utils: cache build directory files

get_target_generated_sources often calls File.from_built_relative on
the same file, if it is used by many sources.  This is a somewhat
expensive call both CPU- and memory-wise, so cache the creation
of build-directory files as well.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>

Author: bonzini

mesonbuild/utils/universal.py

@@ -402,13 +402,15 @@ def from_source_file(source_root: str, subdir: str, fname: str) -> 'File':
         return File(False, subdir, fname)
 
     @staticmethod
+    @lru_cache(maxsize=None)
     def from_built_file(subdir: str, fname: str) -> 'File':
         return File(True, subdir, fname)
 
     @staticmethod
+    @lru_cache(maxsize=None)
     def from_built_relative(relative: str) -> 'File':
         dirpart, fnamepart = os.path.split(relative)
-        return File(True, dirpart, fnamepart)
+        return File.from_built_file(dirpart, fnamepart)
 
     @staticmethod
     def from_absolute_file(fname: str) -> 'File':