Merge pull request #83 from LianaHus/sol_split_the_source_tree

fixed-sized arrays as return type for functions

5 files changed, 64 insertions, 10 deletions

diff --git a/libsolidity/CompilerUtils.cpp b/libsolidity/CompilerUtils.cpp
index b9b554e8..a77e6536 100644
--- a/libsolidity/CompilerUtils.cpp
+++ b/libsolidity/CompilerUtils.cpp
@@ -86,16 +86,27 @@ void CompilerUtils::loadFromMemoryDynamic(
 	bool _padToWordBoundaries,
 	bool _keepUpdatedMemoryOffset
 )
-{
-	solAssert(_type.category() != Type::Category::Array, "Arrays not yet implemented.");
+{		
 	if (_keepUpdatedMemoryOffset)
 		m_context << eth::Instruction::DUP1;
-	unsigned numBytes = loadFromMemoryHelper(_type, _fromCalldata, _padToWordBoundaries);
-	if (_keepUpdatedMemoryOffset)
+
+	if (auto arrayType = dynamic_cast<ArrayType const*>(&_type))
 	{
-		// update memory counter
-		moveToStackTop(_type.sizeOnStack());
-		m_context << u256(numBytes) << eth::Instruction::ADD;
+		solAssert(!arrayType->isDynamicallySized(), "");
+		solAssert(!_fromCalldata, "");
+		solAssert(_padToWordBoundaries, "");
+		if (_keepUpdatedMemoryOffset)
+			m_context << arrayType->memorySize() << eth::Instruction::ADD;
+	}
+	else
+	{
+		unsigned numBytes = loadFromMemoryHelper(_type, _fromCalldata, _padToWordBoundaries);
+		if (_keepUpdatedMemoryOffset)
+		{
+			// update memory counter
+			moveToStackTop(_type.sizeOnStack());
+			m_context << u256(numBytes) << eth::Instruction::ADD;
+		}
 	}
 }
 
diff --git a/libsolidity/ExpressionCompiler.cpp b/libsolidity/ExpressionCompiler.cpp
index 65706602..49bf2559 100644
--- a/libsolidity/ExpressionCompiler.cpp
+++ b/libsolidity/ExpressionCompiler.cpp
@@ -1256,10 +1256,14 @@ void ExpressionCompiler::appendExternalFunctionCall(
 	}
 	else if (firstReturnType)
 	{
-		//@todo manually update free memory pointer if we accept returning memory-stored objects
 		utils().fetchFreeMemoryPointer();
-		utils().loadFromMemoryDynamic(*firstReturnType, false, true, false);
-
+		if (dynamic_cast<ReferenceType const*>(firstReturnType))
+		{
+			utils().loadFromMemoryDynamic(*firstReturnType, false, true, true);
+			utils().storeFreeMemoryPointer();
+		}
+		else
+			utils().loadFromMemoryDynamic(*firstReturnType, false, true, false);
 	}
 }
 
diff --git a/libsolidity/Types.cpp b/libsolidity/Types.cpp
index 68e8e91d..18f2817e 100644
--- a/libsolidity/Types.cpp
+++ b/libsolidity/Types.cpp
@@ -853,6 +853,15 @@ TypePointer ArrayType::externalType() const
 		return std::make_shared<ArrayType>(DataLocation::Memory, baseExt, m_length);
 }
 
+u256 ArrayType::memorySize() const
+{
+	solAssert(!isDynamicallySized(), "");
+	solAssert(m_location == DataLocation::Memory, "");
+	u256 size =  m_length * m_baseType->memoryHeadSize();
+	solAssert(size <= numeric_limits<unsigned>::max(), "Array size does not fit unsigned.");
+	return size;
+}
+
 TypePointer ArrayType::copyForLocation(DataLocation _location, bool _isPointer) const
 {
 	auto copy = make_shared<ArrayType>(_location);
diff --git a/libsolidity/Types.h b/libsolidity/Types.h
index 11218b7a..73111e48 100644
--- a/libsolidity/Types.h
+++ b/libsolidity/Types.h
@@ -501,6 +501,7 @@ public:
 	bool isString() const { return m_arrayKind == ArrayKind::String; }
 	TypePointer const& baseType() const { solAssert(!!m_baseType, ""); return m_baseType;}
 	u256 const& length() const { return m_length; }
+	u256 memorySize() const;
 
 	TypePointer copyForLocation(DataLocation _location, bool _isPointer) const override;
 
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index 8026f216..3124f9cf 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -5325,6 +5325,35 @@ BOOST_AUTO_TEST_CASE(strings_in_struct)
 	BOOST_CHECK(callContractFunction("getLast()") == encodeDyn(s));
 }
 
+BOOST_AUTO_TEST_CASE(fixed_arrays_as_return_type)
+{
+	char const* sourceCode = R"(
+		contract A {
+			function f(uint16 input) constant returns (uint16[5] arr)
+			{
+				arr[0] = input;
+				arr[1] = ++input;
+				arr[2] = ++input;
+				arr[3] = ++input;
+				arr[4] = ++input;
+			}
+		}
+		contract B {
+			function f() returns (uint16[5] res, uint16[5] res2)
+			{
+				var a = new A();
+				res = a.f(2);
+				res2 = a.f(1000);
+			}
+		}
+	)";
+	compileAndRun(sourceCode, 0, "B");
+	BOOST_CHECK(callContractFunction("f()") == encodeArgs(
+		u256(2), u256(3), u256(4), u256(5), u256(6), // first return argument
+		u256(1000), u256(1001), u256(1002), u256(1003), u256(1004)) // second return argument
+	);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }