mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
113 lines
3.4 KiB
C++
113 lines
3.4 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/>.
|
|
*/
|
|
/**
|
|
* Optimisation stage that removes unused variables and functions.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <libyul/optimiser/ASTWalker.h>
|
|
#include <libyul/YulString.h>
|
|
|
|
#include <map>
|
|
#include <set>
|
|
|
|
namespace yul
|
|
{
|
|
struct Dialect;
|
|
struct SideEffects;
|
|
|
|
/**
|
|
* Optimisation stage that removes unused variables and functions and also
|
|
* removes side-effect-free expression statements.
|
|
*
|
|
* If msize is used, we cannot remove any statements that access memory.
|
|
* Because of that, the Unused Pruner should only be invoked on full ASTs,
|
|
* such that it can check for the presence of msize itself, or
|
|
* the `_allowMSizeOptimization` needs to be passed.
|
|
*
|
|
* Note that this does not remove circular references.
|
|
*
|
|
* Prerequisite: Disambiguator
|
|
*/
|
|
class UnusedPruner: public ASTModifier
|
|
{
|
|
public:
|
|
UnusedPruner(
|
|
Dialect const& _dialect,
|
|
Block& _ast,
|
|
bool _allowMSizeOptimization,
|
|
std::map<YulString, SideEffects> const* _functionSideEffects = nullptr,
|
|
std::set<YulString> const& _externallyUsedFunctions = {}
|
|
);
|
|
UnusedPruner(
|
|
Dialect const& _dialect,
|
|
FunctionDefinition& _function,
|
|
bool _allowMSizeOptimization,
|
|
std::set<YulString> const& _externallyUsedFunctions = {}
|
|
);
|
|
|
|
using ASTModifier::operator();
|
|
void operator()(Block& _block) override;
|
|
|
|
// @returns true iff the code changed in the previous run.
|
|
bool shouldRunAgain() const { return m_shouldRunAgain; }
|
|
|
|
// Run the pruner until the code does not change anymore.
|
|
static void runUntilStabilised(
|
|
Dialect const& _dialect,
|
|
Block& _ast,
|
|
bool _allowMSizeOptimization,
|
|
std::map<YulString, SideEffects> const* _functionSideEffects = nullptr,
|
|
std::set<YulString> const& _externallyUsedFunctions = {}
|
|
);
|
|
|
|
/// Run the pruner until the code does not change anymore.
|
|
/// The provided block has to be a full AST.
|
|
/// The pruner itself determines if msize is used and which user-defined functions
|
|
/// are side-effect free.
|
|
static void runUntilStabilisedOnFullAST(
|
|
Dialect const& _dialect,
|
|
Block& _ast,
|
|
std::set<YulString> const& _externallyUsedFunctions = {}
|
|
);
|
|
|
|
// Run the pruner until the code does not change anymore.
|
|
// Only run on the given function.
|
|
// @param _allowMSizeOptimization if true, allows to remove instructions
|
|
// whose only side-effect is a potential change of the return value of
|
|
// the msize instruction.
|
|
static void runUntilStabilised(
|
|
Dialect const& _dialect,
|
|
FunctionDefinition& _functionDefinition,
|
|
bool _allowMSizeOptimization,
|
|
std::set<YulString> const& _externallyUsedFunctions = {}
|
|
);
|
|
|
|
private:
|
|
bool used(YulString _name) const;
|
|
void subtractReferences(std::map<YulString, size_t> const& _subtrahend);
|
|
|
|
Dialect const& m_dialect;
|
|
bool m_allowMSizeOptimization = false;
|
|
std::map<YulString, SideEffects> const* m_functionSideEffects = nullptr;
|
|
bool m_shouldRunAgain = false;
|
|
std::map<YulString, size_t> m_references;
|
|
};
|
|
|
|
}
|