diff options
| -rw-r--r-- | py/obj.h | 3 | ||||
| -rw-r--r-- | py/objarray.c | 4 | ||||
| -rw-r--r-- | py/vm.c | 5 | ||||
| -rw-r--r-- | tests/basics/slice_optimise.py | 23 | ||||
| -rw-r--r-- | tests/basics/slice_optimise.py.exp | 2 |
5 files changed, 33 insertions, 4 deletions
@@ -558,6 +558,8 @@ typedef mp_obj_t (*mp_fun_kw_t)(size_t n, const mp_obj_t *, mp_map_t *); // If MP_TYPE_FLAG_ITER_IS_STREAM is set then the type implicitly gets a "return self" // getiter, and mp_stream_unbuffered_iter for iternext. // If MP_TYPE_FLAG_INSTANCE_TYPE is set then this is an instance type (i.e. defined in Python). +// If MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE is set then the "subscr" slot allows a stack +// allocated slice to be passed in (no references to it will be retained after the call). #define MP_TYPE_FLAG_NONE (0x0000) #define MP_TYPE_FLAG_IS_SUBCLASSED (0x0001) #define MP_TYPE_FLAG_HAS_SPECIAL_ACCESSORS (0x0002) @@ -571,6 +573,7 @@ typedef mp_obj_t (*mp_fun_kw_t)(size_t n, const mp_obj_t *, mp_map_t *); #define MP_TYPE_FLAG_ITER_IS_CUSTOM (0x0100) #define MP_TYPE_FLAG_ITER_IS_STREAM (MP_TYPE_FLAG_ITER_IS_ITERNEXT | MP_TYPE_FLAG_ITER_IS_CUSTOM) #define MP_TYPE_FLAG_INSTANCE_TYPE (0x0200) +#define MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE (0x0400) typedef enum { PRINT_STR = 0, diff --git a/py/objarray.c b/py/objarray.c index 1fd026939..ac4e343d0 100644 --- a/py/objarray.c +++ b/py/objarray.c @@ -626,7 +626,7 @@ MP_DEFINE_CONST_OBJ_TYPE( MP_DEFINE_CONST_OBJ_TYPE( mp_type_bytearray, MP_QSTR_bytearray, - MP_TYPE_FLAG_EQ_CHECKS_OTHER_TYPE | MP_TYPE_FLAG_ITER_IS_GETITER, + MP_TYPE_FLAG_EQ_CHECKS_OTHER_TYPE | MP_TYPE_FLAG_ITER_IS_GETITER | MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE, make_new, bytearray_make_new, print, array_print, iter, array_iterator_new, @@ -654,7 +654,7 @@ MP_DEFINE_CONST_OBJ_TYPE( MP_DEFINE_CONST_OBJ_TYPE( mp_type_memoryview, MP_QSTR_memoryview, - MP_TYPE_FLAG_EQ_CHECKS_OTHER_TYPE | MP_TYPE_FLAG_ITER_IS_GETITER, + MP_TYPE_FLAG_EQ_CHECKS_OTHER_TYPE | MP_TYPE_FLAG_ITER_IS_GETITER | MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE, make_new, memoryview_make_new, iter, array_iterator_new, unary_op, array_unary_op, @@ -865,9 +865,10 @@ unwind_jump:; // 3-argument slice includes step step = POP(); } - if ((*ip == MP_BC_LOAD_SUBSCR || *ip == MP_BC_STORE_SUBSCR) && mp_obj_is_native_type(mp_obj_get_type(sp[-2]))) { + if ((*ip == MP_BC_LOAD_SUBSCR || *ip == MP_BC_STORE_SUBSCR) + && (mp_obj_get_type(sp[-2])->flags & MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE)) { // Fast path optimisation for when the BUILD_SLICE is immediately followed - // by a LOAD/STORE_SUBSCR for a native type to avoid needing to allocate + // by a LOAD/STORE_SUBSCR for an accepting type, to avoid needing to allocate // the slice on the heap. In some cases (e.g. a[1:3] = x) this can result // in no allocations at all. We can't do this for instance types because // the get/set/delattr implementation may keep a reference to the slice. diff --git a/tests/basics/slice_optimise.py b/tests/basics/slice_optimise.py new file mode 100644 index 000000000..f663e16b8 --- /dev/null +++ b/tests/basics/slice_optimise.py @@ -0,0 +1,23 @@ +# Test that the slice-on-stack optimisation does not break various uses of slice +# (see MP_TYPE_FLAG_SUBSCR_ALLOWS_STACK_SLICE type option). +# +# Note: this test has a corresponding .py.exp file because hashing slice objects +# was not allowed in CPython until 3.12. + +try: + from collections import OrderedDict +except ImportError: + print("SKIP") + raise SystemExit + +# Attempt to index with a slice, error should contain the slice (failed key). +try: + dict()[:] +except KeyError as e: + print("KeyError", e.args) + +# Put a slice and another object into an OrderedDict, and retrieve them. +x = OrderedDict() +x[:"a"] = 1 +x["b"] = 2 +print(list(x.keys()), list(x.values())) diff --git a/tests/basics/slice_optimise.py.exp b/tests/basics/slice_optimise.py.exp new file mode 100644 index 000000000..3fa59aae1 --- /dev/null +++ b/tests/basics/slice_optimise.py.exp @@ -0,0 +1,2 @@ +KeyError (slice(None, None, None),) +[slice(None, 'a', None), 'b'] [1, 2] |