[llvm-dev] Hang generating sanitizer tests

[via llvm-dev]

When I run "make check-all" with ToT I am seeing what looks like a hang
generating sanitizer tests:

[...]
[100%] Generating dynamic/Asan-x86_64-calls-Dynamic-Test
make[3]: Leaving directory '/build/debug'
[100%] Built target TAsan-x86_64-calls-Dynamic-Test
[100%] Generating default/Asan-x86_64-inline-Test
make[3]: Leaving directory '/build/debug'
[100%] Built target TAsan-x86_64-inline-Test
[100%] Generating dynamic/Asan-x86_64-inline-Dynamic-Test
make[3]: Leaving directory '/build/debug'
[100%] Built target TAsan-x86_64-inline-Dynamic-Test
make[3]: Entering directory '/build/debug'
Scanning dependencies of target AsanDynamicUnitTests
make[3]: Leaving directory '/build/debug'
[100%] Built target AsanDynamicUnitTests
[100%] Generating Sanitizer-x86_64-Test
make[3]: Leaving directory '/build/debug'
[100%] Built target TSanitizer-x86_64-Test
make[3]: Entering directory '/build/debug'
Scanning dependencies of target SanitizerUnitTests
make[3]: Leaving directory '/build/debug'
[100%] Built target SanitizerUnitTests

It seems hung up in lld linking Asan-x86_64-calls-Test among other
things.  It has been happening for at least a week and source updates
haven't changed the situation.  An strace reveals:

Process 408631 attached
futex(0x7ffdae5c7144, FUTEX_WAIT_PRIVATE, 1, NULL

It's been sitting there for hours, waiting on a mutex.  Rebuilds result
in the same behavior Has anyone else seen this?  Any tips to get things
going?

Thanks!

                          -David