Add XCOFF triple object format type for AIX

This patch adds an XCOFF triple object format type into LLVM.
This XCOFF triple object file type will be used later by object file and assembly generation for the AIX platform.

Differential Revision: https://reviews.llvm.org/D58930

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355989 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCObjectFileInfo.cpp

@@ -801,6 +801,11 @@ void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
     Env = IsWasm;
     initWasmMCObjectFileInfo(TT);
     break;
+  case Triple::XCOFF:
+    Env = IsXCOFF;
+    // TODO: Initialize MCObjectFileInfo for XCOFF format when
+    // MCSectionXCOFF is ready.
+    break;
   case Triple::UnknownObjectFormat:
     report_fatal_error("Cannot initialize MC for unknown object file format.");
     break;
@@ -816,6 +821,7 @@ MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
   case Triple::MachO:
   case Triple::COFF:
   case Triple::Wasm:
+  case Triple::XCOFF:
   case Triple::UnknownObjectFormat:
     report_fatal_error("Cannot get DWARF comdat section for this object file "
                        "format: not implemented.");