From 35908c602b775863a198bcb09e069e1bb291b5f8 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Wed, 2 Dec 2020 18:00:04 +0100
Subject: [PATCH] Modifiers for constructors.

---
 libsolidity/codegen/ir/IRGenerator.cpp        | 42 ++++++++++++++-----
 ..._calling_functions_in_creation_context.sol |  2 +
 .../function_modifier_for_constructor.sol     |  3 +-
 3 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/libsolidity/codegen/ir/IRGenerator.cpp b/libsolidity/codegen/ir/IRGenerator.cpp
index fef88aeb7..ac7475a7a 100644
--- a/libsolidity/codegen/ir/IRGenerator.cpp
+++ b/libsolidity/codegen/ir/IRGenerator.cpp
@@ -639,7 +639,6 @@ string IRGenerator::initStateVariables(ContractDefinition const& _contract)
 
 void IRGenerator::generateImplicitConstructors(ContractDefinition const& _contract)
 {
-	// TODO reset local variables somewhere here.
 	auto listAllParams = [&](
 		map<ContractDefinition const*, vector<string>> const& baseParams) -> vector<string>
 	{
@@ -656,6 +655,7 @@ void IRGenerator::generateImplicitConstructors(ContractDefinition const& _contra
 		ContractDefinition const* contract = _contract.annotation().linearizedBaseContracts[i];
 		baseConstructorParams.erase(contract);
 
+		m_context.resetLocalVariables();
 		m_context.functionCollector().createFunction(IRNames::implicitConstructor(*contract), [&]() {
 			Whiskers t(R"(
 				function <functionName>(<params><comma><baseParams>) {
@@ -667,16 +667,8 @@ void IRGenerator::generateImplicitConstructors(ContractDefinition const& _contra
 			)");
 			vector<string> params;
 			if (contract->constructor())
-			{
-				for (auto const& modifierInvocation: contract->constructor()->modifiers())
-					// This can be ContractDefinition too for super arguments. That is supported.
-					solUnimplementedAssert(
-						!dynamic_cast<ModifierDefinition const*>(modifierInvocation->name().annotation().referencedDeclaration),
-						"Modifiers not implemented yet."
-					);
 				for (ASTPointer<VariableDeclaration> const& varDecl: contract->constructor()->parameters())
 					params += m_context.addLocalVariable(*varDecl).stackSlots();
-			}
 			t("params", joinHumanReadable(params));
 			vector<string> baseParams = listAllParams(baseConstructorParams);
 			t("baseParams", joinHumanReadable(baseParams));
@@ -695,7 +687,37 @@ void IRGenerator::generateImplicitConstructors(ContractDefinition const& _contra
 			else
 				t("hasNextConstructor", false);
 			t("initStateVariables", initStateVariables(*contract));
-			t("userDefinedConstructorBody", contract->constructor() ? generate(contract->constructor()->body()) : "");
+			string body;
+			if (FunctionDefinition const* constructor = contract->constructor())
+			{
+				vector<ModifierInvocation*> realModifiers;
+				for (auto const& modifierInvocation: constructor->modifiers())
+					// Filter out the base constructor calls
+					if (dynamic_cast<ModifierDefinition const*>(modifierInvocation->name().annotation().referencedDeclaration))
+						realModifiers.emplace_back(modifierInvocation.get());
+				if (realModifiers.empty())
+					body = generate(constructor->body());
+				else
+				{
+					for (size_t i = 0; i < realModifiers.size(); ++i)
+					{
+						ModifierInvocation const& modifier = *realModifiers.at(i);
+						string next =
+							i + 1 < realModifiers.size() ?
+							IRNames::modifierInvocation(*realModifiers.at(i + 1)) :
+							IRNames::functionWithModifierInner(*constructor);
+						generateModifier(modifier, *constructor, next);
+					}
+					body =
+						IRNames::modifierInvocation(*constructor->modifiers().at(0)) +
+						"(" +
+						joinHumanReadable(params) +
+						")";
+					// Now generate the actual inner function.
+					generateFunctionWithModifierInner(*constructor);
+				}
+			}
+			t("userDefinedConstructorBody", move(body));
 
 			return t.render();
 		});
diff --git a/test/libsolidity/semanticTests/modifiers/function_modifier_calling_functions_in_creation_context.sol b/test/libsolidity/semanticTests/modifiers/function_modifier_calling_functions_in_creation_context.sol
index ebe8d6086..86eb9ffc6 100644
--- a/test/libsolidity/semanticTests/modifiers/function_modifier_calling_functions_in_creation_context.sol
+++ b/test/libsolidity/semanticTests/modifiers/function_modifier_calling_functions_in_creation_context.sol
@@ -45,5 +45,7 @@ contract C is A {
     }
 }
 
+// ====
+// compileViaYul: also
 // ----
 // getData() -> 0x4300
diff --git a/test/libsolidity/semanticTests/modifiers/function_modifier_for_constructor.sol b/test/libsolidity/semanticTests/modifiers/function_modifier_for_constructor.sol
index c05f7e202..005d8cafa 100644
--- a/test/libsolidity/semanticTests/modifiers/function_modifier_for_constructor.sol
+++ b/test/libsolidity/semanticTests/modifiers/function_modifier_for_constructor.sol
@@ -22,6 +22,7 @@ contract C is A {
         _;
     }
 }
-
+// ====
+// compileViaYul: also
 // ----
 // getData() -> 6