Fix fasm warnings

[soheilshahrouz]

This PR fixes fasm warnings mentioned in this issue. It also replaces some std::string and const std::string& arguments with std::string_view. When an rvalue char* is passed as an std:string& argument, an std::string object needs to be constructed, which involves memory allocation and copying. std::string_view doesn't need to allocate memory and copy the null terminated string because it directly points to rvalue char*.

Types of changes

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed