From 81569f720883735ee6eee0a16173df63d2180d12 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Thu, 16 Jan 2020 19:13:25 +0100
Subject: [PATCH] Remove Scope::Label.

---
 libyul/AsmAnalysis.cpp                   | 12 ----------
 libyul/AsmScope.cpp                      |  8 -------
 libyul/AsmScope.h                        |  5 +---
 libyul/backends/evm/EVMCodeTransform.cpp | 30 ------------------------
 libyul/backends/evm/EVMCodeTransform.h   |  4 ----
 5 files changed, 1 insertion(+), 58 deletions(-)

diff --git a/libyul/AsmAnalysis.cpp b/libyul/AsmAnalysis.cpp
index 5a88671ce..148eeabfe 100644
--- a/libyul/AsmAnalysis.cpp
+++ b/libyul/AsmAnalysis.cpp
@@ -123,10 +123,6 @@ bool AsmAnalyzer::operator()(Identifier const& _identifier)
 			}
 			++m_stackHeight;
 		},
-		[&](Scope::Label const&)
-		{
-			++m_stackHeight;
-		},
 		[&](Scope::Function const&)
 		{
 			m_errorReporter.typeError(
@@ -293,14 +289,6 @@ bool AsmAnalyzer::operator()(FunctionCall const& _funCall)
 			);
 			success = false;
 		},
-		[&](Scope::Label const&)
-		{
-			m_errorReporter.typeError(
-				_funCall.functionName.location,
-				"Attempt to call label instead of function."
-			);
-			success = false;
-		},
 		[&](Scope::Function const& _fun)
 		{
 			/// TODO: compare types too
diff --git a/libyul/AsmScope.cpp b/libyul/AsmScope.cpp
index ae39fc10d..86dbce483 100644
--- a/libyul/AsmScope.cpp
+++ b/libyul/AsmScope.cpp
@@ -25,14 +25,6 @@ using namespace solidity;
 using namespace solidity::yul;
 using namespace solidity::util;
 
-bool Scope::registerLabel(YulString _name)
-{
-	if (exists(_name))
-		return false;
-	identifiers[_name] = Label();
-	return true;
-}
-
 bool Scope::registerVariable(YulString _name, YulType const& _type)
 {
 	if (exists(_name))
diff --git a/libyul/AsmScope.h b/libyul/AsmScope.h
index a452e04ba..6da1ff1e0 100644
--- a/libyul/AsmScope.h
+++ b/libyul/AsmScope.h
@@ -37,20 +37,17 @@ namespace solidity::yul
 struct Scope
 {
 	using YulType = YulString;
-	using LabelID = size_t;
 
 	struct Variable { YulType type; };
-	struct Label { };
 	struct Function
 	{
 		std::vector<YulType> arguments;
 		std::vector<YulType> returns;
 	};
 
-	using Identifier = std::variant<Variable, Label, Function>;
+	using Identifier = std::variant<Variable, Function>;
 
 	bool registerVariable(YulString _name, YulType const& _type);
-	bool registerLabel(YulString _name);
 	bool registerFunction(
 		YulString _name,
 		std::vector<YulType> _arguments,
diff --git a/libyul/backends/evm/EVMCodeTransform.cpp b/libyul/backends/evm/EVMCodeTransform.cpp
index 9f95d1257..f8ce12017 100644
--- a/libyul/backends/evm/EVMCodeTransform.cpp
+++ b/libyul/backends/evm/EVMCodeTransform.cpp
@@ -88,7 +88,6 @@ void VariableReferenceCounter::increaseRefIfFound(YulString _variableName)
 		{
 			++m_context.variableReferences[&_var];
 		},
-		[=](Scope::Label const&) { },
 		[=](Scope::Function const&) { }
 	});
 }
@@ -286,7 +285,6 @@ void CodeTransform::operator()(FunctionCall const& _call)
 		Scope::Function* function = nullptr;
 		yulAssert(m_scope->lookup(_call.functionName.name, GenericVisitor{
 			[=](Scope::Variable&) { yulAssert(false, "Expected function name."); },
-			[=](Scope::Label&) { yulAssert(false, "Expected function name."); },
 			[&](Scope::Function& _function) { function = &_function; }
 		}), "Function name not found.");
 		yulAssert(function, "");
@@ -323,10 +321,6 @@ void CodeTransform::operator()(Identifier const& _identifier)
 				m_assembly.appendConstant(u256(0));
 			decreaseReference(_identifier.name, _var);
 		},
-		[=](Scope::Label& _label)
-		{
-			m_assembly.appendLabelReference(labelID(_label));
-		},
 		[=](Scope::Function&)
 		{
 			yulAssert(false, "Function not removed during desugaring.");
@@ -634,30 +628,6 @@ void CodeTransform::operator()(Block const& _block)
 		BOOST_THROW_EXCEPTION(m_stackErrors.front());
 }
 
-AbstractAssembly::LabelID CodeTransform::labelFromIdentifier(Identifier const& _identifier)
-{
-	AbstractAssembly::LabelID label = AbstractAssembly::LabelID(-1);
-	if (!m_scope->lookup(_identifier.name, GenericVisitor{
-		[=](Scope::Variable&) { yulAssert(false, "Expected label"); },
-		[&](Scope::Label& _label)
-		{
-			label = labelID(_label);
-		},
-		[=](Scope::Function&) { yulAssert(false, "Expected label"); }
-	}))
-	{
-		yulAssert(false, "Identifier not found.");
-	}
-	return label;
-}
-
-AbstractAssembly::LabelID CodeTransform::labelID(Scope::Label const& _label)
-{
-	if (!m_context->labelIDs.count(&_label))
-		m_context->labelIDs[&_label] = m_assembly.newLabelId();
-	return m_context->labelIDs[&_label];
-}
-
 AbstractAssembly::LabelID CodeTransform::functionEntryID(YulString _name, Scope::Function const& _function)
 {
 	if (!m_context->functionEntryIDs.count(&_function))
diff --git a/libyul/backends/evm/EVMCodeTransform.h b/libyul/backends/evm/EVMCodeTransform.h
index 2c2c5991d..fb50be95f 100644
--- a/libyul/backends/evm/EVMCodeTransform.h
+++ b/libyul/backends/evm/EVMCodeTransform.h
@@ -53,7 +53,6 @@ struct StackTooDeepError: virtual YulException
 
 struct CodeTransformContext
 {
-	std::map<Scope::Label const*, AbstractAssembly::LabelID> labelIDs;
 	std::map<Scope::Function const*, AbstractAssembly::LabelID> functionEntryIDs;
 	std::map<Scope::Variable const*, int> variableStackHeights;
 	std::map<Scope::Variable const*, unsigned> variableReferences;
@@ -187,9 +186,6 @@ public:
 
 private:
 	AbstractAssembly::LabelID labelFromIdentifier(Identifier const& _identifier);
-	/// @returns the label ID corresponding to the given label, allocating a new one if
-	/// necessary.
-	AbstractAssembly::LabelID labelID(Scope::Label const& _label);
 	AbstractAssembly::LabelID functionEntryID(YulString _name, Scope::Function const& _function);
 	/// Generates code for an expression that is supposed to return a single value.
 	void visitExpression(Expression const& _expression);