Fix crash in SBStructuredData::GetDescription() when there's no StructuredDataPlugin.

Also, use the StructuredData::Dump method to print the StructuredData if there
is no plugin, rather than just returning an error.

Differential Revision: https://reviews.llvm.org/D88266

Author: jimingham

lldb/include/lldb/Core/StructuredDataImpl.h

@@ -68,14 +68,18 @@ class StructuredDataImpl {
       return error;
     }
 
-    // Grab the plugin.
-    auto plugin_sp = lldb::StructuredDataPluginSP(m_plugin_wp);
+    // Grab the plugin
+    lldb::StructuredDataPluginSP plugin_sp = m_plugin_wp.lock();
+
+    // If there's no plugin, call underlying data's dump method:
     if (!plugin_sp) {
-      error.SetErrorString("Cannot pretty print structured data: "
-                           "plugin doesn't exist.");
+      if (!m_data_sp) {
+        error.SetErrorString("No data to describe.");
+        return error;
+      }
+      m_data_sp->Dump(stream, true);
       return error;
     }
-
     // Get the data's description.
     return plugin_sp->GetDescription(m_data_sp, stream);
   }

lldb/test/API/python_api/sbstructureddata/TestStructuredDataAPI.py

@@ -35,6 +35,13 @@ def structured_data_api_test(self):
         # Tests for invalid data type
         self.invalid_struct_test(example)
 
+        # Test that GetDescription works:
+        s.Clear()
+        error = example.GetDescription(s)
+        self.assertTrue(error.Success(), "GetDescription works")
+        if not "key_float" in s.GetData():
+            self.fail("FAILED: could not find key_float in description output")
+        
         dict_struct = lldb.SBStructuredData()
         dict_struct = example.GetValueForKey("key_dict")