Bug 174044 – RegExp's anchored with .* with \g flag can return wrong match start for strings with multiple matches

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Michael Saboff]

Consider the string:
    s = "\na\na\na\n";
along with the RegExp:
    r = new RegExp(".*\\s.*", "g");

The result of s.match(r) should be a match object with 4 entries, "\na", "\na", "\na" & "\n".
Instead we get "\na", "a\na", "a\na" & "a\n".

[Michael Saboff]

<rdar://problem/33018426>

[Michael Saboff]

Created attachment 314302 [details]
Patch

[Oliver Hunt]

Comment on attachment 314302 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=314302&action=review

> Source/JavaScriptCore/yarr/YarrJIT.cpp:2699
> +        if (m_pattern.m_saveInitialStartValue) {
> +#ifdef HAVE_INITIAL_START_REG
> +            move(index, initialStart);
> +#else
> +            storeToFrame(index, m_pattern.m_initialStartValueFrameLocation);
> +#endif

I almost wish we could bludgeon templates into doing this for us. Almost. (I suspect it would turn into "can I implement register allocation with templates at compile time?" questions :D )

[Michael Saboff]

Committed r219031: <http://trac.webkit.org/changeset/219031>