Commit Graph

7 Commits

Author SHA1 Message Date
Eli Bendersky
6b731486d4 Add backreference matching capabilities to Support/Regex, with
appropriate unit tests. This change in itself is not expected to
affect any functionality at this point, but it will serve as a
stepping stone to improve FileCheck's variable matching capabilities.

Luckily, our regex implementation already supports backreferences,
although a bit of hacking is required to enable it. It supports both
Basic Regular Expressions (BREs) and Extended Regular Expressions
(EREs), without supporting backrefs for EREs, following POSIX strictly
in this respect. And EREs is what we actually use (rightly). This is
contrary to many implementations (including the default on Linux) of
POSIX regexes, that do allow backrefs in EREs.

Adding backref support to our EREs is a very simple change in the
regcomp parsing code. I fail to think of significant cases where it
would clash with existing things, and can bring more versatility to
the regexes we write. There's always the danger of a backref in a
specially crafted regex causing exponential matching times, but since
we mainly use them for testing purposes I don't think it's a big
problem. [it can also be placed behind a flag specific to FileCheck,
if needed].

For more details, see:

* http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-November/055840.html
* http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20121126/156878.html



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168802 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 19:00:02 +00:00
NAKAMURA Takumi
c61ac5120d lib/Support/regcomp.c: Fix cygwin warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127241 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-08 12:25:29 +00:00
Daniel Dunbar
ee7110f047 Fix may-be-used-uninitialized warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81223 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-08 16:14:54 +00:00
Benjamin Kramer
8b3594afdb More MSVC warning fixes:
1. DUPMAX is defined in regcomp.c, no need to redefine it in regutils.
2. MSVC doesn't like snprintf, use _snprintf instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81114 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-06 12:26:28 +00:00
Benjamin Kramer
5b7c3567a1 Remove splint hints to silence warnings from ICC and MSVC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81108 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-06 09:29:39 +00:00
Daniel Dunbar
12420d3a64 Fix some possible-use-of-uninitialized warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80515 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-30 21:13:58 +00:00
Torok Edwin
ce0c81e7dd Add regular expression matching support, based on OpenBSD regexec()/regcomp()
implementation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80493 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-30 08:24:09 +00:00