loadFromMemoryDynamic

libsolidity/CompilerUtils.cpp

@@ -37,32 +37,22 @@ unsigned CompilerUtils::loadFromMemory(unsigned _offset, Type const& _type,
 	bool _fromCalldata, bool _padToWordBoundaries)
 {
 	solAssert(_type.getCategory() != Type::Category::ByteArray, "Unable to statically load dynamic type.");
-	unsigned _encodedSize = _type.getCalldataEncodedSize();
-	unsigned numBytes = _padToWordBoundaries ? getPaddedSize(_encodedSize) : _encodedSize;
-	bool leftAligned = _type.getCategory() == Type::Category::String;
-	if (numBytes == 0)
-		m_context << u256(0);
-	else
-	{
-		eth::Instruction load = _fromCalldata ? eth::Instruction::CALLDATALOAD : eth::Instruction::MLOAD;
-		solAssert(numBytes <= 32, "Static memory load of more than 32 bytes requested.");
-		if (numBytes == 32)
-			m_context << u256(_offset) << load;
-		else
-		{
-			// load data and add leading or trailing zeros by dividing/multiplying depending on alignment
-			u256 shiftFactor = u256(1) << ((32 - numBytes) * 8);
-			m_context << shiftFactor;
-			if (leftAligned)
-				m_context << eth::Instruction::DUP1;
-			m_context << u256(_offset) << load << eth::Instruction::DIV;
-			if (leftAligned)
-				m_context << eth::Instruction::MUL;
-		}
-	}
-	return numBytes;
+	m_context << u256(_offset);
+	return loadFromMemoryHelper(_type, _fromCalldata, _padToWordBoundaries);
+}
+
+void CompilerUtils::loadFromMemoryDynamic(Type const& _type, bool _fromCalldata, bool _padToWordBoundaries)
+{
+	solAssert(_type.getCategory() != Type::Category::ByteArray, "Byte arrays not yet implemented.");
+	m_context << eth::Instruction::DUP1;
+	unsigned numBytes = loadFromMemoryHelper(_type, _fromCalldata, _padToWordBoundaries);
+	// update memory counter
+	for (unsigned i = 0; i < _type.getSizeOnStack(); ++i)
+		m_context << eth::swapInstruction(1 + i);
+	m_context << u256(numBytes) << eth::Instruction::ADD;
 }
 
+
 unsigned CompilerUtils::storeInMemory(unsigned _offset, Type const& _type, bool _padToWordBoundaries)
 {
 	solAssert(_type.getCategory() != Type::Category::ByteArray, "Unable to statically store dynamic type.");
@@ -121,6 +111,7 @@ void CompilerUtils::storeInMemoryDynamic(Type const& _type, bool _padToWordBound
 		unsigned numBytes = prepareMemoryStore(_type, _padToWordBoundaries);
 		if (numBytes > 0)
 		{
+			solAssert(_type.getSizeOnStack() == 1, "Memory store of types with stack size != 1 not implemented.");
 			m_context << eth::Instruction::DUP2 << eth::Instruction::MSTORE;
 			m_context << u256(numBytes) << eth::Instruction::ADD;
 		}
@@ -290,6 +281,30 @@ void CompilerUtils::copyByteArrayToStorage(ByteArrayType const& _targetType,
 	}
 }
 
+unsigned CompilerUtils::loadFromMemoryHelper(Type const& _type, bool _fromCalldata, bool _padToWordBoundaries)
+{
+	unsigned _encodedSize = _type.getCalldataEncodedSize();
+	unsigned numBytes = _padToWordBoundaries ? getPaddedSize(_encodedSize) : _encodedSize;
+	bool leftAligned = _type.getCategory() == Type::Category::String;
+	if (numBytes == 0)
+		m_context << eth::Instruction::POP << u256(0);
+	else
+	{
+		solAssert(numBytes <= 32, "Static memory load of more than 32 bytes requested.");
+		m_context << (_fromCalldata ? eth::Instruction::CALLDATALOAD : eth::Instruction::MLOAD);
+		if (numBytes != 32)
+		{
+			// add leading or trailing zeros by dividing/multiplying depending on alignment
+			u256 shiftFactor = u256(1) << ((32 - numBytes) * 8);
+			m_context << shiftFactor << eth::Instruction::SWAP1 << eth::Instruction::DIV;
+			if (leftAligned)
+				m_context << shiftFactor << eth::Instruction::MUL;
+		}
+	}
+
+	return numBytes;
+}
+
 void CompilerUtils::clearByteArray(ByteArrayType const& _type) const
 {
 	solAssert(_type.getLocation() == ByteArrayType::Location::Storage, "");

libsolidity/CompilerUtils.h

@@ -40,10 +40,13 @@ public:
 	/// @param _type data type to load
 	/// @param _fromCalldata if true, load from calldata, not from memory
 	/// @param _padToWordBoundaries if true, assume the data is padded to word (32 byte) boundaries
-	/// @returns the number of bytes consumed in memory (can be different from _bytes if
-	/// _padToWordBoundaries is true)
+	/// @returns the number of bytes consumed in memory.
 	unsigned loadFromMemory(unsigned _offset, Type const& _type = IntegerType(256),
 		bool _fromCalldata = false, bool _padToWordBoundaries = false);
+	/// Dynamic version of @see loadFromMemory, expects the memory offset on the stack.
+	/// Stack pre: memory_offset
+	/// Stack post: value... (memory_offset+length)
+	void loadFromMemoryDynamic(Type const& _type, bool _fromCalldata = false, bool _padToWordBoundaries = true);
 	/// Stores data from stack in memory.
 	/// @param _offset offset in memory
 	/// @param _type type of the data on the stack
@@ -92,6 +95,8 @@ public:
 private:
 	/// Prepares the given type for storing in memory by shifting it if necessary.
 	unsigned prepareMemoryStore(Type const& _type, bool _padToWordBoundaries) const;
+	/// Loads type from memory assuming memory offset is on stack top.
+	unsigned loadFromMemoryHelper(Type const& _type, bool _fromCalldata, bool _padToWordBoundaries);
 	/// Appends a loop that clears a sequence of storage slots (excluding end).
 	/// Stack pre: end_ref start_ref
 	/// Stack post: end_ref

test/SolidityCompiler.cpp

@@ -96,7 +96,7 @@ BOOST_AUTO_TEST_CASE(smoke_test)
 							 "}\n";
 	bytes code = compileContract(sourceCode);
 
-	unsigned boilerplateSize = 69;
+	unsigned boilerplateSize = 70;
 	bytes expectation({byte(Instruction::JUMPDEST),
 					   byte(Instruction::PUSH1), 0x0, // initialize local variable x
 					   byte(Instruction::PUSH1), 0x2,
@@ -114,8 +114,8 @@ BOOST_AUTO_TEST_CASE(ifStatement)
 							 "  function f() { bool x; if (x) 77; else if (!x) 78; else 79; }"
 							 "}\n";
 	bytes code = compileContract(sourceCode);
-	unsigned shift = 56;
-	unsigned boilerplateSize = 69;
+	unsigned shift = 57;
+	unsigned boilerplateSize = 70;
 	bytes expectation({byte(Instruction::JUMPDEST),
 					   byte(Instruction::PUSH1), 0x0,
 					   byte(Instruction::DUP1),
@@ -155,8 +155,8 @@ BOOST_AUTO_TEST_CASE(loops)
 							 "  function f() { while(true){1;break;2;continue;3;return;4;} }"
 							 "}\n";
 	bytes code = compileContract(sourceCode);
-	unsigned shift = 56;
-	unsigned boilerplateSize = 69;
+	unsigned shift = 57;
+	unsigned boilerplateSize = 70;
 	bytes expectation({byte(Instruction::JUMPDEST),
 					   byte(Instruction::JUMPDEST),
 					   byte(Instruction::PUSH1), 0x1,