/*

  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 <libsolidity/analysis/ControlFlowGraph.h>

#include <libsolidity/ast/AST.h>

#include <libsolidity/ast/ASTVisitor.h>

#include <libyul/optimiser/ASTWalker.h>

#include <array>

#include <memory>

namespace solidity::frontend

{

/**

 * Helper class that builds the control flow of a function or modifier.

 */

class ControlFlowBuilder: private ASTConstVisitor, private yul::ASTWalker

{

public:

  static std::unique_ptr<FunctionFlow> createFunctionFlow(

    CFG::NodeContainer& _nodeContainer,

    FunctionDefinition const& _function,

    ContractDefinition const* _contract

  );

private:

  explicit ControlFlowBuilder(

    CFG::NodeContainer& _nodeContainer,

    FunctionFlow const& _functionFlow,

    ContractDefinition const* _contract

  );

  // Visits for constructing the control flow.

  bool visit(BinaryOperation const& _operation) override;

  bool visit(UnaryOperation const& _operation) override;

  bool visit(Conditional const& _conditional) override;

  bool visit(TryStatement const& _tryStatement) override;

  bool visit(IfStatement const& _ifStatement) override;

  bool visit(ForStatement const& _forStatement) override;

  bool visit(WhileStatement const& _whileStatement) override;

  bool visit(Break const&) override;

  bool visit(Continue const&) override;

  bool visit(Throw const&) override;

  bool visit(RevertStatement const&) override;

  bool visit(PlaceholderStatement const&) override;

  bool visit(FunctionCall const& _functionCall) override;

  bool visit(ModifierInvocation const& _modifierInvocation) override;

  // Visits for constructing the control flow as well as filling variable occurrences.

  bool visit(FunctionDefinition const& _functionDefinition) override;

  bool visit(Return const& _return) override;

  // Visits for filling variable occurrences.

  bool visit(FunctionTypeName const& _functionTypeName) override;

  bool visit(InlineAssembly const& _inlineAssembly) override;

  void visit(yul::Statement const& _statement) override;

  void operator()(yul::If const& _if) override;

  void operator()(yul::Switch const& _switch) override;

  void operator()(yul::ForLoop const& _for) override;

  void operator()(yul::Break const&) override;

  void operator()(yul::Continue const&) override;

  void operator()(yul::Identifier const& _identifier) override;

  void operator()(yul::Assignment const& _assignment) override;

  void operator()(yul::FunctionCall const& _functionCall) override;

  void operator()(yul::FunctionDefinition const& _functionDefinition) override;

  void operator()(yul::Leave const& _leaveStatement) override;

  bool visit(VariableDeclaration const& _variableDeclaration) override;

  bool visit(VariableDeclarationStatement const& _variableDeclarationStatement) override;

  bool visit(Identifier const& _identifier) override;

protected:

  bool visitNode(ASTNode const&) override;

private:

  using ASTConstVisitor::visit;

  using yul::ASTWalker::visit;

  using yul::ASTWalker::operator();

  /// Appends the control flow of @a _node to the current control flow.

  void appendControlFlow(ASTNode const& _node);

  /// Starts at @a _entry and parses the control flow of @a _node.

  /// @returns The node at which the parsed control flow ends.

  /// m_currentNode is not affected (it is saved and restored).

  CFGNode* createFlow(CFGNode* _entry, ASTNode const& _node);

  /// Creates an arc from @a _from to @a _to.

  static void connect(CFGNode* _from, CFGNode* _to);

  /// Splits the control flow starting at the current node into n paths.

  /// m_currentNode is set to nullptr and has to be set manually or

  /// using mergeFlow later.

  template<size_t n>

  std::array<CFGNode*, n> splitFlow()

  {

    std::array<CFGNode*, n> result;

    for (auto& node: result)

    {

      node = m_nodeContainer.newNode();

      connect(m_currentNode, node);

    }

    m_currentNode = nullptr;

    return result;

  }

  /// Splits the control flow starting at the current node into @a _n paths.

  /// m_currentNode is set to nullptr and has to be set manually or

  /// using mergeFlow later.

  std::vector<CFGNode*> splitFlow(size_t n)

  {

    std::vector<CFGNode*> result(n);

    for (auto& node: result)

    {

      node = m_nodeContainer.newNode();

      connect(m_currentNode, node);

    }

    m_currentNode = nullptr;

    return result;

  }

  /// Merges the control flow of @a _nodes to @a _endNode.

  /// If @a _endNode is nullptr, a new node is created and used as end node.

  /// Sets the merge destination as current node.

  /// Note: @a _endNode may be one of the nodes in @a _nodes.

  template<typename C>

  void mergeFlow(C const& _nodes, CFGNode* _endNode = nullptr)

  {

    CFGNode* mergeDestination = (_endNode == nullptr) ? m_nodeContainer.newNode() : _endNode;

    for (auto& node: _nodes)

      if (node != mergeDestination)

        connect(node, mergeDestination);

    m_currentNode = mergeDestination;

  }

void solidity::frontend::ControlFlowBuilder::mergeFlow<std::__1::array<solidity::frontend::CFGNode*, 2ul> >(std::__1::array<solidity::frontend::CFGNode*, 2ul> const&, solidity::frontend::CFGNode*)

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  {

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    CFGNode* mergeDestination = (_endNode == nullptr) ? m_nodeContainer.newNode() : _endNode;

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    for (auto& node: _nodes)

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      if (node != mergeDestination)

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        connect(node, mergeDestination);

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    m_currentNode = mergeDestination;

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  }

void solidity::frontend::ControlFlowBuilder::mergeFlow<std::__1::vector<solidity::frontend::CFGNode*, std::__1::allocator<solidity::frontend::CFGNode*> > >(std::__1::vector<solidity::frontend::CFGNode*, std::__1::allocator<solidity::frontend::CFGNode*> > const&, solidity::frontend::CFGNode*)

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  {

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    CFGNode* mergeDestination = (_endNode == nullptr) ? m_nodeContainer.newNode() : _endNode;

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    for (auto& node: _nodes)

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      if (node != mergeDestination)

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        connect(node, mergeDestination);

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    m_currentNode = mergeDestination;

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  }

  CFGNode* newLabel();

  CFGNode* createLabelHere();

  void placeAndConnectLabel(CFGNode *_node);

  CFG::NodeContainer& m_nodeContainer;

  CFGNode* m_currentNode = nullptr;

  CFGNode* m_returnNode = nullptr;

  CFGNode* m_revertNode = nullptr;

  CFGNode* m_transactionReturnNode = nullptr;

  ContractDefinition const* m_contract = nullptr;

  /// The current jump destination of break Statements.

  CFGNode* m_breakJump = nullptr;

  /// The current jump destination of continue Statements.

  CFGNode* m_continueJump = nullptr;

  CFGNode* m_placeholderEntry = nullptr;

  CFGNode* m_placeholderExit = nullptr;

  InlineAssembly const* m_inlineAssembly = nullptr;

  /// Helper class that replaces the break and continue jump destinations for the

  /// current scope and restores the originals at the end of the scope.

  class BreakContinueScope

  {

  public:

    BreakContinueScope(ControlFlowBuilder& _parser, CFGNode* _breakJump, CFGNode* _continueJump);

    ~BreakContinueScope();

  private:

    ControlFlowBuilder& m_parser;

    CFGNode* m_origBreakJump;

    CFGNode* m_origContinueJump;

  };

};

}