Merge pull request ethereum#2224 from ethereum/julia-switch

Implement switch statement in the assembly parser/printer

libsolidity/inlineasm/AsmAnalysis.cpp

@@ -285,6 +285,48 @@ bool AsmAnalyzer::operator()(assembly::FunctionCall const& _funCall)
 	return success;
 }
 
+bool AsmAnalyzer::operator()(Switch const& _switch)
+{
+	bool success = true;
+
+	int const initialStackHeight = m_stackHeight;
+	if (!boost::apply_visitor(*this, *_switch.expression))
+		success = false;
+	expectDeposit(1, initialStackHeight, locationOf(*_switch.expression));
+
+	set<tuple<LiteralKind, string>> cases;
+	for (auto const& _case: _switch.cases)
+	{
+		if (_case.value)
+		{
+			int const initialStackHeight = m_stackHeight;
+			if (!(*this)(*_case.value))
+				success = false;
+			expectDeposit(1, initialStackHeight, _case.value->location);
+			m_stackHeight--;
+
+			/// Note: the parser ensures there is only one default case
+			auto val = make_tuple(_case.value->kind, _case.value->value);
+			if (!cases.insert(val).second)
+			{
+				m_errors.push_back(make_shared<Error>(
+					Error::Type::DeclarationError,
+					"Duplicate case defined",
+					_case.location
+				));
+				success = false;
+			}
+		}
+
+		if (!(*this)(_case.body))
+			success = false;
+	}
+
+	m_stackHeight--;
+
+	return success;
+}
+
 bool AsmAnalyzer::operator()(Block const& _block)
 {
 	bool success = true;

libsolidity/inlineasm/AsmAnalysis.h

@@ -47,6 +47,7 @@ struct Identifier;
 struct StackAssignment;
 struct FunctionDefinition;
 struct FunctionCall;
+struct Switch;
 
 struct Scope;
 
@@ -78,6 +79,7 @@ class AsmAnalyzer: public boost::static_visitor<bool>
 	bool operator()(assembly::VariableDeclaration const& _variableDeclaration);
 	bool operator()(assembly::FunctionDefinition const& _functionDefinition);
 	bool operator()(assembly::FunctionCall const& _functionCall);
+	bool operator()(assembly::Switch const& _switch);
 	bool operator()(assembly::Block const& _block);
 
 private:

libsolidity/inlineasm/AsmAnalysisInfo.h

@@ -43,10 +43,11 @@ struct Identifier;
 struct StackAssignment;
 struct FunctionDefinition;
 struct FunctionCall;
+struct Switch;
 
 struct Scope;
 
-using Statement = boost::variant<Instruction, Literal, Label, StackAssignment, Identifier, Assignment, FunctionCall, FunctionalInstruction, VariableDeclaration, FunctionDefinition, Block>;
+using Statement = boost::variant<Instruction, Literal, Label, StackAssignment, Identifier, Assignment, FunctionCall, FunctionalInstruction, VariableDeclaration, FunctionDefinition, Switch, Block>;
 
 struct AsmAnalysisInfo
 {

libsolidity/inlineasm/AsmCodeGen.cpp

@@ -266,6 +266,10 @@ class CodeTransform: public boost::static_visitor<>
 		CodeTransform(m_state, m_assembly, _block, m_identifierAccess, m_initialStackHeight);
 		checkStackHeight(&_block);
 	}
+	void operator()(assembly::Switch const&)
+	{
+		solAssert(false, "Switch not removed during desugaring phase.");
+	}
 	void operator()(assembly::FunctionDefinition const&)
 	{
 		solAssert(false, "Function definition not removed during desugaring phase.");

libsolidity/inlineasm/AsmData.h

@@ -50,9 +50,10 @@ struct VariableDeclaration;
 struct FunctionalInstruction;
 struct FunctionDefinition;
 struct FunctionCall;
+struct Switch;
 struct Block;
 
-using Statement = boost::variant<Instruction, Literal, Label, StackAssignment, Identifier, Assignment, FunctionCall, FunctionalInstruction, VariableDeclaration, FunctionDefinition, Block>;
+using Statement = boost::variant<Instruction, Literal, Label, StackAssignment, Identifier, Assignment, FunctionCall, FunctionalInstruction, VariableDeclaration, FunctionDefinition, Switch, Block>;
 
 /// Direct EVM instruction (except PUSHi and JUMPDEST)
 struct Instruction { SourceLocation location; solidity::Instruction instruction; };
@@ -77,6 +78,10 @@ struct VariableDeclaration { SourceLocation location; TypedNameList variables; s
 struct Block { SourceLocation location; std::vector<Statement> statements; };
 /// Function definition ("function f(a, b) -> (d, e) { ... }")
 struct FunctionDefinition { SourceLocation location; std::string name; TypedNameList arguments; TypedNameList returns; Block body; };
+/// Switch case or default case
+struct Case { SourceLocation location; std::shared_ptr<Literal> value; Block body; };
+/// Switch statement
+struct Switch { SourceLocation location; std::shared_ptr<Statement> expression; std::vector<Case> cases; };
 
 struct LocationExtractor: boost::static_visitor<SourceLocation>
 {

libsolidity/inlineasm/AsmParser.cpp

@@ -67,6 +67,26 @@ assembly::Statement Parser::parseStatement()
 		return parseFunctionDefinition();
 	case Token::LBrace:
 		return parseBlock();
+	case Token::Switch:
+	{
+		assembly::Switch _switch = createWithLocation<assembly::Switch>();
+		m_scanner->next();
+		_switch.expression = make_shared<Statement>(parseExpression());
+		if (_switch.expression->type() == typeid(assembly::Instruction))
+			fatalParserError("Instructions are not supported as expressions for switch.");
+		while (m_scanner->currentToken() == Token::Case)
+			_switch.cases.emplace_back(parseCase());
+		if (m_scanner->currentToken() == Token::Default)
+			_switch.cases.emplace_back(parseCase());
+		if (m_scanner->currentToken() == Token::Default)
+			fatalParserError("Only one default case allowed.");
+		else if (m_scanner->currentToken() == Token::Case)
+			fatalParserError("Case not allowed after default case.");
+		if (_switch.cases.size() == 0)
+			fatalParserError("Switch statement without any cases.");
+		_switch.location.end = _switch.cases.back().body.location.end;
+		return _switch;
+	}
 	case Token::Assign:
 	{
 		if (m_julia)
@@ -134,6 +154,26 @@ assembly::Statement Parser::parseStatement()
 	return statement;
 }
 
+assembly::Case Parser::parseCase()
+{
+	assembly::Case _case = createWithLocation<assembly::Case>();
+	if (m_scanner->currentToken() == Token::Default)
+		m_scanner->next();
+	else if (m_scanner->currentToken() == Token::Case)
+	{
+		m_scanner->next();
+		assembly::Statement statement = parseElementaryOperation();
+		if (statement.type() != typeid(assembly::Literal))
+			fatalParserError("Literal expected.");
+		_case.value = make_shared<Literal>(std::move(boost::get<assembly::Literal>(statement)));
+	}
+	else
+		fatalParserError("Case or default case expected.");
+	_case.body = parseBlock();
+	_case.location.end = _case.body.location.end;
+	return _case;
+}
+
 assembly::Statement Parser::parseExpression()
 {
 	Statement operation = parseElementaryOperation(true);

libsolidity/inlineasm/AsmParser.h

@@ -62,6 +62,7 @@ class Parser: public ParserBase
 
 	Block parseBlock();
 	Statement parseStatement();
+	Case parseCase();
 	/// Parses a functional expression that has to push exactly one stack element
 	Statement parseExpression();
 	std::map<std::string, dev::solidity::Instruction> const& instructions();

libsolidity/inlineasm/AsmPrinter.cpp

@@ -167,6 +167,20 @@ string AsmPrinter::operator()(assembly::FunctionCall const& _functionCall)
 		")";
 }
 
+string AsmPrinter::operator()(Switch const& _switch)
+{
+	string out = "switch " + boost::apply_visitor(*this, *_switch.expression);
+	for (auto const& _case: _switch.cases)
+	{
+		if (!_case.value)
+			out += "\ndefault ";
+		else
+			out += "\ncase " + (*this)(*_case.value) + " ";
+		out += (*this)(_case.body);
+	}
+	return out;
+}
+
 string AsmPrinter::operator()(Block const& _block)
 {
 	if (_block.statements.empty())

libsolidity/inlineasm/AsmPrinter.h

@@ -40,6 +40,7 @@ struct Assignment;
 struct VariableDeclaration;
 struct FunctionDefinition;
 struct FunctionCall;
+struct Switch;
 struct Block;
 
 class AsmPrinter: public boost::static_visitor<std::string>
@@ -57,6 +58,7 @@ class AsmPrinter: public boost::static_visitor<std::string>
 	std::string operator()(assembly::VariableDeclaration const& _variableDeclaration);
 	std::string operator()(assembly::FunctionDefinition const& _functionDefinition);
 	std::string operator()(assembly::FunctionCall const& _functionCall);
+	std::string operator()(assembly::Switch const& _switch);
 	std::string operator()(assembly::Block const& _block);
 
 private:

libsolidity/inlineasm/AsmScopeFiller.cpp

@@ -97,6 +97,15 @@ bool ScopeFiller::operator()(assembly::FunctionDefinition const& _funDef)
 	return success;
 }
 
+bool ScopeFiller::operator()(Switch const& _switch)
+{
+	bool success = true;
+	for (auto const& _case: _switch.cases)
+		if (!(*this)(_case.body))
+			success = false;
+	return success;
+}
+
 bool ScopeFiller::operator()(Block const& _block)
 {
 	bool success = true;

libsolidity/inlineasm/AsmScopeFiller.h

@@ -46,6 +46,7 @@ struct Identifier;
 struct StackAssignment;
 struct FunctionDefinition;
 struct FunctionCall;
+struct Switch;
 
 struct Scope;
 
@@ -69,6 +70,7 @@ class ScopeFiller: public boost::static_visitor<bool>
 	bool operator()(assembly::VariableDeclaration const& _variableDeclaration);
 	bool operator()(assembly::FunctionDefinition const& _functionDefinition);
 	bool operator()(assembly::FunctionCall const&) { return true; }
+	bool operator()(assembly::Switch const& _switch);
 	bool operator()(assembly::Block const& _block);
 
 private:

test/libsolidity/InlineAssembly.cpp

@@ -223,6 +223,53 @@ BOOST_AUTO_TEST_CASE(variable_use_before_decl)
 	CHECK_PARSE_ERROR("{ let x := mul(2, x) }", DeclarationError, "Variable x used before it was declared.");
 }
 
+BOOST_AUTO_TEST_CASE(switch_statement)
+{
+	BOOST_CHECK(successParse("{ switch 42 default {} }"));
+	BOOST_CHECK(successParse("{ switch 42 case 1 {} }"));
+	BOOST_CHECK(successParse("{ switch 42 case 1 {} case 2 {} }"));
+	BOOST_CHECK(successParse("{ switch 42 case 1 {} default {} }"));
+	BOOST_CHECK(successParse("{ switch 42 case 1 {} case 2 {} default {} }"));
+	BOOST_CHECK(successParse("{ switch mul(1, 2) case 1 {} case 2 {} default {} }"));
+	BOOST_CHECK(successParse("{ function f() -> x {} switch f() case 1 {} case 2 {} default {} }"));
+}
+
+BOOST_AUTO_TEST_CASE(switch_no_cases)
+{
+	CHECK_PARSE_ERROR("{ switch 42 }", ParserError, "Switch statement without any cases.");
+}
+
+BOOST_AUTO_TEST_CASE(switch_duplicate_case)
+{
+	CHECK_PARSE_ERROR("{ switch 42 case 1 {} case 1 {} default {} }", DeclarationError, "Duplicate case defined");
+}
+
+BOOST_AUTO_TEST_CASE(switch_invalid_expression)
+{
+	CHECK_PARSE_ERROR("{ switch {} default {} }", ParserError, "Expected elementary inline assembly operation.");
+	CHECK_PARSE_ERROR("{ 1 2 switch mul default {} }", ParserError, "Instructions are not supported as expressions for switch.");
+}
+
+BOOST_AUTO_TEST_CASE(switch_default_before_case)
+{
+	CHECK_PARSE_ERROR("{ switch 42 default {} case 1 {} }", ParserError, "Case not allowed after default case.");
+}
+
+BOOST_AUTO_TEST_CASE(switch_duplicate_default_case)
+{
+	CHECK_PARSE_ERROR("{ switch 42 default {} default {} }", ParserError, "Only one default case allowed.");
+}
+
+BOOST_AUTO_TEST_CASE(switch_invalid_case)
+{
+	CHECK_PARSE_ERROR("{ switch 42 case mul(1, 2) {} case 2 {} default {} }", ParserError, "Literal expected.");
+}
+
+BOOST_AUTO_TEST_CASE(switch_invalid_body)
+{
+	CHECK_PARSE_ERROR("{ switch 42 case 1 mul case 2 {} default {} }", ParserError, "Expected token LBrace got 'Identifier'");
+}
+
 BOOST_AUTO_TEST_CASE(blocks)
 {
 	BOOST_CHECK(successParse("{ let x := 7 { let y := 3 } { let z := 2 } }"));
@@ -336,6 +383,11 @@ BOOST_AUTO_TEST_CASE(print_string_literal_unicode)
 	parsePrintCompare(parsed);
 }
 
+BOOST_AUTO_TEST_CASE(print_switch)
+{
+	parsePrintCompare("{\n    switch 42\n    case 1 {\n    }\n    case 2 {\n    }\n    default {\n    }\n}");
+}
+
 BOOST_AUTO_TEST_CASE(function_definitions_multiple_args)
 {
 	parsePrintCompare("{\n    function f(a, d)\n    {\n        mstore(a, d)\n    }\n    function g(a, d) -> x, y\n    {\n    }\n}");