[Webkit-unassigned] [Bug 62443] Make dynamic annotations weak symbols and prevent identical code folding by the linker

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=62443


Dmitry Vyukov <dvyukov at google.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dvyukov at google.com




--- Comment #5 from Dmitry Vyukov <dvyukov at google.com>  2011-06-14 01:25:25 PST ---
Hi Eric, 

> What happens w/o this change?

As for __attribute__((weak)), our tools define strong symbols with the same names, so if WebKit annotations are not weak symbols we either get linker errors or our symbols do not trump WebKit symbols.

As for Identical Code Folding and strange function bodies, linkers can fold symbols with identical bodies (as you may guess it especially affects empty functions because there are a lot of them). Then some tools (in particular, Valgrind) are unable to intercept such functions. It's possible to suppress such behavior with linker-specific flags, but (1) the problem is hard to debug (so it will make harm before people guess they need additional flags), (2) it can significantly increase binary size (especially crucial for ARM devices), (3) libraries have loose control over linker flags and (4) it's better to provide a solution that works either way anyway.

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.