Lerking/micropython
1
0
Fork 0
mirror of https://github.com/micropython/micropython.git synced 2026-01-07 04:30:24 +01:00
Code Issues Actions 27 Packages Projects Releases Wiki Activity

py: Optimise types for common case where type has a single parent type.

Browse Source 
The common cases for inheritance are 0 or 1 parent types, for both built-in
types (eg built-in exceptions) as well as user defined types.  So it makes
sense to optimise the case of 1 parent type by storing just the type and
not a tuple of 1 value (that value being the single parent type).

This patch makes such an optimisation.  Even though there is a bit more
code to handle the two cases (either a single type or a tuple with 2 or
more values) it helps reduce overall code size because it eliminates the
need to create a static tuple to hold single parents (eg for the built-in
exceptions).  It also helps reduce RAM usage for user defined types that
only derive from a single parent.

Changes in code size (in bytes) due to this patch:

    bare-arm:       -16
    minimal (x86): -176
    unix (x86-64): -320
    unix nanbox:   -384
    stmhal:         -64
    cc3200:         -32
    esp8266:       -108
This commit is contained in:
Damien George
2017-04-06 12:09:01 +10:00
parent fc710169b7
commit 816413e4b2
5 changed files with 101 additions and 95 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
py/obj.h
View File

@@ -525,8 +525,11 @@ struct _mp_obj_type_t {
// One of disjoint protocols (interfaces), like mp_stream_p_t, etc.
const void *protocol;
// A tuple containing all the base types of this type.
struct _mp_obj_tuple_t *bases_tuple;
// A pointer to the parents of this type:
// - 0 parents: pointer is NULL (object is implicitly the single parent)
// - 1 parent: a pointer to the type of that parent
// - 2 or more parents: pointer to a tuple object containing the parent types
const void *parent;
// A dict mapping qstrs to objects local methods/constants/etc.
struct _mp_obj_dict_t *locals_dict;