A previous change brought the new, relaxed implementation of "on failure
memory ordering" for synchronization primitives in LLVM over to TSan
land [1]. It included the following assert:
```
// 31.7.2.18: "The failure argument shall not be memory_order_release
// nor memory_order_acq_rel". LLVM (2021-05) fallbacks to Monotonic
// (mo_relaxed) when those are used.
CHECK(IsLoadOrder(fmo));
static bool IsLoadOrder(morder mo) {
return mo == mo_relaxed || mo == mo_consume
|| mo == mo_acquire || mo == mo_seq_cst;
}
```
A previous workaround for a false positive when using an old Darwin
synchronization API assumed this failure mode to be unused and passed a
dummy value [2]. We update this value to `mo_relaxed` which is also the
value used by the actual implementation to avoid triggering the assert.
[1] https://reviews.llvm.org/D99434
[2] https://reviews.llvm.org/D21733
rdar://78122243
Differential Revision: https://reviews.llvm.org/D105844
Suppress the warning:
```
'fake_shared_weak_count' has virtual functions but non-virtual destructor [-Wnon-virtual-dtor]
```
The warning has been recently enabled [1], but the associated cleanup
missed this instance in Darwin code [2].
[1] 9c31e12609
[2] d48f2d7c02
Differential Revision: https://reviews.llvm.org/D94139
The xpc_connection_* APIs that we are intercepting are available
starting at macOS 10.7. This is old enough so that we don't need to
guard them.
llvm-svn: 369150
Vitaly Buka