Remove ContainsMSize from side-effect-collector.

libsolidity/analysis/SyntaxChecker.cpp

@@ -262,10 +262,7 @@ bool SyntaxChecker::visit(InlineAssembly const& _inlineAssembly)
 	if (!m_useYulOptimizer)
 		return false;
 
-	if (yul::SideEffectsCollector(
+	if (yul::MSizeFinder::containsMSize(_inlineAssembly.dialect(), _inlineAssembly.operations()))
-		_inlineAssembly.dialect(),
-		_inlineAssembly.operations()
-	).containsMSize())
 		m_errorReporter.syntaxError(
 			_inlineAssembly.location(),
 			"The msize instruction cannot be used when the Yul optimizer is activated because "

libyul/optimiser/LoadResolver.cpp

@@ -31,7 +31,7 @@ using namespace yul;
 
 void LoadResolver::run(Dialect const& _dialect, Block& _ast)
 {
-	bool containsMSize = SideEffectsCollector(_dialect, _ast).containsMSize();
+	bool containsMSize = MSizeFinder::containsMSize(_dialect, _ast);
 	LoadResolver{_dialect, !containsMSize}(_ast);
 }
 

libyul/optimiser/Semantics.cpp

@@ -61,8 +61,6 @@ void SideEffectsCollector::operator()(FunctionalInstruction const& _instr)
 		m_sideEffectFree = false;
 	if (!eth::SemanticInformation::sideEffectFreeIfNoMSize(_instr.instruction))
 		m_sideEffectFreeIfNoMSize = false;
-	if (_instr.instruction == eth::Instruction::MSIZE)
-		m_containsMSize = true;
 	if (eth::SemanticInformation::invalidatesStorage(_instr.instruction))
 		m_invalidatesStorage = true;
 	if (eth::SemanticInformation::invalidatesMemory(_instr.instruction))
@@ -81,8 +79,6 @@ void SideEffectsCollector::operator()(FunctionCall const& _functionCall)
 			m_sideEffectFree = false;
 		if (!f->sideEffectFreeIfNoMSize)
 			m_sideEffectFreeIfNoMSize = false;
-		if (f->isMSize)
-			m_containsMSize = true;
 		if (f->invalidatesStorage)
 			m_invalidatesStorage = true;
 		if (f->invalidatesMemory)
@@ -98,6 +94,30 @@ void SideEffectsCollector::operator()(FunctionCall const& _functionCall)
 	}
 }
 
+bool MSizeFinder::containsMSize(Dialect const& _dialect, Block const& _ast)
+{
+	MSizeFinder finder(_dialect);
+	finder(_ast);
+	return finder.m_msizeFound;
+}
+
+void MSizeFinder::operator()(FunctionalInstruction const& _instr)
+{
+	ASTWalker::operator()(_instr);
+
+	if (_instr.instruction == eth::Instruction::MSIZE)
+		m_msizeFound = true;
+}
+
+void MSizeFinder::operator()(FunctionCall const& _functionCall)
+{
+	ASTWalker::operator()(_functionCall);
+
+	if (BuiltinFunction const* f = m_dialect.builtin(_functionCall.functionName.name))
+		if (f->isMSize)
+			m_msizeFound = true;
+}
+
 MovableChecker::MovableChecker(Dialect const& _dialect, Expression const& _expression):
 	MovableChecker(_dialect)
 {

libyul/optimiser/Semantics.h

@@ -53,7 +53,6 @@ public:
 			return m_sideEffectFree;
 	}
 	bool sideEffectFreeIfNoMSize() const { return m_sideEffectFreeIfNoMSize; }
-	bool containsMSize() const { return m_containsMSize; }
 	bool invalidatesStorage() const { return m_invalidatesStorage; }
 	bool invalidatesMemory() const { return m_invalidatesMemory; }
 
@@ -67,16 +66,35 @@ private:
 	/// Is the current expression side-effect free up to msize, i.e. can be removed
 	/// without changing the semantics except for the value returned by the msize instruction.
 	bool m_sideEffectFreeIfNoMSize = true;
-	/// Does the current code contain the MSize operation?
-	/// Note that this is a purely syntactic property meaning that even if this is false,
-	/// the code can still contain calls to functions that contain the msize instruction.
-	bool m_containsMSize = false;
 	/// If false, storage is guaranteed to be unchanged by the code under all
 	/// circumstances.
 	bool m_invalidatesStorage = false;
 	bool m_invalidatesMemory = false;
 };
 
+/**
+ * Class that can be used to find out if certain code contains the MSize instruction.
+ *
+ * Note that this is a purely syntactic property meaning that even if this is false,
+ * the code can still contain calls to functions that contain the msize instruction.
+ *
+ * The only safe way to determine this is by passing the full AST.
+ */
+class MSizeFinder: public ASTWalker
+{
+public:
+	static bool containsMSize(Dialect const& _dialect, Block const& _ast);
+
+	using ASTWalker::operator();
+	void operator()(FunctionalInstruction const& _instr);
+	void operator()(FunctionCall const& _funCall);
+
+private:
+	MSizeFinder(Dialect const& _dialect): m_dialect(_dialect) {}
+	Dialect const& m_dialect;
+	bool m_msizeFound = false;
+};
+
 /**
  * Specific AST walker that determines whether an expression is movable
  * and collects the referenced variables.

libyul/optimiser/StackCompressor.cpp

@@ -165,7 +165,7 @@ bool StackCompressor::run(
 		_object.code->statements.size() > 0 && _object.code->statements.at(0).type() == typeid(Block),
 		"Need to run the function grouper before the stack compressor."
 	);
-	bool allowMSizeOptimzation = !SideEffectsCollector(_dialect, *_object.code).containsMSize();
+	bool allowMSizeOptimzation = !MSizeFinder::containsMSize(_dialect, *_object.code);
 	for (size_t iterations = 0; iterations < _maxIterations; iterations++)
 	{
 		map<YulString, int> stackSurplus = CompilabilityChecker::run(_dialect, _object, _optimizeStackAllocation);

libyul/optimiser/UnusedPruner.cpp

@@ -138,7 +138,7 @@ void UnusedPruner::runUntilStabilised(
 	set<YulString> const& _externallyUsedFunctions
 )
 {
-	bool allowMSizeOptimization = !SideEffectsCollector(_dialect, _ast).containsMSize();
+	bool allowMSizeOptimization = !MSizeFinder::containsMSize(_dialect, _ast);
 	runUntilStabilised(_dialect, _ast, allowMSizeOptimization, _externallyUsedFunctions);
 }