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Introducing the "linker_weak" linkage type. This will be used for Objective-C

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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
This commit is contained in:
Bill Wendling
2010-06-29 21:24:00 +00:00
parent 30689a3a7f
commit 1767723dbe
26 changed files with 94 additions and 39 deletions
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7
llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
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@@ -755,11 +755,12 @@ shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
/// the directive emitted (this occurs in ObjC metadata).
if (!GV) return false;
// Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
// Check whether the mangled name has the "Private", "LinkerPrivate", or
// "LinkerWeak" prefix.
if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
// FIXME: ObjC metadata is currently emitted as internal symbols that have
// \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
// this horrible hack can go away.
// \1L and \1l prefixes on them. Fix them to be Private / LinkerPrivate /
// LinkerWeak and this horrible hack can go away.
MCSymbol *Sym = Mang->getSymbol(GV);
if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
return false;