* Update to RegExp parsing and AST.

Better handling of captures.
Ignores back-references to captures that can never be captured at that point.
RegExpBackReference keeps link to the RegExpCapture.
Fix for bad formatting.

[Lasse Reichstein, 2008-11-14 13:43:17]

Capture-reachability + backref links to capture.
Please review.

[Christian Plesner Hansen, 2008-11-14 13:55:17]

Lgtm, with comments.

http://codereview.chromium.org/10750/diff/1/2
File regexp2000/src/ast.h (right):

http://codereview.chromium.org/10750/diff/1/2#newcode1346
Line 1346: CapturePermanentlyUnreachable } CaptureAvailability;
You should use all-caps names for enums.  Also, the formatting is odd.

http://codereview.chromium.org/10750/diff/1/4
File regexp2000/src/parser.cc (right):

http://codereview.chromium.org/10750/diff/1/4#newcode4043
Line 4043: captures_->Add(NULL);
This looks suspect.  Why do this instead of using a counter?

http://codereview.chromium.org/10750/diff/1/5
File regexp2000/src/regexp-macro-assembler-ia32.cc (right):

http://codereview.chromium.org/10750/diff/1/5#newcode286
Line 286: void RegExpMacroAssemblerIA32::GoTo(Label *to) {
Why not use the opportunity to put the * next to the type too.

http://codereview.chromium.org/10750/diff/1/5#newcode431
Line 431: void LoadConstantBufferAddress(Register reg, const ArraySlice<T>&
buffer) {
Why is this a reference and why is it const?