diff options
| author | Jean Boussier <[email protected]> | 2025-02-24 11:39:00 +0100 |
|---|---|---|
| committer | Jean Boussier <[email protected]> | 2025-02-24 18:32:46 +0100 |
| commit | 87f9c3c65e38fa3e5c6ef097e2cf63ff448f48d6 (patch) | |
| tree | 511d0e2492dad3ec4f140ee4728abe4d8fa4c45c /string.c | |
| parent | 21ac0a3a640a2a86e8716675f82221f178e29088 (diff) | |
String#gsub! Elide MatchData allocation when we know it can't escape
In gsub is used with a string replacement or a map that doesn't
have a default proc, we know for sure no code can cause the MatchData
to escape the `gsub` call.
In such case, we still have to allocate a new MatchData because we
don't know what is the lifetime of the backref, but for any subsequent
match we can re-use the MatchData we allocated ourselves, reducing
allocations significantly.
This partially fixes [Misc #20652], except when a block is used,
and partially reduce the performance impact of
abc0304cb28cb9dcc3476993bc487884c139fd11 / [Bug #17507]
```
compare-ruby: ruby 3.5.0dev (2025-02-24T09:44:57Z master 5cf146399f) +PRISM [arm64-darwin24]
built-ruby: ruby 3.5.0dev (2025-02-24T10:58:27Z gsub-elude-match da966636e9) +PRISM [arm64-darwin24]
warming up....
| |compare-ruby|built-ruby|
|:----------------|-----------:|---------:|
|escape | 3.577k| 3.697k|
| | -| 1.03x|
|escape_bin | 5.869k| 6.743k|
| | -| 1.15x|
|escape_utf8 | 3.448k| 3.738k|
| | -| 1.08x|
|escape_utf8_bin | 6.361k| 7.267k|
| | -| 1.14x|
```
Co-Authored-By: Étienne Barrié <[email protected]>
Diffstat (limited to 'string.c')
| -rw-r--r-- | string.c | 41 |
1 files changed, 28 insertions, 13 deletions
@@ -6122,14 +6122,17 @@ get_pat_quoted(VALUE pat, int check) } static long -rb_pat_search(VALUE pat, VALUE str, long pos, int set_backref_str) +rb_pat_search0(VALUE pat, VALUE str, long pos, int set_backref_str, VALUE *match) { if (BUILTIN_TYPE(pat) == T_STRING) { pos = rb_str_byteindex(str, pat, pos); if (set_backref_str) { if (pos >= 0) { str = rb_str_new_frozen_String(str); - rb_backref_set_string(str, pos, RSTRING_LEN(pat)); + VALUE match_data = rb_backref_set_string(str, pos, RSTRING_LEN(pat)); + if (match) { + *match = match_data; + } } else { rb_backref_set(Qnil); @@ -6138,10 +6141,16 @@ rb_pat_search(VALUE pat, VALUE str, long pos, int set_backref_str) return pos; } else { - return rb_reg_search0(pat, str, pos, 0, set_backref_str); + return rb_reg_search0(pat, str, pos, 0, set_backref_str, match); } } +static long +rb_pat_search(VALUE pat, VALUE str, long pos, int set_backref_str) +{ + return rb_pat_search0(pat, str, pos, set_backref_str, NULL); +} + /* * call-seq: @@ -6293,12 +6302,12 @@ rb_str_sub(int argc, VALUE *argv, VALUE str) static VALUE str_gsub(int argc, VALUE *argv, VALUE str, int bang) { - VALUE pat, val = Qnil, repl, match0 = Qnil, dest, hash = Qnil; + VALUE pat, val = Qnil, repl, match0 = Qnil, dest, hash = Qnil, match = Qnil; long beg, beg0, end0; long offset, blen, slen, len, last; enum {STR, ITER, FAST_MAP, MAP} mode = STR; char *sp, *cp; - int need_backref = -1; + int need_backref_str = -1; rb_encoding *str_enc; switch (argc) { @@ -6324,7 +6333,8 @@ str_gsub(int argc, VALUE *argv, VALUE str, int bang) } pat = get_pat_quoted(argv[0], 1); - beg = rb_pat_search(pat, str, 0, need_backref); + beg = rb_pat_search0(pat, str, 0, need_backref_str, &match); + if (beg < 0) { if (bang) return Qnil; /* no match, no substitution */ return str_duplicate(rb_cString, str); @@ -6341,7 +6351,6 @@ str_gsub(int argc, VALUE *argv, VALUE str, int bang) ENC_CODERANGE_SET(dest, rb_enc_asciicompat(str_enc) ? ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID); do { - VALUE match = rb_backref_get(); struct re_registers *regs = RMATCH_REGS(match); if (RB_TYPE_P(pat, T_STRING)) { beg0 = beg; @@ -6354,7 +6363,7 @@ str_gsub(int argc, VALUE *argv, VALUE str, int bang) if (mode == ITER) match0 = rb_reg_nth_match(0, match); } - if (mode) { + if (mode != STR) { if (mode == ITER) { val = rb_obj_as_string(rb_yield(match0)); } @@ -6378,10 +6387,10 @@ str_gsub(int argc, VALUE *argv, VALUE str, int bang) rb_raise(rb_eRuntimeError, "block should not cheat"); } } - else if (need_backref) { + else if (need_backref_str) { val = rb_reg_regsub(repl, str, regs, RB_TYPE_P(pat, T_STRING) ? Qnil : pat); - if (need_backref < 0) { - need_backref = val != repl; + if (need_backref_str < 0) { + need_backref_str = val != repl; } } else { @@ -6409,14 +6418,20 @@ str_gsub(int argc, VALUE *argv, VALUE str, int bang) } cp = RSTRING_PTR(str) + offset; if (offset > RSTRING_LEN(str)) break; - beg = rb_pat_search(pat, str, offset, need_backref); + + // In FAST_MAP and STR mode the backref can't escape so we can re-use the MatchData safely. + if (mode != FAST_MAP && mode != STR) { + match = Qnil; + } + beg = rb_pat_search0(pat, str, offset, need_backref_str, &match); RB_GC_GUARD(match); } while (beg >= 0); + if (RSTRING_LEN(str) > offset) { rb_enc_str_buf_cat(dest, cp, RSTRING_LEN(str) - offset, str_enc); } - rb_pat_search(pat, str, last, 1); + rb_pat_search0(pat, str, last, 1, &match); if (bang) { str_shared_replace(str, dest); } |