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revision 989 by zherczeg, Sat Jul 7 11:11:02 2012 UTC revision 1363 by ph10, Tue Oct 1 16:54:40 2013 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.32  Version 8.34 xx-xxxx-201x
5  ------------  --------------------------
6    
7    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
8        executable memory. Patch inspired by Carsten Klein.
9    
10    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
11        this macro is never tested and has no effect, because the work to support
12        coverage involves only compiling and linking options and special targets in
13        the Makefile. The comment in config.h implied that defining the macro would
14        enable coverage support, which is totally false. There was also support for
15        setting this macro in the CMake files (my fault, I just copied it from
16        configure). SUPPORT_GCOV has now been removed.
17    
18    3.  Make a small performance improvement in strlen16() and strlen32() in
19        pcretest.
20    
21    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
22        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
23        these cases). There was also one in pcretest.c.
24    
25    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
26    
27    6.  In UTF mode, the code for checking whether a group could match an empty
28        string (which is used for indefinitely repeated groups to allow for
29        breaking an infinite loop) was broken when the group contained a repeated
30        negated single-character class with a character that occupied more than one
31        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
32        UTF-8 mode). The effect was undefined: the group might or might not be
33        deemed as matching an empty string, or the program might have crashed.
34    
35    7.  The code for checking whether a group could match an empty string was not
36        recognizing that \h, \H, \v, \V, and \R must match a character.
37    
38    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
39        an empty string. If it can, pcretest shows this in its information output.
40    
41    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
42        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
43        matched by pcre_exec() without using JIT:
44    
45        (a) If the rest of the pattern did not match after a maximal run of
46            grapheme clusters, the code for backing up to try with fewer of them
47            did not always back up over a full grapheme when characters that do not
48            have the modifier quality were involved, e.g. Hangul syllables.
49    
50        (b) If the match point in a subject started with modifier character, and
51            there was no match, the code could incorrectly back up beyond the match
52            point, and potentially beyond the first character in the subject,
53            leading to a segfault or an incorrect match result.
54    
55    10. A conditional group with an assertion condition could lead to PCRE
56        recording an incorrect first data item for a match if no other first data
57        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
58        first data item, and therefore matched "ca" after "c" instead of at the
59        start.
60    
61    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
62        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
63    
64    12. The source of pcregrep now includes z/OS-specific code so that it can be
65        compiled for z/OS as part of the special z/OS distribution.
66    
67    13. Added the -T and -TM options to pcretest.
68    
69    14. The code in pcre_compile.c for creating the table of named capturing groups
70        has been refactored. Instead of creating the table dynamically during the
71        actual compiling pass, the information is remembered during the pre-compile
72        pass (on the stack unless there are more than 20 named groups, in which
73        case malloc() is used) and the whole table is created before the actual
74        compile happens. This has simplified the code (it is now nearly 150 lines
75        shorter) and prepared the way for better handling of references to groups
76        with duplicate names.
77    
78    15. A back reference to a named subpattern when there is more than one of the
79        same name now checks them in the order in which they appear in the pattern.
80        The first one that is set is used for the reference. Previously only the
81        first one was inspected. This change makes PCRE more compatible with Perl.
82    
83    16. Unicode character properties were updated from Unicode 6.3.0.
84    
85    17. The compile-time code for auto-possessification has been refactored, based
86        on a patch by Zoltan Herczeg. It now happens after instead of during
87        compilation. The code is cleaner, and more cases are handled. The option
88        PCRE_NO_AUTO_POSSESSIFY is added for testing purposes, and the -O and /O
89        options in pcretest are provided to set it.
90    
91    
92    Version 8.33 28-May-2013
93    ------------------------
94    
95    1.  Added 'U' to some constants that are compared to unsigned integers, to
96        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
97        variables that are added to signed variables, to ensure the result is
98        signed and can be negated.
99    
100    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
101        CMake config files.
102    
103    3.  Revise the creation of config.h.generic so that all boolean macros are
104        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
105        overriding via -D on the command line possible.
106    
107    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
108        to unsigned int is reported to make a quite noticeable speed difference in
109        a specific Windows environment. Testing on Linux did also appear to show
110        some benefit (and it is clearly not harmful). Also fixed the definition of
111        Xop which should be unsigned.
112    
113    5.  Related to (4), changing the definition of the intermediate variable cc
114        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
115        improvements.
116    
117    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
118        unnecessary spaces.
119    
120    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
121        and later.
122    
123    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
124    
125    9.  Optimizing fast_forward_start_bits in JIT.
126    
127    10. Adding support for callouts in JIT, and fixing some issues revealed
128        during this work. Namely:
129    
130        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
131    
132        (b) Minimum length was not checked before the matching is started.
133    
134    11. The value of capture_last that is passed to callouts was incorrect in some
135        cases when there was a capture on one path that was subsequently abandoned
136        after a backtrack. Also, the capture_last value is now reset after a
137        recursion, since all captures are also reset in this case.
138    
139    12. The interpreter no longer returns the "too many substrings" error in the
140        case when an overflowing capture is in a branch that is subsequently
141        abandoned after a backtrack.
142    
143    13. In the pathological case when an offset vector of size 2 is used, pcretest
144        now prints out the matched string after a yield of 0 or 1.
145    
146    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
147        Only supported by the JIT compiler at the moment.
148    
149    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
150    
151    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
152        offset of the starting point of the matching process, provided the offsets
153        vector is large enough.
154    
155    17. The \A escape now records a lookbehind value of 1, though its execution
156        does not actually inspect the previous character. This is to ensure that,
157        in partial multi-segment matching, at least one character from the old
158        segment is retained when a new segment is processed. Otherwise, if there
159        are no lookbehinds in the pattern, \A might match incorrectly at the start
160        of a new segment.
161    
162    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
163    
164    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
165        gives some modest performance improvement in 8-bit mode.
166    
167    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
168        be expressed in certain programming languages using Universal Character
169        Names.
170    
171    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
172        which points out that "non characters" are not "characters that may not
173        appear in Unicode strings" but rather "characters that are reserved for
174        internal use and have only local meaning".
175    
176    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
177        there was a conditional group that depended on an assertion, if the
178        assertion was false, the callout that immediately followed the alternation
179        in the condition was skipped when pcre_exec() was used for matching.
180    
181    23. Allow an explicit callout to be inserted before an assertion that is the
182        condition for a conditional group, for compatibility with automatic
183        callouts, which always insert a callout at this point.
184    
185    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
186        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
187    
188    25. (*PRUNE) is now supported by the JIT compiler.
189    
190    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
191    
192    27. Fix the case where there are two or more SKIPs with arguments that may be
193        ignored.
194    
195    28. (*SKIP) is now supported by the JIT compiler.
196    
197    29. (*THEN) is now supported by the JIT compiler.
198    
199    30. Update RunTest with additional test selector options.
200    
201    31. The way PCRE handles backtracking verbs has been changed in two ways.
202    
203        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
204        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
205        backtracking. In some cases this makes it more Perl-compatible, but Perl's
206        rather obscure rules do not always do the same thing.
207    
208        (2) Previously, backtracking verbs were confined within assertions. This is
209        no longer the case for positive assertions, except for (*ACCEPT). Again,
210        this sometimes improves Perl compatibility, and sometimes does not.
211    
212    32. A number of tests that were in test 2 because Perl did things differently
213        have been moved to test 1, because either Perl or PCRE has changed, and
214        these tests are now compatible.
215    
216    32. Backtracking control verbs are now handled in the same way in JIT and
217        interpreter.
218    
219    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
220        contained a forward subroutine reference caused a compile error.
221    
222    34. Auto-detect and optimize limited repetitions in JIT.
223    
224    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
225        blocking (*UTF) etc.
226    
227    36. In the interpreter, maximizing pattern repetitions for characters and
228        character types now use tail recursion, which reduces stack usage.
229    
230    37. The value of the max lookbehind was not correctly preserved if a compiled
231        and saved regex was reloaded on a host of different endianness.
232    
233    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
234        of the compiled pattern block, expand the flags field from 16 to 32 bits
235        because it was almost full.
236    
237    39. Try madvise first before posix_madvise.
238    
239    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
240        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
241        original change locked out all matches of empty strings. This has been
242        changed so that one match of an empty string per line is recognized.
243        Subsequent searches on the same line (for colouring or for --only-matching,
244        for example) do not recognize empty strings.
245    
246    41. Applied a user patch to fix a number of spelling mistakes in comments.
247    
248    42. Data lines longer than 65536 caused pcretest to crash.
249    
250    43. Clarified the data type for length and startoffset arguments for pcre_exec
251        and pcre_dfa_exec in the function-specific man pages, where they were
252        explicitly stated to be in bytes, never having been updated. I also added
253        some clarification to the pcreapi man page.
254    
255    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
256        a segmentation fault.
257    
258    
259    Version 8.32 30-November-2012
260    -----------------------------
261    
262  1.  Improved JIT compiler optimizations for first character search and single  1.  Improved JIT compiler optimizations for first character search and single
263      character iterators.      character iterators.
# Line 12  Version 8.32 Line 267  Version 8.32
267    
268  3.  Single character iterator optimizations in the JIT compiler.  3.  Single character iterator optimizations in the JIT compiler.
269    
270    4.  Improved JIT compiler optimizations for character ranges.
271    
272    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
273        Reported by Giuseppe D'Angelo.
274    
275    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
276        of a line, was being set incorrectly in cases where .* appeared inside
277        atomic brackets at the start of a pattern, or where there was a subsequent
278        *PRUNE or *SKIP.
279    
280    7.  Improved instruction cache flush for POWER/PowerPC.
281        Patch by Daniel Richard G.
282    
283    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
284        grep:
285    
286        (a) There is now no limit to the number of patterns to be matched.
287    
288        (b) An error is given if a pattern is too long.
289    
290        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
291            are now supported.
292    
293        (d) --exclude-from and --include-from (multiple use) have been added.
294    
295        (e) Exclusions and inclusions now apply to all files and directories, not
296            just to those obtained from scanning a directory recursively.
297    
298        (f) Multiple uses of -f and --file-list are now supported.
299    
300        (g) In a Windows environment, the default for -d has been changed from
301            "read" (the GNU grep default) to "skip", because otherwise the presence
302            of a directory in the file list provokes an error.
303    
304        (h) The documentation has been revised and clarified in places.
305    
306    9.  Improve the matching speed of capturing brackets.
307    
308    10. Changed the meaning of \X so that it now matches a Unicode extended
309        grapheme cluster.
310    
311    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
312        out POSIX threads when JIT support is configured.
313    
314    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
315    
316    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
317        structure could go wrong in environments where size_t is not the same size
318        as int.
319    
320    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
321        set.
322    
323    15. The EBCDIC support had decayed; later updates to the code had included
324        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
325        general tidy up of EBCDIC-related issues, and the documentation was also
326        not quite right. There is now a test that can be run on ASCII systems to
327        check some of the EBCDIC-related things (but is it not a full test).
328    
329    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
330        in a small tidy to the code.
331    
332    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
333    
334    18. If the --only-matching (-o) option in pcregrep is specified multiple
335        times, each one causes appropriate output. For example, -o1 -o2 outputs the
336        substrings matched by the 1st and 2nd capturing parentheses. A separating
337        string can be specified by --om-separator (default empty).
338    
339    19. Improving the first n character searches.
340    
341    20. Turn case lists for horizontal and vertical white space into macros so that
342        they are defined only once.
343    
344    21. This set of changes together give more compatible Unicode case-folding
345        behaviour for characters that have more than one other case when UCP
346        support is available.
347    
348        (a) The Unicode property table now has offsets into a new table of sets of
349            three or more characters that are case-equivalent. The MultiStage2.py
350            script that generates these tables (the pcre_ucd.c file) now scans
351            CaseFolding.txt instead of UnicodeData.txt for character case
352            information.
353    
354        (b) The code for adding characters or ranges of characters to a character
355            class has been abstracted into a generalized function that also handles
356            case-independence. In UTF-mode with UCP support, this uses the new data
357            to handle characters with more than one other case.
358    
359        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
360            whose other case is greater than 256 are now correctly matched
361            caselessly. Previously, the high codepoint matched the low one, but not
362            vice versa.
363    
364        (d) The processing of \h, \H, \v, and \ in character classes now makes use
365            of the new class addition function, using character lists defined as
366            macros alongside the case definitions of 20 above.
367    
368        (e) Caseless back references now work with characters that have more than
369            one other case.
370    
371        (f) General caseless matching of characters with more than one other case
372            is supported.
373    
374    22. Unicode character properties were updated from Unicode 6.2.0
375    
376    23. Improved CMake support under Windows. Patch by Daniel Richard G.
377    
378    24. Add support for 32-bit character strings, and UTF-32
379    
380    25. Major JIT compiler update (code refactoring and bugfixing).
381        Experimental Sparc 32 support is added.
382    
383    26. Applied a modified version of Daniel Richard G's patch to create
384        pcre.h.generic and config.h.generic by "make" instead of in the
385        PrepareRelease script.
386    
387    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
388        pcre_compile.c when checking for a zero character.
389    
390    28. Introducing a native interface for JIT. Through this interface, the compiled
391        machine code can be directly executed. The purpose of this interface is to
392        provide fast pattern matching, so several sanity checks are not performed.
393        However, feature tests are still performed. The new interface provides
394        1.4x speedup compared to the old one.
395    
396    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
397        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
398        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
399    
400    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
401        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
402        the "old" RFC 2279). Instead, it ended up passing a negative length to
403        pcre_exec().
404    
405    31. Add support for GCC's visibility feature to hide internal functions.
406    
407    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
408        "unknown -C option" after outputting 0 or 1.
409    
410    33. There is now support for generating a code coverage report for the test
411        suite in environments where gcc is the compiler and lcov is installed. This
412        is mainly for the benefit of the developers.
413    
414    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
415        unaddressable using valgrind annotations, allowing valgrind to detect
416        invalid memory accesses. This is mainly for the benefit of the developers.
417    
418    25. (*UTF) can now be used to start a pattern in any of the three libraries.
419    
420    26. Give configure error if --enable-cpp but no C++ compiler found.
421    
422    
423  Version 8.31 06-July-2012  Version 8.31 06-July-2012
424  -------------------------  -------------------------
# Line 1356  Version 7.9 11-Apr-09 Line 1763  Version 7.9 11-Apr-09
1763  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
1764      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
1765      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1766      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1767        8.33.]
1768    
1769  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1770      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 1599  Version 7.7 07-May-08 Line 2007  Version 7.7 07-May-08
2007      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2008      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2009      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2010      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2011      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2012      was subsequently set up correctly.)      was subsequently set up correctly.)
2013    

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