Compute packing offsets.

Types.cpp

@@ -35,6 +35,56 @@ namespace dev
 namespace solidity
 {
 
+std::pair<u256, unsigned> const* MemberList::getMemberStorageOffset(string const& _name) const
+{
+	if (!m_storageOffsets)
+	{
+		bigint slotOffset = 0;
+		unsigned byteOffset = 0;
+		map<string, pair<u256, unsigned>> offsets;
+		for (auto const& nameAndType: m_memberTypes)
+		{
+			TypePointer const& type = nameAndType.second;
+			if (!type->canBeStored())
+				continue;
+			if (byteOffset + type->getStorageBytes() > 32)
+			{
+				// would overflow, go to next slot
+				++slotOffset;
+				byteOffset = 0;
+			}
+			if (slotOffset >= bigint(1) << 256)
+				BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Object too large for storage."));
+			offsets[nameAndType.first] = make_pair(u256(slotOffset), byteOffset);
+			solAssert(type->getStorageSize() >= 1, "Invalid storage size.");
+			if (type->getStorageSize() == 1 && byteOffset + type->getStorageBytes() <= 32)
+				byteOffset += type->getStorageBytes();
+			else
+			{
+				slotOffset += type->getStorageSize();
+				byteOffset = 0;
+			}
+		}
+		if (byteOffset > 0)
+			++slotOffset;
+		if (slotOffset >= bigint(1) << 256)
+			BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Object too large for storage."));
+		m_storageSize = u256(slotOffset);
+		m_storageOffsets.reset(new decltype(offsets)(move(offsets)));
+	}
+	if (m_storageOffsets->count(_name))
+		return &((*m_storageOffsets)[_name]);
+	else
+		return nullptr;
+}
+
+u256 const& MemberList::getStorageSize() const
+{
+	// trigger lazy computation
+	getMemberStorageOffset("");
+	return m_storageSize;
+}
+
 TypePointer Type::fromElementaryTypeName(Token::Value _typeToken)
 {
 	char const* tokenCstr = Token::toString(_typeToken);
@@ -751,12 +801,7 @@ bool StructType::operator==(Type const& _other) const
 
 u256 StructType::getStorageSize() const
 {
-	bigint size = 0;
+	return max<u256>(1, getMembers().getStorageSize());
-	for (pair<string, TypePointer> const& member: getMembers())
-		size += member.second->getStorageSize();
-	if (size >= bigint(1) << 256)
-		BOOST_THROW_EXCEPTION(TypeError() << errinfo_comment("Struct too large for storage."));
-	return max<u256>(1, u256(size));
 }
 
 bool StructType::canLiveOutsideStorage() const
@@ -787,6 +832,7 @@ MemberList const& StructType::getMembers() const
 
 u256 StructType::getStorageOffsetOfMember(string const& _name) const
 {
+
 	//@todo cache member offset?
 	u256 offset;
 	for (ASTPointer<VariableDeclaration> const& variable: m_struct.getMembers())
@@ -811,6 +857,15 @@ bool EnumType::operator==(Type const& _other) const
 	return other.m_enum == m_enum;
 }
 
+unsigned EnumType::getStorageBytes() const
+{
+	size_t elements = m_enum.getMembers().size();
+	if (elements <= 1)
+		return 1;
+	else
+		return dev::bytesRequired(elements - 1);
+}
+
 string EnumType::toString() const
 {
 	return string("enum ") + m_enum.getName();
@@ -955,6 +1010,13 @@ string FunctionType::toString() const
 	return name + ")";
 }
 
+u256 FunctionType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable function type requested."));
+}
+
 unsigned FunctionType::getSizeOnStack() const
 {
 	Location location = m_location;
@@ -1077,6 +1139,13 @@ string MappingType::toString() const
 	return "mapping(" + getKeyType()->toString() + " => " + getValueType()->toString() + ")";
 }
 
+u256 VoidType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable void type requested."));
+}
+
 bool TypeType::operator==(Type const& _other) const
 {
 	if (_other.getCategory() != getCategory())
@@ -1085,6 +1154,13 @@ bool TypeType::operator==(Type const& _other) const
 	return *getActualType() == *other.getActualType();
 }
 
+u256 TypeType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable type type requested."));
+}
+
 MemberList const& TypeType::getMembers() const
 {
 	// We need to lazy-initialize it because of recursive references.
@@ -1122,6 +1198,13 @@ ModifierType::ModifierType(const ModifierDefinition& _modifier)
 	swap(params, m_parameterTypes);
 }
 
+u256 ModifierType::getStorageSize() const
+{
+	BOOST_THROW_EXCEPTION(
+		InternalCompilerError()
+			<< errinfo_comment("Storage size of non-storable type type requested."));
+}
+
 bool ModifierType::operator==(Type const& _other) const
 {
 	if (_other.getCategory() != getCategory())

Types.h

@@ -60,12 +60,19 @@ public:
 				return it.second;
 		return TypePointer();
 	}
+	/// @returns the offset of the given member in storage slots and bytes inside a slot or
+	/// a nullptr if the member is not part of storage.
+	std::pair<u256, unsigned> const* getMemberStorageOffset(std::string const& _name) const;
+	/// @returns the number of storage slots occupied by the members.
+	u256 const& getStorageSize() const;
 
 	MemberMap::const_iterator begin() const { return m_memberTypes.begin(); }
 	MemberMap::const_iterator end() const { return m_memberTypes.end(); }
 
 private:
 	MemberMap m_memberTypes;
+	mutable u256 m_storageSize = 0;
+	mutable std::unique_ptr<std::map<std::string, std::pair<u256, unsigned>>> m_storageOffsets;
 };
 
 /**
@@ -97,6 +104,8 @@ public:
 	/// @returns a pointer to _a or _b if the other is implicitly convertible to it or nullptr otherwise
 	static TypePointer commonType(TypePointer const& _a, TypePointer const& _b);
 
+	/// Calculates the
+
 	virtual Category getCategory() const = 0;
 	virtual bool isImplicitlyConvertibleTo(Type const& _other) const { return *this == _other; }
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const
@@ -126,9 +135,15 @@ public:
 	unsigned getCalldataEncodedSize() const { return getCalldataEncodedSize(true); }
 	/// @returns true if the type is dynamically encoded in calldata
 	virtual bool isDynamicallySized() const { return false; }
-	/// @returns number of bytes required to hold this value in storage.
+	/// @returns the number of storage slots required to hold this value in storage.
 	/// For dynamically "allocated" types, it returns the size of the statically allocated head,
 	virtual u256 getStorageSize() const { return 1; }
+	/// Multiple small types can be packed into a single storage slot. If such a packing is possible
+	/// this function @returns the size in bytes smaller than 32. Data is moved to the next slot if
+	/// it does not fit.
+	/// In order to avoid computation at runtime of whether such moving is necessary, structs and
+	/// array data (not each element) always start a new slot.
+	virtual unsigned getStorageBytes() const { return 32; }
 	/// Returns true if the type can be stored in storage.
 	virtual bool canBeStored() const { return true; }
 	/// Returns false if the type cannot live outside the storage, i.e. if it includes some mapping.
@@ -179,6 +194,7 @@ public:
 	virtual bool operator==(Type const& _other) const override;
 
 	virtual unsigned getCalldataEncodedSize(bool _padded = true) const override { return _padded ? 32 : m_bits / 8; }
+	virtual unsigned getStorageBytes() const override { return m_bits / 8; }
 	virtual bool isValueType() const override { return true; }
 
 	virtual MemberList const& getMembers() const { return isAddress() ? AddressMemberList : EmptyMemberList; }
@@ -251,6 +267,7 @@ public:
 	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const override;
 
 	virtual unsigned getCalldataEncodedSize(bool _padded) const override { return _padded && m_bytes > 0 ? 32 : m_bytes; }
+	virtual unsigned getStorageBytes() const override { return m_bytes; }
 	virtual bool isValueType() const override { return true; }
 
 	virtual std::string toString() const override { return "bytes" + dev::toString(m_bytes); }
@@ -275,6 +292,7 @@ public:
 	virtual TypePointer binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const override;
 
 	virtual unsigned getCalldataEncodedSize(bool _padded) const { return _padded ? 32 : 1; }
+	virtual unsigned getStorageBytes() const override { return 1; }
 	virtual bool isValueType() const override { return true; }
 
 	virtual std::string toString() const override { return "bool"; }
@@ -348,6 +366,7 @@ public:
 	virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
 	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
 	virtual bool operator==(Type const& _other) const override;
+	virtual unsigned getStorageBytes() const override { return 20; }
 	virtual bool isValueType() const override { return true; }
 	virtual std::string toString() const override;
 
@@ -411,6 +430,7 @@ public:
 	virtual TypePointer unaryOperatorResult(Token::Value _operator) const override;
 	virtual bool operator==(Type const& _other) const override;
 	virtual unsigned getSizeOnStack() const override { return 1; }
+	virtual unsigned getStorageBytes() const override;
 	virtual std::string toString() const override;
 	virtual bool isValueType() const override { return true; }
 
@@ -480,7 +500,7 @@ public:
 	virtual bool operator==(Type const& _other) const override;
 	virtual std::string toString() const override;
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable function type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override;
 	virtual MemberList const& getMembers() const override;
@@ -565,7 +585,7 @@ public:
 	virtual TypePointer binaryOperatorResult(Token::Value, TypePointer const&) const override { return TypePointer(); }
 	virtual std::string toString() const override { return "void"; }
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable void type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override { return 0; }
 };
@@ -585,7 +605,7 @@ public:
 	virtual TypePointer binaryOperatorResult(Token::Value, TypePointer const&) const override { return TypePointer(); }
 	virtual bool operator==(Type const& _other) const override;
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable type type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override { return 0; }
 	virtual std::string toString() const override { return "type(" + m_actualType->toString() + ")"; }
@@ -611,7 +631,7 @@ public:
 
 	virtual TypePointer binaryOperatorResult(Token::Value, TypePointer const&) const override { return TypePointer(); }
 	virtual bool canBeStored() const override { return false; }
-	virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable type type requested.")); }
+	virtual u256 getStorageSize() const override;
 	virtual bool canLiveOutsideStorage() const override { return false; }
 	virtual unsigned getSizeOnStack() const override { return 0; }
 	virtual bool operator==(Type const& _other) const override;