Merge pull request #1711 from ethereum/asmfunctions

Assembly: Analysis stage for functions.

1 files changed, 128 insertions, 0 deletions

diff --git a/libsolidity/inlineasm/AsmScope.h b/libsolidity/inlineasm/AsmScope.h
new file mode 100644
index 00000000..37e0f0b8
--- /dev/null
+++ b/libsolidity/inlineasm/AsmScope.h
@@ -0,0 +1,128 @@
+/*
+	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/>.
+*/
+/**
+ * Scopes for identifiers.
+ */
+
+#pragma once
+
+#include <libsolidity/interface/Exceptions.h>
+
+#include <boost/variant.hpp>
+
+#include <functional>
+#include <memory>
+
+namespace dev
+{
+namespace solidity
+{
+namespace assembly
+{
+
+template <class...>
+struct GenericVisitor{};
+
+template <class Visitable, class... Others>
+struct GenericVisitor<Visitable, Others...>: public GenericVisitor<Others...>
+{
+	using GenericVisitor<Others...>::operator ();
+	explicit GenericVisitor(
+		std::function<void(Visitable&)> _visitor,
+		std::function<void(Others&)>... _otherVisitors
+	):
+		GenericVisitor<Others...>(_otherVisitors...),
+		m_visitor(_visitor)
+	{}
+
+	void operator()(Visitable& _v) const { m_visitor(_v); }
+
+	std::function<void(Visitable&)> m_visitor;
+};
+template <>
+struct GenericVisitor<>: public boost::static_visitor<> {
+	void operator()() const {}
+};
+
+
+struct Scope
+{
+	struct Variable
+	{
+		/// Used during code generation to store the stack height. @todo move there.
+		int stackHeight = 0;
+		/// Used during analysis to check whether we already passed the declaration inside the block.
+		/// @todo move there.
+		bool active = false;
+	};
+
+	struct Label
+	{
+		size_t id = unassignedLabelId;
+		static const size_t errorLabelId = -1;
+		static const size_t unassignedLabelId = 0;
+	};
+
+	struct Function
+	{
+		Function(size_t _arguments, size_t _returns): arguments(_arguments), returns(_returns) {}
+		size_t arguments = 0;
+		size_t returns = 0;
+	};
+
+	using Identifier = boost::variant<Variable, Label, Function>;
+	using Visitor = GenericVisitor<Variable const, Label const, Function const>;
+	using NonconstVisitor = GenericVisitor<Variable, Label, Function>;
+
+	bool registerVariable(std::string const& _name);
+	bool registerLabel(std::string const& _name);
+	bool registerFunction(std::string const& _name, size_t _arguments, size_t _returns);
+
+	/// Looks up the identifier in this or super scopes and returns a valid pointer if found
+	/// or a nullptr if not found. Variable lookups up across function boundaries will fail, as
+	/// will any lookups across assembly boundaries.
+	/// The pointer will be invalidated if the scope is modified.
+	/// @param _crossedFunction if true, we already crossed a function boundary during recursive lookup
+	Identifier* lookup(std::string const& _name);
+	/// Looks up the identifier in this and super scopes (will not find variables across function
+	/// boundaries and generally stops at assembly boundaries) and calls the visitor, returns
+	/// false if not found.
+	template <class V>
+	bool lookup(std::string const& _name, V const& _visitor)
+	{
+		if (Identifier* id = lookup(_name))
+		{
+			boost::apply_visitor(_visitor, *id);
+			return true;
+		}
+		else
+			return false;
+	}
+	/// @returns true if the name exists in this scope or in super scopes (also searches
+	/// across function and assembly boundaries).
+	bool exists(std::string const& _name);
+
+	Scope* superScope = nullptr;
+	/// If true, variables from the super scope are not visible here (other identifiers are),
+	/// but they are still taken into account to prevent shadowing.
+	bool functionScope = false;
+	std::map<std::string, Identifier> identifiers;
+};
+
+}
+}
+}