Expand documentation about JIT compilation.
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.TH PCRE2TEST 1 "08 September 2015" "PCRE 10.21"
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.TH PCRE2TEST 1 "12 September 2015" "PCRE 10.21"
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.SH NAME
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pcre2test - a program for testing Perl-compatible regular expressions.
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.SH SYNOPSIS
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@ -262,7 +262,7 @@ below.
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.sp
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#newline_default [<newline-list>]
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.sp
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When PCRE2 is built, a default newline convention can be specified. This
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When PCRE2 is built, a default newline convention can be specified. This
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determines which characters and/or character pairs are recognized as indicating
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a newline in a pattern or subject string. The default can be overridden when a
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pattern is compiled. The standard test files contain tests of various newline
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@ -473,7 +473,7 @@ for a description of their effects.
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allow_empty_class set PCRE2_ALLOW_EMPTY_CLASS
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alt_bsux set PCRE2_ALT_BSUX
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alt_circumflex set PCRE2_ALT_CIRCUMFLEX
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alt_verbnames set PCRE2_ALT_VERBNAMES
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alt_verbnames set PCRE2_ALT_VERBNAMES
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anchored set PCRE2_ANCHORED
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auto_callout set PCRE2_AUTO_CALLOUT
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/i caseless set PCRE2_CASELESS
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@ -614,21 +614,54 @@ actual length of the pattern is passed.
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.SS "JIT compilation"
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.rs
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.sp
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The \fB/jit\fP modifier may optionally be followed by an equals sign and a
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number in the range 0 to 7:
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Just-in-time (JIT) compiling is a heavyweight optimization that can greatly
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speed up pattern matching. See the
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.\" HREF
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\fBpcre2jit\fP
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.\"
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documentation for details. JIT compiling happens, optionally, after a pattern
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has been successfully compiled into an internal form. The JIT compiler converts
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this to optimized machine code. It needs to know whether the match-time options
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PCRE2_PARTIAL_HARD and PCRE2_PARTIAL_SOFT are going to be used, because
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different code is generated for the different cases. See the \fBpartial\fP
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modifier in "Subject Modifiers"
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.\" HTML <a href="#subjectmodifiers">
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.\" </a>
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below
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.\"
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for details of how these options are specified for each match attempt.
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.P
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JIT compilation is requested by the \fB/jit\fP pattern modifier, which may
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optionally be followed by an equals sign and a number in the range 0 to 7.
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The three bits that make up the number specify which of the three JIT operating
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modes are to be compiled:
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.sp
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1 compile JIT code for non-partial matching
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2 compile JIT code for soft partial matching
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4 compile JIT code for hard partial matching
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.sp
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The possible values for the \fB/jit\fP modifier are therefore:
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.sp
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0 disable JIT
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1 use JIT for normal match only
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2 use JIT for soft partial match only
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3 use JIT for normal match and soft partial match
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4 use JIT for hard partial match only
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6 use JIT for soft and hard partial match
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1 normal matching only
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2 soft partial matching only
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3 normal and soft partial matching
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4 hard partial matching only
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6 soft and hard partial matching only
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7 all three modes
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.sp
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If no number is given, 7 is assumed. If JIT compilation is successful, the
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compiled JIT code will automatically be used when \fBpcre2_match()\fP is run
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for the appropriate type of match, except when incompatible run-time options
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are specified. For more details, see the
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If no number is given, 7 is assumed. The phrase "partial matching" means a call
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to \fBpcre2_match()\fP with either the PCRE2_PARTIAL_SOFT or the
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PCRE2_PARTIAL_HARD option set. Note that such a call may return a complete
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match; the options enable the possibility of a partial match, but do not
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require it. Note also that if you request JIT compilation only for partial
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matching (for example, /jit=2) but do not set the \fBpartial\fP modifier on a
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subject line, that match will not use JIT code because none was compiled for
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non-partial matching.
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.P
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If JIT compilation is successful, the compiled JIT code will automatically be
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used when an appropriate type of match is run, except when incompatible
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run-time options are specified. For more details, see the
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.\" HREF
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\fBpcre2jit\fP
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.\"
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@ -789,6 +822,7 @@ warning message, except for \fBreplace\fP, which causes an error. Note that,
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matching that uses this pattern.
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.
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.
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.\" HTML <a name="subjectmodifiers"></a>
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.SH "SUBJECT MODIFIERS"
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.rs
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.sp
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@ -1485,6 +1519,6 @@ Cambridge, England.
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.rs
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.sp
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.nf
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Last updated: 08 September 2015
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Last updated: 12 September 2015
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Copyright (c) 1997-2015 University of Cambridge.
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.fi
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