thakis added a comment. The module hash is computed in CompilerInvocation::getModuleHash() in http://llvm-cs.pcc.me.uk/tools/clang/lib/Frontend/CompilerInvocation.cpp#3402 Repository: rL LLVM CHANGES SINCE LAST ACTION https://reviews.llvm.org/D57533/new/ https://reviews.llvm.org/D57533