improve probes lookup by dropping use of regex

[mmarchini]

This PR alone won't solve the performance issues, but combined with #410 I was able to reduce startup time when looking up a large library from almost 20s to about 300ms.

Also, let's keep #526 open since there are other performance improvements we can do (for example, only expand wildcards if there's a wildcard in our probe name).

[mmarchini]

Not fully working yet. Will take a look into this again tomorrow.

[mmarchini]

I should probably point out that we won't be able to use regex in probe definitions with this PR, but I don't think that's an issue as long as we have wildcards working.

[mmarchini]

Ok, should be good to merge if there's no objections to #557 (comment) and if the CI is green.

[ajor]

I'm fine with not having regex anymore (it was just easier to implement wildcards that way), but this does remove the option to have wildcards in the middle of strings, e.g. tracepoint:syscalls:sys_enter_*chown I was wrong

[dalehamel]

Not sure if we should fix this here too, but list and attach should use the same method to match and filter probes, but it is currently duplicated (and inconsistent):

https://github.com/iovisor/bpftrace/blob/master/src/list.cpp#L116-L139
https://github.com/iovisor/bpftrace/blob/master/src/bpftrace.cpp#L152

Probably not in the scope of this PR, but we should cut an issue to fix that too.

[mmarchini]

@dalehamel yes, we need to improve consistency between attaching and listing probes, but it should be worked on another PR.

[mmarchini]

This is good to go from my side.

[dalehamel]

yes, we need to improve consistency between attaching and listing probes, but it should be worked on another PR.

yup, I cut #565 to address that

[brendangregg]

Thanks!

[ajor]

Nice tests!