mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-07-08 03:45:36 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

gh-125063: Emit slices as constants in the bytecode compiler (#125064)

Browse source 
* Make slices marshallable

* Emit slices as constants

* Update Python/marshal.c

Co-authored-by: Peter Bierma <zintensitydev@gmail.com>

* Refactor codegen_slice into two functions so it
always has the same net effect

* Fix for free-threaded builds

* Simplify marshal loading of slices

* Only return SUCCESS/ERROR from codegen_slice

---------

Co-authored-by: Mark Shannon <mark@hotpy.org>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
This commit is contained in:
Michael Droettboom 2024-10-08 13:18:39 -04:00 • committed by GitHub
parent 7dca7322cc
commit c6127af868
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
6 changed files with 122 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

78
Python/codegen.c
View file

@ -194,6 +194,7 @@ static int codegen_visit_expr(compiler *, expr_ty);
static int codegen_augassign(compiler *, stmt_ty);
static int codegen_annassign(compiler *, stmt_ty);
static int codegen_subscript(compiler *, expr_ty);
static int codegen_slice_two_parts(compiler *, expr_ty);
static int codegen_slice(compiler *, expr_ty);
static bool are_all_items_const(asdl_expr_seq *, Py_ssize_t, Py_ssize_t);
@ -5005,12 +5006,8 @@ codegen_visit_expr(compiler *c, expr_ty e)
}
break;
case Slice_kind:
{
int n = codegen_slice(c, e);
RETURN_IF_ERROR(n);
ADDOP_I(c, loc, BUILD_SLICE, n);
RETURN_IF_ERROR(codegen_slice(c, e));
break;
}
case Name_kind:
return codegen_nameop(c, loc, e->v.Name.id, e->v.Name.ctx);
/* child nodes of List and Tuple will have expr_context set */
@ -5023,9 +5020,22 @@ codegen_visit_expr(compiler *c, expr_ty e)
}
static bool
is_two_element_slice(expr_ty s)
is_constant_slice(expr_ty s)
{
return s->kind == Slice_kind &&
(s->v.Slice.lower == NULL ||
s->v.Slice.lower->kind == Constant_kind) &&
(s->v.Slice.upper == NULL ||
s->v.Slice.upper->kind == Constant_kind) &&
(s->v.Slice.step == NULL ||
s->v.Slice.step->kind == Constant_kind);
}
static bool
should_apply_two_element_slice_optimization(expr_ty s)
{
return !is_constant_slice(s) &&
s->kind == Slice_kind &&
s->v.Slice.step == NULL;
}
@ -5046,8 +5056,8 @@ codegen_augassign(compiler *c, stmt_ty s)
break;
case Subscript_kind:
VISIT(c, expr, e->v.Subscript.value);
if (is_two_element_slice(e->v.Subscript.slice)) {
RETURN_IF_ERROR(codegen_slice(c, e->v.Subscript.slice));
if (should_apply_two_element_slice_optimization(e->v.Subscript.slice)) {
RETURN_IF_ERROR(codegen_slice_two_parts(c, e->v.Subscript.slice));
ADDOP_I(c, loc, COPY, 3);
ADDOP_I(c, loc, COPY, 3);
ADDOP_I(c, loc, COPY, 3);
@ -5084,7 +5094,7 @@ codegen_augassign(compiler *c, stmt_ty s)
ADDOP_NAME(c, loc, STORE_ATTR, e->v.Attribute.attr, names);
break;
case Subscript_kind:
if (is_two_element_slice(e->v.Subscript.slice)) {
if (should_apply_two_element_slice_optimization(e->v.Subscript.slice)) {
ADDOP_I(c, loc, SWAP, 4);
ADDOP_I(c, loc, SWAP, 3);
ADDOP_I(c, loc, SWAP, 2);
@ -5231,8 +5241,10 @@ codegen_subscript(compiler *c, expr_ty e)
}
VISIT(c, expr, e->v.Subscript.value);
if (is_two_element_slice(e->v.Subscript.slice) && ctx != Del) {
RETURN_IF_ERROR(codegen_slice(c, e->v.Subscript.slice));
if (should_apply_two_element_slice_optimization(e->v.Subscript.slice) &&
ctx != Del
) {
RETURN_IF_ERROR(codegen_slice_two_parts(c, e->v.Subscript.slice));
if (ctx == Load) {
ADDOP(c, loc, BINARY_SLICE);
}
@ -5254,15 +5266,9 @@ codegen_subscript(compiler *c, expr_ty e)
return SUCCESS;
}
/* Returns the number of the values emitted,
* thus are needed to build the slice, or -1 if there is an error. */
static int
codegen_slice(compiler *c, expr_ty s)
codegen_slice_two_parts(compiler *c, expr_ty s)
{
int n = 2;
assert(s->kind == Slice_kind);
/* only handles the cases where BUILD_SLICE is emitted */
if (s->v.Slice.lower) {
VISIT(c, expr, s->v.Slice.lower);
}
@ -5277,11 +5283,45 @@ codegen_slice(compiler *c, expr_ty s)
ADDOP_LOAD_CONST(c, LOC(s), Py_None);
}
return 0;
}
static int
codegen_slice(compiler *c, expr_ty s)
{
int n = 2;
assert(s->kind == Slice_kind);
if (is_constant_slice(s)) {
PyObject *start = NULL;
if (s->v.Slice.lower) {
start = s->v.Slice.lower->v.Constant.value;
}
PyObject *stop = NULL;
if (s->v.Slice.upper) {
stop = s->v.Slice.upper->v.Constant.value;
}
PyObject *step = NULL;
if (s->v.Slice.step) {
step = s->v.Slice.step->v.Constant.value;
}
PyObject *slice = PySlice_New(start, stop, step);
if (slice == NULL) {
return ERROR;
}
ADDOP_LOAD_CONST_NEW(c, LOC(s), slice);
return SUCCESS;
}
RETURN_IF_ERROR(codegen_slice_two_parts(c, s));
if (s->v.Slice.step) {
n++;
VISIT(c, expr, s->v.Slice.step);
}
return n;
ADDOP_I(c, LOC(s), BUILD_SLICE, n);
return SUCCESS;
}