From 90c98a3289dc9dc7ef1e8fb131de139e39427e13 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Thu, 19 Dec 2019 16:01:28 +0100
Subject: [PATCH] Introduce typed EVM dialect.

---
 libyul/AssemblyStack.cpp           |  2 +-
 libyul/backends/evm/EVMDialect.cpp | 64 +++++++++++++++++++++++++-----
 libyul/backends/evm/EVMDialect.h   | 20 +++++++++-
 3 files changed, 75 insertions(+), 11 deletions(-)

diff --git a/libyul/AssemblyStack.cpp b/libyul/AssemblyStack.cpp
index 35bcdf65c..87215179e 100644
--- a/libyul/AssemblyStack.cpp
+++ b/libyul/AssemblyStack.cpp
@@ -157,7 +157,7 @@ void AssemblyStack::compileEVM(AbstractAssembly& _assembly, bool _evm15, bool _o
 			dialect = &EVMDialect::strictAssemblyForEVMObjects(m_evmVersion);
 			break;
 		case Language::Yul:
-			dialect = &EVMDialect::yulForEVM(m_evmVersion);
+			dialect = &EVMDialectTyped::instance(m_evmVersion);
 			break;
 		default:
 			solAssert(false, "Invalid language.");
diff --git a/libyul/backends/evm/EVMDialect.cpp b/libyul/backends/evm/EVMDialect.cpp
index 6e2407ced..399445efa 100644
--- a/libyul/backends/evm/EVMDialect.cpp
+++ b/libyul/backends/evm/EVMDialect.cpp
@@ -203,15 +203,6 @@ EVMDialect const& EVMDialect::strictAssemblyForEVMObjects(langutil::EVMVersion _
 	return *dialects[_version];
 }
 
-EVMDialect const& EVMDialect::yulForEVM(langutil::EVMVersion _version)
-{
-	static map<langutil::EVMVersion, unique_ptr<EVMDialect const>> dialects;
-	static YulStringRepository::ResetCallback callback{[&] { dialects.clear(); }};
-	if (!dialects[_version])
-		dialects[_version] = make_unique<EVMDialect>(_version, false);
-	return *dialects[_version];
-}
-
 SideEffects EVMDialect::sideEffectsOfInstruction(evmasm::Instruction _instruction)
 {
 	return SideEffects{
@@ -222,3 +213,58 @@ SideEffects EVMDialect::sideEffectsOfInstruction(evmasm::Instruction _instructio
 		evmasm::SemanticInformation::invalidatesMemory(_instruction)
 	};
 }
+
+EVMDialectTyped::EVMDialectTyped(langutil::EVMVersion _evmVersion, bool _objectAccess):
+	EVMDialect(_evmVersion, _objectAccess)
+{
+	defaultType = "u256"_yulstring;
+	m_functions["lt"_yulstring].returns = {"bool"_yulstring};
+	m_functions["gt"_yulstring].returns = {"bool"_yulstring};
+	m_functions["slt"_yulstring].returns = {"bool"_yulstring};
+	m_functions["sgt"_yulstring].returns = {"bool"_yulstring};
+	m_functions["eq"_yulstring].returns = {"bool"_yulstring};
+	m_functions["iszero"_yulstring].returns = {"bool"_yulstring};
+	m_functions["bitand"_yulstring] = m_functions["and"_yulstring];
+	m_functions["bitor"_yulstring] = m_functions["or"_yulstring];
+	m_functions["bitxor"_yulstring] = m_functions["xor"_yulstring];
+	m_functions["and"_yulstring].parameters = {"bool"_yulstring, "bool"_yulstring};
+	m_functions["and"_yulstring].returns = {"bool"_yulstring};
+	m_functions["or"_yulstring].parameters = {"bool"_yulstring, "bool"_yulstring};
+	m_functions["or"_yulstring].returns = {"bool"_yulstring};
+	m_functions["xor"_yulstring].parameters = {"bool"_yulstring, "bool"_yulstring};
+	m_functions["xor"_yulstring].returns = {"bool"_yulstring};
+	m_functions["isfalse"_yulstring] = m_functions["iszero"_yulstring];
+	m_functions["isfalse"_yulstring].parameters = {"bool"_yulstring};
+	m_functions["popbool"_yulstring] = m_functions["pop"_yulstring];
+	m_functions["popbool"_yulstring].parameters = {"bool"_yulstring};
+	m_functions.insert(createFunction("bool_to_u256", 1, 1, {}, false, [](
+		FunctionCall const&,
+		AbstractAssembly&,
+		BuiltinContext&,
+		std::function<void()> _visitArguments
+	) {
+		_visitArguments();
+	}));
+	m_functions["bool_to_u256"_yulstring].parameters = {"bool"_yulstring};
+	m_functions.insert(createFunction("u256_to_bool", 1, 1, {}, false, [](
+		FunctionCall const&,
+		AbstractAssembly& _assembly,
+		BuiltinContext&,
+		std::function<void()> _visitArguments
+	) {
+		// TODO Should a value larger than 1 be invalid?
+		_visitArguments();
+		_assembly.appendInstruction(evmasm::Instruction::ISZERO);
+		_assembly.appendInstruction(evmasm::Instruction::ISZERO);
+	}));
+	m_functions["u256_to_bool"_yulstring].returns = {"bool"_yulstring};
+}
+
+EVMDialectTyped const& EVMDialectTyped::instance(langutil::EVMVersion _version)
+{
+	static map<langutil::EVMVersion, unique_ptr<EVMDialectTyped const>> dialects;
+	static YulStringRepository::ResetCallback callback{[&] { dialects.clear(); }};
+	if (!dialects[_version])
+		dialects[_version] = make_unique<EVMDialectTyped>(_version, true);
+	return *dialects[_version];
+}
diff --git a/libyul/backends/evm/EVMDialect.h b/libyul/backends/evm/EVMDialect.h
index 0d7d8b6d9..a670b020f 100644
--- a/libyul/backends/evm/EVMDialect.h
+++ b/libyul/backends/evm/EVMDialect.h
@@ -74,7 +74,6 @@ struct EVMDialect: public Dialect
 
 	static EVMDialect const& strictAssemblyForEVM(langutil::EVMVersion _version);
 	static EVMDialect const& strictAssemblyForEVMObjects(langutil::EVMVersion _version);
-	static EVMDialect const& yulForEVM(langutil::EVMVersion _version);
 
 	langutil::EVMVersion evmVersion() const { return m_evmVersion; }
 
@@ -88,4 +87,23 @@ protected:
 	std::map<YulString, BuiltinFunctionForEVM> m_functions;
 };
 
+/**
+ * EVM dialect with types u256 (default) and bool.
+ * Difference to EVMDialect:
+ *  - All comparison functions return type bool
+ *  - bitwise operations are called bitor, bitand, bitxor and bitnot
+ *  - and, or, xor take bool and return bool
+ *  - iszero returns bool
+ *  - isfalse takes bool and returns bool
+ *  - there are conversion functions bool_to_u256 and u256_to_bool.
+ *  - there is popbool
+ */
+struct EVMDialectTyped: public EVMDialect
+{
+	/// Constructor, should only be used internally. Use the factory function below.
+	EVMDialectTyped(langutil::EVMVersion _evmVersion, bool _objectAccess);
+
+	static EVMDialectTyped const& instance(langutil::EVMVersion _version);
+};
+
 }