diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -845,10 +845,15 @@
     // We populate subsections by repeatedly splitting the last (highest
     // address) subsection.
     llvm::stable_sort(symbolIndices, [&](uint32_t lhs, uint32_t rhs) {
-      // Put private-label symbols after other symbols at the same address.
-      if (nList[lhs].n_value == nList[rhs].n_value)
-        return !isPrivateLabel(getSymName(nList[lhs])) &&
-               isPrivateLabel(getSymName(nList[rhs]));
+      // Put private-label symbols that have no flags after other symbols at the
+      // same address.
+      StringRef lhsName = getSymName(nList[lhs]);
+      StringRef rhsName = getSymName(nList[rhs]);
+      if (nList[lhs].n_value == nList[rhs].n_value) {
+        if (isPrivateLabel(lhsName) && isPrivateLabel(rhsName))
+          return nList[lhs].n_desc > nList[rhs].n_desc;
+        return !isPrivateLabel(lhsName) && isPrivateLabel(rhsName);
+      }
       return nList[lhs].n_value < nList[rhs].n_value;
     });
     for (size_t j = 0; j < symbolIndices.size(); ++j) {
@@ -874,11 +879,13 @@
       if (!subsectionsViaSymbols || symbolOffset == 0 ||
           sym.n_desc & N_ALT_ENTRY || !isa<ConcatInputSection>(isec)) {
         isec->hasAltEntry = symbolOffset != 0;
-        // If we have an private-label symbol that's an alias, just reuse the
-        // aliased symbol. Our sorting step above ensures that any such symbols
-        // will appear after the non-private-label ones. See
-        // weak-def-alias-ignored.s for the motivation behind this.
-        if (symbolOffset == 0 && isPrivateLabel(name) && j != 0)
+        // If we have an private-label symbol that's an alias, and that alias
+        // doesn't have any flags of its own, then we can just reuse the aliased
+        // symbol. Our sorting step above ensures that any such symbols will
+        // appear after the non-private-label ones. See weak-def-alias-ignored.s
+        // for the motivation behind this.
+        if (symbolOffset == 0 && isPrivateLabel(name) && j != 0 &&
+            sym.n_desc == 0)
           symbols[symIndex] = symbols[symbolIndices[j - 1]];
         else
           symbols[symIndex] = createDefined(sym, name, isec, symbolOffset,
diff --git a/lld/test/MachO/weak-def-alias-private-label.s b/lld/test/MachO/weak-def-alias-private-label.s
--- a/lld/test/MachO/weak-def-alias-private-label.s
+++ b/lld/test/MachO/weak-def-alias-private-label.s
@@ -1,10 +1,10 @@
 # REQUIRES: x86
-## This test checks that when we coalesce weak definitions, any private-label
-## aliases to those weak defs don't cause the coalesced data to be retained.
-## This test explicitly creates those private-label symbols, but it was actually
-## motivated by MC's aarch64 backend which automatically creates them when
-## emitting object files. I've chosen to explicitly create them here since we
-## can then reference those symbols for a more complete test.
+## This test checks that when we coalesce weak definitions, any flag-less
+## private-label aliases to those weak defs don't cause the coalesced data to be
+## retained. This test explicitly creates those private-label symbols, but it
+## was actually motivated by MC's aarch64 backend which automatically creates
+## them when emitting object files. I've chosen to explicitly create them here
+## since we can then reference those symbols for a more complete test.
 ##
 ## Not retaining the data matters for more than just size -- we have a use case
 ## that depends on proper data coalescing to emit a valid file format.
@@ -25,8 +25,11 @@
 # RUN: rm -rf %t; split-file %s %t
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/weak-then-private.s -o %t/weak-then-private.o
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/private-then-weak.s -o %t/private-then-weak.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/no-dead-strip.s -o %t/no-dead-strip.o
 # RUN: %lld -dylib %t/weak-then-private.o %t/private-then-weak.o -o %t/test1
 # RUN: %lld -dylib %t/private-then-weak.o %t/weak-then-private.o -o %t/test2
+# RUN: %lld -dead_strip %t/no-dead-strip.o -o %t/no-dead-strip
+
 # RUN: llvm-objdump --macho --syms --section="__DATA,__data" --weak-bind %t/test1 | FileCheck %s
 # RUN: llvm-objdump --macho --syms --section="__DATA,__data" --weak-bind %t/test2 | FileCheck %s
 
@@ -48,6 +51,14 @@
 # CHECK-NEXT:  __DATA   __data             0x00001008 pointer         0   _weak
 # CHECK-NEXT:  __DATA   __data             0x00001010 pointer         0   _weak
 
+## Verify that we don't drop any flags that private-label aliases have (such as
+## .no_dead_strip). This is a regression test. We previously had subsections
+## that were mistakenly stripped.
+
+# RUN: llvm-objdump --macho --section-headers %t/no-dead-strip | FileCheck %s \
+# RUN:   --check-prefix=NO-DEAD-STRIP
+# NO-DEAD-STRIP: __data        00000010
+
 #--- weak-then-private.s
 .globl _weak
 .weak_definition _weak
@@ -73,3 +84,22 @@
   .quad l_ignored
 
 .subsections_via_symbols
+
+#--- no-dead-strip.s
+.globl _main
+
+_main:
+  ret
+
+.data
+.no_dead_strip l_foo, l_bar
+
+_foo:
+l_foo:
+  .quad 0x123
+
+l_bar:
+_bar:
+  .quad 0x123
+
+.subsections_via_symbols