https://github.com/python/cpython/commit/b3cfd36ba4f17c19d587427b90ca9378ad009978
commit: b3cfd36ba4f17c19d587427b90ca9378ad009978
branch: main
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2026-05-07T11:47:08+02:00
summary:
gh-149202: Don't use -fno-omit-frame-pointer on ppc64le (#149485)
The power ABI specification requires that compilers maintain a back
chain by default, so unwinding already works without a dedicated
frame pointer. Don't use -fno-omit-frame-pointer on ppc64le.
files:
M Doc/using/configure.rst
M Lib/test/test_frame_pointer_unwind.py
M configure
M configure.ac
diff --git a/Doc/using/configure.rst b/Doc/using/configure.rst
index a0e46ff4e375b6..77771bb70e1a30 100644
--- a/Doc/using/configure.rst
+++ b/Doc/using/configure.rst
@@ -792,6 +792,8 @@ also be used to improve performance.
- ``-marm`` and/or ``-mno-thumb`` is added on 32-bit ARM when supported,
- on s390x platforms, when supported, ``-mbackchain`` is added *instead*.
of the above frame pointer flags.
+ - on ppc64le platforms, no compiler flags is needed since the power ABI
+ requires that compilers maintain a back chain by default.
Frame pointers enable profilers, debuggers, and system tracing tools
(``perf``, ``eBPF``, ``dtrace``, ``gdb``) to walk the C call stack
diff --git a/Lib/test/test_frame_pointer_unwind.py
b/Lib/test/test_frame_pointer_unwind.py
index 5cd94e5b27f394..faa012c9c00d8f 100644
--- a/Lib/test/test_frame_pointer_unwind.py
+++ b/Lib/test/test_frame_pointer_unwind.py
@@ -56,6 +56,12 @@ def _frame_pointers_expected(machine):
if sys.maxsize < 2**32:
return None
return True
+ if machine == "ppc64le":
+ # The power ABI specification requires that compilers maintain a
+ # back chain by default, so unwinding already works without a
+ # dedicated frame pointer.
+ # https://openpowerfoundation.org/specifications/64bitelfabi/
+ return True
if machine == "x86_64":
final_opt = ""
for opt in cflags.split():
diff --git a/configure b/configure
index 3377bf7516ebd2..cff7dfbfba8b9a 100755
--- a/configure
+++ b/configure
@@ -10435,6 +10435,14 @@ fi
;; #(
*) :
;;
+esac
+ case $host_cpu in #(
+ powerpc64le) :
+
+ frame_pointer_cflags=""
+ ;; #(
+ *) :
+ ;;
esac
case $host_cpu in #(
s390*) :
diff --git a/configure.ac b/configure.ac
index fc2db4d5e8aebb..ac3269ab765c0d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2557,6 +2557,9 @@ AS_VAR_IF([ac_cv_gcc_compat], [yes], [
frame_pointer_cflags="$frame_pointer_cflags -mno-thumb"
], [], [-Werror])
])
+ AS_CASE([$host_cpu], [powerpc64le], [
+ frame_pointer_cflags=""
+ ])
AS_CASE([$host_cpu], [s390*], [
AX_CHECK_COMPILE_FLAG([-mbackchain], [
dnl Do not use no-omit-frame-pointer; see gh-149362
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