Calling any of the OpenCLOptions::is*() functions (except isKnown()) with an unknown extension string results in a seg fault. This patch checks that the extension exists in the map before attempting to access it.
Would it be better if these functions returned false for unknown extensions? I think it would be consistent with the function names (e.g., isEnabled() returns false for an unknown extensions, because an unknown extension cannot be enabled).
I'm not really sure how to test this code. Best I can tell, there's no way for the clang executable to call these functions with invalid strings. I only ran into the seg faults when I was programmatically setting options using the clang API.
Oh, I see. We could also create a g-test for this but it's probably not worth enough. Perhaps if you just update a comment that the API behavior becomes clear it should be good enough.
Btw how about we use isKnown instead because it does exactly that? Also, I think we should update the comment to explain this change in the API behavior and add a comment for isKnown.
My thinking was that this way, there's only one look-up in OptMap, but when using isKnown() there are two. I don't know how good a compiler would be at inlining isKnown() and de-duplicating the look-ups.
But maybe the overhead doesn't really matter in this case and calling isKnown() is clearer?
I would say it is likely to be inlined in the optimized builds, removing duplicate calls to find would be trickier but since it's part of the standard libraries I think it is very likely going to happen.
Ok, if you are concerned about the performance we can leave it as is and only update the comments.