Quick fix to not access inaccessible sequences.

1 files changed, 9 insertions, 0 deletions

diff --git a/CommonSubexpressionEliminator.cpp b/CommonSubexpressionEliminator.cpp
index b2fa7311..fe86908f 100644
--- a/CommonSubexpressionEliminator.cpp
+++ b/CommonSubexpressionEliminator.cpp
@@ -46,6 +46,7 @@ vector<AssemblyItem> CommonSubexpressionEliminator::getOptimizedItems()
 		targetStackContents[height] = m_state.stackElement(height, SourceLocation());
 
 	AssemblyItems items = CSECodeGenerator(m_state.expressionClasses(), m_storeOperations).generateCode(
+		m_initialState.sequenceNumber(),
 		m_initialState.stackHeight(),
 		initialStackContents,
 		targetStackContents
@@ -112,6 +113,7 @@ CSECodeGenerator::CSECodeGenerator(
 }
 
 AssemblyItems CSECodeGenerator::generateCode(
+	unsigned _initialSequenceNumber,
 	int _initialStackHeight,
 	map<int, Id> const& _initialStack,
 	map<int, Id> const& _targetStackContents
@@ -137,7 +139,14 @@ AssemblyItems CSECodeGenerator::generateCode(
 	for (auto const& p: m_neededBy)
 		for (auto id: {p.first, p.second})
 			if (unsigned seqNr = m_expressionClasses.representative(id).sequenceNumber)
+			{
+				if (seqNr < _initialSequenceNumber)
+					// Invalid sequenced operation.
+					// @todo quick fix for now. Proper fix needs to choose representative with higher
+					// sequence number during dependency analyis.
+					BOOST_THROW_EXCEPTION(StackTooDeepException());
 				sequencedExpressions.insert(make_pair(seqNr, id));
+			}
 
 	// Perform all operations on storage and memory in order, if they are needed.
 	for (auto const& seqAndId: sequencedExpressions)