In the graph-diff tool, we should use the symbol name for the labels in
the graph instead of the function ids.
Added some inline comments.
Drop the formatv and the raw literal. It's in the old code sure, but formatv implementation in LLVM is rather expensive for two braces and the raw literal here makes zero sense. Use a Twine instead. Same goes for a a few below.
truncateString returns a Twine, you're not storing it anywhere so it's still on the stack at that point, what's the point of the explicit conversion here? .str(). A lot of things including formatv can accept a Twine as an argument.
Quite a big style nit. I'd say get rid of the switch completely.