On 2010-10-14 17:51, Sean Kelly wrote:
Jacob Carlborg<d...@me.com> wrote:
On 2010-10-13 20:18, Walter Bright wrote:
Jacob Carlborg wrote:
I don't know how you have implemented TLS on Mac OS X but it does
support TLS via the Posix API pthreads. This is the only page from
Apple's documentation I could find for now (I'm certain I've seen a
better page)
http://developer.apple.com/macosx/multithreadedprogramming.html .
Yeah, I know about pthreads TLS, but that's wholly inadequate.
According to these:
http://lifecs.likai.org/2010/05/mac-os-x-thread-local-storage.html
and
http://lists.apple.com/archives/darwin-dev/2005/Sep/msg00005.html
the
implementation of TLS in the Posix API on Mac OS X should be as fast
as the EFL implementation. As the blog post mentions, there is an
inline version of pthread_getspecific. I also have to add that I
have
no idea if the pthreads can be used to implement TLS in the
compiler.
With gcc on OSX, try this:
__thread int x;
It will fail. Furthermore, OSX has no documented way to allocate TLS
static data in the object file. I spent considerable effort figuring
out
a way to do this and get around the numerous bugs in the OSX linker
that
tried to stop me.
I just read a bit about how TLS is implemented on linux, just of
curiosity what was the problem, the linker, runtime, loader or all? On
linux the static TLS data is put in the the object file like any other
data. The only difference is it has a different name of the
section/segment and an additional flag. Then of course the linker,
runtime and loader know about these sections and make any necessary
initializations when the application loads.
On OSX the object file format lacks a way to specify a TLS data section,
and so the linker would need upgrading as well. And the compiler, since
it needs to generate the object files.
As I said, the static TLS data is put in the object file like any other
data. I can see that the linker could/would be a problem. Of course the
compiler needs to be updated but there should be any problems updating
dmd. I guess you're referring to gcc. I also have to say that I haven't
fully understood what the linker does in this case, with the TLS data.
--
/Jacob Carlborg
