From b451b0e9a772f009f4161f7a46476190d0d17ac1 Mon Sep 17 00:00:00 2001
From: Pablo Galindo <Pablogsal@gmail.com>
Date: Wed, 21 Oct 2020 22:46:52 +0100
Subject: [PATCH] bpo-38980: Add -fno-semantic-interposition when building with
 optimizations (GH-22862)

---
 Doc/whatsnew/3.10.rst                                     | 8 ++++++++
 .../next/Build/2020-10-21-18-31-54.bpo-38980.xz7BNd.rst   | 3 +++
 configure                                                 | 8 ++++++++
 configure.ac                                              | 8 ++++++++
 4 files changed, 27 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Build/2020-10-21-18-31-54.bpo-38980.xz7BNd.rst

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
index e275a7cb457..e464be6eb7e 100644
--- a/Doc/whatsnew/3.10.rst
+++ b/Doc/whatsnew/3.10.rst
@@ -256,6 +256,14 @@ Optimizations
   It is about 36% faster now.  (Contributed by Pablo Galindo and Yury Selivanov
   in :issue:`42093`.)
 
+* When building Python with ``--enable-optimizations`` now
+  ``-fno-semantic-interposition`` is added to both the compile and link line.
+  This speeds builds of the Python interpreter created with ``--enable-shared``
+  with ``gcc`` by up to 30%. See `this article
+  <https://developers.redhat.com/blog/2020/06/25/red-hat-enterprise-linux-8-2-brings-faster-python-3-8-run-speeds/>`_
+  for more details. (Contributed by Victor Stinner and Pablo Galindo in
+  :issue:`38980`)
+
 Deprecated
 ==========
 
diff --git a/Misc/NEWS.d/next/Build/2020-10-21-18-31-54.bpo-38980.xz7BNd.rst b/Misc/NEWS.d/next/Build/2020-10-21-18-31-54.bpo-38980.xz7BNd.rst
new file mode 100644
index 00000000000..c9d34cf12c2
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2020-10-21-18-31-54.bpo-38980.xz7BNd.rst
@@ -0,0 +1,3 @@
+Add ``-fno-semantic-interposition`` to both the compile and link line when
+building with ``--enable-optimizations``. Patch by Victor Stinner and Pablo
+Galindo.
diff --git a/configure b/configure
index 88b78947767..df7118f68d3 100755
--- a/configure
+++ b/configure
@@ -6482,6 +6482,14 @@ if test "$Py_OPT" = 'true' ; then
   DEF_MAKE_ALL_RULE="profile-opt"
   REQUIRE_PGO="yes"
   DEF_MAKE_RULE="build_all"
+  case $CC in
+    *gcc*)
+      CFLAGS_NODIST="$CFLAGS_NODIST -fno-semantic-interposition"
+      LDFLAGS_NODIST="$LDFLAGS_NODIST -fno-semantic-interposition"
+      ;;
+  esac
+
+
 else
   DEF_MAKE_ALL_RULE="build_all"
   REQUIRE_PGO="no"
diff --git a/configure.ac b/configure.ac
index 6ffe90a4c42..c63c1e88a23 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1318,6 +1318,14 @@ if test "$Py_OPT" = 'true' ; then
   DEF_MAKE_ALL_RULE="profile-opt"
   REQUIRE_PGO="yes"
   DEF_MAKE_RULE="build_all"
+  case $CC in
+    *gcc*)
+      CFLAGS_NODIST="$CFLAGS_NODIST -fno-semantic-interposition"
+      LDFLAGS_NODIST="$LDFLAGS_NODIST -fno-semantic-interposition"
+      ;;
+  esac
+
+
 else
   DEF_MAKE_ALL_RULE="build_all"
   REQUIRE_PGO="no"