Only analyze memory in DataFlowAnalyzer if it is needed in the optimizer step.

Author: chriseth

libyul/optimiser/CommonSubexpressionEliminator.cpp

@@ -48,7 +48,7 @@ CommonSubexpressionEliminator::CommonSubexpressionEliminator(
 	Dialect const& _dialect,
 	map<YulString, SideEffects> _functionSideEffects
 ):
-	DataFlowAnalyzer(_dialect, std::move(_functionSideEffects))
+	DataFlowAnalyzer(_dialect, MemoryAndStorage::Ignore, std::move(_functionSideEffects))
 {
 }
 

libyul/optimiser/DataFlowAnalyzer.cpp

@@ -44,47 +44,54 @@ using namespace solidity::yul;
 
 DataFlowAnalyzer::DataFlowAnalyzer(
 	Dialect const& _dialect,
+	MemoryAndStorage _analyzeStores,
 	map<YulString, SideEffects> _functionSideEffects
 ):
 	m_dialect(_dialect),
 	m_functionSideEffects(std::move(_functionSideEffects)),
-	m_knowledgeBase(_dialect, [this](YulString _var) { return variableValue(_var); })
+	m_knowledgeBase(_dialect, [this](YulString _var) { return variableValue(_var); }),
+	m_analyzeStores(_analyzeStores == MemoryAndStorage::Analyze)
 {
-	if (auto const* builtin = _dialect.memoryStoreFunction(YulString{}))
-		m_storeFunctionName[static_cast<unsigned>(StoreLoadLocation::Memory)] = builtin->name;
-	if (auto const* builtin = _dialect.memoryLoadFunction(YulString{}))
-		m_loadFunctionName[static_cast<unsigned>(StoreLoadLocation::Memory)] = builtin->name;
-	if (auto const* builtin = _dialect.storageStoreFunction(YulString{}))
-		m_storeFunctionName[static_cast<unsigned>(StoreLoadLocation::Storage)] = builtin->name;
-	if (auto const* builtin = _dialect.storageLoadFunction(YulString{}))
-		m_loadFunctionName[static_cast<unsigned>(StoreLoadLocation::Storage)] = builtin->name;
+	if (m_analyzeStores)
+	{
+		if (auto const* builtin = _dialect.memoryStoreFunction(YulString{}))
+			m_storeFunctionName[static_cast<unsigned>(StoreLoadLocation::Memory)] = builtin->name;
+		if (auto const* builtin = _dialect.memoryLoadFunction(YulString{}))
+			m_loadFunctionName[static_cast<unsigned>(StoreLoadLocation::Memory)] = builtin->name;
+		if (auto const* builtin = _dialect.storageStoreFunction(YulString{}))
+			m_storeFunctionName[static_cast<unsigned>(StoreLoadLocation::Storage)] = builtin->name;
+		if (auto const* builtin = _dialect.storageLoadFunction(YulString{}))
+			m_loadFunctionName[static_cast<unsigned>(StoreLoadLocation::Storage)] = builtin->name;
+	}
 }
 
 void DataFlowAnalyzer::operator()(ExpressionStatement& _statement)
 {
-	if (auto vars = isSimpleStore(StoreLoadLocation::Storage, _statement))
-	{
-		ASTModifier::operator()(_statement);
-		cxx20::erase_if(m_state.storage, mapTuple([&](auto&& key, auto&& value) {
-			return
-				!m_knowledgeBase.knownToBeDifferent(vars->first, key) &&
-				!m_knowledgeBase.knownToBeEqual(vars->second, value);
-		}));
-		m_state.storage[vars->first] = vars->second;
-	}
-	else if (auto vars = isSimpleStore(StoreLoadLocation::Memory, _statement))
+	if (m_analyzeStores)
 	{
-		ASTModifier::operator()(_statement);
-		cxx20::erase_if(m_state.memory, mapTuple([&](auto&& key, auto&& /* value */) {
-			return !m_knowledgeBase.knownToBeDifferentByAtLeast32(vars->first, key);
-		}));
-		m_state.memory[vars->first] = vars->second;
-	}
-	else
-	{
-		clearKnowledgeIfInvalidated(_statement.expression);
-		ASTModifier::operator()(_statement);
+		if (auto vars = isSimpleStore(StoreLoadLocation::Storage, _statement))
+		{
+			ASTModifier::operator()(_statement);
+			cxx20::erase_if(m_state.storage, mapTuple([&](auto&& key, auto&& value) {
+				return
+					!m_knowledgeBase.knownToBeDifferent(vars->first, key) &&
+					!m_knowledgeBase.knownToBeEqual(vars->second, value);
+			}));
+			m_state.storage[vars->first] = vars->second;
+			return;
+		}
+		else if (auto vars = isSimpleStore(StoreLoadLocation::Memory, _statement))
+		{
+			ASTModifier::operator()(_statement);
+			cxx20::erase_if(m_state.memory, mapTuple([&](auto&& key, auto&& /* value */) {
+				return !m_knowledgeBase.knownToBeDifferentByAtLeast32(vars->first, key);
+			}));
+			m_state.memory[vars->first] = vars->second;
+			return;
+		}
 	}
+	clearKnowledgeIfInvalidated(_statement.expression);
+	ASTModifier::operator()(_statement);
 }
 
 void DataFlowAnalyzer::operator()(Assignment& _assignment)
@@ -346,6 +353,8 @@ void DataFlowAnalyzer::assignValue(YulString _variable, Expression const* _value
 
 void DataFlowAnalyzer::clearKnowledgeIfInvalidated(Block const& _block)
 {
+	if (!m_analyzeStores)
+		return;
 	SideEffectsCollector sideEffects(m_dialect, _block, &m_functionSideEffects);
 	if (sideEffects.invalidatesStorage())
 		m_state.storage.clear();
@@ -355,6 +364,8 @@ void DataFlowAnalyzer::clearKnowledgeIfInvalidated(Block const& _block)
 
 void DataFlowAnalyzer::clearKnowledgeIfInvalidated(Expression const& _expr)
 {
+	if (!m_analyzeStores)
+		return;
 	SideEffectsCollector sideEffects(m_dialect, _expr, &m_functionSideEffects);
 	if (sideEffects.invalidatesStorage())
 		m_state.storage.clear();
@@ -367,6 +378,8 @@ void DataFlowAnalyzer::joinKnowledge(
 	unordered_map<YulString, YulString> const& _olderMemory
 )
 {
+	if (!m_analyzeStores)
+		return;
 	joinKnowledgeHelper(m_state.storage, _olderStorage);
 	joinKnowledgeHelper(m_state.memory, _olderMemory);
 }

libyul/optimiser/DataFlowAnalyzer.h

@@ -81,12 +81,14 @@ struct AssignedValue
 class DataFlowAnalyzer: public ASTModifier
 {
 public:
+	enum class MemoryAndStorage { Analyze, Ignore };
 	/// @param _functionSideEffects
 	///            Side-effects of user-defined functions. Worst-case side-effects are assumed
 	///            if this is not provided or the function is not found.
 	///            The parameter is mostly used to determine movability of expressions.
 	explicit DataFlowAnalyzer(
 		Dialect const& _dialect,
+		MemoryAndStorage _analyzeStores,
 		std::map<YulString, SideEffects> _functionSideEffects = {}
 	);
 
@@ -189,6 +191,8 @@ class DataFlowAnalyzer: public ASTModifier
 protected:
 	KnowledgeBase m_knowledgeBase;
 
+	/// If true, analyzes memory and storage content via mload/mstore and sload/sstore.
+	bool m_analyzeStores = true;
 	YulString m_storeFunctionName[static_cast<unsigned>(StoreLoadLocation::Last) + 1];
 	YulString m_loadFunctionName[static_cast<unsigned>(StoreLoadLocation::Last) + 1];
 

libyul/optimiser/EqualStoreEliminator.h

@@ -47,7 +47,7 @@ class EqualStoreEliminator: public DataFlowAnalyzer
 		Dialect const& _dialect,
 		std::map<YulString, SideEffects> _functionSideEffects
 	):
-		DataFlowAnalyzer(_dialect, std::move(_functionSideEffects))
+		DataFlowAnalyzer(_dialect, MemoryAndStorage::Analyze, std::move(_functionSideEffects))
 	{}
 
 protected:

libyul/optimiser/ExpressionSimplifier.h

@@ -51,7 +51,9 @@ class ExpressionSimplifier: public DataFlowAnalyzer
 	void visit(Expression& _expression) override;
 
 private:
-	explicit ExpressionSimplifier(Dialect const& _dialect): DataFlowAnalyzer(_dialect) {}
+	explicit ExpressionSimplifier(Dialect const& _dialect):
+		DataFlowAnalyzer(_dialect, MemoryAndStorage::Ignore)
+	{}
 };
 
 }

libyul/optimiser/LoadResolver.h

@@ -53,7 +53,7 @@ class LoadResolver: public DataFlowAnalyzer
 		bool _containsMSize,
 		std::optional<size_t> _expectedExecutionsPerDeployment
 	):
-		DataFlowAnalyzer(_dialect, std::move(_functionSideEffects)),
+		DataFlowAnalyzer(_dialect, MemoryAndStorage::Analyze, std::move(_functionSideEffects)),
 		m_containsMSize(_containsMSize),
 		m_expectedExecutionsPerDeployment(std::move(_expectedExecutionsPerDeployment))
 	{}

libyul/optimiser/Rematerialiser.cpp

@@ -43,7 +43,7 @@ Rematerialiser::Rematerialiser(
 	set<YulString> _varsToAlwaysRematerialize,
 	bool _onlySelectedVariables
 ):
-	DataFlowAnalyzer(_dialect),
+	DataFlowAnalyzer(_dialect, MemoryAndStorage::Ignore),
 	m_referenceCounts(ReferencesCounter::countReferences(_ast)),
 	m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize)),
 	m_onlySelectedVariables(_onlySelectedVariables)

libyul/optimiser/Rematerialiser.h

@@ -95,7 +95,7 @@ class LiteralRematerialiser: public DataFlowAnalyzer
 
 private:
 	LiteralRematerialiser(Dialect const& _dialect):
-		DataFlowAnalyzer(_dialect)
+		DataFlowAnalyzer(_dialect, MemoryAndStorage::Ignore)
 	{}
 };
 

libyul/optimiser/StackCompressor.cpp

@@ -56,7 +56,7 @@ namespace
 class RematCandidateSelector: public DataFlowAnalyzer
 {
 public:
-	explicit RematCandidateSelector(Dialect const& _dialect): DataFlowAnalyzer(_dialect) {}
+	explicit RematCandidateSelector(Dialect const& _dialect): DataFlowAnalyzer(_dialect, MemoryAndStorage::Ignore) {}
 
 	/// @returns a map from function name to rematerialisation costs to a vector of variables to rematerialise
 	/// and variables that occur in their expression.