Merge pull request #15001 from ethereum/transientStorageParserHack

Enable parser to accept `transient` as data location or identifier

Author: matheusaaguiar

Changelog.md

@@ -1,6 +1,7 @@
 ### 0.8.27 (unreleased)
 
 Language Features:
+ * Accept declarations of state variables with ``transient`` data location (parser support only, no code generation yet).
 
 
 Compiler Features:

docs/grammar/SolidityLexer.g4

@@ -85,6 +85,7 @@ SignedIntegerType:
 Storage: 'storage';
 String: 'string';
 Struct: 'struct';
+Transient: 'transient';  // not a real keyword
 True: 'true';
 Try: 'try';
 Type: 'type';

docs/grammar/SolidityParser.g4

@@ -262,7 +262,7 @@ userDefinedValueTypeDefinition:
  * The declaration of a state variable.
  */
 stateVariableDeclaration
-locals [boolean constantnessSet = false, boolean visibilitySet = false, boolean overrideSpecifierSet = false]
+locals [boolean constantnessSet = false, boolean visibilitySet = false, boolean overrideSpecifierSet = false, boolean locationSet = false]
 :
 	type=typeName
 	(
@@ -272,6 +272,7 @@ locals [boolean constantnessSet = false, boolean visibilitySet = false, boolean
 		| {!$constantnessSet}? Constant {$constantnessSet = true;}
 		| {!$overrideSpecifierSet}? overrideSpecifier {$overrideSpecifierSet = true;}
 		| {!$constantnessSet}? Immutable {$constantnessSet = true;}
+		| {!$locationSet}? Transient {$locationSet = true;}
 	)*
 	name=identifier
 	(Assign initialValue=expression)?
@@ -419,7 +420,7 @@ inlineArrayExpression: LBrack (expression ( Comma expression)* ) RBrack;
 /**
  * Besides regular non-keyword Identifiers, some keywords like 'from' and 'error' can also be used as identifiers.
  */
-identifier: Identifier | From | Error | Revert | Global;
+identifier: Identifier | From | Error | Revert | Global | Transient;
 
 literal: stringLiteral | numberLiteral | booleanLiteral | hexStringLiteral | unicodeStringLiteral;
 

libsolidity/analysis/DeclarationTypeChecker.cpp

@@ -407,6 +407,7 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 			{
 				case Location::Memory: return "\"memory\"";
 				case Location::Storage: return "\"storage\"";
+				case Location::Transient: return "\"transient\"";
 				case Location::CallData: return "\"calldata\"";
 				case Location::Unspecified: return "none";
 			}
@@ -456,8 +457,24 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 	}
 	else if (_variable.isStateVariable())
 	{
-		solAssert(varLoc == Location::Unspecified, "");
-		typeLoc = (_variable.isConstant() || _variable.immutable()) ? DataLocation::Memory : DataLocation::Storage;
+		switch (varLoc)
+		{
+			case Location::Unspecified:
+				typeLoc = (_variable.isConstant() || _variable.immutable()) ? DataLocation::Memory : DataLocation::Storage;
+				break;
+			case Location::Transient:
+				if (_variable.isConstant() || _variable.immutable())
+					m_errorReporter.declarationError(
+						2197_error,
+						_variable.location(),
+						"Transient cannot be used as data location for constant or immutable variables."
+					);
+				typeLoc = DataLocation::Transient;
+				break;
+			default:
+				solAssert(false);
+				break;
+		}
 	}
 	else if (
 		dynamic_cast<StructDefinition const*>(_variable.scope()) ||
@@ -477,6 +494,9 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 			case Location::CallData:
 				typeLoc = DataLocation::CallData;
 				break;
+			case Location::Transient:
+				solUnimplemented("Transient data location cannot be used in this kind of variable or parameter declaration.");
+				break;
 			case Location::Unspecified:
 				solAssert(!_variable.hasReferenceOrMappingType(), "Data location not properly set.");
 		}
@@ -497,6 +517,9 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 			m_errorReporter.fatalTypeError(9259_error, _variable.location(), "Only constants of value type and byte array type are implemented.");
 	}
 
+	if (!type->isValueType())
+		solUnimplementedAssert(typeLoc != DataLocation::Transient, "Transient data location is only supported for value types.");
+
 	_variable.annotation().type = type;
 }
 

libsolidity/ast/AST.cpp

@@ -816,7 +816,9 @@ std::set<VariableDeclaration::Location> VariableDeclaration::allowedDataLocation
 {
 	using Location = VariableDeclaration::Location;
 
-	if (!hasReferenceOrMappingType() || isStateVariable() || isEventOrErrorParameter())
+	if (isStateVariable())
+		return std::set<Location>{Location::Unspecified, Location::Transient};
+	else if (!hasReferenceOrMappingType() || isEventOrErrorParameter())
 		return std::set<Location>{ Location::Unspecified };
 	else if (isCallableOrCatchParameter())
 	{

libsolidity/ast/AST.h

@@ -1052,7 +1052,7 @@ class FunctionDefinition: public CallableDeclaration, public StructurallyDocumen
 class VariableDeclaration: public Declaration, public StructurallyDocumented
 {
 public:
-	enum Location { Unspecified, Storage, Memory, CallData };
+	enum Location { Unspecified, Storage, Transient, Memory, CallData };
 	enum class Mutability { Mutable, Immutable, Constant };
 	static std::string mutabilityToString(Mutability _mutability)
 	{

libsolidity/ast/ASTJsonExporter.cpp

@@ -1058,6 +1058,8 @@ std::string ASTJsonExporter::location(VariableDeclaration::Location _location)
 		return "memory";
 	case VariableDeclaration::Location::CallData:
 		return "calldata";
+	case VariableDeclaration::Location::Transient:
+		return "transient";
 	}
 	// To make the compiler happy
 	return {};

libsolidity/ast/ASTJsonImporter.cpp

@@ -1190,6 +1190,8 @@ VariableDeclaration::Location ASTJsonImporter::location(Json const& _node)
 		return VariableDeclaration::Location::Memory;
 	else if (storageLocStr == "calldata")
 		return VariableDeclaration::Location::CallData;
+	else if (storageLocStr == "transient")
+		return VariableDeclaration::Location::Transient;
 	else
 		astAssert(false, "Unknown location declaration");
 

libsolidity/ast/Types.cpp

@@ -1544,6 +1544,8 @@ TypeResult ReferenceType::unaryOperatorResult(Token _operator) const
 		return TypeProvider::emptyTuple();
 	case DataLocation::Storage:
 		return isPointer() ? nullptr : TypeProvider::emptyTuple();
+	case DataLocation::Transient:
+		solUnimplemented("Transient data location is only supported for value types.");
 	}
 	return nullptr;
 }
@@ -1571,6 +1573,9 @@ std::string ReferenceType::stringForReferencePart() const
 		return "calldata";
 	case DataLocation::Memory:
 		return "memory";
+	case DataLocation::Transient:
+		solUnimplemented("Transient data location is only supported for value types.");
+		break;
 	}
 	solAssert(false, "");
 	return "";
@@ -1584,6 +1589,9 @@ std::string ReferenceType::identifierLocationSuffix() const
 	case DataLocation::Storage:
 		id += "_storage";
 		break;
+	case DataLocation::Transient:
+		solUnimplemented("Transient data location is only supported for value types.");
+		break;
 	case DataLocation::Memory:
 		id += "_memory";
 		break;
@@ -1748,6 +1756,9 @@ BoolResult ArrayType::validForLocation(DataLocation _loc) const
 			if (storageSizeUpperBound() >= bigint(1) << 256)
 				return BoolResult::err("Type too large for storage.");
 			break;
+		case DataLocation::Transient:
+			solUnimplemented("Transient data location is only supported for value types.");
+			break;
 	}
 	return true;
 }
@@ -1828,6 +1839,9 @@ std::vector<std::tuple<std::string, Type const*>> ArrayType::makeStackItems() co
 		case DataLocation::Storage:
 			// byte offset inside storage value is omitted
 			return {std::make_tuple("slot", TypeProvider::uint256())};
+		case DataLocation::Transient:
+			solUnimplemented("Transient data location is only supported for value types.");
+			break;
 	}
 	solAssert(false, "");
 }
@@ -2568,6 +2582,9 @@ std::vector<std::tuple<std::string, Type const*>> StructType::makeStackItems() c
 			return {std::make_tuple("mpos", TypeProvider::uint256())};
 		case DataLocation::Storage:
 			return {std::make_tuple("slot", TypeProvider::uint256())};
+		case DataLocation::Transient:
+			solUnimplemented("Transient data location is only supported for value types.");
+			break;
 	}
 	solAssert(false, "");
 }

libsolidity/ast/Types.h

@@ -70,7 +70,7 @@ inline rational makeRational(bigint const& _numerator, bigint const& _denominato
 		return rational(_numerator, _denominator);
 }
 
-enum class DataLocation { Storage, CallData, Memory };
+enum class DataLocation { Storage, Transient, CallData, Memory };
 
 
 /**