Severity: wishlist
There are times, when the expression is too simple or will not be used too
often to justify the extra time in -P that is required for JIT compilation.
Make it simpler for users to pass flags to the PCRE backend, and start
with a flag to disable JIT (enabled by default)
>From caeca5e806fe1b2e368833f05bb4cfb75763d1b3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= <care...@gmail.com>
Date: Sat, 16 Oct 2021 01:38:11 -0700
Subject: [PATCH] pcre: add a flag to disable JIT
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Mainly useful for performance testing.
Signed-off-by: Carlo Marcelo Arenas Belón <care...@gmail.com>
---
doc/grep.texi | 4 +++-
src/grep.c | 13 +++++++++++--
src/grep.h | 1 +
src/pcresearch.c | 6 ++++--
tests/Makefile.am | 1 +
tests/pcre-nojit | 22 ++++++++++++++++++++++
6 files changed, 42 insertions(+), 5 deletions(-)
create mode 100755 tests/pcre-nojit
diff --git a/doc/grep.texi b/doc/grep.texi
index e5b9fd8..8fb41ac 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -1138,7 +1138,7 @@ Interpret patterns as fixed strings, not regular expressions.
(@option{-F} is specified by POSIX.)
@item -P
-@itemx --perl-regexp
+@itemx --perl-regexp[=@var{FLAG}]
@opindex -P
@opindex --perl-regexp
@cindex matching Perl-compatible regular expressions
@@ -1146,6 +1146,8 @@ Interpret patterns as Perl-compatible regular expressions (PCREs).
PCRE support is here to stay, but consider this option experimental when
combined with the @option{-z} (@option{--null-data}) option, and note that
@samp{grep@ -P} may warn of unimplemented features.
+The optional flag 'no-jit' could be used to disable JIT, and only use the
+slower PCRE's interpreter.
@xref{Other Options}.
@end table
diff --git a/src/grep.c b/src/grep.c
index a55194c..44e21b7 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -508,7 +508,7 @@ static struct option const long_options[] =
{"extended-regexp", no_argument, NULL, 'E'},
{"fixed-regexp", no_argument, NULL, 'F'},
{"fixed-strings", no_argument, NULL, 'F'},
- {"perl-regexp", no_argument, NULL, 'P'},
+ {"perl-regexp", optional_argument, NULL, 'P'},
{"after-context", required_argument, NULL, 'A'},
{"before-context", required_argument, NULL, 'B'},
{"binary-files", required_argument, NULL, BINARY_FILES_OPTION},
@@ -563,6 +563,7 @@ bool match_icase;
bool match_words;
bool match_lines;
char eolbyte;
+bool pcre_jit = true;
/* For error messages. */
/* The input file name, or (if standard input) null or a --label argument. */
@@ -1987,7 +1988,8 @@ Pattern selection and interpretation:\n"), getprogname ());
-E, --extended-regexp PATTERNS are extended regular expressions\n\
-F, --fixed-strings PATTERNS are strings\n\
-G, --basic-regexp PATTERNS are basic regular expressions\n\
- -P, --perl-regexp PATTERNS are Perl regular expressions\n"));
+ -P, --perl-regexp[=FLAG] PATTERNS are Perl regular expressions\n\
+ FLAG is 'no-jit' (JIT enabled by default)\n"));
/* -X is deliberately undocumented. */
printf (_("\
-e, --regexp=PATTERNS use PATTERNS for matching\n\
@@ -2545,6 +2547,13 @@ main (int argc, char **argv)
case 'P':
matcher = setmatcher ("perl", matcher);
+ if (optarg)
+ {
+ if (STREQ (optarg, "no-jit"))
+ pcre_jit = false;
+ else
+ die (EXIT_TROUBLE, 0, _("unknown PCRE flag"));
+ }
break;
case 'G':
diff --git a/src/grep.h b/src/grep.h
index 04c15dd..263e98c 100644
--- a/src/grep.h
+++ b/src/grep.h
@@ -29,6 +29,7 @@ extern bool match_icase; /* -i */
extern bool match_words; /* -w */
extern bool match_lines; /* -x */
extern char eolbyte; /* -z */
+extern bool pcre_jit; /* --perl-regexp=no-jit */
extern char const *pattern_file_name (idx_t, idx_t *);
diff --git a/src/pcresearch.c b/src/pcresearch.c
index 09f92c8..988d753 100644
--- a/src/pcresearch.c
+++ b/src/pcresearch.c
@@ -180,7 +180,9 @@ Pcompile (char *pattern, idx_t size, reg_syntax_t ignored, bool exact)
if (!pc->cre)
die (EXIT_TROUBLE, 0, "%s", ep);
- int pcre_study_flags = PCRE_STUDY_EXTRA_NEEDED | PCRE_STUDY_JIT_COMPILE;
+ int pcre_study_flags = PCRE_STUDY_EXTRA_NEEDED;
+ if (pcre_jit)
+ pcre_study_flags |= PCRE_STUDY_JIT_COMPILE;
pc->extra = pcre_study (pc->cre, pcre_study_flags, &ep);
if (ep)
die (EXIT_TROUBLE, 0, "%s", ep);
@@ -191,7 +193,7 @@ Pcompile (char *pattern, idx_t size, reg_syntax_t ignored, bool exact)
/* The PCRE documentation says that a 32 KiB stack is the default. */
if (e)
- pc->jit_stack_size = 32 << 10;
+ pc->jit_stack_size = (pcre_jit) ? 32 << 10 : 0;
#endif
free (re);
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c84cdc0..cd83e00 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -135,6 +135,7 @@ TESTS = \
null-byte \
options \
pcre \
+ pcre-nojit \
pcre-abort \
pcre-context \
pcre-count \
diff --git a/tests/pcre-nojit b/tests/pcre-nojit
new file mode 100755
index 0000000..e752f33
--- /dev/null
+++ b/tests/pcre-nojit
@@ -0,0 +1,22 @@
+#! /bin/sh
+# Simple PCRE tests with JIT disabled.
+#
+# Copyright (C) 2001, 2006, 2009-2021 Free Software Foundation, Inc.
+#
+# Copying and distribution of this file, with or without modification,
+# are permitted in any medium without royalty provided the copyright
+# notice and this notice are preserved.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+require_pcre_
+
+fail=0
+
+echo | grep --perl-regex=no-jit '\s*$' || fail=1
+echo | grep -z --perl-regex=no-jit '\s$' || fail=1
+echo '.ab' | returns_ 1 grep --perl-regex=no-jit -wx ab || fail=1
+echo x | grep --perl-regex=no-jit -z '[^a]' || fail=1
+printf 'x\n\0' | returns_ 1 grep -z --perl-regex=no-jit 'x$' || fail=1
+printf 'a\nb\0' | grep -zx --perl-regex=no-jit a && fail=1
+
+Exit $fail
--
2.34.0.rc1.349.g8f33748433
