Merge pull request #6658 from ethereum/stringLiterals

[SolYul] String literals

libsolidity/codegen/YulUtilFunctions.cpp

@@ -606,6 +606,9 @@ string YulUtilFunctions::allocationFunction()
 
 string YulUtilFunctions::conversionFunction(Type const& _from, Type const& _to)
 {
+	if (_from.sizeOnStack() != 1 || _to.sizeOnStack() != 1)
+		return conversionFunctionSpecial(_from, _to);
+
 	string functionName =
 		"convert_" +
 		_from.identifier() +
@@ -923,3 +926,69 @@ string YulUtilFunctions::suffixedVariableNameList(string const& _baseName, size_
 	}
 	return result;
 }
+
+string YulUtilFunctions::conversionFunctionSpecial(Type const& _from, Type const& _to)
+{
+	string functionName =
+		"convert_" +
+		_from.identifier() +
+		"_to_" +
+		_to.identifier();
+	return m_functionCollector->createFunction(functionName, [&]() {
+		solUnimplementedAssert(
+			_from.category() == Type::Category::StringLiteral,
+			"Type conversion " + _from.toString() + " -> " + _to.toString() + " not yet implemented."
+		);
+		string const& data = dynamic_cast<StringLiteralType const&>(_from).value();
+		if (_to.category() == Type::Category::FixedBytes)
+		{
+			unsigned const numBytes = dynamic_cast<FixedBytesType const&>(_to).numBytes();
+			solAssert(data.size() <= 32, "");
+			Whiskers templ(R"(
+				function <functionName>() -> converted {
+					converted := <data>
+				}
+			)");
+			templ("functionName", functionName);
+			templ("data", formatNumber(
+				h256::Arith(h256(data, h256::AlignLeft)) &
+				(~(u256(-1) >> (8 * numBytes)))
+			));
+			return templ.render();
+		}
+		else if (_to.category() == Type::Category::Array)
+		{
+			auto const& arrayType = dynamic_cast<ArrayType const&>(_to);
+			solAssert(arrayType.isByteArray(), "");
+			size_t words = (data.size() + 31) / 32;
+			size_t storageSize = 32 + words * 32;
+
+			Whiskers templ(R"(
+				function <functionName>() -> converted {
+					converted := <allocate>(<storageSize>)
+					mstore(converted, <size>)
+					<#word>
+						mstore(add(converted, <offset>), <wordValue>)
+					</word>
+				}
+			)");
+			templ("functionName", functionName);
+			templ("allocate", allocationFunction());
+			templ("storageSize", to_string(storageSize));
+			templ("size", to_string(data.size()));
+			vector<map<string, string>> wordParams(words);
+			for (size_t i = 0; i < words; ++i)
+			{
+				wordParams[i]["offset"] = to_string(32 + i * 32);
+				wordParams[i]["wordValue"] = "0x" + h256(data.substr(32 * i, 32), h256::AlignLeft).hex();
+			}
+			templ("word", wordParams);
+			return templ.render();
+		}
+		else
+			solAssert(
+				false,
+				"Invalid conversion from string literal to " + _to.toString() + " requested."
+			);
+	});
+}

libsolidity/codegen/YulUtilFunctions.h

@@ -155,6 +155,11 @@ public:
 	static std::string suffixedVariableNameList(std::string const& _baseName, size_t _startSuffix, size_t _endSuffix);
 
 private:
+
+	/// Special case of conversionFunction - handles everything that does not
+	/// use exactly one variable to hold the value.
+	std::string conversionFunctionSpecial(Type const& _from, Type const& _to);
+
 	langutil::EVMVersion m_evmVersion;
 	std::shared_ptr<MultiUseYulFunctionCollector> m_functionCollector;
 };

libsolidity/codegen/ir/IRGeneratorForStatements.cpp

@@ -357,7 +357,6 @@ bool IRGeneratorForStatements::visit(Literal const& _literal)
 		defineExpression(_literal) << toCompactHexWithPrefix(literalType.literalValue(&_literal)) << "\n";
 		break;
 	case Type::Category::StringLiteral:
-		solUnimplemented("");
 		break; // will be done during conversion
 	default:
 		solUnimplemented("Only integer, boolean and string literals implemented for now.");
@@ -368,12 +367,20 @@ bool IRGeneratorForStatements::visit(Literal const& _literal)
 string IRGeneratorForStatements::expressionAsType(Expression const& _expression, Type const& _to)
 {
 	Type const& from = type(_expression);
-	string varName = m_context.variable(_expression);
-
-	if (from == _to)
-		return varName;
+	if (from.sizeOnStack() == 0)
+	{
+		solAssert(from != _to, "");
+		return m_utils.conversionFunction(from, _to) + "()";
+	}
 	else
-		return m_utils.conversionFunction(from, _to) + "(" + std::move(varName) + ")";
+	{
+		string varName = m_context.variable(_expression);
+
+		if (from == _to)
+			return varName;
+		else
+			return m_utils.conversionFunction(from, _to) + "(" + std::move(varName) + ")";
+	}
 }
 
 ostream& IRGeneratorForStatements::defineExpression(Expression const& _expression)

test/libsolidity/semanticTests/viaYul/string_literals.sol

@@ -0,0 +1,29 @@
+contract C {
+    function short_dyn() public pure returns (string memory x) {
+        x = "abc";
+    }
+    function long_dyn() public pure returns (string memory x) {
+        x = "12345678901234567890123456789012345678901234567890123456789012345678901234567890";
+    }
+    function short_bytes_dyn() public pure returns (bytes memory x) {
+        x = "abc";
+    }
+    function long_bytes_dyn() public pure returns (bytes memory x) {
+        x = "12345678901234567890123456789012345678901234567890123456789012345678901234567890";
+    }
+    function bytesNN() public pure returns (bytes3 x) {
+        x = "abc";
+    }
+    function bytesNN_padded() public pure returns (bytes4 x) {
+        x = "abc";
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// short_dyn() -> 0x20, 3, "abc"
+// long_dyn() -> 0x20, 80, "12345678901234567890123456789012", "34567890123456789012345678901234", "5678901234567890"
+// short_bytes_dyn() -> 0x20, 3, "abc"
+// long_bytes_dyn() -> 0x20, 80, "12345678901234567890123456789012", "34567890123456789012345678901234", "5678901234567890"
+// bytesNN() -> 0x6162630000000000000000000000000000000000000000000000000000000000
+// bytesNN_padded() -> 0x6162630000000000000000000000000000000000000000000000000000000000