Implement the "linker_private_weak" linkage type. This will be used for
Objective-C metadata types which should be marked as "weak", but which the
linker will remove upon final linkage. However, this linkage isn't specific to
Objective-C.

For example, the "objc_msgSend_fixup_alloc" symbol is defined like this:

      .globl l_objc_msgSend_fixup_alloc
      .weak_definition l_objc_msgSend_fixup_alloc
      .section __DATA, __objc_msgrefs, coalesced
      .align 3
l_objc_msgSend_fixup_alloc:
       .quad   _objc_msgSend_fixup
       .quad   L_OBJC_METH_VAR_NAME_1

This is different from the "linker_private" linkage type, because it can't have
the metadata defined with ".weak_definition".

Currently only supported on Darwin platforms.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107433 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index eda08e7..9056cef 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -286,6 +286,8 @@
     Out << "GlobalValue::PrivateLinkage"; break;
   case GlobalValue::LinkerPrivateLinkage:
     Out << "GlobalValue::LinkerPrivateLinkage"; break;
+  case GlobalValue::LinkerPrivateWeakLinkage:
+    Out << "GlobalValue::LinkerPrivateWeakLinkage"; break;
   case GlobalValue::AvailableExternallyLinkage:
     Out << "GlobalValue::AvailableExternallyLinkage "; break;
   case GlobalValue::LinkOnceAnyLinkage: