mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
Refactor RedundantAssignEliminator.
This commit is contained in:
chriseth
parent
d7a802e4bf
commit
3622b30a1d
@ -295,6 +295,31 @@ decltype(auto) mapTuple(Callable&& _callable)
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return detail::MapTuple<Callable>{std::forward<Callable>(_callable)};
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}
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/// Merges map @a _b into map @a _a. If the same key exists in both maps,
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/// calls @a _conflictSolver to combine the two values.
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template <class K, class V, class F>
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void joinMap(std::map<K, V>& _a, std::map<K, V>&& _b, F _conflictSolver)
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{
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auto ita = _a.begin();
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auto aend = _a.end();
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auto itb = _b.begin();
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auto bend = _b.end();
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for (; itb != bend; ++ita)
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{
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if (ita == aend)
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ita = _a.insert(ita, std::move(*itb++));
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else if (ita->first < itb->first)
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continue;
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else if (itb->first < ita->first)
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ita = _a.insert(ita, std::move(*itb++));
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else
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{
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_conflictSolver(ita->second, std::move(itb->second));
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++itb;
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}
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}
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}
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// String conversion functions, mainly to/from hex/nibble/byte representations.
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@ -167,6 +167,8 @@ add_library(yul
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optimiser/ReasoningBasedSimplifier.h
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optimiser/RedundantAssignEliminator.cpp
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optimiser/RedundantAssignEliminator.h
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optimiser/RedundantStoreBase.cpp
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optimiser/RedundantStoreBase.h
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optimiser/Rematerialiser.cpp
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optimiser/Rematerialiser.h
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optimiser/SMTSolver.cpp
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@ -38,7 +38,7 @@ void RedundantAssignEliminator::run(OptimiserStepContext& _context, Block& _ast)
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RedundantAssignEliminator rae{_context.dialect};
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rae(_ast);
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AssignmentRemover remover{rae.m_pendingRemovals};
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StatementRemover remover{rae.m_pendingRemovals};
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remover(_ast);
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}
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@ -49,7 +49,7 @@ void RedundantAssignEliminator::operator()(Identifier const& _identifier)
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void RedundantAssignEliminator::operator()(VariableDeclaration const& _variableDeclaration)
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{
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ASTWalker::operator()(_variableDeclaration);
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RedundantStoreBase::operator()(_variableDeclaration);
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for (auto const& var: _variableDeclaration.variables)
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m_declaredVariables.emplace(var.name);
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@ -60,151 +60,17 @@ void RedundantAssignEliminator::operator()(Assignment const& _assignment)
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visit(*_assignment.value);
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for (auto const& var: _assignment.variableNames)
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changeUndecidedTo(var.name, State::Unused);
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if (_assignment.variableNames.size() == 1)
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// Default-construct it in "Undecided" state if it does not yet exist.
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m_assignments[_assignment.variableNames.front().name][&_assignment];
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}
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void RedundantAssignEliminator::operator()(If const& _if)
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{
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visit(*_if.condition);
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TrackedAssignments skipBranch{m_assignments};
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(*this)(_if.body);
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merge(m_assignments, move(skipBranch));
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}
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void RedundantAssignEliminator::operator()(Switch const& _switch)
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{
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visit(*_switch.expression);
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TrackedAssignments const preState{m_assignments};
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bool hasDefault = false;
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vector<TrackedAssignments> branches;
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for (auto const& c: _switch.cases)
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{
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if (!c.value)
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hasDefault = true;
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(*this)(c.body);
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branches.emplace_back(move(m_assignments));
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m_assignments = preState;
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}
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if (hasDefault)
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{
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m_assignments = move(branches.back());
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branches.pop_back();
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}
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for (auto& branch: branches)
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merge(m_assignments, move(branch));
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}
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void RedundantAssignEliminator::operator()(FunctionDefinition const& _functionDefinition)
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{
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std::set<YulString> outerDeclaredVariables;
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std::set<YulString> outerReturnVariables;
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TrackedAssignments outerAssignments;
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ForLoopInfo forLoopInfo;
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swap(m_declaredVariables, outerDeclaredVariables);
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swap(m_returnVariables, outerReturnVariables);
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swap(m_assignments, outerAssignments);
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swap(m_forLoopInfo, forLoopInfo);
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ScopedSaveAndRestore outerDeclaredVariables(m_declaredVariables, {});
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ScopedSaveAndRestore outerReturnVariables(m_returnVariables, {});
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for (auto const& retParam: _functionDefinition.returnVariables)
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m_returnVariables.insert(retParam.name);
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(*this)(_functionDefinition.body);
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for (auto const& param: _functionDefinition.parameters)
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finalize(param.name, State::Unused);
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for (auto const& retParam: _functionDefinition.returnVariables)
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finalize(retParam.name, State::Used);
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swap(m_declaredVariables, outerDeclaredVariables);
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swap(m_returnVariables, outerReturnVariables);
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swap(m_assignments, outerAssignments);
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swap(m_forLoopInfo, forLoopInfo);
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}
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void RedundantAssignEliminator::operator()(ForLoop const& _forLoop)
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{
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ForLoopInfo outerForLoopInfo;
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swap(outerForLoopInfo, m_forLoopInfo);
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++m_forLoopNestingDepth;
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// If the pre block was not empty,
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// we would have to deal with more complicated scoping rules.
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assertThrow(_forLoop.pre.statements.empty(), OptimizerException, "");
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// We just run the loop twice to account for the back edge.
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// There need not be more runs because we only have three different states.
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visit(*_forLoop.condition);
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TrackedAssignments zeroRuns{m_assignments};
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(*this)(_forLoop.body);
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merge(m_assignments, move(m_forLoopInfo.pendingContinueStmts));
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m_forLoopInfo.pendingContinueStmts = {};
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(*this)(_forLoop.post);
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visit(*_forLoop.condition);
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if (m_forLoopNestingDepth < 6)
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{
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// Do the second run only for small nesting depths to avoid horrible runtime.
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TrackedAssignments oneRun{m_assignments};
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(*this)(_forLoop.body);
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merge(m_assignments, move(m_forLoopInfo.pendingContinueStmts));
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m_forLoopInfo.pendingContinueStmts.clear();
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(*this)(_forLoop.post);
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visit(*_forLoop.condition);
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// Order of merging does not matter because "max" is commutative and associative.
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merge(m_assignments, move(oneRun));
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}
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else
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{
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// Shortcut to avoid horrible runtime:
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// Change all assignments that were newly introduced in the for loop to "used".
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// We do not have to do that with the "break" or "continue" paths, because
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// they will be joined later anyway.
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// TODO parallel traversal might be more efficient here.
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for (auto& var: m_assignments)
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for (auto& assignment: var.second)
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{
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auto zeroIt = zeroRuns.find(var.first);
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if (zeroIt != zeroRuns.end() && zeroIt->second.count(assignment.first))
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continue;
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assignment.second = State::Value::Used;
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}
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}
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// Order of merging does not matter because "max" is commutative and associative.
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merge(m_assignments, move(zeroRuns));
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merge(m_assignments, move(m_forLoopInfo.pendingBreakStmts));
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m_forLoopInfo.pendingBreakStmts.clear();
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// Restore potential outer for-loop states.
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swap(m_forLoopInfo, outerForLoopInfo);
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--m_forLoopNestingDepth;
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}
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void RedundantAssignEliminator::operator()(Break const&)
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{
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m_forLoopInfo.pendingBreakStmts.emplace_back(move(m_assignments));
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m_assignments.clear();
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}
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void RedundantAssignEliminator::operator()(Continue const&)
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{
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m_forLoopInfo.pendingContinueStmts.emplace_back(move(m_assignments));
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m_assignments.clear();
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RedundantStoreBase::operator()(_functionDefinition);
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}
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void RedundantAssignEliminator::operator()(Leave const&)
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@ -215,101 +81,76 @@ void RedundantAssignEliminator::operator()(Leave const&)
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void RedundantAssignEliminator::operator()(Block const& _block)
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{
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set<YulString> outerDeclaredVariables;
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swap(m_declaredVariables, outerDeclaredVariables);
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ScopedSaveAndRestore outerDeclaredVariables(m_declaredVariables, {});
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ASTWalker::operator()(_block);
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RedundantStoreBase::operator()(_block);
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for (auto const& var: m_declaredVariables)
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finalize(var, State::Unused);
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swap(m_declaredVariables, outerDeclaredVariables);
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}
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template <class K, class V, class F>
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void joinMap(std::map<K, V>& _a, std::map<K, V>&& _b, F _conflictSolver)
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void RedundantAssignEliminator::visit(Statement const& _statement)
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{
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// TODO Perhaps it is better to just create a sorted list
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// and then use insert(begin, end)
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RedundantStoreBase::visit(_statement);
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auto ita = _a.begin();
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auto aend = _a.end();
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auto itb = _b.begin();
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auto bend = _b.end();
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if (auto const* assignment = get_if<Assignment>(&_statement))
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if (assignment->variableNames.size() == 1)
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// Default-construct it in "Undecided" state if it does not yet exist.
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m_stores[assignment->variableNames.front().name][&_statement];
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}
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for (; itb != bend; ++ita)
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{
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if (ita == aend)
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ita = _a.insert(ita, std::move(*itb++));
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else if (ita->first < itb->first)
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continue;
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else if (itb->first < ita->first)
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ita = _a.insert(ita, std::move(*itb++));
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else
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void RedundantAssignEliminator::shortcutNestedLoop(TrackedStores const& _zeroRuns)
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{
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// Shortcut to avoid horrible runtime:
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// Change all assignments that were newly introduced in the for loop to "used".
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// We do not have to do that with the "break" or "continue" paths, because
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// they will be joined later anyway.
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// TODO parallel traversal might be more efficient here.
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for (auto& [variable, stores]: m_stores)
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for (auto& assignment: stores)
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{
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_conflictSolver(ita->second, std::move(itb->second));
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++itb;
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auto zeroIt = _zeroRuns.find(variable);
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if (zeroIt != _zeroRuns.end() && zeroIt->second.count(assignment.first))
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continue;
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assignment.second = State::Value::Used;
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}
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}
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}
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void RedundantAssignEliminator::merge(TrackedAssignments& _target, TrackedAssignments&& _other)
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void RedundantAssignEliminator::finalizeFunctionDefinition(FunctionDefinition const& _functionDefinition)
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{
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joinMap(_target, move(_other), [](
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map<Assignment const*, State>& _assignmentHere,
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map<Assignment const*, State>&& _assignmentThere
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)
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{
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return joinMap(_assignmentHere, move(_assignmentThere), State::join);
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});
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}
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void RedundantAssignEliminator::merge(TrackedAssignments& _target, vector<TrackedAssignments>&& _source)
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{
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for (TrackedAssignments& ts: _source)
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merge(_target, move(ts));
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_source.clear();
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for (auto const& param: _functionDefinition.parameters)
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finalize(param.name, State::Unused);
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for (auto const& retParam: _functionDefinition.returnVariables)
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finalize(retParam.name, State::Used);
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}
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void RedundantAssignEliminator::changeUndecidedTo(YulString _variable, RedundantAssignEliminator::State _newState)
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{
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for (auto& assignment: m_assignments[_variable])
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for (auto& assignment: m_stores[_variable])
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if (assignment.second == State::Undecided)
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assignment.second = _newState;
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}
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void RedundantAssignEliminator::finalize(YulString _variable, RedundantAssignEliminator::State _finalState)
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{
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std::map<Assignment const*, State> assignments;
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joinMap(assignments, std::move(m_assignments[_variable]), State::join);
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m_assignments.erase(_variable);
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std::map<Statement const*, State> stores = std::move(m_stores[_variable]);
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m_stores.erase(_variable);
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for (auto& breakAssignments: m_forLoopInfo.pendingBreakStmts)
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{
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joinMap(assignments, std::move(breakAssignments[_variable]), State::join);
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util::joinMap(stores, std::move(breakAssignments[_variable]), State::join);
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breakAssignments.erase(_variable);
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}
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for (auto& continueAssignments: m_forLoopInfo.pendingContinueStmts)
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{
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joinMap(assignments, std::move(continueAssignments[_variable]), State::join);
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util::joinMap(stores, std::move(continueAssignments[_variable]), State::join);
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continueAssignments.erase(_variable);
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}
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for (auto const& assignment: assignments)
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{
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State const state = assignment.second == State::Undecided ? _finalState : assignment.second;
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if (state == State::Unused && SideEffectsCollector{*m_dialect, *assignment.first->value}.movable())
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m_pendingRemovals.insert(assignment.first);
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}
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}
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void AssignmentRemover::operator()(Block& _block)
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{
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ranges::actions::remove_if(_block.statements, [&](Statement const& _statement) -> bool {
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return holds_alternative<Assignment>(_statement) && m_toRemove.count(&std::get<Assignment>(_statement));
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});
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ASTModifier::operator()(_block);
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for (auto&& [statement, state]: stores)
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if (
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(state == State::Unused || (state == State::Undecided && _finalState == State::Unused)) &&
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SideEffectsCollector{m_dialect, *std::get<Assignment>(*statement).value}.movable()
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)
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m_pendingRemovals.insert(statement);
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}
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@ -25,6 +25,7 @@
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#include <libyul/ASTForward.h>
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#include <libyul/optimiser/ASTWalker.h>
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#include <libyul/optimiser/OptimiserStep.h>
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#include <libyul/optimiser/RedundantStoreBase.h>
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#include <map>
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#include <vector>
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@ -106,91 +107,37 @@ struct Dialect;
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*
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* Prerequisite: Disambiguator, ForLoopInitRewriter.
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*/
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class RedundantAssignEliminator: public ASTWalker
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class RedundantAssignEliminator: public RedundantStoreBase
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{
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public:
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static constexpr char const* name{"RedundantAssignEliminator"};
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static void run(OptimiserStepContext&, Block& _ast);
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explicit RedundantAssignEliminator(Dialect const& _dialect): m_dialect(&_dialect) {}
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RedundantAssignEliminator() = delete;
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RedundantAssignEliminator(RedundantAssignEliminator const&) = delete;
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RedundantAssignEliminator& operator=(RedundantAssignEliminator const&) = delete;
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RedundantAssignEliminator(RedundantAssignEliminator&&) = default;
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RedundantAssignEliminator& operator=(RedundantAssignEliminator&&) = default;
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explicit RedundantAssignEliminator(Dialect const& _dialect): RedundantStoreBase(_dialect) {}
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void operator()(Identifier const& _identifier) override;
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void operator()(VariableDeclaration const& _variableDeclaration) override;
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void operator()(Assignment const& _assignment) override;
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void operator()(If const& _if) override;
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void operator()(Switch const& _switch) override;
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void operator()(FunctionDefinition const&) override;
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void operator()(ForLoop const&) override;
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void operator()(Break const&) override;
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void operator()(Continue const&) override;
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void operator()(Leave const&) override;
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void operator()(Block const& _block) override;
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using RedundantStoreBase::visit;
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void visit(Statement const& _statement) override;
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private:
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class State
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{
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public:
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enum Value { Unused, Undecided, Used };
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State(Value _value = Undecided): m_value(_value) {}
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inline bool operator==(State _other) const { return m_value == _other.m_value; }
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inline bool operator!=(State _other) const { return !operator==(_other); }
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static inline void join(State& _a, State const& _b)
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{
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// Using "max" works here because of the order of the values in the enum.
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_a.m_value = Value(std::max(int(_a.m_value), int(_b.m_value)));
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}
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private:
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Value m_value = Undecided;
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};
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void shortcutNestedLoop(TrackedStores const& _beforeLoop) override;
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void finalizeFunctionDefinition(FunctionDefinition const& _functionDefinition) override;
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// TODO check that this does not cause nondeterminism!
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// This could also be a pseudo-map from state to assignment.
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using TrackedAssignments = std::map<YulString, std::map<Assignment const*, State>>;
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/// Joins the assignment mapping of @a _source into @a _target according to the rules laid out
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/// above.
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/// Will destroy @a _source.
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static void merge(TrackedAssignments& _target, TrackedAssignments&& _source);
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static void merge(TrackedAssignments& _target, std::vector<TrackedAssignments>&& _source);
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void changeUndecidedTo(YulString _variable, State _newState);
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/// Called when a variable goes out of scope. Sets the state of all still undecided
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/// assignments to the final state. In this case, this also applies to pending
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/// break and continue TrackedAssignments.
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/// break and continue TrackedStores.
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void finalize(YulString _variable, State _finalState);
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Dialect const* m_dialect;
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std::set<YulString> m_declaredVariables;
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std::set<YulString> m_returnVariables;
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std::set<Assignment const*> m_pendingRemovals;
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TrackedAssignments m_assignments;
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/// Working data for traversing for-loops.
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struct ForLoopInfo
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{
|
||||
/// Tracked assignment states for each break statement.
|
||||
std::vector<TrackedAssignments> pendingBreakStmts;
|
||||
/// Tracked assignment states for each continue statement.
|
||||
std::vector<TrackedAssignments> pendingContinueStmts;
|
||||
};
|
||||
ForLoopInfo m_forLoopInfo;
|
||||
size_t m_forLoopNestingDepth = 0;
|
||||
};
|
||||
|
||||
class AssignmentRemover: public ASTModifier
|
||||
{
|
||||
public:
|
||||
explicit AssignmentRemover(std::set<Assignment const*> const& _toRemove):
|
||||
m_toRemove(_toRemove)
|
||||
{}
|
||||
void operator()(Block& _block) override;
|
||||
|
||||
private:
|
||||
std::set<Assignment const*> const& m_toRemove;
|
||||
};
|
||||
|
||||
}
|
||||
|
||||
166
libyul/optimiser/RedundantStoreBase.cpp
Normal file
166
libyul/optimiser/RedundantStoreBase.cpp
Normal file
@ -0,0 +1,166 @@
|
||||
/*
|
||||
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/>.
|
||||
*/
|
||||
// SPDX-License-Identifier: GPL-3.0
|
||||
/**
|
||||
* Base class for both RedundantAssignEliminator and RedundantStoreEliminator.
|
||||
*/
|
||||
|
||||
#include <libyul/optimiser/RedundantStoreBase.h>
|
||||
|
||||
#include <libyul/optimiser/Semantics.h>
|
||||
#include <libyul/optimiser/OptimiserStep.h>
|
||||
#include <libyul/AST.h>
|
||||
|
||||
#include <libsolutil/CommonData.h>
|
||||
|
||||
#include <range/v3/action/remove_if.hpp>
|
||||
|
||||
using namespace std;
|
||||
using namespace solidity;
|
||||
using namespace solidity::yul;
|
||||
|
||||
void RedundantStoreBase::operator()(If const& _if)
|
||||
{
|
||||
visit(*_if.condition);
|
||||
|
||||
TrackedStores skipBranch{m_stores};
|
||||
(*this)(_if.body);
|
||||
|
||||
merge(m_stores, move(skipBranch));
|
||||
}
|
||||
|
||||
void RedundantStoreBase::operator()(Switch const& _switch)
|
||||
{
|
||||
visit(*_switch.expression);
|
||||
|
||||
TrackedStores const preState{m_stores};
|
||||
|
||||
bool hasDefault = false;
|
||||
vector<TrackedStores> branches;
|
||||
for (auto const& c: _switch.cases)
|
||||
{
|
||||
if (!c.value)
|
||||
hasDefault = true;
|
||||
(*this)(c.body);
|
||||
branches.emplace_back(move(m_stores));
|
||||
m_stores = preState;
|
||||
}
|
||||
|
||||
if (hasDefault)
|
||||
{
|
||||
m_stores = move(branches.back());
|
||||
branches.pop_back();
|
||||
}
|
||||
for (auto& branch: branches)
|
||||
merge(m_stores, move(branch));
|
||||
}
|
||||
|
||||
void RedundantStoreBase::operator()(FunctionDefinition const& _functionDefinition)
|
||||
{
|
||||
ScopedSaveAndRestore outerAssignments(m_stores, {});
|
||||
ScopedSaveAndRestore forLoopInfo(m_forLoopInfo, {});
|
||||
|
||||
(*this)(_functionDefinition.body);
|
||||
|
||||
finalizeFunctionDefinition(_functionDefinition);
|
||||
}
|
||||
|
||||
void RedundantStoreBase::operator()(ForLoop const& _forLoop)
|
||||
{
|
||||
ScopedSaveAndRestore outerForLoopInfo(m_forLoopInfo, {});
|
||||
ScopedSaveAndRestore forLoopNestingDepth(m_forLoopNestingDepth, m_forLoopNestingDepth + 1);
|
||||
|
||||
// If the pre block was not empty,
|
||||
// we would have to deal with more complicated scoping rules.
|
||||
assertThrow(_forLoop.pre.statements.empty(), OptimizerException, "");
|
||||
|
||||
// We just run the loop twice to account for the back edge.
|
||||
// There need not be more runs because we only have three different states.
|
||||
|
||||
visit(*_forLoop.condition);
|
||||
|
||||
TrackedStores zeroRuns{m_stores};
|
||||
|
||||
(*this)(_forLoop.body);
|
||||
merge(m_stores, move(m_forLoopInfo.pendingContinueStmts));
|
||||
m_forLoopInfo.pendingContinueStmts = {};
|
||||
(*this)(_forLoop.post);
|
||||
|
||||
visit(*_forLoop.condition);
|
||||
|
||||
if (m_forLoopNestingDepth < 6)
|
||||
{
|
||||
// Do the second run only for small nesting depths to avoid horrible runtime.
|
||||
TrackedStores oneRun{m_stores};
|
||||
|
||||
(*this)(_forLoop.body);
|
||||
|
||||
merge(m_stores, move(m_forLoopInfo.pendingContinueStmts));
|
||||
m_forLoopInfo.pendingContinueStmts.clear();
|
||||
(*this)(_forLoop.post);
|
||||
|
||||
visit(*_forLoop.condition);
|
||||
// Order of merging does not matter because "max" is commutative and associative.
|
||||
merge(m_stores, move(oneRun));
|
||||
}
|
||||
else
|
||||
// Shortcut to avoid horrible runtime.
|
||||
shortcutNestedLoop(zeroRuns);
|
||||
|
||||
// Order of merging does not matter because "max" is commutative and associative.
|
||||
merge(m_stores, move(zeroRuns));
|
||||
merge(m_stores, move(m_forLoopInfo.pendingBreakStmts));
|
||||
m_forLoopInfo.pendingBreakStmts.clear();
|
||||
}
|
||||
|
||||
void RedundantStoreBase::operator()(Break const&)
|
||||
{
|
||||
m_forLoopInfo.pendingBreakStmts.emplace_back(move(m_stores));
|
||||
m_stores.clear();
|
||||
}
|
||||
|
||||
void RedundantStoreBase::operator()(Continue const&)
|
||||
{
|
||||
m_forLoopInfo.pendingContinueStmts.emplace_back(move(m_stores));
|
||||
m_stores.clear();
|
||||
}
|
||||
|
||||
void RedundantStoreBase::merge(TrackedStores& _target, TrackedStores&& _other)
|
||||
{
|
||||
util::joinMap(_target, move(_other), [](
|
||||
map<Statement const*, State>& _assignmentHere,
|
||||
map<Statement const*, State>&& _assignmentThere
|
||||
)
|
||||
{
|
||||
return util::joinMap(_assignmentHere, move(_assignmentThere), State::join);
|
||||
});
|
||||
}
|
||||
|
||||
void RedundantStoreBase::merge(TrackedStores& _target, vector<TrackedStores>&& _source)
|
||||
{
|
||||
for (TrackedStores& ts: _source)
|
||||
merge(_target, move(ts));
|
||||
_source.clear();
|
||||
}
|
||||
|
||||
void StatementRemover::operator()(Block& _block)
|
||||
{
|
||||
ranges::actions::remove_if(_block.statements, [&](Statement const& _statement) -> bool {
|
||||
return m_toRemove.count(&_statement);
|
||||
});
|
||||
ASTModifier::operator()(_block);
|
||||
}
|
||||
113
libyul/optimiser/RedundantStoreBase.h
Normal file
113
libyul/optimiser/RedundantStoreBase.h
Normal file
@ -0,0 +1,113 @@
|
||||
/*
|
||||
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/>.
|
||||
*/
|
||||
// SPDX-License-Identifier: GPL-3.0
|
||||
/**
|
||||
* Base class for both RedundantAssignEliminator and RedundantStoreEliminator.
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <libyul/optimiser/ASTWalker.h>
|
||||
#include <libyul/AST.h>
|
||||
|
||||
#include <range/v3/action/remove_if.hpp>
|
||||
|
||||
#include <variant>
|
||||
|
||||
|
||||
namespace solidity::yul
|
||||
{
|
||||
struct Dialect;
|
||||
|
||||
/**
|
||||
* Base class for both RedundantAssignEliminator and RedundantStoreEliminator.
|
||||
*
|
||||
* Prerequisite: Disambiguator, ForLoopInitRewriter.
|
||||
*/
|
||||
class RedundantStoreBase: public ASTWalker
|
||||
{
|
||||
public:
|
||||
explicit RedundantStoreBase(Dialect const& _dialect): m_dialect(_dialect) {}
|
||||
|
||||
using ASTWalker::operator();
|
||||
void operator()(If const& _if) override;
|
||||
void operator()(Switch const& _switch) override;
|
||||
void operator()(FunctionDefinition const&) override;
|
||||
void operator()(ForLoop const&) override;
|
||||
void operator()(Break const&) override;
|
||||
void operator()(Continue const&) override;
|
||||
|
||||
protected:
|
||||
class State
|
||||
{
|
||||
public:
|
||||
enum Value { Unused, Undecided, Used };
|
||||
State(Value _value = Undecided): m_value(_value) {}
|
||||
inline bool operator==(State _other) const { return m_value == _other.m_value; }
|
||||
inline bool operator!=(State _other) const { return !operator==(_other); }
|
||||
static inline void join(State& _a, State const& _b)
|
||||
{
|
||||
// Using "max" works here because of the order of the values in the enum.
|
||||
_a.m_value = Value(std::max(int(_a.m_value), int(_b.m_value)));
|
||||
}
|
||||
private:
|
||||
Value m_value = Undecided;
|
||||
};
|
||||
|
||||
using TrackedStores = std::map<YulString, std::map<Statement const*, State>>;
|
||||
|
||||
/// This function is called for a loop that is nested too deep to avoid
|
||||
/// horrible runtime and should just resolve the situation in a pragmatic
|
||||
/// and correct manner.
|
||||
virtual void shortcutNestedLoop(TrackedStores const& _beforeLoop) = 0;
|
||||
|
||||
/// This function is called right before the scoped restore of the function definition.
|
||||
virtual void finalizeFunctionDefinition(FunctionDefinition const& /*_functionDefinition*/) {}
|
||||
|
||||
/// Joins the assignment mapping of @a _source into @a _target according to the rules laid out
|
||||
/// above.
|
||||
/// Will destroy @a _source.
|
||||
static void merge(TrackedStores& _target, TrackedStores&& _source);
|
||||
static void merge(TrackedStores& _target, std::vector<TrackedStores>&& _source);
|
||||
|
||||
Dialect const& m_dialect;
|
||||
std::set<Statement const*> m_pendingRemovals;
|
||||
TrackedStores m_stores;
|
||||
|
||||
/// Working data for traversing for-loops.
|
||||
struct ForLoopInfo
|
||||
{
|
||||
/// Tracked assignment states for each break statement.
|
||||
std::vector<TrackedStores> pendingBreakStmts;
|
||||
/// Tracked assignment states for each continue statement.
|
||||
std::vector<TrackedStores> pendingContinueStmts;
|
||||
};
|
||||
ForLoopInfo m_forLoopInfo;
|
||||
size_t m_forLoopNestingDepth = 0;
|
||||
};
|
||||
|
||||
class StatementRemover: public ASTModifier
|
||||
{
|
||||
public:
|
||||
explicit StatementRemover(std::set<Statement const*> const& _toRemove): m_toRemove(_toRemove) {}
|
||||
|
||||
void operator()(Block& _block) override;
|
||||
private:
|
||||
std::set<Statement const*> const& m_toRemove;
|
||||
};
|
||||
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user