Support member access

Author: matheusaaguiar

Changelog.md

@@ -3,6 +3,7 @@
 Language Features:
 
 Compiler Features:
+* Constant Evaluator: Support for constants referenced by member access expressions.
 * ethdebug: Experimental support for instructions and source locations under EOF.
 
 Bugfixes:

libsolidity/analysis/ConstantEvaluator.cpp

@@ -407,3 +407,15 @@ void ConstantEvaluator::endVisit(TupleExpression const& _tuple)
 	if (!_tuple.isInlineArray() && _tuple.components().size() == 1)
 		m_values[&_tuple] = evaluate(*_tuple.components().front());
 }
+
+void ConstantEvaluator::endVisit(MemberAccess const& _memberAccess)
+{
+	auto const* referencedDeclaration = _memberAccess.annotation().referencedDeclaration;
+	if (!referencedDeclaration)
+		return;
+	if (
+		auto const* variable = dynamic_cast<VariableDeclaration const*>(referencedDeclaration);
+		variable && variable->isConstant()
+	)
+		m_values[&_memberAccess] = evaluate(*variable);
+}

libsolidity/analysis/ConstantEvaluator.h

@@ -79,6 +79,7 @@ class ConstantEvaluator: private ASTConstVisitor
 	void endVisit(Literal const& _literal) override;
 	void endVisit(Identifier const& _identifier) override;
 	void endVisit(TupleExpression const& _tuple) override;
+	void endVisit(MemberAccess const& _memberAcess) override;
 
 	langutil::ErrorReporter& m_errorReporter;
 	/// Current recursion depth.

libsolidity/analysis/ReferencesResolver.cpp

@@ -39,6 +39,8 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/algorithm/string/split.hpp>
 
+#include <range/v3/algorithm/find_if.hpp>
+
 using namespace solidity;
 using namespace solidity::langutil;
 using namespace solidity::frontend;
@@ -504,3 +506,35 @@ void ReferencesResolver::validateYulIdentifierName(yul::YulName _name, SourceLoc
 			"The identifier name \"" + _name.str() + "\" is reserved."
 		);
 }
+
+void ReferencesResolver::endVisit(MemberAccess const& _memberAccess)
+{
+	// This is only for specific cases to support ConstantEvaluator.
+	std::vector<Declaration const*> candidates;
+	if (auto const* identifier = dynamic_cast<Identifier const*>(&_memberAccess.expression()))
+	{
+		if (auto const* contract = dynamic_cast<ContractDefinition const*>(identifier->annotation().referencedDeclaration))
+			candidates += contract->stateVariables();
+		else if (auto const* importedModule = dynamic_cast<ImportDirective const*>(identifier->annotation().referencedDeclaration))
+		{
+			SourceUnit const* sourceUnit = importedModule->annotation().sourceUnit;
+			solAssert(sourceUnit);
+			candidates += ASTNode::filteredNodes<VariableDeclaration>(sourceUnit->nodes());
+			candidates += ASTNode::filteredNodes<ContractDefinition>(sourceUnit->nodes());
+		}
+	}
+	else if (auto const* nestedMemberAccess = dynamic_cast<MemberAccess const*>(&_memberAccess.expression()))
+	{
+		auto const* contract = dynamic_cast<ContractDefinition const*>(nestedMemberAccess->annotation().referencedDeclaration);
+		if (!contract)
+			return;
+		candidates += contract->stateVariables();
+	}
+
+	auto declaration = ranges::find_if(
+		candidates,
+		[&](Declaration const* _declaration) { return _declaration->name() == _memberAccess.memberName(); }
+	);
+	if (declaration != ranges::end(candidates))
+		_memberAccess.annotation().referencedDeclaration = *declaration;
+}

libsolidity/analysis/ReferencesResolver.h

@@ -86,6 +86,7 @@ class ReferencesResolver: private ASTConstVisitor, private yul::ASTWalker
 	bool visit(Return const& _return) override;
 	bool visit(UsingForDirective const& _usingFor) override;
 	bool visit(BinaryOperation const& _binaryOperation) override;
+	void endVisit(MemberAccess const& _memberAccess) override;
 
 	void operator()(yul::FunctionDefinition const& _function) override;
 	void operator()(yul::Identifier const& _identifier) override;