Fix -Wsometimes-uninitialized in r199754

Also make the -m16 check x86-specific. Other archs may have a different take on
things.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@199755 91177308-0d34-0410-b5e6-96231b3b80d8
Debug info: use the file a typedef is defined in as its decl_file instead
of the current compilation unit.
As a side effect this enables many more LTO uniquing opportunities.

rdar://problem/15851206

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@199757 91177308-0d34-0410-b5e6-96231b3b80d8
revert 199757 for buildbot breakage.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@199758 91177308-0d34-0410-b5e6-96231b3b80d8
Debug info: use the file a typedef is defined in as its decl_file instead
of the current compilation unit.
As a side effect this enables many more LTO uniquing opportunities.

This reapplies r199757 with a better testcase.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@199760 91177308-0d34-0410-b5e6-96231b3b80d8