From 95d88c4044fb74af8c3259db6413214fe9a106e2 Mon Sep 17 00:00:00 2001 From: ph10 Date: Tue, 18 Oct 2016 11:22:40 +0000 Subject: [PATCH] Fix optimization bugs when pattern starts with lookahead. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@573 6239d852-aaf2-0410-a92c-79f79f948069 Petr Písař: Ported to 10.22. Signed-off-by: Petr Písař --- src/pcre2_compile.c | 63 ++++++++++++++++++++++++++++++---------------------- testdata/testinput1 | 6 +++++ testdata/testinput2 | 2 ++ testdata/testinput4 | 6 +++++ testdata/testoutput1 | 8 +++++++ testdata/testoutput2 | 6 ++++- testdata/testoutput4 | 8 +++++++ 7 files changed, 72 insertions(+), 27 deletions(-) diff --git a/src/pcre2_compile.c b/src/pcre2_compile.c index b3ebb25..fe37310 100644 --- a/src/pcre2_compile.c +++ b/src/pcre2_compile.c @@ -5553,8 +5553,9 @@ for (;; ptr++) *lengthptr += delta; } - /* This is compiling for real. If there is a set first byte for - the group, and we have not yet set a "required byte", set it. */ + /* This is compiling for real. If there is a set first code unit + for the group, and we have not yet set a "required code unit", set + it. */ else { @@ -7185,7 +7186,7 @@ for (;; ptr++) zerofirstcuflags = firstcuflags; groupsetfirstcu = FALSE; - if (bravalue >= OP_ONCE) + if (bravalue >= OP_ONCE) /* Not an assertion */ { /* If we have not yet set a firstcu in this branch, take it from the subpattern, remembering that it was set here so that a repeat of more @@ -7225,15 +7226,19 @@ for (;; ptr++) } } - /* For a forward assertion, we take the reqcu, if set. This can be - helpful if the pattern that follows the assertion doesn't set a different - char. For example, it's useful for /(?=abcde).+/. We can't set firstcu - for an assertion, however because it leads to incorrect effect for patterns - such as /(?=a)a.+/ when the "real" "a" would then become a reqcu instead - of a firstcu. This is overcome by a scan at the end if there's no - firstcu, looking for an asserted first char. */ - - else if (bravalue == OP_ASSERT && subreqcuflags >= 0) + /* For a forward assertion, we take the reqcu, if set, provided that the + group has also set a firstcu. This can be helpful if the pattern that + follows the assertion doesn't set a different char. For example, it's + useful for /(?=abcde).+/. We can't set firstcu for an assertion, however + because it leads to incorrect effect for patterns such as /(?=a)a.+/ when + the "real" "a" would then become a reqcu instead of a firstcu. This is + overcome by a scan at the end if there's no firstcu, looking for an + asserted first char. A similar effect for patterns like /(?=.*X)X$/ means + we must only take the reqcu when the group also set a firstcu. Otherwise, + in that example, 'X' ends up set for both. */ + + else if (bravalue == OP_ASSERT && subreqcuflags >= 0 && + subfirstcuflags >= 0) { reqcu = subreqcu; reqcuflags = subreqcuflags; @@ -8036,8 +8041,8 @@ matching and for non-DOTALL patterns that start with .* (which must start at the beginning or after \n). As in the case of is_anchored() (see above), we have to take account of back references to capturing brackets that contain .* because in that case we can't make the assumption. Also, the appearance of .* -inside atomic brackets or in a pattern that contains *PRUNE or *SKIP does not -count, because once again the assumption no longer holds. +inside atomic brackets or in an assertion, or in a pattern that contains *PRUNE +or *SKIP does not count, because once again the assumption no longer holds. Arguments: code points to start of the compiled pattern or a group @@ -8046,13 +8051,14 @@ Arguments: the less precise approach cb points to the compile data atomcount atomic group level + inassert TRUE if in an assertion Returns: TRUE or FALSE */ static BOOL is_startline(PCRE2_SPTR code, unsigned int bracket_map, compile_block *cb, - int atomcount) + int atomcount, BOOL inassert) { do { PCRE2_SPTR scode = first_significant_code( @@ -8083,7 +8089,7 @@ do { return FALSE; default: /* Assertion */ - if (!is_startline(scode, bracket_map, cb, atomcount)) return FALSE; + if (!is_startline(scode, bracket_map, cb, atomcount, TRUE)) return FALSE; do scode += GET(scode, 1); while (*scode == OP_ALT); scode += 1 + LINK_SIZE; break; @@ -8097,7 +8103,8 @@ do { if (op == OP_BRA || op == OP_BRAPOS || op == OP_SBRA || op == OP_SBRAPOS) { - if (!is_startline(scode, bracket_map, cb, atomcount)) return FALSE; + if (!is_startline(scode, bracket_map, cb, atomcount, inassert)) + return FALSE; } /* Capturing brackets */ @@ -8107,33 +8114,36 @@ do { { int n = GET2(scode, 1+LINK_SIZE); int new_map = bracket_map | ((n < 32)? (1u << n) : 1); - if (!is_startline(scode, new_map, cb, atomcount)) return FALSE; + if (!is_startline(scode, new_map, cb, atomcount, inassert)) return FALSE; } /* Positive forward assertions */ else if (op == OP_ASSERT) { - if (!is_startline(scode, bracket_map, cb, atomcount)) return FALSE; + if (!is_startline(scode, bracket_map, cb, atomcount, TRUE)) + return FALSE; } /* Atomic brackets */ else if (op == OP_ONCE || op == OP_ONCE_NC) { - if (!is_startline(scode, bracket_map, cb, atomcount + 1)) return FALSE; + if (!is_startline(scode, bracket_map, cb, atomcount + 1, inassert)) + return FALSE; } /* .* means "start at start or after \n" if it isn't in atomic brackets or - brackets that may be referenced, as long as the pattern does not contain - *PRUNE or *SKIP, because these break the feature. Consider, for example, - /.*?a(*PRUNE)b/ with the subject "aab", which matches "ab", i.e. not at the - start of a line. There is also an option that disables this optimization. */ + brackets that may be referenced or an assertion, and as long as the pattern + does not contain *PRUNE or *SKIP, because these break the feature. Consider, + for example, /.*?a(*PRUNE)b/ with the subject "aab", which matches "ab", + i.e. not at the start of a line. There is also an option that disables this + optimization. */ else if (op == OP_TYPESTAR || op == OP_TYPEMINSTAR || op == OP_TYPEPOSSTAR) { if (scode[1] != OP_ANY || (bracket_map & cb->backref_map) != 0 || - atomcount > 0 || cb->had_pruneorskip || + atomcount > 0 || cb->had_pruneorskip || inassert || (cb->external_options & PCRE2_NO_DOTSTAR_ANCHOR) != 0) return FALSE; } @@ -9023,7 +9033,8 @@ if ((re->overall_options & (PCRE2_ANCHORED|PCRE2_NO_START_OPTIMIZE)) == 0) when *PRUNE and SKIP are not present. (There is an option that disables this case.) */ - else if (is_startline(codestart, 0, &cb, 0)) re->flags |= PCRE2_STARTLINE; + else if (is_startline(codestart, 0, &cb, 0, FALSE)) + re->flags |= PCRE2_STARTLINE; } /* Handle the "required code unit", if one is set. In the case of an anchored diff --git a/testdata/testinput1 b/testdata/testinput1 index 6d7bc80..0d680d3 100644 --- a/testdata/testinput1 +++ b/testdata/testinput1 @@ -5792,4 +5792,10 @@ name)/mark aaaccccaaa bccccb +/(?=.*[A-Z])(?=.*[a-z])(?=.*[0-9])(?=.*[,;:])(?=.{8,16})(?!.*[\s])/ + \ Fred:099 + +/(?=.*X)X$/ + \ X + # End of testinput1 diff --git a/testdata/testinput2 b/testdata/testinput2 index 2d4bbe5..94fbfab 100644 --- a/testdata/testinput2 +++ b/testdata/testinput2 @@ -4823,4 +4823,6 @@ a)"xI /(?abc)(?(R)xyz)/B +/(?=.*[A-Z])/I + # End of testinput2 diff --git a/testdata/testinput4 b/testdata/testinput4 index ce9145d..73582b7 100644 --- a/testdata/testinput4 +++ b/testdata/testinput4 @@ -2282,4 +2282,10 @@ \x{389} \x{20ac} +/(?=.*b)\pL/ + 11bb + +/(?(?=.*b)(?=.*b)\pL|.*c)/ + 11bb + # End of testinput4 diff --git a/testdata/testoutput1 b/testdata/testoutput1 index d28bf91..02e07bf 100644 --- a/testdata/testoutput1 +++ b/testdata/testoutput1 @@ -9257,4 +9257,12 @@ No match 1: b 2: cccc +/(?=.*[A-Z])(?=.*[a-z])(?=.*[0-9])(?=.*[,;:])(?=.{8,16})(?!.*[\s])/ + \ Fred:099 + 0: + +/(?=.*X)X$/ + \ X + 0: X + # End of testinput1 diff --git a/testdata/testoutput2 b/testdata/testoutput2 index ef7e329..bdb289d 100644 --- a/testdata/testoutput2 +++ b/testdata/testoutput2 @@ -8751,7 +8751,6 @@ Subject length lower bound = 1 /(?(?=.*b).*b|^d)/I Capturing subpattern count = 0 -First code unit at start or follows newline Subject length lower bound = 1 /xyz/auto_callout @@ -15223,6 +15222,11 @@ No match End ------------------------------------------------------------------ +/(?=.*[A-Z])/I +Capturing subpattern count = 0 +May match empty string +Subject length lower bound = 0 + # End of testinput2 Error -63: PCRE2_ERROR_BADDATA (unknown error number) Error -62: bad serialized data diff --git a/testdata/testoutput4 b/testdata/testoutput4 index 701d411..d2d5e51 100644 --- a/testdata/testoutput4 +++ b/testdata/testoutput4 @@ -3703,4 +3703,12 @@ No match \x{20ac} No match +/(?=.*b)\pL/ + 11bb + 0: b + +/(?(?=.*b)(?=.*b)\pL|.*c)/ + 11bb + 0: b + # End of testinput4 -- 2.7.4