Move CallGraph structure to a separate module

libsolidity/ast/CallGraph.cpp

@@ -0,0 +1,46 @@
+/*
+	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
+
+#include <libsolidity/ast/CallGraph.h>
+
+using namespace std;
+using namespace solidity::frontend;
+
+bool CallGraph::CompareByID::operator()(Node const& _lhs, Node const& _rhs) const
+{
+	if (_lhs.index() != _rhs.index())
+		return _lhs.index() < _rhs.index();
+
+	if (holds_alternative<SpecialNode>(_lhs))
+		return get<SpecialNode>(_lhs) < get<SpecialNode>(_rhs);
+	return get<CallableDeclaration const*>(_lhs)->id() < get<CallableDeclaration const*>(_rhs)->id();
+}
+
+bool CallGraph::CompareByID::operator()(Node const& _lhs, int64_t _rhs) const
+{
+	solAssert(!holds_alternative<SpecialNode>(_lhs), "");
+
+	return get<CallableDeclaration const*>(_lhs)->id() < _rhs;
+}
+
+bool CallGraph::CompareByID::operator()(int64_t _lhs, Node const& _rhs) const
+{
+	solAssert(!holds_alternative<SpecialNode>(_rhs), "");
+
+	return _lhs < get<CallableDeclaration const*>(_rhs)->id();
+}