Commit Graph

6 Commits

Author SHA1 Message Date
David Majnemer 9b21c33da4 CodeGen: Don't emit a thread-wrapper if we can't touch the backing variable
OS X TLS has all accesses going through the thread-wrapper function and
gives the backing thread-local variable internal linkage.  This means
that thread-wrappers must have WeakAnyLinkage so that references to the
internal thread-local variables do not get propagated to other code.

It also means that translation units which do not provide a definition
for the thread-local variable cannot attempt to emit a thread-wrapper
because the thread wrapper will attempt to reference the backing
variable.

Differential Revision: http://reviews.llvm.org/D4109

llvm-svn: 212841
2014-07-11 20:28:10 +00:00
David Majnemer 35ab328e94 CodeGen: Correct linkage of thread_local for OS X
The backing store of thread local variables is internal for OS X and all
accesses must go through the thread wrapper.

However, individual TUs may have inlined through the thread wrapper.
To fix this, give the thread wrapper functions WeakAnyLinkage.  This
prevents them from getting inlined into call-sites.

This fixes PR19989.

llvm-svn: 210632
2014-06-11 04:08:55 +00:00
Bill Wendling 95cae88bcf Use the Itanium ABI for thread_local on Darwin.
After some discussion, it was decided to use the Itanium ABI for thread_local on
Darwin OS X platforms. This involved a couple of changes. First, we use
"_tlv_atexit" instead of "__cxa_thread_atexit". Secondly, the global variables
are marked with 'internal' linkage, because we want all access to be calls to
the Itanium-specific entry point, which has normal linkage.
<rdar://problem/13733006>

llvm-svn: 180941
2013-05-02 19:18:03 +00:00
Richard Smith e6c878c0c6 Revert r180739 and r180748: they broke C++11 thread_local on non-Darwin systems and did not do the right thing on Darwin.
Original commit message:

Emit the TLS intialization functions into a list.

Add the TLS initialization functions to a list of initialization functions. The
back-end takes this list and places the function pointers into the correct
section. This way they're called before `main().'

<rdar://problem/13733006>

llvm-svn: 180809
2013-04-30 21:34:13 +00:00
Bill Wendling 219df4c0af Modify triple to try to make it pass on ARM.
llvm-svn: 180748
2013-04-29 23:14:24 +00:00
Bill Wendling 96a77693be Emit the TLS intialization functions into a list.
Add the TLS initialization functions to a list of initialization functions. The
back-end takes this list and places the function pointers into the correct
section. This way they're called before `main().'

<rdar://problem/13733006>

llvm-svn: 180739
2013-04-29 22:27:16 +00:00