Hello, The pcre-dev group you sent this to is for PCRE1, which is at end-of-life; the group is likely to disappear at some time. For PCRE2, please use pcre2-...@googlegroups.com. I have added that address to this email. (Further discussion could perhaps remove pcre-dev.) I don't know much about the internals of the JIT implementation in PCRE2. The JIT maintainer is on the pcre2-dev list so should see your query.
Regards, Philip On Tue, 10 May 2022 at 20:13, Ervin Hegedüs via Pcre-dev <pcre-dev@exim.org> wrote: > Hi, > > I'm a total beginner in PCRE2, now I'm "playing" with the code. > > I reviewed the man pages and documentation. If I'm not mistaken, PCRE2 > supports JIT (on most popular architectures - eg. AMD64), but the user has > to turn it on. > > The pcre2jit man page says > > *In some circumstances you may need to call additional functions. These are > described in the section entitled "Controlling the JIT stack" below.* > > Is there any way to decide, in which case do I need to use those functions? > I mean the patterns are totally unknown to me, it could be very complex or > can be very simple. > > Now I try this solution: > > > https://github.com/digitalwave/msc_retest/blob/pcre2support-jit/src/regex.cc#L161-L195 > > I chose 1MB, because man page says > > *A maximum stack size of 512KiB to 1MiB should be more than enough for any > pattern.* > > Do I need to add the manual stack allocation? Or would be enough just > simple call the > > pcre2_jit_compile(re, PCRE2_JIT_COMPLETE); > > and if the call fails, then match won't use JIT - but the application won't > terminate? > > Calling the > > pcre2_jit_stack_create(1, 1024 * 1024, NULL); > > allocates the whole 1MB of memory? I just ask, because I showed some > details about compiled regex in that code, and it says: > > DETAILED INFORMATION: > ===================== > PCRE2_INFO_BACKREFMAX: 0 > PCRE2_INFO_CAPTURECOUNT: 0 > PCRE2_INFO_DEPTHLIMIT: 4294967295 > PCRE2_INFO_JITSIZE: 76976 > PCRE2_INFO_MINLENGTH: 3 > PCRE2_INFO_MATCHLIMIT: 4294967295 > PCRE2_INFO_SIZE: 20149 > > The PCRE2_INFO_JITSIZE: 76976 means it uses almost 77kB of 1MB, but the 1MB > has been allocated? So if I have 200 regexes, then it means the application > needs +200MB memory? > > > Thanks for your helps, > > > > a. > -- > ## List details at https://lists.exim.org/mailman/listinfo/pcre-dev > -- ## List details at https://lists.exim.org/mailman/listinfo/pcre-dev
