Pierre Joye wrote: > On Jul 23, 2015 9:47 PM, "Christoph Becker" <cmbecke...@gmx.de> wrote: >> >> Ah, I should have explained better that libpcre's JIT support is >> implemented as own virtual machine, and libpcre has functions to use a >> custom stack which is allocated on the heap. If these functions are not >> used (as it's now in ext/pcre) a fixed 32K on the machine stack are > used.[1] >> >> Anyhow, it is not possible to change the stack (size) during a call to >> pcre_exec() (unless, maybe, libpcre would be modified), and it is not >> possible (to my knowledge) to calculate the required stack size in >> advance. The required stack size depends on pattern and subject. >> >> So basically, we have to call pcre_exec(), and if it fails due to >> limited stack size, we either fail as well, or we try again. In the >> latter case we could either use a bigger stack or do without JIT. In >> the former case we should at least give users a setting to choose the >> desired stack size, which is quite comparable to pcre.backtrack_limit >> and pcre.recursion_limit. >> >> Therefore I tend to prefer a new ini setting (say, pcre.jitstack_limit). >> That would mean, however, to add yet another ini setting, of which >> there are already so many. >> >> [1] <http://www.pcre.org/original/doc/html/pcrejit.html#SEC8> > > Only to be sure, ou mean it is a different issue than the common one (dozen > of bugs for pcre about it)? Solved by increasing the stack size of the > process or binary?
I'm pretty sure that is another issue. The JIT functionality of libpcre is available only for PHP 7, and the issue reported in #70110 only happens when pcre.jit is enabled. And to my knowledge #70110 is the first reported bug that's caused by the JIT. > Also an ini setting may not be portable. That's something to double check :) ACK. However, AFAICT pcre_jit_stack_alloc() and pcre_assign_jit_stack() are supposed to be portable for systems where JIT support is available. -- Christoph M. Becker -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
