - return false; + *_out = _item; + return true; } }; -struct JumpToNext +struct PushPop: SimplePeepholeOptimizerMethod<PushPop, 2> { - static size_t windowSize() { return 3; } - static bool apply(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out) + static bool applySimple(AssemblyItem const& _push, AssemblyItem const& _pop, std::back_insert_iterator<AssemblyItems>) + { + auto t = _push.type(); + return _pop == Instruction::POP && ( + SemanticInformation::isDupInstruction(_push) || + t == Push || t == PushString || t == PushTag || t == PushSub || + t == PushSubSize || t == PushProgramSize || t == PushData || t == PushLibraryAddress + ); + } +}; + +struct OpPop: SimplePeepholeOptimizerMethod<OpPop, 2> +{ + static bool applySimple( + AssemblyItem const& _op, + AssemblyItem const& _pop, + std::back_insert_iterator<AssemblyItems> _out + ) + { + if (_pop == Instruction::POP && _op.type() == Operation) + { + Instruction instr = _op.instruction(); + if (instructionInfo(instr).ret == 1 && !instructionInfo(instr).sideEffects) + { + for (int j = 0; j < instructionInfo(instr).args; j++) + *_out = Instruction::POP; + return true; + } + } + return false; + } +}; + +struct DoubleSwap: SimplePeepholeOptimizerMethod<DoubleSwap, 2> +{ + static size_t applySimple(AssemblyItem const& _s1, AssemblyItem const& _s2, std::back_insert_iterator<AssemblyItems>) + { + return _s1 == _s2 && SemanticInformation::isSwapInstruction(_s1); + } +}; + +struct JumpToNext: SimplePeepholeOptimizerMethod<JumpToNext, 3> +{ + static size_t applySimple( + AssemblyItem const& _pushTag, + AssemblyItem const& _jump, + AssemblyItem const& _tag, + std::back_insert_iterator<AssemblyItems> _out + ) { if ( - _in[0].type() == PushTag && - (_in[1] == Instruction::JUMP || _in[1] == Instruction::JUMPI) && - _in[2].type() == Tag && - _in[0].data() == _in[2].data() + _pushTag.type() == PushTag && + (_jump == Instruction::JUMP || _jump == Instruction::JUMPI) && + _tag.type() == Tag && + _pushTag.data() == _tag.data() ) { - if (_in[1] == Instruction::JUMPI) - *_out = AssemblyItem(Instruction::POP, _in[1].location()); - *_out = _in[2]; + if (_jump == Instruction::JUMPI) + *_out = AssemblyItem(Instruction::POP, _jump.location()); + *_out = _tag; return true; } else @@ -91,19 +162,23 @@ struct JumpToNext } }; -struct TagConjunctions +struct TagConjunctions: SimplePeepholeOptimizerMethod<TagConjunctions, 3> { - static size_t windowSize() { return 3; } - static bool apply(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out) + static bool applySimple( + AssemblyItem const& _pushTag, + AssemblyItem const& _pushConstant, + AssemblyItem const& _and, + std::back_insert_iterator<AssemblyItems> _out + ) { if ( - _in[0].type() == PushTag && - _in[2] == Instruction::AND && - _in[1].type() == Push && - (_in[1].data() & u256(0xFFFFFFFF)) == u256(0xFFFFFFFF) + _pushTag.type() == PushTag && + _and == Instruction::AND && + _pushConstant.type() == Push && + (_pushConstant.data() & u256(0xFFFFFFFF)) == u256(0xFFFFFFFF) ) { - *_out = _in[0]; + *_out = _pushTag; return true; } else @@ -111,11 +186,35 @@ struct TagConjunctions } }; -struct OptimiserState +/// Removes everything after a JUMP (or similar) until the next JUMPDEST. +struct UnreachableCode { - AssemblyItems const& items; - size_t i; - std::back_insert_iterator<AssemblyItems> out; + static bool apply(OptimiserState& _state) + { + auto it = _state.items.begin() + _state.i; + auto end = _state.items.end(); + if (it == end) + return false; + if ( + it[0] != Instruction::JUMP && + it[0] != Instruction::RETURN && + it[0] != Instruction::STOP && + it[0] != Instruction::SUICIDE + ) + return false; + + size_t i = 1; + while (it + i != end && it[i].type() != Tag) + i++; + if (i > 1) + { + *_state.out = it[0]; + _state.i += i; + return true; + } + else + return false; + } }; void applyMethods(OptimiserState&) @@ -126,9 +225,7 @@ void applyMethods(OptimiserState&) template <typename Method, typename... OtherMethods> void applyMethods(OptimiserState& _state, Method, OtherMethods... _other) { - if (_state.i + Method::windowSize() <= _state.items.size() && Method::apply(_state.items.begin() + _state.i, _state.out)) - _state.i += Method::windowSize(); - else + if (!Method::apply(_state)) applyMethods(_state, _other...); } @@ -136,7 +233,7 @@ bool PeepholeOptimiser::optimise() { OptimiserState state {m_items, 0, std::back_inserter(m_optimisedItems)}; while (state.i < m_items.size()) - applyMethods(state, PushPop(), DoubleSwap(), JumpToNext(), TagConjunctions(), Identity()); + applyMethods(state, PushPop(), OpPop(), DoubleSwap(), JumpToNext(), UnreachableCode(), TagConjunctions(), Identity()); if (m_optimisedItems.size() < m_items.size()) { m_items = std::move(m_optimisedItems); |