[RISCV] Add lowering of addressing sequences for PIC

This patch allows lowering of PIC addresses by using PC-relative
addressing for DSO-local symbols and accessing the address through the
global offset table for non-DSO-local symbols.

Differential Revision: https://reviews.llvm.org/D55303

llvm-svn: 363058
diff --git a/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h b/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h
index 990040f..09bbfd2 100644
--- a/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h
+++ b/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h
@@ -53,6 +53,7 @@
   MO_HI,
   MO_PCREL_LO,
   MO_PCREL_HI,
+  MO_GOT_HI,
 };
 } // namespace RISCVII