Add vendor specific calling convention to DWARF

This patch adds LLVM's and GCC's calling conventions so they can be
emitted in the DWARF debug info.

Patch by: Adrien Guinet

Differential revision: https://reviews.llvm.org/D42350

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328191 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed