[lldb] Instantiate lazily named classes on macOS Ventura.

[JDevlieghere]

Summary

Recent revisions of the Objective-C runtime changed
objc_debug_class_getNameRaw() in a way that no longer triggers lazy
names to be instantiated. This has the unintended side-effect of making
generic bridged Swift classes, such as _SwiftDeferredNSDictionary<U,V>
to become invisible to the Objective-C runtime.

This patch detects this situation and forces the names to be
instantiated by calling class_getName() and discarding the result before
calling objc_debug_class_getNameRaw() again.

Many thanks to Mike Ash for outlining the solution and Adrian for
authoring the downstream patch.

rdar://95245318

[aprantl]

Thanks!

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp

__lldb_apple_objc_v2_get_dynamic_class_info2(void *gdb_objc_realized_classes_ptr,
 
     uint32_t idx = 0;
     for (uint32_t i=0; i<=count; ++i)
     {
         if (idx < max_class_infos)
         {
             Class isa = realized_class_list[i];
             const char *name_ptr = objc_debug_class_getNameRaw(isa);
-            if (name_ptr == NULL)
+            if (!name_ptr)
                 continue;
             const char *s = name_ptr;
             uint32_t h = 5381;
             for (unsigned char c = *s; c; c = *++s)
                 h = ((h << 5) + h) + c;
             class_infos[idx].hash = h;
             class_infos[idx].isa = isa;
             DEBUG_PRINTF ("[%u] isa = %8p %s\n", idx, class_infos[idx].isa, name_ptr);

 
 static const char *g_get_dynamic_class_info3_body = R"(
 
 extern "C" {
     int printf(const char * format, ...);
     void free(void *ptr);
     size_t objc_getRealizedClassList_trylock(Class *buffer, size_t len);
     const char* objc_debug_class_getNameRaw(Class cls);
+    const char* class_getName(Class cls);
 }
 
 #define DEBUG_PRINTF(fmt, ...) if (should_log) printf(fmt, ## __VA_ARGS__)
 
 struct ClassInfo
 {
     Class isa;
     uint32_t hash;
__lldb_apple_objc_v2_get_dynamic_class_info3(void *gdb_objc_realized_classes_ptr,
 
     uint32_t idx = 0;
     for (uint32_t i=0; i<=count; ++i)
     {
         if (idx < max_class_infos)
         {
             Class isa = realized_class_list[i];
             const char *name_ptr = objc_debug_class_getNameRaw(isa);
-            if (name_ptr == NULL)
+            if (!name_ptr) {
+               class_getName(isa); // Realize name of lazy classes.
+               name_ptr = objc_debug_class_getNameRaw(isa);
+            }
+            if (!name_ptr)
                 continue;
             const char *s = name_ptr;
             uint32_t h = 5381;
             for (unsigned char c = *s; c; c = *++s)
                 h = ((h << 5) + h) + c;
             class_infos[idx].hash = h;
             class_infos[idx].isa = isa;
             DEBUG_PRINTF ("[%u] isa = %8p %s\n", idx, class_infos[idx].isa, name_ptr);