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

tools/llvm-nm/llvm-nm.cpp

@@ -89,7 +89,8 @@ static char TypeCharForSymbol(GlobalValue &GV) {
 static void DumpSymbolNameForGlobalValue(GlobalValue &GV) {
   // Private linkage and available_externally linkage don't exist in symtab.
   if (GV.hasPrivateLinkage() || GV.hasLinkerPrivateLinkage() ||
-      GV.hasAvailableExternallyLinkage()) return;
+      GV.hasLinkerPrivateWeakLinkage() || GV.hasAvailableExternallyLinkage())
+    return;
   
   const std::string SymbolAddrStr = "        "; // Not used yet...
   char TypeChar = TypeCharForSymbol(GV);