Allow L symbols in no_dead_strip sections.

If a section cannot be dead stripped, it is safe to use L symbols, since
the linker will keep all of it in the end.

llvm-svn: 221431

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

@@ -588,6 +588,10 @@ bool TargetLoweringObjectFileMachO::isSectionAtomizableBySymbols(
         SMO.getSectionName() == "__cfstring")
       return false;
 
+    // no_dead_strip sections are not atomized in practice.
+    if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP))
+      return false;
+
     switch (SMO.getType()) {
     default:
       return true;

llvm/test/CodeGen/X86/osx-private-labels.ll

@@ -69,3 +69,8 @@
 ; CHECK: .section	__DATA,__foobar,interposing
 ; CHECK-NEXT: .align	3
 ; CHECK-NEXT: L_private12:
+
+@private13 = private global i32 42, section "__DATA, __objc_classlist, regular, no_dead_strip"
+; CHECK: .section	__DATA,__objc_classlist,regular,no_dead_strip
+; CHECK-NEXT: .align	2
+; CHECK-NEXT: L_private13: