[cmake-developers] slow regex implementation in RegularExpression

[Alexandru Ciobanu]

> The performance variation is interesting.  It is probably worthwhile
> to use a profiling tool (such as valgrind --tool=callgrind and kcachegrind)
> to see where PCRE is spending its time.


99.8% of the time in spent in match() from libpcre which is called by pcre_exec().

Please find attached the screenshot I made in the profiler (Mac OS X).


> There are two other regexp implementations Qt has considered:
> 
> - Boost::Regex. Discarded because Boost does not keep ABI
> compatibility, which is important for Qt (but I'd say it's not for
> CMake)
> 
> - C++11. Not possible if support for old compilers is required.
> 
> Alex, have you tried those two?


Pau, I looked briefly at Boost Xpressive, but I was discouraged when I saw that it depends on other Boost headers and libraries.

I haven't tried the C++11, but as you say, that option automatically disqualifies many systems with older compilers.

I am currently trying on making CMake work with TRE.  

sincerely,
Alex Ciobanu
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