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git/grep.h
Ævar Arnfjörð Bjarmason 94da9193a6 grep: add support for PCRE v2
Add support for v2 of the PCRE API. This is a new major version of
PCRE that came out in early 2015[1].

The regular expression syntax is the same, but while the API is
similar, pretty much every function is either renamed or takes
different arguments. Thus using it via entirely new functions makes
sense, as opposed to trying to e.g. have one compile_pcre_pattern()
that would call either PCRE v1 or v2 functions.

Git can now be compiled with either USE_LIBPCRE1=YesPlease or
USE_LIBPCRE2=YesPlease, with USE_LIBPCRE=YesPlease currently being a
synonym for the former. Providing both is a compile-time error.

With earlier patches to enable JIT for PCRE v1 the performance of the
release versions of both libraries is almost exactly the same, with
PCRE v2 being around 1% slower.

However after I reported this to the pcre-dev mailing list[2] I got a
lot of help with the API use from Zoltán Herczeg, he subsequently
optimized some of the JIT functionality in v2 of the library.

Running the p7820-grep-engines.sh performance test against the latest
Subversion trunk of both, with both them and git compiled as -O3, and
the test run against linux.git, gives the following results. Just the
/perl/ tests shown:

    $ GIT_PERF_REPEAT_COUNT=30 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_MAKE_COMMAND='grep -q LIBPCRE2 Makefile && make -j8 USE_LIBPCRE2=YesPlease CC=~/perl5/installed/bin/gcc NO_R_TO_GCC_LINKER=YesPlease CFLAGS=-O3 LIBPCREDIR=/home/avar/g/pcre2/inst LDFLAGS=-Wl,-rpath,/home/avar/g/pcre2/inst/lib || make -j8 USE_LIBPCRE=YesPlease CC=~/perl5/installed/bin/gcc NO_R_TO_GCC_LINKER=YesPlease CFLAGS=-O3 LIBPCREDIR=/home/avar/g/pcre/inst LDFLAGS=-Wl,-rpath,/home/avar/g/pcre/inst/lib' ./run HEAD~5 HEAD~ HEAD p7820-grep-engines.sh
    [...]
    Test                                            HEAD~5            HEAD~                    HEAD
    -----------------------------------------------------------------------------------------------------------------
    7820.3: perl grep 'how.to'                      0.31(1.10+0.48)   0.21(0.35+0.56) -32.3%   0.21(0.34+0.55) -32.3%
    7820.7: perl grep '^how to'                     0.56(2.70+0.40)   0.24(0.64+0.52) -57.1%   0.20(0.28+0.60) -64.3%
    7820.11: perl grep '[how] to'                   0.56(2.66+0.38)   0.29(0.95+0.45) -48.2%   0.23(0.45+0.54) -58.9%
    7820.15: perl grep '(e.t[^ ]*|v.ry) rare'       1.02(5.77+0.42)   0.31(1.02+0.54) -69.6%   0.23(0.50+0.54) -77.5%
    7820.19: perl grep 'm(ú|u)lt.b(æ|y)te'          0.38(1.57+0.42)   0.27(0.85+0.46) -28.9%   0.21(0.33+0.57) -44.7%

See commit ("perf: add a comparison test of grep regex engines",
2017-04-19) for details on the machine the above test run was executed
on.

Here HEAD~2 is git with PCRE v1 without JIT, HEAD~ is PCRE v1 with
JIT, and HEAD is PCRE v2 (also with JIT). See previous commits of mine
mentioning p7820-grep-engines.sh for more details on the test setup.

For ease of readability, a different run just of HEAD~ (PCRE v1 with
JIT v.s. PCRE v2), again with just the /perl/ tests shown:

    [...]
    Test                                            HEAD~             HEAD
    ----------------------------------------------------------------------------------------
    7820.3: perl grep 'how.to'                      0.21(0.42+0.52)   0.21(0.31+0.58) +0.0%
    7820.7: perl grep '^how to'                     0.25(0.65+0.50)   0.20(0.31+0.57) -20.0%
    7820.11: perl grep '[how] to'                   0.30(0.90+0.50)   0.23(0.46+0.53) -23.3%
    7820.15: perl grep '(e.t[^ ]*|v.ry) rare'       0.30(1.19+0.38)   0.23(0.51+0.51) -23.3%
    7820.19: perl grep 'm(ú|u)lt.b(æ|y)te'          0.27(0.84+0.48)   0.21(0.34+0.57) -22.2%

I.e. the two are either neck-to-neck, but PCRE v2 usually pulls ahead,
when it does it's around 20% faster.

A brief note on thread safety: As noted in pcre2api(3) & pcre2jit(3)
the compiled pattern can be shared between threads, but not some of
the JIT context, however the grep threading support does all pattern &
JIT compilation in separate threads, so this code doesn't need to
concern itself with thread safety.

See commit 63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09) for the
initial addition of PCRE v1. This change follows some of the same
patterns it did (and which were discussed on list at the time),
e.g. mocking up types with typedef instead of ifdef-ing them out when
USE_LIBPCRE2 isn't defined. This adds some trivial memory use to the
program, but makes the code look nicer.

1. https://lists.exim.org/lurker/message/20150105.162835.0666407a.en.html
2. https://lists.exim.org/lurker/thread/20170419.172322.833ee099.en.html

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-02 08:29:05 +09:00

248 lines
5.6 KiB
C

#ifndef GREP_H
#define GREP_H
#include "color.h"
#ifdef USE_LIBPCRE1
#include <pcre.h>
#ifdef PCRE_CONFIG_JIT
#if PCRE_MAJOR >= 8 && PCRE_MINOR >= 32
#ifndef NO_LIBPCRE1_JIT
#define GIT_PCRE1_USE_JIT
#endif
#endif
#endif
#ifndef PCRE_STUDY_JIT_COMPILE
#define PCRE_STUDY_JIT_COMPILE 0
#endif
#if PCRE_MAJOR <= 8 && PCRE_MINOR < 20
typedef int pcre_jit_stack;
#endif
#else
typedef int pcre;
typedef int pcre_extra;
typedef int pcre_jit_stack;
#endif
#ifdef USE_LIBPCRE2
#define PCRE2_CODE_UNIT_WIDTH 8
#include <pcre2.h>
#else
typedef int pcre2_code;
typedef int pcre2_match_data;
typedef int pcre2_compile_context;
typedef int pcre2_match_context;
typedef int pcre2_jit_stack;
#endif
#include "kwset.h"
#include "thread-utils.h"
#include "userdiff.h"
enum grep_pat_token {
GREP_PATTERN,
GREP_PATTERN_HEAD,
GREP_PATTERN_BODY,
GREP_AND,
GREP_OPEN_PAREN,
GREP_CLOSE_PAREN,
GREP_NOT,
GREP_OR
};
enum grep_context {
GREP_CONTEXT_HEAD,
GREP_CONTEXT_BODY
};
enum grep_header_field {
GREP_HEADER_FIELD_MIN = 0,
GREP_HEADER_AUTHOR = GREP_HEADER_FIELD_MIN,
GREP_HEADER_COMMITTER,
GREP_HEADER_REFLOG,
/* Must be at the end of the enum */
GREP_HEADER_FIELD_MAX
};
struct grep_pat {
struct grep_pat *next;
const char *origin;
int no;
enum grep_pat_token token;
char *pattern;
size_t patternlen;
enum grep_header_field field;
regex_t regexp;
pcre *pcre1_regexp;
pcre_extra *pcre1_extra_info;
pcre_jit_stack *pcre1_jit_stack;
const unsigned char *pcre1_tables;
int pcre1_jit_on;
pcre2_code *pcre2_pattern;
pcre2_match_data *pcre2_match_data;
pcre2_compile_context *pcre2_compile_context;
pcre2_match_context *pcre2_match_context;
pcre2_jit_stack *pcre2_jit_stack;
uint32_t pcre2_jit_on;
kwset_t kws;
unsigned fixed:1;
unsigned ignore_case:1;
unsigned word_regexp:1;
};
enum grep_expr_node {
GREP_NODE_ATOM,
GREP_NODE_NOT,
GREP_NODE_AND,
GREP_NODE_TRUE,
GREP_NODE_OR
};
enum grep_pattern_type {
GREP_PATTERN_TYPE_UNSPECIFIED = 0,
GREP_PATTERN_TYPE_BRE,
GREP_PATTERN_TYPE_ERE,
GREP_PATTERN_TYPE_FIXED,
GREP_PATTERN_TYPE_PCRE
};
struct grep_expr {
enum grep_expr_node node;
unsigned hit;
union {
struct grep_pat *atom;
struct grep_expr *unary;
struct {
struct grep_expr *left;
struct grep_expr *right;
} binary;
} u;
};
struct grep_opt {
struct grep_pat *pattern_list;
struct grep_pat **pattern_tail;
struct grep_pat *header_list;
struct grep_pat **header_tail;
struct grep_expr *pattern_expression;
const char *prefix;
int prefix_length;
regex_t regexp;
int linenum;
int invert;
int ignore_case;
int status_only;
int name_only;
int unmatch_name_only;
int count;
int word_regexp;
int fixed;
int all_match;
int debug;
#define GREP_BINARY_DEFAULT 0
#define GREP_BINARY_NOMATCH 1
#define GREP_BINARY_TEXT 2
int binary;
int allow_textconv;
int extended;
int use_reflog_filter;
int pcre1;
int pcre2;
int relative;
int pathname;
int null_following_name;
int color;
int max_depth;
int funcname;
int funcbody;
int extended_regexp_option;
int pattern_type_option;
char color_context[COLOR_MAXLEN];
char color_filename[COLOR_MAXLEN];
char color_function[COLOR_MAXLEN];
char color_lineno[COLOR_MAXLEN];
char color_match_context[COLOR_MAXLEN];
char color_match_selected[COLOR_MAXLEN];
char color_selected[COLOR_MAXLEN];
char color_sep[COLOR_MAXLEN];
int regflags;
unsigned pre_context;
unsigned post_context;
unsigned last_shown;
int show_hunk_mark;
int file_break;
int heading;
void *priv;
void (*output)(struct grep_opt *opt, const void *data, size_t size);
void *output_priv;
};
extern void init_grep_defaults(void);
extern int grep_config(const char *var, const char *value, void *);
extern void grep_init(struct grep_opt *, const char *prefix);
void grep_commit_pattern_type(enum grep_pattern_type, struct grep_opt *opt);
extern void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen, const char *origin, int no, enum grep_pat_token t);
extern void append_grep_pattern(struct grep_opt *opt, const char *pat, const char *origin, int no, enum grep_pat_token t);
extern void append_header_grep_pattern(struct grep_opt *, enum grep_header_field, const char *);
extern void compile_grep_patterns(struct grep_opt *opt);
extern void free_grep_patterns(struct grep_opt *opt);
extern int grep_buffer(struct grep_opt *opt, char *buf, unsigned long size);
struct grep_source {
char *name;
enum grep_source_type {
GREP_SOURCE_SHA1,
GREP_SOURCE_FILE,
GREP_SOURCE_BUF,
GREP_SOURCE_SUBMODULE,
} type;
void *identifier;
char *buf;
unsigned long size;
char *path; /* for attribute lookups */
struct userdiff_driver *driver;
};
void grep_source_init(struct grep_source *gs, enum grep_source_type type,
const char *name, const char *path,
const void *identifier);
void grep_source_clear_data(struct grep_source *gs);
void grep_source_clear(struct grep_source *gs);
void grep_source_load_driver(struct grep_source *gs);
int grep_source(struct grep_opt *opt, struct grep_source *gs);
extern struct grep_opt *grep_opt_dup(const struct grep_opt *opt);
extern int grep_threads_ok(const struct grep_opt *opt);
#ifndef NO_PTHREADS
/*
* Mutex used around access to the attributes machinery if
* opt->use_threads. Must be initialized/destroyed by callers!
*/
extern int grep_use_locks;
extern pthread_mutex_t grep_attr_mutex;
extern pthread_mutex_t grep_read_mutex;
static inline void grep_read_lock(void)
{
if (grep_use_locks)
pthread_mutex_lock(&grep_read_mutex);
}
static inline void grep_read_unlock(void)
{
if (grep_use_locks)
pthread_mutex_unlock(&grep_read_mutex);
}
#else
#define grep_read_lock()
#define grep_read_unlock()
#endif
#endif