Implement function modifiers.

libsolidity/codegen/ir/IRGeneratorForStatements.h

@@ -40,8 +40,13 @@ class YulUtilFunctions;
 class IRGeneratorForStatements: public ASTConstVisitor
 {
 public:
-	IRGeneratorForStatements(IRGenerationContext& _context, YulUtilFunctions& _utils):
+	IRGeneratorForStatements(
+		IRGenerationContext& _context,
+		YulUtilFunctions& _utils,
+		std::function<std::string()> _placeholderCallback = {}
+	):
 		m_context(_context),
+		m_placeholderCallback(std::move(_placeholderCallback)),
 		m_utils(_utils)
 	{}
 
@@ -58,6 +63,9 @@ public:
 	/// Calculates expression's value and returns variable where it was stored
 	IRVariable evaluateExpression(Expression const& _expression, Type const& _to);
 
+	/// Defines @a _var using the value of @a _value while performing type conversions, if required.
+	void define(IRVariable const& _var, IRVariable const& _value) { declareAssign(_var, _value, true); }
+
 	/// @returns the name of a function that computes the value of the given constant
 	/// and also generates the function.
 	std::string constantValueFunction(VariableDeclaration const& _constant);
@@ -66,6 +74,7 @@ public:
 	bool visit(Conditional const& _conditional) override;
 	bool visit(Assignment const& _assignment) override;
 	bool visit(TupleExpression const& _tuple) override;
+	void endVisit(PlaceholderStatement const& _placeholder) override;
 	bool visit(Block const& _block) override;
 	void endVisit(Block const& _block) override;
 	bool visit(IfStatement const& _ifStatement) override;
@@ -135,8 +144,7 @@ private:
 	/// @returns an output stream that can be used to define @a _var using a function call or
 	/// single stack slot expression.
 	std::ostream& define(IRVariable const& _var);
-	/// Defines @a _var using the value of @a _value while performing type conversions, if required.
-	void define(IRVariable const& _var, IRVariable const& _value) { declareAssign(_var, _value, true); }
+
 	/// Assigns @a _var to the value of @a _value while performing type conversions, if required.
 	void assign(IRVariable const& _var, IRVariable const& _value) { declareAssign(_var, _value, false); }
 	/// Declares variable @a _var.
@@ -189,6 +197,7 @@ private:
 
 	std::ostringstream m_code;
 	IRGenerationContext& m_context;
+	std::function<std::string()> m_placeholderCallback;
 	YulUtilFunctions& m_utils;
 	std::optional<IRLValue> m_currentLValue;
 	langutil::SourceLocation m_currentLocation;