[FormatManager] Move Language lookup into the obviously non-cached part (NFC)

[aprantl]

Summary

This refactoring makes the lookup caching easier to reason about. This has no observable effect although it does slightly change what is being cached.

Before this patch a negative lookup in the LanguageCategory would be cached, but a positive wouldn't.
After this patch LanguageCategory lookups aren't cached, period.

[aprantl]

Actually, it's worse, LanguageCategory::Get does its own caching.

[aprantl]

and again.. it passes in a ValueObject, so it shouldn't be caching.

[jingham]

This seems reasonable.

[aprantl]

@davide said he's working on a patch that turns the ValueObject parameter into a Language. With that in place the caching it does is sound again.

lldb/source/DataFormatters/FormatManager.cpp

 template <typename ImplSP>
 ImplSP FormatManager::Get(ValueObject &valobj,
                           lldb::DynamicValueType use_dynamic) {
   FormattersMatchData match_data(valobj, use_dynamic);
   if (ImplSP retval_sp = GetCached<ImplSP>(match_data))
     return retval_sp;
 
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_DATAFORMATTERS));
-  LLDB_LOGF(log, "[%s] Search failed. Giving hardcoded a chance.", __FUNCTION__);
+
+  LLDB_LOGF(log, "[%s] Search failed. Giving language a chance.", __FUNCTION__);
+  for (lldb::LanguageType lang_type : match_data.GetCandidateLanguages()) {
+    if (LanguageCategory *lang_category = GetCategoryForLanguage(lang_type)) {
+      ImplSP retval_sp;
+      if (lang_category->Get(match_data, retval_sp))
+        if (retval_sp) {
+          LLDB_LOGF(log, "[%s] Language search success. Returning.",
+                    __FUNCTION__);
+          return retval_sp;
+        }
+    }
+  }
+
+  LLDB_LOGF(log, "[%s] Search failed. Giving hardcoded a chance.",
+            __FUNCTION__);
   return GetHardcoded<ImplSP>(match_data);
 }
 
 template <typename ImplSP>
 ImplSP FormatManager::GetCached(FormattersMatchData &match_data) {
   ImplSP retval_sp;
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_DATAFORMATTERS));
   if (match_data.GetTypeForCache()) {
     LLDB_LOGF(log, "\n\n[%s] Looking into cache for type %s", __FUNCTION__,
               match_data.GetTypeForCache().AsCString("<invalid>"));
     if (m_format_cache.Get(match_data.GetTypeForCache(), retval_sp)) {
       if (log) {
         LLDB_LOGF(log, "[%s] Cache search success. Returning.", __FUNCTION__);
         LLDB_LOGV(log, "Cache hits: {0} - Cache Misses: {1}",
                   m_format_cache.GetCacheHits(),
                   m_format_cache.GetCacheMisses());
       }
       return retval_sp;
     }
     LLDB_LOGF(log, "[%s] Cache search failed. Going normal route",
               __FUNCTION__);
   }
 
   m_categories_map.Get(match_data, retval_sp);
-  if (!retval_sp) {
-    LLDB_LOGF(log, "[%s] Search failed. Giving language a chance.",
-              __FUNCTION__);
-    for (lldb::LanguageType lang_type : match_data.GetCandidateLanguages()) {
-      if (LanguageCategory *lang_category = GetCategoryForLanguage(lang_type)) {
-        if (lang_category->Get(match_data, retval_sp))
-          break;
-      }
-    }
-    if (retval_sp) {
-      LLDB_LOGF(log, "[%s] Language search success. Returning.", __FUNCTION__);
-      return retval_sp;
-    }
-  }
-
   if (match_data.GetTypeForCache() && (!retval_sp || !retval_sp->NonCacheable())) {
     LLDB_LOGF(log, "[%s] Caching %p for type %s", __FUNCTION__,
               static_cast<void *>(retval_sp.get()),
               match_data.GetTypeForCache().AsCString("<invalid>"));
     m_format_cache.Set(match_data.GetTypeForCache(), retval_sp);
   }
   LLDB_LOGV(log, "Cache hits: {0} - Cache Misses: {1}",
             m_format_cache.GetCacheHits(), m_format_cache.GetCacheMisses());