mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-10-09 08:31:26 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 13

bpo-40222: "Zero cost" exception handling (GH-25729)

Browse source 
"Zero cost" exception handling.

* Uses a lookup table to determine how to handle exceptions.
* Removes SETUP_FINALLY and POP_TOP block instructions, eliminating (most of) the runtime overhead of try statements.
* Reduces the size of the frame object by about 60%.
This commit is contained in:
Mark Shannon 2021-05-07 15:19:19 +01:00 • committed by GitHub
parent b32c8e9795
commit adcd220556
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
30 changed files with 6614 additions and 5687 deletions
Download patch file Download diff file Expand all files Collapse all files

3
Lib/importlib/_bootstrap_external.py
View file

@ -352,6 +352,7 @@ _code_type = type(_write_atomic.__code__)
# Python 3.10b1 3437 (Undo making 'annotations' future by default - We like to dance among core devs!)
# Python 3.10b1 3438 Safer line number table handling.
# Python 3.10b1 3439 (Add ROT_N)
# Python 3.11a1 3450 Use exception table for unwinding ("zero cost" exception handling)
#
# MAGIC must change whenever the bytecode emitted by the compiler may no
@ -361,7 +362,7 @@ _code_type = type(_write_atomic.__code__)
# Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
# in PC/launcher.c must also be updated.
MAGIC_NUMBER = (3439).to_bytes(2, 'little') + b'\r\n'
MAGIC_NUMBER = (3450).to_bytes(2, 'little') + b'\r\n'
_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c
_PYCACHE = '__pycache__'