- Makes code more in line with LLVM style (e.g. const char * -> StringRef)
- Do not use formatv since we can construct message just by +
- Replace some odd types such as const StringRef with more common type
- Do not use default arguments if they are not necessary
I sometimes find the format string more readable than lots of small strings fragments +'d together. But I don't feel strongly enough about to to break local convention.
Not everybody memorizes this Python-style format string, and lld doesn't have a lot of code that needs formatting strings (so even if there's something better, investing in it isn't worth the cost), so we generally avoid using that in lld.