Revert "[lldb][MachO] Fix inspection of global variables that start with 'O' (llvm#161521)"

This reverts commit 1aefbce.

Author: adrian-prantl

lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp

@@ -2812,29 +2812,32 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
                         is_gsym = true;
                         sym[sym_idx].SetExternal(true);
 
-                        llvm::StringRef symbol_name_ref(symbol_name);
-                        if (symbol_name_ref.starts_with(
-                                g_objc_v2_prefix_class)) {
-                          symbol_name_non_abi_mangled = symbol_name + 1;
-                          symbol_name =
-                              symbol_name + g_objc_v2_prefix_class.size();
-                          type = eSymbolTypeObjCClass;
-                          demangled_is_synthesized = true;
-
-                        } else if (symbol_name_ref.starts_with(
-                                       g_objc_v2_prefix_metaclass)) {
-                          symbol_name_non_abi_mangled = symbol_name + 1;
-                          symbol_name =
-                              symbol_name + g_objc_v2_prefix_metaclass.size();
-                          type = eSymbolTypeObjCMetaClass;
-                          demangled_is_synthesized = true;
-                        } else if (symbol_name_ref.starts_with(
-                                       g_objc_v2_prefix_ivar)) {
-                          symbol_name_non_abi_mangled = symbol_name + 1;
-                          symbol_name =
-                              symbol_name + g_objc_v2_prefix_ivar.size();
-                          type = eSymbolTypeObjCIVar;
-                          demangled_is_synthesized = true;
+                        if (symbol_name && symbol_name[0] == '_' &&
+                            symbol_name[1] == 'O') {
+                          llvm::StringRef symbol_name_ref(symbol_name);
+                          if (symbol_name_ref.starts_with(
+                                  g_objc_v2_prefix_class)) {
+                            symbol_name_non_abi_mangled = symbol_name + 1;
+                            symbol_name =
+                                symbol_name + g_objc_v2_prefix_class.size();
+                            type = eSymbolTypeObjCClass;
+                            demangled_is_synthesized = true;
+
+                          } else if (symbol_name_ref.starts_with(
+                                         g_objc_v2_prefix_metaclass)) {
+                            symbol_name_non_abi_mangled = symbol_name + 1;
+                            symbol_name =
+                                symbol_name + g_objc_v2_prefix_metaclass.size();
+                            type = eSymbolTypeObjCMetaClass;
+                            demangled_is_synthesized = true;
+                          } else if (symbol_name_ref.starts_with(
+                                         g_objc_v2_prefix_ivar)) {
+                            symbol_name_non_abi_mangled = symbol_name + 1;
+                            symbol_name =
+                                symbol_name + g_objc_v2_prefix_ivar.size();
+                            type = eSymbolTypeObjCIVar;
+                            demangled_is_synthesized = true;
+                          }
                         } else {
                           if (nlist.n_value != 0)
                             symbol_section = section_info.GetSection(
@@ -3722,7 +3725,7 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
 
       if (is_debug) {
         switch (nlist.n_type) {
-        case N_GSYM: {
+        case N_GSYM:
           // global symbol: name,,NO_SECT,type,0
           // Sometimes the N_GSYM value contains the address.
 
@@ -3738,30 +3741,33 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
           is_gsym = true;
           sym[sym_idx].SetExternal(true);
 
-          llvm::StringRef symbol_name_ref(symbol_name);
-          if (symbol_name_ref.starts_with(g_objc_v2_prefix_class)) {
-            symbol_name_non_abi_mangled = symbol_name + 1;
-            symbol_name = symbol_name + g_objc_v2_prefix_class.size();
-            type = eSymbolTypeObjCClass;
-            demangled_is_synthesized = true;
-
-          } else if (symbol_name_ref.starts_with(g_objc_v2_prefix_metaclass)) {
-            symbol_name_non_abi_mangled = symbol_name + 1;
-            symbol_name = symbol_name + g_objc_v2_prefix_metaclass.size();
-            type = eSymbolTypeObjCMetaClass;
-            demangled_is_synthesized = true;
-          } else if (symbol_name_ref.starts_with(g_objc_v2_prefix_ivar)) {
-            symbol_name_non_abi_mangled = symbol_name + 1;
-            symbol_name = symbol_name + g_objc_v2_prefix_ivar.size();
-            type = eSymbolTypeObjCIVar;
-            demangled_is_synthesized = true;
+          if (symbol_name && symbol_name[0] == '_' && symbol_name[1] == 'O') {
+            llvm::StringRef symbol_name_ref(symbol_name);
+            if (symbol_name_ref.starts_with(g_objc_v2_prefix_class)) {
+              symbol_name_non_abi_mangled = symbol_name + 1;
+              symbol_name = symbol_name + g_objc_v2_prefix_class.size();
+              type = eSymbolTypeObjCClass;
+              demangled_is_synthesized = true;
+
+            } else if (symbol_name_ref.starts_with(
+                           g_objc_v2_prefix_metaclass)) {
+              symbol_name_non_abi_mangled = symbol_name + 1;
+              symbol_name = symbol_name + g_objc_v2_prefix_metaclass.size();
+              type = eSymbolTypeObjCMetaClass;
+              demangled_is_synthesized = true;
+            } else if (symbol_name_ref.starts_with(g_objc_v2_prefix_ivar)) {
+              symbol_name_non_abi_mangled = symbol_name + 1;
+              symbol_name = symbol_name + g_objc_v2_prefix_ivar.size();
+              type = eSymbolTypeObjCIVar;
+              demangled_is_synthesized = true;
+            }
           } else {
             if (nlist.n_value != 0)
               symbol_section =
                   section_info.GetSection(nlist.n_sect, nlist.n_value);
             type = eSymbolTypeData;
           }
-        } break;
+          break;
 
         case N_FNAME:
           // procedure name (f77 kludge): name,,NO_SECT,0,0