diff --git a/lld/MachO/ConcatOutputSection.cpp b/lld/MachO/ConcatOutputSection.cpp
--- a/lld/MachO/ConcatOutputSection.cpp
+++ b/lld/MachO/ConcatOutputSection.cpp
@@ -329,7 +329,7 @@
           thunkName, /*file=*/nullptr, thunkInfo.isec, /*value=*/0,
           /*size=*/thunkSize, /*isWeakDef=*/false, /*isPrivateExtern=*/true,
           /*isThumb=*/false, /*isReferencedDynamically=*/false,
-          /*noDeadStrip=*/false);
+          /*noDeadStrip=*/false, /*isWeakDefCanBeHidden=*/false);
       thunkInfo.sym->used = true;
       target->populateThunk(thunkInfo.isec, funcSym);
       finalizeOne(thunkInfo.isec);
diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -1465,8 +1465,16 @@
           StringRef symbolName = defined->getName();
           if (config->exportedSymbols.match(symbolName)) {
             if (defined->privateExtern) {
-              warn("cannot export hidden symbol " + symbolName +
-                   "\n>>> defined in " + toString(defined->getFile()));
+              if (!defined->weakDefCanBeHidden)
+                warn("cannot export hidden symbol " + symbolName +
+                     "\n>>> defined in " + toString(defined->getFile()));
+              else
+                // weak_def_can_be_hidden symbols behaves similarly to
+                // private_extern symbols in most cases, except for when
+                // it is explicitly exported.
+                // LD64 allows exporting the former, but not the latter.
+                // So we do the same here.
+                defined->privateExtern = false;
             }
           } else {
             defined->privateExtern = true;
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -567,16 +567,24 @@
     // with ld64's semantics, because it means the non-private-extern
     // definition will continue to take priority if more private extern
     // definitions are encountered. With lld's semantics there's no observable
-    // difference between a symbol that's isWeakDefCanBeHidden or one that's
-    // privateExtern -- neither makes it into the dynamic symbol table. So just
-    // promote isWeakDefCanBeHidden to isPrivateExtern here.
-    if (isWeakDefCanBeHidden)
-      isPrivateExtern = true;
-
+    // difference between a symbol that's isWeakDefCanBeHidden(autohide) or one
+    // that's privateExtern -- neither makes it into the dynamic symbol table,
+    // unless the autohide symbol is explicitly exported.
+    // But if a symbol is both privateExtern and autohide then it can't
+    // be exported.
+    // So we nullify the autohide flag when privateExtern is present
+    // and promote the symbol to privateExtern when it is not already.
+    if (isWeakDefCanBeHidden) {
+      if (isPrivateExtern)
+        isWeakDefCanBeHidden = false;
+      else
+        isPrivateExtern = true;
+    }
     return symtab->addDefined(
         name, isec->getFile(), isec, value, size, sym.n_desc & N_WEAK_DEF,
         isPrivateExtern, sym.n_desc & N_ARM_THUMB_DEF,
-        sym.n_desc & REFERENCED_DYNAMICALLY, sym.n_desc & N_NO_DEAD_STRIP);
+        sym.n_desc & REFERENCED_DYNAMICALLY, sym.n_desc & N_NO_DEAD_STRIP,
+        isWeakDefCanBeHidden);
   }
   assert(!isWeakDefCanBeHidden &&
          "weak_def_can_be_hidden on already-hidden symbol?");
@@ -596,7 +604,8 @@
     return symtab->addDefined(
         name, file, nullptr, sym.n_value, /*size=*/0,
         /*isWeakDef=*/false, sym.n_type & N_PEXT, sym.n_desc & N_ARM_THUMB_DEF,
-        /*isReferencedDynamically=*/false, sym.n_desc & N_NO_DEAD_STRIP);
+        /*isReferencedDynamically=*/false, sym.n_desc & N_NO_DEAD_STRIP,
+        /*isWeakDefCanBeHidden=*/false);
   }
   return make<Defined>(name, file, nullptr, sym.n_value, /*size=*/0,
                        /*isWeakDef=*/false,
@@ -1422,7 +1431,8 @@
                             /*size=*/0, objSym.isWeak(), isPrivateExtern,
                             /*isThumb=*/false,
                             /*isReferencedDynamically=*/false,
-                            /*noDeadStrip=*/false);
+                            /*noDeadStrip=*/false,
+                            /*isWeakDefCanBeHidden=*/false);
 }
 
 BitcodeFile::BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
diff --git a/lld/MachO/MarkLive.cpp b/lld/MachO/MarkLive.cpp
--- a/lld/MachO/MarkLive.cpp
+++ b/lld/MachO/MarkLive.cpp
@@ -67,7 +67,7 @@
         // FIXME: Instead of doing this here, maybe the Driver code doing
         // the matching should add them to explicitUndefineds? Then the
         // explicitUndefineds code below would handle this automatically.
-        assert(!defined->privateExtern &&
+        assert((!defined->privateExtern || defined->weakDefCanBeHidden) &&
                "should have been rejected by driver");
         addSym(defined);
         continue;
diff --git a/lld/MachO/SymbolTable.h b/lld/MachO/SymbolTable.h
--- a/lld/MachO/SymbolTable.h
+++ b/lld/MachO/SymbolTable.h
@@ -40,7 +40,8 @@
   Defined *addDefined(StringRef name, InputFile *, InputSection *,
                       uint64_t value, uint64_t size, bool isWeakDef,
                       bool isPrivateExtern, bool isThumb,
-                      bool isReferencedDynamically, bool noDeadStrip);
+                      bool isReferencedDynamically, bool noDeadStrip,
+                      bool isWeakDefCanBeHidden);
 
   Symbol *addUndefined(StringRef name, InputFile *, bool isWeakRef);
 
diff --git a/lld/MachO/SymbolTable.cpp b/lld/MachO/SymbolTable.cpp
--- a/lld/MachO/SymbolTable.cpp
+++ b/lld/MachO/SymbolTable.cpp
@@ -49,8 +49,8 @@
                                  InputSection *isec, uint64_t value,
                                  uint64_t size, bool isWeakDef,
                                  bool isPrivateExtern, bool isThumb,
-                                 bool isReferencedDynamically,
-                                 bool noDeadStrip) {
+                                 bool isReferencedDynamically, bool noDeadStrip,
+                                 bool isWeakDefCanBeHidden) {
   Symbol *s;
   bool wasInserted;
   bool overridesWeakDef = false;
@@ -66,6 +66,7 @@
         // See further comment in createDefined() in InputFiles.cpp
         if (defined->isWeakDef()) {
           defined->privateExtern &= isPrivateExtern;
+          defined->weakDefCanBeHidden |= isWeakDefCanBeHidden;
           defined->referencedDynamically |= isReferencedDynamically;
           defined->noDeadStrip |= noDeadStrip;
         }
@@ -100,6 +101,7 @@
       s, name, file, isec, value, size, isWeakDef, /*isExternal=*/true,
       isPrivateExtern, isThumb, isReferencedDynamically, noDeadStrip);
   defined->overridesWeakDef = overridesWeakDef;
+  defined->weakDefCanBeHidden = isWeakDefCanBeHidden;
   return defined;
 }
 
@@ -195,10 +197,11 @@
                                    uint64_t value, bool isPrivateExtern,
                                    bool includeInSymtab,
                                    bool referencedDynamically) {
-  Defined *s = addDefined(name, nullptr, isec, value, /*size=*/0,
-                          /*isWeakDef=*/false, isPrivateExtern,
-                          /*isThumb=*/false, referencedDynamically,
-                          /*noDeadStrip=*/false);
+  Defined *s =
+      addDefined(name, nullptr, isec, value, /*size=*/0,
+                 /*isWeakDef=*/false, isPrivateExtern,
+                 /*isThumb=*/false, referencedDynamically,
+                 /*noDeadStrip=*/false, /*isWeakDefCanBeHidden=*/false);
   s->includeInSymtab = includeInSymtab;
   return s;
 }
diff --git a/lld/MachO/Symbols.h b/lld/MachO/Symbols.h
--- a/lld/MachO/Symbols.h
+++ b/lld/MachO/Symbols.h
@@ -160,6 +160,8 @@
   // to the output.
   bool noDeadStrip : 1;
 
+  bool weakDefCanBeHidden : 1;
+
 private:
   const bool weakDef : 1;
   const bool external : 1;
diff --git a/lld/test/MachO/export-options.s b/lld/test/MachO/export-options.s
--- a/lld/test/MachO/export-options.s
+++ b/lld/test/MachO/export-options.s
@@ -119,6 +119,21 @@
 # GLOBBY-DAG: globby_also
 # GLOBBY-NOT: literal_only
 
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos \
+# RUN:     %t/autohide.s -o %t/autohide.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos \
+# RUN:     %t/autohide-private-extern.s -o %t/autohide-private-extern.o
+## Test that we can export the autohide symbol but not when it's also
+## private-extern
+# RUN: %lld -dylib -exported_symbol "_foo" %t/autohide.o -o %t/exp-autohide.dylib
+# RUN: llvm-nm -g %t/exp-autohide.dylib | FileCheck %s --check-prefix=EXP-AUTOHIDE
+# EXP-AUTOHIDE: T _foo
+
+# RUN: not %lld -dylib -exported_symbol "_foo" %t/autohide-private-extern.o \
+# RUN: -o /dev/null  2>&1 | FileCheck %s --check-prefix=AUTOHIDE-PRIVATE
+# AUTOHIDE-PRIVATE: error: cannot export hidden symbol _foo
+
+
 #--- default.s
 
 .globl _keep_globl, _hide_globl
@@ -164,3 +179,16 @@
   l?ter[aeiou]l_*[^y] # comment
 
   *gl?bby_*
+
+#--- autohide.s
+.globl _foo
+.weak_def_can_be_hidden _foo
+_foo:
+  retq
+
+#--- autohide-private-extern.s
+.globl _foo
+.weak_def_can_be_hidden _foo
+.private_extern _foo
+_foo:
+  retq