fix(LLDB): Repair OC_Bridge variable display issue when load-on-demand is true

When symbols.load-on-demand is enabled in LLDB, variables from OC-bridged Swift objects were not being displayed. This was due to SymbolFileOndemand not correctly overriding the GetAstData method, causing it to return an empty implementation from the base SymbolFile class.
This commit fixes the issue by providing the correct implementation of GetAstData in SymbolFileOndemand, ensuring that the necessary AST data is loaded and OC-bridged variables can be correctly resolved and displayed during debugging.

Author: ccc

lldb/include/lldb/Symbol/SymbolFileOnDemand.h

@@ -178,6 +178,8 @@ class SymbolFileOnDemand : public lldb_private::SymbolFile {
 
   void PreloadSymbols() override;
 
+  std::vector<lldb::DataBufferSP> GetASTData(lldb::LanguageType language) override;
+
   uint64_t GetDebugInfoSize(bool load_all_debug_info = false) override;
   lldb_private::StatsDuration::Duration GetDebugInfoParseTime() override;
   lldb_private::StatsDuration::Duration GetDebugInfoIndexTime() override;

lldb/source/Symbol/SymbolFileOnDemand.cpp

@@ -535,6 +535,15 @@ void SymbolFileOnDemand::PreloadSymbols() {
   return m_sym_file_impl->PreloadSymbols();
 }
 
+std::vector<lldb::DataBufferSP> SymbolFileOnDemand::GetASTData(lldb::LanguageType language) {
+  if (!m_debug_info_enabled) {
+    LLDB_LOG(GetLog(), "[{0}] {1} is skipped", GetSymbolFileName(),
+             __FUNCTION__);
+    return {};
+  }
+  return m_sym_file_impl->GetASTData(language);
+}
+
 uint64_t SymbolFileOnDemand::GetDebugInfoSize(bool load_all_debug_info) {
   // Always return the real debug info size.
   LLDB_LOG(GetLog(), "[{0}] {1} is not skipped", GetSymbolFileName(),