[lldb] Don't search the metadata map three times when retrieving metadata

HasMetadata checks if our metadata map knows the given object. GetMetadata
also does this check and then does another search to actually retrieve
the value. This can all just be one lookup.

Author: Teemperor

lldb/include/lldb/Symbol/ClangExternalASTSourceCommon.h

@@ -128,7 +128,6 @@ class ClangExternalASTSourceCommon : public clang::ExternalASTSource {
 
   ClangASTMetadata *GetMetadata(const void *object);
   void SetMetadata(const void *object, ClangASTMetadata &metadata);
-  bool HasMetadata(const void *object);
 
   static ClangExternalASTSourceCommon *Lookup(clang::ExternalASTSource *source);
 

lldb/source/Symbol/ClangASTContext.cpp

@@ -2419,7 +2419,7 @@ ClangASTMetadata *ClangASTContext::GetMetadata(clang::ASTContext *ast,
   ClangExternalASTSourceCommon *external_source =
       ClangExternalASTSourceCommon::Lookup(ast->getExternalSource());
 
-  if (external_source && external_source->HasMetadata(object))
+  if (external_source)
     return external_source->GetMetadata(object);
   else
     return nullptr;

lldb/source/Symbol/ClangExternalASTSourceCommon.cpp

@@ -53,8 +53,9 @@ ClangExternalASTSourceCommon::~ClangExternalASTSourceCommon() {
 
 ClangASTMetadata *
 ClangExternalASTSourceCommon::GetMetadata(const void *object) {
-  if (HasMetadata(object))
-    return &m_metadata[object];
+  auto It = m_metadata.find(object);
+  if (It != m_metadata.end())
+    return &It->second;
   else
     return nullptr;
 }
@@ -64,10 +65,6 @@ void ClangExternalASTSourceCommon::SetMetadata(const void *object,
   m_metadata[object] = metadata;
 }
 
-bool ClangExternalASTSourceCommon::HasMetadata(const void *object) {
-  return m_metadata.find(object) != m_metadata.end();
-}
-
 void ClangASTMetadata::Dump(Stream *s) {
   lldb::user_id_t uid = GetUserID();