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Diffstat (limited to 'libyul/optimiser/SimplificationRules.cpp')
| -rw-r--r-- | libyul/optimiser/SimplificationRules.cpp | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/libyul/optimiser/SimplificationRules.cpp b/libyul/optimiser/SimplificationRules.cpp new file mode 100644 index 00000000..762473e5 --- /dev/null +++ b/libyul/optimiser/SimplificationRules.cpp @@ -0,0 +1,189 @@ +/* + 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/>. +*/ +/** + * Module for applying replacement rules against Expressions. + */ + +#include <libyul/optimiser/SimplificationRules.h> + +#include <libyul/optimiser/Utilities.h> +#include <libyul/optimiser/ASTCopier.h> +#include <libyul/optimiser/Semantics.h> +#include <libyul/optimiser/SyntacticalEquality.h> + +#include <libsolidity/inlineasm/AsmData.h> + +#include <libevmasm/RuleList.h> + +using namespace std; +using namespace dev; +using namespace dev::yul; + + +SimplificationRule<Pattern> const* SimplificationRules::findFirstMatch(Expression const& _expr) +{ + if (_expr.type() != typeid(FunctionalInstruction)) + return nullptr; + + static SimplificationRules rules; + assertThrow(rules.isInitialized(), OptimizerException, "Rule list not properly initialized."); + + FunctionalInstruction const& instruction = boost::get<FunctionalInstruction>(_expr); + for (auto const& rule: rules.m_rules[byte(instruction.instruction)]) + { + rules.resetMatchGroups(); + if (rule.pattern.matches(_expr)) + return &rule; + } + return nullptr; +} + +bool SimplificationRules::isInitialized() const +{ + return !m_rules[byte(solidity::Instruction::ADD)].empty(); +} + +void SimplificationRules::addRules(vector<SimplificationRule<Pattern>> const& _rules) +{ + for (auto const& r: _rules) + addRule(r); +} + +void SimplificationRules::addRule(SimplificationRule<Pattern> const& _rule) +{ + m_rules[byte(_rule.pattern.instruction())].push_back(_rule); +} + +SimplificationRules::SimplificationRules() +{ + // Multiple occurrences of one of these inside one rule must match the same equivalence class. + // Constants. + Pattern A(PatternKind::Constant); + Pattern B(PatternKind::Constant); + Pattern C(PatternKind::Constant); + // Anything. + Pattern X; + Pattern Y; + A.setMatchGroup(1, m_matchGroups); + B.setMatchGroup(2, m_matchGroups); + C.setMatchGroup(3, m_matchGroups); + X.setMatchGroup(4, m_matchGroups); + Y.setMatchGroup(5, m_matchGroups); + + addRules(simplificationRuleList(A, B, C, X, Y)); + assertThrow(isInitialized(), OptimizerException, "Rule list not properly initialized."); +} + +Pattern::Pattern(solidity::Instruction _instruction, vector<Pattern> const& _arguments): + m_kind(PatternKind::Operation), + m_instruction(_instruction), + m_arguments(_arguments) +{ +} + +void Pattern::setMatchGroup(unsigned _group, map<unsigned, Expression const*>& _matchGroups) +{ + m_matchGroup = _group; + m_matchGroups = &_matchGroups; +} + +bool Pattern::matches(Expression const& _expr) const +{ + if (m_kind == PatternKind::Constant) + { + if (_expr.type() != typeid(Literal)) + return false; + Literal const& literal = boost::get<Literal>(_expr); + if (literal.kind != assembly::LiteralKind::Number) + return false; + if (m_data && *m_data != u256(literal.value)) + return false; + assertThrow(m_arguments.empty(), OptimizerException, ""); + } + else if (m_kind == PatternKind::Operation) + { + if (_expr.type() != typeid(FunctionalInstruction)) + return false; + FunctionalInstruction const& instr = boost::get<FunctionalInstruction>(_expr); + if (m_instruction != instr.instruction) + return false; + assertThrow(m_arguments.size() == instr.arguments.size(), OptimizerException, ""); + for (size_t i = 0; i < m_arguments.size(); ++i) + if (!m_arguments[i].matches(instr.arguments.at(i))) + return false; + } + else + { + assertThrow(m_arguments.empty(), OptimizerException, ""); + } + // We support matching multiple expressions that require the same value + // based on identical ASTs, which have to be movable. + if (m_matchGroup) + { + if (m_matchGroups->count(m_matchGroup)) + { + Expression const* firstMatch = (*m_matchGroups)[m_matchGroup]; + assertThrow(firstMatch, OptimizerException, "Match set but to null."); + return + SyntacticalEqualityChecker::equal(*firstMatch, _expr) && + MovableChecker(_expr).movable(); + } + else + (*m_matchGroups)[m_matchGroup] = &_expr; + } + return true; +} + +solidity::Instruction Pattern::instruction() const +{ + assertThrow(m_kind == PatternKind::Operation, OptimizerException, ""); + return m_instruction; +} + +Expression Pattern::toExpression(SourceLocation const& _location) const +{ + if (matchGroup()) + return ASTCopier().translate(matchGroupValue()); + if (m_kind == PatternKind::Constant) + { + assertThrow(m_data, OptimizerException, "No match group and no constant value given."); + return Literal{_location, assembly::LiteralKind::Number, formatNumber(*m_data), ""}; + } + else if (m_kind == PatternKind::Operation) + { + vector<Expression> arguments; + for (auto const& arg: m_arguments) + arguments.emplace_back(arg.toExpression(_location)); + return FunctionalInstruction{_location, m_instruction, std::move(arguments)}; + } + assertThrow(false, OptimizerException, "Pattern of kind 'any', but no match group."); +} + +u256 Pattern::d() const +{ + Literal const& literal = boost::get<Literal>(matchGroupValue()); + assertThrow(literal.kind == assembly::LiteralKind::Number, OptimizerException, ""); + return u256(literal.value); +} + +Expression const& Pattern::matchGroupValue() const +{ + assertThrow(m_matchGroup > 0, OptimizerException, ""); + assertThrow(!!m_matchGroups, OptimizerException, ""); + assertThrow((*m_matchGroups)[m_matchGroup], OptimizerException, ""); + return *(*m_matchGroups)[m_matchGroup]; +} |