solidity/libyul/optimiser/BlockClassFinder.h
2019-05-13 17:30:00 +02:00

119 lines
3.2 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/>.
*/
/**
* Optimiser component that finds classes of equivalent blocks.
*/
#pragma once
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/AsmDataForward.h>
#include <libyul/YulString.h>
#include <libyul/AsmData.h>
namespace yul
{
struct BlockClassMember
{
Block const* block = nullptr;
std::vector<YulString> externalReferences;
std::set<YulString> externalAssignments;
std::set<YulString> externalReads;
};
struct BlockClass
{
std::vector<BlockClassMember> members;
YulString nameHint;
bool hasFreeBreakOrContinue = false;
};
/**
* Optimiser component that finds classes of equivalent blocks.
*
* Prerequisite: Disambiguator
*
* Works best after running the FunctionHoister and FunctionGrouper
*/
class BlockClassFinder: public ASTWalker
{
public:
using ASTWalker::operator();
void operator()(Literal const&) override;
void operator()(Identifier const&) override;
void operator()(FunctionalInstruction const& _instr) override;
void operator()(FunctionCall const& _funCall) override;
void operator()(ExpressionStatement const& _statement) override;
void operator()(Assignment const& _assignment) override;
void operator()(VariableDeclaration const& _varDecl) override;
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;
void operator()(Block const& _block) override;
static std::vector<BlockClass> run(Block const& _block);
private:
struct GlobalState
{
struct BlockID
{
size_t blockClass = 0;
size_t indexInClass = 0;
};
std::map<uint64_t, std::vector<BlockID>> hashToBlockIDs;
std::map<Block const*, size_t> blockToClassID;
std::vector<BlockClass> blockClasses;
BlockClassMember const& block(BlockID const& id)
{
return blockClasses.at(id.blockClass).members.at(id.indexInClass);
}
};
BlockClassFinder(GlobalState& _globalState): m_globalState(_globalState) {}
void hash(uint64_t _value)
{
m_hash *= 1099511628211u;
m_hash ^= _value;
}
GlobalState& m_globalState;
bool isExternal(YulString _identifier) const;
uint64_t m_hash = 14695981039346656037u;
std::map<YulString, size_t> m_identifierMapping;
std::vector<YulString> m_externalIdentifiers;
std::set<YulString> m_externalAssignments;
std::set<YulString> m_externalReads;
size_t m_externalIdentifierCount = 0;
size_t m_internalIdentifierCount = 0;
bool m_isAssignmentLHS = false;
size_t m_loopDepth = 0;
bool m_hasFreeBreakOrContinue = false;
YulString m_functionName;
};
}