[PowerPC] Fix sanitizer frame unwind on 32-bit ABIs
[PowerPC] Fix sanitizer frame unwind on 32-bit ABIs

This fixes many sanitizer problems with -m32.  It is really intended
for gcc but patches to the sanitizers make their way through llvm
first.

ref:  https://gcc.gnu.org/ml/gcc-patches/2017-02/msg00855.html


git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@297995 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt