Add a new top level statistic that tracks how many modules have variable errors.

[clayborg]

Summary

We have a statistic on each module named "debugInfoHadVariableErrors" which tracks when we have debug info, but an error prevented the variables from being displayed. This patch adds a new top level statistic named "totalModuleCountWithVariableErrors" which is a count of the modules that have "debugInfoHadVariableErrors" set to true.

lldb/source/Target/Statistics.cpp

for (const auto &target : debugger.GetTargetList().Targets())
       json_targets.emplace_back(target->ReportStatistics());
   }
   std::vector<ModuleStats> modules;
   std::lock_guard<std::recursive_mutex> guard(
       Module::GetAllocationModuleCollectionMutex());
   const uint64_t num_modules = Module::GetNumberAllocatedModules();
   uint32_t num_debug_info_enabled_modules = 0;
   uint32_t num_modules_has_debug_info = 0;
+  uint32_t num_modules_with_variable_errors = 0;
   uint32_t num_stripped_modules = 0;
   for (size_t image_idx = 0; image_idx < num_modules; ++image_idx) {
     Module *module = Module::GetAllocatedModuleAtIndex(image_idx);
     ModuleStats module_stat;
     module_stat.identifier = (intptr_t)module;
     module_stat.path = module->GetFileSpec().GetPath();
     if (ConstString object_name = module->GetObjectName()) {
       module_stat.path.append(1, '(');
if (sym_file) {
       module_stat.debug_info_enabled = sym_file->GetLoadDebugInfoEnabled() &&
                                        module_stat.debug_info_size > 0;
       module_stat.debug_info_had_variable_errors =
           sym_file->GetDebugInfoHadFrameVariableErrors();
       if (module_stat.debug_info_enabled)
         ++num_debug_info_enabled_modules;
       if (module_stat.debug_info_size > 0)
         ++num_modules_has_debug_info;
+      if (module_stat.debug_info_had_variable_errors)
+        ++num_modules_with_variable_errors;
     }
     symtab_parse_time += module_stat.symtab_parse_time;
     symtab_index_time += module_stat.symtab_index_time;
     debug_parse_time += module_stat.debug_parse_time;
     debug_index_time += module_stat.debug_index_time;
     debug_info_size += module_stat.debug_info_size;
     module->ForEachTypeSystem([&](lldb::TypeSystemSP ts) {
       if (auto stats = ts->ReportStatistics())
json::Object global_stats{
       {"totalSymbolTablesSavedToCache", symtabs_saved},
       {"totalDebugInfoParseTime", debug_parse_time},
       {"totalDebugInfoIndexTime", debug_index_time},
       {"totalDebugInfoIndexLoadedFromCache", debug_index_loaded},
       {"totalDebugInfoIndexSavedToCache", debug_index_saved},
       {"totalDebugInfoByteSize", debug_info_size},
       {"totalModuleCount", num_modules},
       {"totalModuleCountHasDebugInfo", num_modules_has_debug_info},
+      {"totalModuleCountWithVariableErrors", num_modules_with_variable_errors},
       {"totalDebugInfoEnabled", num_debug_info_enabled_modules},
       {"totalSymbolTableStripped", num_stripped_modules},
   };
   return std::move(global_stats);
 }

lldb/test/API/commands/statistics/basic/TestStats.py

def test_had_frame_variable_errors(self):
 
         # Delete the main.o file that contains the debug info so we force an
         # error when we run to main and try to get variables
         os.unlink(main_obj)
 
         (target, process, thread, bkpt) = lldbutil.run_to_name_breakpoint(self, 'main')
 
         # Get stats and verify we had errors.
-        exe_stats = self.find_module_in_metrics(exe, self.get_stats())
+        stats = self.get_stats()
+        exe_stats = self.find_module_in_metrics(exe, stats)
         self.assertTrue(exe_stats is not None)
 
         # Make sure we have "debugInfoHadVariableErrors" variable that is set to
         # false before failing to get local variables due to missing .o file.
         self.assertEqual(exe_stats['debugInfoHadVariableErrors'], False)
 
+        # Verify that the top level statistic that aggregates the number of
+        # modules with debugInfoHadVariableErrors is zero
+        self.assertEqual(stats['totalModuleCountWithVariableErrors'], 0)
+
         # Try and fail to get variables
         vars = thread.GetFrameAtIndex(0).GetVariables(True, True, False, True)
 
         # Make sure we got an error back that indicates that variables were not
         # available
         self.assertTrue(vars.GetError().Fail())
 
         # Get stats and verify we had errors.
-        exe_stats = self.find_module_in_metrics(exe, self.get_stats())
+        stats = self.get_stats()
+        exe_stats = self.find_module_in_metrics(exe, stats)
         self.assertTrue(exe_stats is not None)
 
         # Make sure we have "hadFrameVariableErrors" variable that is set to
         # true after failing to get local variables due to missing .o file.
         self.assertEqual(exe_stats['debugInfoHadVariableErrors'], True)
+
+        # Verify that the top level statistic that aggregates the number of
+        # modules with debugInfoHadVariableErrors is greater than zero
+        self.assertGreater(stats['totalModuleCountWithVariableErrors'], 0)