[Yul] Adds break/continue keywords in parsing and EVM code generation.

christianparpart · christianparpart · commit a122e9355785 · 2019-03-04T09:11:58.000+01:00
diff --git a/libsolidity/analysis/ViewPureChecker.cpp b/libsolidity/analysis/ViewPureChecker.cpp
@@ -94,6 +94,12 @@ class AssemblyViewPureChecker: public boost::static_visitor<void>
 		(*this)(_for.body);
 		(*this)(_for.post);
 	}
+	void operator()(yul::Break const&)
+	{
+	}
+	void operator()(yul::Continue const&)
+	{
+	}
 	void operator()(yul::Block const& _block)
 	{
 		for (auto const& s: _block.statements)
diff --git a/libyul/AsmAnalysis.h b/libyul/AsmAnalysis.h
@@ -93,6 +93,8 @@ class AsmAnalyzer: public boost::static_visitor<bool>
 	bool operator()(If const& _if);
 	bool operator()(Switch const& _switch);
 	bool operator()(ForLoop const& _forLoop);
+	bool operator()(Break const&) { return true; }
+	bool operator()(Continue const&) { return true; }
 	bool operator()(Block const& _block);
 
 private:
diff --git a/libyul/AsmData.h b/libyul/AsmData.h
@@ -78,6 +78,10 @@ struct Case { langutil::SourceLocation location; std::unique_ptr<Literal> value;
 /// Switch statement
 struct Switch { langutil::SourceLocation location; std::unique_ptr<Expression> expression; std::vector<Case> cases; };
 struct ForLoop { langutil::SourceLocation location; Block pre; std::unique_ptr<Expression> condition; Block post; Block body; };
+/// Break statement (valid within for loop)
+struct Break { langutil::SourceLocation location; };
+/// Continue statement (valid within for loop)
+struct Continue { langutil::SourceLocation location; };
 
 struct LocationExtractor: boost::static_visitor<langutil::SourceLocation>
 {
diff --git a/libyul/AsmDataForward.h b/libyul/AsmDataForward.h
@@ -41,12 +41,14 @@ struct If;
 struct Switch;
 struct Case;
 struct ForLoop;
+struct Break;
+struct Continue;
 struct ExpressionStatement;
 struct Block;
 
 struct TypedName;
 
 using Expression = boost::variant<FunctionalInstruction, FunctionCall, Identifier, Literal>;
-using Statement = boost::variant<ExpressionStatement, Instruction, Label, StackAssignment, Assignment, VariableDeclaration, FunctionDefinition, If, Switch, ForLoop, Block>;
+using Statement = boost::variant<ExpressionStatement, Instruction, Label, StackAssignment, Assignment, VariableDeclaration, FunctionDefinition, If, Switch, ForLoop, Break, Continue, Block>;
 
 }
diff --git a/libyul/AsmParser.cpp b/libyul/AsmParser.cpp
@@ -23,6 +23,7 @@
 #include <libyul/AsmParser.h>
 #include <liblangutil/Scanner.h>
 #include <liblangutil/ErrorReporter.h>
+#include <libdevcore/Utils.h>
 
 #include <boost/algorithm/string.hpp>
 
@@ -104,6 +105,28 @@ Statement Parser::parseStatement()
 	}
 	case Token::For:
 		return parseForLoop();
+	case Token::Break:
+		if (m_forLoopDepth > 0)
+		{
+			m_scanner->next();
+			return Statement{ createWithLocation<Break>() };
+		}
+		else
+		{
+			m_errorReporter.syntaxError(location(), "Keyword break outside for-loop is not allowed.");
+			break;
+		}
+	case Token::Continue:
+		if (m_forLoopDepth > 0)
+		{
+			m_scanner->next();
+			return Statement{ createWithLocation<Continue>() };
+		}
+		else
+		{
+			m_errorReporter.syntaxError(location(), "Keyword continue outside for-loop is not allowed.");
+			break;
+		}
 	case Token::Assign:
 	{
 		if (m_dialect->flavour != AsmFlavour::Loose)
@@ -245,6 +268,7 @@ ForLoop Parser::parseForLoop()
 {
 	RecursionGuard recursionGuard(*this);
 	ForLoop forLoop = createWithLocation<ForLoop>();
+	auto loopDepthGuard = scopedIncrement(m_forLoopDepth);
 	expectToken(Token::For);
 	forLoop.pre = parseBlock();
 	forLoop.condition = make_unique<Expression>(parseExpression());
diff --git a/libyul/AsmParser.h b/libyul/AsmParser.h
@@ -39,7 +39,7 @@ class Parser: public langutil::ParserBase
 {
 public:
 	explicit Parser(langutil::ErrorReporter& _errorReporter, std::shared_ptr<Dialect> _dialect):
-		ParserBase(_errorReporter), m_dialect(std::move(_dialect)) {}
+		ParserBase(_errorReporter), m_dialect(std::move(_dialect)), m_forLoopDepth{0} {}
 
 	/// Parses an inline assembly block starting with `{` and ending with `}`.
 	/// @param _reuseScanner if true, do check for end of input after the `}`.
@@ -87,6 +87,7 @@ class Parser: public langutil::ParserBase
 
 private:
 	std::shared_ptr<Dialect> m_dialect;
+	int m_forLoopDepth;
 };
 
 }
diff --git a/libyul/AsmPrinter.cpp b/libyul/AsmPrinter.cpp
@@ -224,6 +224,16 @@ string AsmPrinter::operator()(ForLoop const& _forLoop) const
 	return out;
 }
 
+string AsmPrinter::operator()(Break const&) const
+{
+	return "break";
+}
+
+string AsmPrinter::operator()(Continue const&) const
+{
+	return "continue";
+}
+
 string AsmPrinter::operator()(Block const& _block) const
 {
 	if (_block.statements.empty())
diff --git a/libyul/AsmPrinter.h b/libyul/AsmPrinter.h
@@ -50,6 +50,8 @@ class AsmPrinter: public boost::static_visitor<std::string>
 	std::string operator()(If const& _if) const;
 	std::string operator()(Switch const& _switch) const;
 	std::string operator()(ForLoop const& _forLoop) const;
+	std::string operator()(Break const& _break) const;
+	std::string operator()(Continue const& _continue) const;
 	std::string operator()(Block const& _block) const;
 
 private:
diff --git a/libyul/AsmScopeFiller.h b/libyul/AsmScopeFiller.h
@@ -63,6 +63,8 @@ class ScopeFiller: public boost::static_visitor<bool>
 	bool operator()(If const& _if);
 	bool operator()(Switch const& _switch);
 	bool operator()(ForLoop const& _forLoop);
+	bool operator()(Break const&) { return true; }
+	bool operator()(Continue const&) { return true; }
 	bool operator()(Block const& _block);
 
 private:
diff --git a/libyul/backends/evm/EVMCodeTransform.cpp b/libyul/backends/evm/EVMCodeTransform.cpp
@@ -68,7 +68,6 @@ void VariableReferenceCounter::operator()(ForLoop const& _forLoop)
 	m_scope = originalScope;
 }
 
-
 void VariableReferenceCounter::operator()(Block const& _block)
 {
 	Scope* originalScope = m_scope;
@@ -91,7 +90,6 @@ void VariableReferenceCounter::increaseRefIfFound(YulString _variableName)
 	));
 }
 
-
 CodeTransform::CodeTransform(
 	AbstractAssembly& _assembly,
 	AsmAnalysisInfo& _analysisInfo,
@@ -619,8 +617,10 @@ void CodeTransform::operator()(ForLoop const& _forLoop)
 	// TODO: When we implement break and continue, the labels and the stack heights at that point
 	// have to be stored in a stack.
 	AbstractAssembly::LabelID loopStart = m_assembly.newLabelId();
-	AbstractAssembly::LabelID loopEnd = m_assembly.newLabelId();
 	AbstractAssembly::LabelID postPart = m_assembly.newLabelId();
+	AbstractAssembly::LabelID loopEnd = m_assembly.newLabelId();
+
+	m_context->forLoopStack.emplace(Context::ForLoopLabels{postPart, loopEnd});
 
 	m_assembly.setSourceLocation(_forLoop.location);
 	m_assembly.appendLabel(loopStart);
@@ -642,9 +642,24 @@ void CodeTransform::operator()(ForLoop const& _forLoop)
 	m_assembly.appendLabel(loopEnd);
 
 	finalizeBlock(_forLoop.pre, stackStartHeight);
+	m_context->forLoopStack.pop();
 	m_scope = originalScope;
 }
 
+void CodeTransform::operator()(Break const& _break)
+{
+	yulAssert(!m_context->forLoopStack.empty(), "Invalid break-statement. Requires surrounding for-loop in code generation.");
+	m_assembly.setSourceLocation(_break.location);
+	m_assembly.appendLabel(m_context->forLoopStack.top().done);
+}
+
+void CodeTransform::operator()(Continue const& _continue)
+{
+	yulAssert(!m_context->forLoopStack.empty(), "Invalid continue-statement. Requires surrounding for-loop in code generation.");
+	m_assembly.setSourceLocation(_continue.location);
+	m_assembly.appendLabel(m_context->forLoopStack.top().post);
+}
+
 void CodeTransform::operator()(Block const& _block)
 {
 	Scope* originalScope = m_scope;
diff --git a/libyul/backends/evm/EVMCodeTransform.h b/libyul/backends/evm/EVMCodeTransform.h
@@ -30,6 +30,8 @@
 #include <boost/variant.hpp>
 #include <boost/optional.hpp>
 
+#include <stack>
+
 namespace langutil
 {
 class ErrorReporter;
@@ -57,6 +59,13 @@ struct CodeTransformContext
 	std::map<Scope::Function const*, AbstractAssembly::LabelID> functionEntryIDs;
 	std::map<Scope::Variable const*, int> variableStackHeights;
 	std::map<Scope::Variable const*, unsigned> variableReferences;
+
+	struct ForLoopLabels {
+		AbstractAssembly::LabelID post; ///< jump label to the beginning of the post-expression
+		AbstractAssembly::LabelID done; ///< jump label to the end of the for-loop
+	};
+
+	std::stack<ForLoopLabels> forLoopStack;
 };
 
 /**
@@ -166,6 +175,8 @@ class CodeTransform: public boost::static_visitor<>
 	void operator()(Switch const& _switch);
 	void operator()(FunctionDefinition const&);
 	void operator()(ForLoop const&);
+	void operator()(Break const&);
+	void operator()(Continue const&);
 	void operator()(Block const& _block);
 
 private:
diff --git a/libyul/optimiser/ASTCopier.cpp b/libyul/optimiser/ASTCopier.cpp
@@ -138,6 +138,15 @@ Statement ASTCopier::operator()(ForLoop const& _forLoop)
 		translate(_forLoop.body)
 	};
 }
+Statement ASTCopier::operator()(Break const& _break)
+{
+	return Break{ _break };
+}
+
+Statement ASTCopier::operator()(Continue const& _continue)
+{
+	return Continue{ _continue };
+}
 
 Statement ASTCopier::operator ()(Block const& _block)
 {
diff --git a/libyul/optimiser/ASTCopier.h b/libyul/optimiser/ASTCopier.h
@@ -58,6 +58,8 @@ class StatementCopier: public boost::static_visitor<Statement>
 	virtual Statement operator()(Switch const& _switch) = 0;
 	virtual Statement operator()(FunctionDefinition const&) = 0;
 	virtual Statement operator()(ForLoop const&) = 0;
+	virtual Statement operator()(Break const&) = 0;
+	virtual Statement operator()(Continue const&) = 0;
 	virtual Statement operator()(Block const& _block) = 0;
 };
 
@@ -83,6 +85,8 @@ class ASTCopier: public ExpressionCopier, public StatementCopier
 	Statement operator()(Switch const& _switch) override;
 	Statement operator()(FunctionDefinition const&) override;
 	Statement operator()(ForLoop const&) override;
+	Statement operator()(Break const&) override;
+	Statement operator()(Continue const&) override;
 	Statement operator()(Block const& _block) override;
 
 	virtual Expression translate(Expression const& _expression);
diff --git a/libyul/optimiser/ASTWalker.cpp b/libyul/optimiser/ASTWalker.cpp
@@ -161,6 +161,14 @@ void ASTModifier::operator()(ForLoop& _for)
 	(*this)(_for.body);
 }
 
+void ASTModifier::operator()(Break&)
+{
+}
+
+void ASTModifier::operator()(Continue&)
+{
+}
+
 void ASTModifier::operator()(Block& _block)
 {
 	walkVector(_block.statements);
diff --git a/libyul/optimiser/ASTWalker.h b/libyul/optimiser/ASTWalker.h
@@ -56,6 +56,8 @@ class ASTWalker: public boost::static_visitor<>
 	virtual void operator()(Switch const& _switch);
 	virtual void operator()(FunctionDefinition const&);
 	virtual void operator()(ForLoop const&);
+	virtual void operator()(Break const&) {}
+	virtual void operator()(Continue const&) {}
 	virtual void operator()(Block const& _block);
 
 	virtual void visit(Statement const& _st);
@@ -91,6 +93,8 @@ class ASTModifier: public boost::static_visitor<>
 	virtual void operator()(Switch& _switch);
 	virtual void operator()(FunctionDefinition&);
 	virtual void operator()(ForLoop&);
+	virtual void operator()(Break&);
+	virtual void operator()(Continue&);
 	virtual void operator()(Block& _block);
 
 	virtual void visit(Statement& _st);
diff --git a/libyul/optimiser/SyntacticalEquality.h b/libyul/optimiser/SyntacticalEquality.h
@@ -55,6 +55,8 @@ class SyntacticallyEqual
 	bool statementEqual(Switch const& _lhs, Switch const& _rhs);
 	bool switchCaseEqual(Case const& _lhs, Case const& _rhs);
 	bool statementEqual(ForLoop const& _lhs, ForLoop const& _rhs);
+	bool statementEqual(Break const& _lhs, Break const& _rhs) { return true; }
+	bool statementEqual(Continue const& _lhs, Continue const& _rhs) { return true; }
 	bool statementEqual(Block const& _lhs, Block const& _rhs);
 private:
 	bool statementEqual(Instruction const& _lhs, Instruction const& _rhs);

Original file line number	Diff line number	Diff line change
`@@ -94,6 +94,12 @@ class AssemblyViewPureChecker: public boost::static_visitor<void>`
`94`	`94`	`(*this)(_for.body);`
`95`	`95`	`(*this)(_for.post);`
`96`	`96`	`}`
	`97`	`+ void operator()(yul::Break const&)`
	`98`	`+ {`
	`99`	`+ }`
	`100`	`+ void operator()(yul::Continue const&)`
	`101`	`+ {`
	`102`	`+ }`
`97`	`103`	`void operator()(yul::Block const& _block)`
`98`	`104`	`{`
`99`	`105`	`for (auto const& s: _block.statements)`
Original file line number	Diff line number	Diff line change
`@@ -39,7 +39,7 @@ class Parser: public langutil::ParserBase`
`39`	`39`	`{`
`40`	`40`	`public:`
`41`	`41`	`explicit Parser(langutil::ErrorReporter& _errorReporter, std::shared_ptr<Dialect> _dialect):`
`42`		`- ParserBase(_errorReporter), m_dialect(std::move(_dialect)) {}`
	`42`	`+ ParserBase(_errorReporter), m_dialect(std::move(_dialect)), m_forLoopDepth{0} {}`
`43`	`43`
`44`	`44`	/// Parses an inline assembly block starting with `{` and ending with `}`.
`45`	`45`	/// @param _reuseScanner if true, do check for end of input after the `}`.
`@@ -87,6 +87,7 @@ class Parser: public langutil::ParserBase`
`87`	`87`
`88`	`88`	`private:`
`89`	`89`	`std::shared_ptr<Dialect> m_dialect;`
	`90`	`+ int m_forLoopDepth;`
`90`	`91`	`};`
`91`	`92`
`92`	`93`	`}`