Skip to content

gh-153568: Reduce parser allocations #157374

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
pablogsal wants to merge 7 commits into
base: main
Choose a base branch
from
Open

gh-153568: Reduce parser allocations #157374

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
6985b95
gh-153568: Allocate parser tokens in blocks
pablogsal Sep 12, 2026
d9079a8
gh-153568: Avoid copying fixed parser token text
pablogsal Sep 12, 2026
a82c5a4
gh-153568: Allocate the parser identifier cache on first use
pablogsal Sep 12, 2026
ae1f4ed
gh-153568: Reuse the tokenizer newline buffer
pablogsal Sep 12, 2026
78b008a
gh-153568: Clear memo filters before the parser error pass
pablogsal Sep 12, 2026
e517f90
gh-153568: Reuse parsed name nodes during backtracking
pablogsal Sep 12, 2026
0cd6ee2
gh-153568: Reuse parsed numbers during backtracking
pablogsal Sep 12, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 6 additions & 2 deletions Grammar/python.gram
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1229,8 +1229,12 @@ invalid_arguments:
RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, _PyPegen_get_last_comprehension_item(PyPegen_last_item(b, comprehension_ty)), "Generator expression must be parenthesized") }
| a=args ',' args { _PyPegen_arguments_parsing_error(p, a) }
invalid_kwarg:
| a[Token*]=('True'|'False'|'None') b='=' {
RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to %s", PyBytes_AS_STRING(a->bytes)) }
| a='True' b='=' {
RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to True") }
| a='False' b='=' {
RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to False") }
| a='None' b='=' {
RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to None") }
| a=NAME b='=' expression for_if_clauses {
RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?")}
| !(NAME '=') a=expression b='=' {
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2026-09-12-12-00-00.gh-issue-153568.parser.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Reduce temporary allocations while parsing Python source.
6 changes: 2 additions & 4 deletions Parser/action_helpers.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -932,16 +932,14 @@ _PyPegen_add_type_comment_to_arg(Parser *p, arg_ty a, Token *tc)
0 indicates success and nonzero indicates failure (an exception may be set) */
int
_PyPegen_check_barry_as_flufl(Parser *p, Token* t) {
assert(t->bytes != NULL);
assert(t->type == NOTEQUAL);

const char* tok_str = PyBytes_AS_STRING(t->bytes);
if (p->flags & PyPARSE_BARRY_AS_BDFL && strcmp(tok_str, "<>") != 0) {
if (p->flags & PyPARSE_BARRY_AS_BDFL && !t->is_barry) {
RAISE_SYNTAX_ERROR("with Barry as BDFL, use '<>' instead of '!='");
return -1;
}
if (!(p->flags & PyPARSE_BARRY_AS_BDFL)) {
return strcmp(tok_str, "!=");
return t->is_barry;
}
return 0;
}
Expand Down
Loading
Loading