An application can use the mere fact of epoll_wait returning an fd
as synchronization with the write on the fd that triggered the notification.
This pattern come up in an internal networking server (b/229276331).
If an fd is added to epoll, setup a link from the fd to the epoll fd
and use it for synchronization as well.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D124518
Currently we inconsistently use u32 and int for thread ids,
there are also "unique tid" and "os tid" and just lots of other
things identified by integers.
Additionally new tsan runtime will introduce yet another
thread identifier that is very different from current tids.
Similarly for stack IDs, it's easy to confuse u32 with other
integer identifiers. And when a function accepts u32 or a struct
contains u32 field, it's not always clear what it is.
Add Tid and StackID typedefs to make it clear what is what.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D107152
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Previously tsan modelled dup2(oldfd, newfd) as write on newfd.
We hit several cases where the write lead to false positives:
1. Some software dups a closed pipe in place of a socket before closing
the socket (to prevent races actually).
2. Some daemons dup /dev/null in place of stdin/stdout.
On the other hand we have not seen cases when write here catches real bugs.
So model dup2 as read on newfd instead.
llvm-svn: 240687
Dmitry Vyukov