Skip to content

[2.7] bpo-32616: Disable computed gotos by default for clang < 5 #5574

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

Merged
methane merged 2 commits into from
Feb 7, 2018
Merged

[2.7] bpo-32616: Disable computed gotos by default for clang < 5 #5574

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
fc21968
bpo-32616: Disable computed gotos by default for clang < 5
methane Feb 7, 2018
ebeb212
Add NEWS entry
methane Feb 7, 2018
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
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Build/2018-02-07-11-24-38.bpo-32616.o7mFJ3.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Disable computed gotos by default for clang < 5.0. It caused significant
performance regression.
12 changes: 10 additions & 2 deletions Python/ceval.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -689,11 +689,19 @@ PyObject *
PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
{
#ifdef DYNAMIC_EXECUTION_PROFILE
#undef USE_COMPUTED_GOTOS
#undef USE_COMPUTED_GOTOS
#endif
#ifdef HAVE_COMPUTED_GOTOS
#ifndef USE_COMPUTED_GOTOS
#define USE_COMPUTED_GOTOS 1
#if defined(__clang__) && (__clang_major__ < 5)
/* Computed gotos caused significant performance regression
* with clang < 5.0.
* https://bugs.python.org/issue32616
*/
#define USE_COMPUTED_GOTOS 0
#else
#define USE_COMPUTED_GOTOS 1
#endif
#endif
#else
#if defined(USE_COMPUTED_GOTOS) && USE_COMPUTED_GOTOS
Expand Down