Report memoryguard in stack too deep error.

Author: ekpyron

libyul/backends/evm/EVMObjectCompiler.cpp

@@ -25,6 +25,8 @@
 #include <libyul/backends/evm/EVMDialect.h>
 #include <libyul/backends/evm/OptimizedEVMCodeTransform.h>
 
+#include <libyul/optimiser/FunctionCallFinder.h>
+
 #include <libyul/Object.h>
 #include <libyul/Exceptions.h>
 
@@ -74,7 +76,22 @@ void EVMObjectCompiler::run(Object& _object, bool _optimize)
 			OptimizedEVMCodeTransform::UseNamedLabels::ForFirstFunctionOfEachName
 		);
 		if (!stackErrors.empty())
-			BOOST_THROW_EXCEPTION(stackErrors.front());
+		{
+			vector<FunctionCall*> memoryGuardCalls = FunctionCallFinder::run(
+				*_object.code,
+				"memoryguard"_yulstring
+			);
+			auto stackError = stackErrors.front();
+			string msg = stackError.comment() ? *stackError.comment() : "";
+			if (memoryGuardCalls.empty())
+				msg += "\nNo memoryguard was present. "
+					"Consider using memory-safe assembly only and annotating it via "
+					"\"/// @solidity memory-safe-assembly\".";
+			else
+				msg += "\nmemoryguard was present.";
+			stackError << util::errinfo_comment(msg);
+			BOOST_THROW_EXCEPTION(stackError);
+		}
 	}
 	else
 	{