Cherrypick Objective-C Runtime Changes

lldb/include/lldb/Target/DynamicLoader.h

@@ -251,6 +251,14 @@ class DynamicLoader : public PluginInterface {
     return false;
   }
 
+  /// Return whether the dynamic loader is fully initialized and it's safe to
+  /// call its APIs.
+  ///
+  /// On some systems (e.g. Darwin based systems), lldb will get notified by
+  /// the dynamic loader before it itself finished initializing and it's not
+  /// safe to call certain APIs or SPIs.
+  virtual bool IsFullyInitialized() { return true; }
+
 protected:
   // Utility methods for derived classes
 
@@ -294,7 +302,7 @@ class DynamicLoader : public PluginInterface {
   // Read a pointer from memory at the given addr. Return LLDB_INVALID_ADDRESS
   // if the read fails.
   lldb::addr_t ReadPointer(lldb::addr_t addr);
-  
+
   // Calls into the Process protected method LoadOperatingSystemPlugin:
   void LoadOperatingSystemPlugin(bool flush);
 

lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp

@@ -1119,6 +1119,12 @@ bool DynamicLoaderMacOSXDYLD::GetSharedCacheInformation(
   return false;
 }
 
+bool DynamicLoaderMacOSXDYLD::IsFullyInitialized() {
+  if (ReadAllImageInfosStructure())
+    return m_dyld_all_image_infos.libSystemInitialized;
+  return false;
+}
+
 void DynamicLoaderMacOSXDYLD::Initialize() {
   PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                 GetPluginDescriptionStatic(), CreateInstance);

lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.h

@@ -68,6 +68,8 @@ class DynamicLoaderMacOSXDYLD : public lldb_private::DynamicLoaderDarwin {
 
   uint32_t GetPluginVersion() override;
 
+  bool IsFullyInitialized() override;
+
 protected:
   void PutToLog(lldb_private::Log *log) const;