solidity/libyul/optimiser/Semantics.cpp
Jun Zhang c2362c3362
Purge using namespace std from libyul/optimiser
Signed-off-by: Jun Zhang <jun@junz.org>
2023-08-28 21:14:56 +08:00

237 lines
6.9 KiB
C++

/*
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
/**
* Specific AST walkers that collect semantical facts.
*/
#include <libyul/optimiser/Semantics.h>
#include <libyul/optimiser/OptimizerUtilities.h>
#include <libyul/Exceptions.h>
#include <libyul/AST.h>
#include <libyul/Dialect.h>
#include <libevmasm/SemanticInformation.h>
#include <libsolutil/CommonData.h>
#include <libsolutil/Algorithms.h>
#include <limits>
using namespace solidity;
using namespace solidity::yul;
SideEffectsCollector::SideEffectsCollector(
Dialect const& _dialect,
Expression const& _expression,
std::map<YulString, SideEffects> const* _functionSideEffects
):
SideEffectsCollector(_dialect, _functionSideEffects)
{
visit(_expression);
}
SideEffectsCollector::SideEffectsCollector(Dialect const& _dialect, Statement const& _statement):
SideEffectsCollector(_dialect)
{
visit(_statement);
}
SideEffectsCollector::SideEffectsCollector(
Dialect const& _dialect,
Block const& _ast,
std::map<YulString, SideEffects> const* _functionSideEffects
):
SideEffectsCollector(_dialect, _functionSideEffects)
{
operator()(_ast);
}
SideEffectsCollector::SideEffectsCollector(
Dialect const& _dialect,
ForLoop const& _ast,
std::map<YulString, SideEffects> const* _functionSideEffects
):
SideEffectsCollector(_dialect, _functionSideEffects)
{
operator()(_ast);
}
void SideEffectsCollector::operator()(FunctionCall const& _functionCall)
{
ASTWalker::operator()(_functionCall);
YulString functionName = _functionCall.functionName.name;
if (BuiltinFunction const* f = m_dialect.builtin(functionName))
m_sideEffects += f->sideEffects;
else if (m_functionSideEffects && m_functionSideEffects->count(functionName))
m_sideEffects += m_functionSideEffects->at(functionName);
else
m_sideEffects += SideEffects::worst();
}
bool MSizeFinder::containsMSize(Dialect const& _dialect, Block const& _ast)
{
MSizeFinder finder(_dialect);
finder(_ast);
return finder.m_msizeFound;
}
bool MSizeFinder::containsMSize(Dialect const& _dialect, Object const& _object)
{
if (containsMSize(_dialect, *_object.code))
return true;
for (std::shared_ptr<ObjectNode> const& node: _object.subObjects)
if (auto const* object = dynamic_cast<Object const*>(node.get()))
if (containsMSize(_dialect, *object))
return true;
return false;
}
void MSizeFinder::operator()(FunctionCall const& _functionCall)
{
ASTWalker::operator()(_functionCall);
if (BuiltinFunction const* f = m_dialect.builtin(_functionCall.functionName.name))
if (f->isMSize)
m_msizeFound = true;
}
std::map<YulString, SideEffects> SideEffectsPropagator::sideEffects(
Dialect const& _dialect,
CallGraph const& _directCallGraph
)
{
// Any loop currently makes a function non-movable, because
// it could be a non-terminating loop.
// The same is true for any function part of a call cycle.
// In the future, we should refine that, because the property
// is actually a bit different from "not movable".
std::map<YulString, SideEffects> ret;
for (auto const& function: _directCallGraph.functionsWithLoops + _directCallGraph.recursiveFunctions())
{
ret[function].movable = false;
ret[function].canBeRemoved = false;
ret[function].canBeRemovedIfNoMSize = false;
ret[function].cannotLoop = false;
}
for (auto const& call: _directCallGraph.functionCalls)
{
YulString funName = call.first;
SideEffects sideEffects;
auto _visit = [&, visited = std::set<YulString>{}](YulString _function, auto&& _recurse) mutable {
if (!visited.insert(_function).second)
return;
if (sideEffects == SideEffects::worst())
return;
if (BuiltinFunction const* f = _dialect.builtin(_function))
sideEffects += f->sideEffects;
else
{
if (ret.count(_function))
sideEffects += ret[_function];
for (YulString callee: _directCallGraph.functionCalls.at(_function))
_recurse(callee, _recurse);
}
};
for (auto const& _v: call.second)
_visit(_v, _visit);
ret[funName] += sideEffects;
}
return ret;
}
MovableChecker::MovableChecker(Dialect const& _dialect, Expression const& _expression):
MovableChecker(_dialect)
{
visit(_expression);
}
void MovableChecker::operator()(Identifier const& _identifier)
{
SideEffectsCollector::operator()(_identifier);
m_variableReferences.emplace(_identifier.name);
}
void MovableChecker::visit(Statement const&)
{
assertThrow(false, OptimizerException, "Movability for statement requested.");
}
std::pair<TerminationFinder::ControlFlow, size_t> TerminationFinder::firstUnconditionalControlFlowChange(
std::vector<Statement> const& _statements
)
{
for (size_t i = 0; i < _statements.size(); ++i)
{
ControlFlow controlFlow = controlFlowKind(_statements[i]);
if (controlFlow != ControlFlow::FlowOut)
return {controlFlow, i};
}
return {ControlFlow::FlowOut, std::numeric_limits<size_t>::max()};
}
TerminationFinder::ControlFlow TerminationFinder::controlFlowKind(Statement const& _statement)
{
if (
std::holds_alternative<VariableDeclaration>(_statement) &&
std::get<VariableDeclaration>(_statement).value &&
containsNonContinuingFunctionCall(*std::get<VariableDeclaration>(_statement).value)
)
return ControlFlow::Terminate;
else if (
std::holds_alternative<Assignment>(_statement) &&
containsNonContinuingFunctionCall(*std::get<Assignment>(_statement).value)
)
return ControlFlow::Terminate;
else if (
std::holds_alternative<ExpressionStatement>(_statement) &&
containsNonContinuingFunctionCall(std::get<ExpressionStatement>(_statement).expression)
)
return ControlFlow::Terminate;
else if (std::holds_alternative<Break>(_statement))
return ControlFlow::Break;
else if (std::holds_alternative<Continue>(_statement))
return ControlFlow::Continue;
else if (std::holds_alternative<Leave>(_statement))
return ControlFlow::Leave;
else
return ControlFlow::FlowOut;
}
bool TerminationFinder::containsNonContinuingFunctionCall(Expression const& _expr)
{
if (auto functionCall = std::get_if<FunctionCall>(&_expr))
{
for (auto const& arg: functionCall->arguments)
if (containsNonContinuingFunctionCall(arg))
return true;
if (auto builtin = m_dialect.builtin(functionCall->functionName.name))
return !builtin->controlFlowSideEffects.canContinue;
else if (m_functionSideEffects && m_functionSideEffects->count(functionCall->functionName.name))
return !m_functionSideEffects->at(functionCall->functionName.name).canContinue;
}
return false;
}