Status of '-pg'-style profiling in clang 3.2?

I’m attempting to profile a C++ program by building like so:

clang++ -pg foo.cc -o foo

According to the LLVM 3.0 release notes, this is supported:

“The optimizer and code generator now supports gprof and gcov-style coverage and profiling information, and includes a new llvm-cov tool (but also works with gcov). Clang exposes coverage and profiling through GCC-compatible command line options.”

(see http://llvm.org/releases/3.0/docs/ReleaseNotes.html )

However, running foo does not produce gmon.out. Replacing clang++ with g++ (and changing nothing else) does produce gmon.out with expected contents.

$ clang++ --version

clang version 3.2 (tags/RELEASE_32/final)
Target: x86_64-pc-linux-gnu
Thread model: posix

This clang++ was built from the release 3.2 source with default configuration.

Any clues on what might be wrong?

Thanks,
Sean