solidity/libyul/ControlFlowSideEffectsCollector.h

131 lines
3.9 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
#pragma once
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/ControlFlowSideEffects.h>
#include <set>
#include <stack>
#include <optional>
#include <list>
namespace solidity::yul
{
struct Dialect;
struct ControlFlowNode
{
std::vector<ControlFlowNode const*> successors;
/// Name of the called function if the node calls a function.
std::optional<YulString> functionCall;
};
/**
* The control flow of a function with entry and exit nodes.
*/
struct FunctionFlow
{
ControlFlowNode const* entry;
ControlFlowNode const* exit;
};
/**
* Requires: Disambiguator, Function Hoister.
*/
class ControlFlowBuilder: private ASTWalker
{
public:
/// Computes the control-flows of all function defined in the block.
/// Assumes the functions are hoisted to the topmost block.
explicit ControlFlowBuilder(Block const& _ast);
std::map<YulString, FunctionFlow> const& functionFlows() const { return m_functionFlows; }
private:
using ASTWalker::operator();
void operator()(FunctionCall const& _functionCall) override;
void operator()(If const& _if) override;
void operator()(Switch const& _switch) override;
void operator()(FunctionDefinition const& _functionDefinition) override;
void operator()(ForLoop const& _forLoop) override;
void operator()(Break const& _break) override;
void operator()(Continue const& _continue) override;
void operator()(Leave const& _leaveStatement) override;
void newConnectedNode();
ControlFlowNode* newNode();
std::vector<std::shared_ptr<ControlFlowNode>> m_nodes;
ControlFlowNode* m_currentNode = nullptr;
ControlFlowNode const* m_leave = nullptr;
ControlFlowNode const* m_break = nullptr;
ControlFlowNode const* m_continue = nullptr;
std::map<YulString, FunctionFlow> m_functionFlows;
};
/**
* Requires: Disambiguator, Function Hoister.
*/
class ControlFlowSideEffectsCollector
{
public:
explicit ControlFlowSideEffectsCollector(
Dialect const& _dialect,
Block const& _ast
);
std::map<YulString, ControlFlowSideEffects> const& functionSideEffects() const
{
return m_functionSideEffects;
}
private:
/// @returns false if nothing could be processed.
bool processFunction(YulString _name);
/// @returns the next pending node of the function that is not
/// a function call to a function that might not continue.
/// De-queues the node or returns nullptr if no such node is found.
ControlFlowNode const* nextProcessableNode(YulString _functionName);
/// @returns the side-effects of either a builtin call or a user defined function
/// call (as far as already computed).
ControlFlowSideEffects const& sideEffects(YulString _functionName) const;
/// Queues the given node to be processed (if not already visited)
/// and if it is a function call, records that `_functionName` calls
/// `*_node->functionCall`.
void recordReachabilityAndQueue(YulString _functionName, ControlFlowNode const* _node);
Dialect const& m_dialect;
ControlFlowBuilder m_cfgBuilder;
std::map<YulString, ControlFlowSideEffects> m_functionSideEffects;
std::map<YulString, std::list<ControlFlowNode const*>> m_pendingNodes;
std::map<YulString, std::set<ControlFlowNode const*>> m_processedNodes;
/// `x` is in `m_functionCalls[y]` if a direct call to `x` is reachable inside `y`
std::map<YulString, std::set<YulString>> m_functionCalls;
};
}