From 5d2323c91486cfcab9322b01d52ba35525e06272 Mon Sep 17 00:00:00 2001
From: Christian <c@ethdev.com>
Date: Mon, 23 Feb 2015 01:31:05 +0100
Subject: [PATCH] Index and length access for dynamic arrays.

---
 AST.cpp                | 12 +++++++++++-
 ExpressionCompiler.cpp | 18 ++++++++----------
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/AST.cpp b/AST.cpp
index 179461152..c37e8c374 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -603,7 +603,17 @@ void MemberAccess::checkTypeRequirements()
 	if (!m_type)
 		BOOST_THROW_EXCEPTION(createTypeError("Member \"" + *m_memberName + "\" not found or not "
 											  "visible in " + type.toString()));
-	m_isLValue = (type.getCategory() == Type::Category::Struct);
+	// This should probably move somewhere else.
+	if (type.getCategory() == Type::Category::Struct)
+		m_isLValue = true;
+	else if (type.getCategory() == Type::Category::Array)
+	{
+		auto const& arrayType(dynamic_cast<ArrayType const&>(type));
+		m_isLValue = (*m_memberName == "length" &&
+			arrayType.getLocation() != ArrayType::Location::CallData && arrayType.isDynamicallySized());
+	}
+	else
+		m_isLValue = false;
 }
 
 void IndexAccess::checkTypeRequirements()
diff --git a/ExpressionCompiler.cpp b/ExpressionCompiler.cpp
index dcd411c3e..a54915bc7 100644
--- a/ExpressionCompiler.cpp
+++ b/ExpressionCompiler.cpp
@@ -546,7 +546,8 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 				m_context << eth::Instruction::SWAP1 << eth::Instruction::POP;
 				break;
 			case ArrayType::Location::Storage:
-				m_context << eth::Instruction::SLOAD;
+				m_currentLValue = LValue(m_context, LValue::LValueType::Storage, _memberAccess.getType());
+				m_currentLValue.retrieveValueIfLValueNotRequested(_memberAccess);
 				break;
 			default:
 				solAssert(false, "Unsupported array location.");
@@ -583,13 +584,10 @@ bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 		ArrayType const& arrayType = dynamic_cast<ArrayType const&>(baseType);
 		solAssert(arrayType.getLocation() == ArrayType::Location::Storage,
 			"TODO: Index acces only implemented for storage arrays.");
-		solAssert(!arrayType.isDynamicallySized(),
-			"TODO: Index acces only implemented for fixed-size arrays.");
-		solAssert(!arrayType.isByteArray(),
-			"TODO: Index acces not implemented for byte arrays.");
+		solAssert(!arrayType.isByteArray(), "TODO: Index acces not implemented for byte arrays.");
 		solAssert(_indexAccess.getIndexExpression(), "Index expression expected.");
-		// TODO: for dynamically-sized arrays, update the length for each write
-		// TODO: do we want to check the index?
+		if (arrayType.isDynamicallySized())
+			CompilerUtils(m_context).computeHashStatic();
 		_indexAccess.getIndexExpression()->accept(*this);
 		m_context << arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL
 			<< eth::Instruction::ADD;
@@ -1075,7 +1073,7 @@ void ExpressionCompiler::LValue::retrieveValue(Location const& _location, bool _
 	{
 	case LValueType::Stack:
 	{
-		unsigned stackPos = m_context->baseToCurrentStackOffset(unsigned(m_baseStackOffset));
+		unsigned stackPos = m_context->baseToCurrentStackOffset(m_baseStackOffset);
 		if (stackPos >= 15) //@todo correct this by fetching earlier or moving to memory
 			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_location)
 												  << errinfo_comment("Stack too deep."));
@@ -1124,7 +1122,7 @@ void ExpressionCompiler::LValue::storeValue(Type const& _sourceType, Location co
 	{
 	case LValueType::Stack:
 	{
-		unsigned stackDiff = m_context->baseToCurrentStackOffset(unsigned(m_baseStackOffset)) - m_size + 1;
+		unsigned stackDiff = m_context->baseToCurrentStackOffset(m_baseStackOffset) - m_size + 1;
 		if (stackDiff > 16)
 			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_location)
 												  << errinfo_comment("Stack too deep."));
@@ -1227,7 +1225,7 @@ void ExpressionCompiler::LValue::setToZero(Location const& _location) const
 	{
 	case LValueType::Stack:
 	{
-		unsigned stackDiff = m_context->baseToCurrentStackOffset(unsigned(m_baseStackOffset));
+		unsigned stackDiff = m_context->baseToCurrentStackOffset(m_baseStackOffset);
 		if (stackDiff > 16)
 			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_location)
 												  << errinfo_comment("Stack too deep."));