Introducing the "linker_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. 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".

llvm-svn: 107205

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 8487c83ce36..d741245d775 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -735,6 +735,9 @@ CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) {
   else if (SL == GlobalValue::LinkerPrivateLinkage &&
            DL == GlobalValue::LinkerPrivateLinkage)
     return GlobalValue::LinkerPrivateLinkage;
+  else if (SL == GlobalValue::LinkerWeakLinkage &&
+           DL == GlobalValue::LinkerWeakLinkage)
+    return GlobalValue::LinkerWeakLinkage;
   else {
     assert (SL == GlobalValue::PrivateLinkage &&
             DL == GlobalValue::PrivateLinkage && "Unexpected linkage type");