gh-109181: Speed up Traceback object creation by lazily compute the line number

[pablogsal]

• Issue: Exceptions slow in 3.11, depending on location #109181

[pablogsal]

From this test:

from time import perf_counter as time
from timeit import repeat

for e in range(2, 6):
    n = 10 ** e
    exec(f'''def f():
        if 0 == 1:
            {'unreached;' * n}
        try:
            raise RuntimeError
        except RuntimeError:
            pass''')
    number = 10**6 // n
    t = min(repeat(f, number=number)) / number
    print(f'{n:6} {t * 1e6 :7.1f} μs')

Before:

./python.exe bloch.py
   100     1.4 μs
  1000    10.5 μs
 10000   102.4 μs
100000  1241.8 μs

After:

./python.exe bloch.py
   100     0.7 μs
  1000     0.6 μs
 10000     0.5 μs
100000     0.5 μs

[miss-islington-app]

Thanks @pablogsal for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11, 3.12.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @pablogsal, I could not cleanly backport this to 3.12 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker abb15420c11d9dda9c89f74eac8417240b321109 3.12

[miss-islington-app]

Sorry, @pablogsal, I could not cleanly backport this to 3.11 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker abb15420c11d9dda9c89f74eac8417240b321109 3.11

[bedevere-app]

GH-111550 is a backport of this pull request to the 3.11 branch.

[bedevere-app]

GH-111551 is a backport of this pull request to the 3.12 branch.