Clang Code Coverage - Mac OS X - Linker Error

I solved this.

I was missing the following Linker Flags

-Wall -fprofile-arcs -ftest-coverage

Other Linker Flag -fprofile-arcs fixes the issue for me.

Build Settings > Other Linker Flags > -fprofile-arcs

The above answer did not work for me on OSX Yosemite (10.10.3) with Xcode 6.3.1. It seems that Apple moved these libraries around. I was able to get it to work with the following compile options:

-lclang_rt.profile_osx 
-L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/6.1.0/lib/darwin