From 41c11c2a743ea85be67d0840dbbb6d5125bb8798 Mon Sep 17 00:00:00 2001
From: Caroline Tice <cmtice@google.com>
Date: Fri, 25 Mar 2016 16:19:29 -0700
Subject: Add top-level flag, --enable-libatomic-ifuncs=[yes/no]

This CL adds a top-level configure flag, --enable-libatomic-ifuncs.
IF this is set to 'no', then libatomic will not be configured/built
to use IFUNC.

This is to fix https://buganizer.corp.google.com/issues/22699878

Change-Id: I76741fe854fc9c32a230b67c72920adfb00473ee
---
 gcc-4.9/configure              | 19 +++++++++++++++++++
 gcc-4.9/configure.ac           | 12 ++++++++++++
 gcc-4.9/libatomic/acinclude.m4 |  5 +++++
 3 files changed, 36 insertions(+)

(limited to 'gcc-4.9')

diff --git a/gcc-4.9/configure b/gcc-4.9/configure
index b209bc951..186f52fec 100755
--- a/gcc-4.9/configure
+++ b/gcc-4.9/configure
@@ -785,6 +785,7 @@ with_debug_prefix_map
 with_build_config
 enable_vtable_verify
 enable_bionic_libs
+enable_libatomic_ifuncs
 enable_serial_configure
 with_build_time_tools
 enable_maintainer_mode
@@ -1485,6 +1486,7 @@ Optional Features:
                           Objective-C runtime
   --enable-vtable-verify    Enable vtable verification feature
   --enable-bionic-libs    Use bionic libstdc++ libraries
+  --enable-bionic-libs    Enable/disable IFUNCs in libatomic library
   --enable-serial-[{host,target,build}-]configure
                           force sequential configuration of sub-packages for
                           the host, target or build machine, or all
@@ -7240,6 +7242,23 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $enable_bionic_libs" >&5
 $as_echo "$enable_bionic_libs" >&6; }
 
+# Use same top-level configure hooks in libatomic.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --enable-libatomic-ifuncs" >&5
+$as_echo_n "checking for --enable-libatomic-ifuncs... " >&6; }
+# Check whether --enable-libatomic-ifuncs was given.
+if test "${enable_libatomic_ifuncs+set}" = set; then :
+  enableval=$enable_libatomic_ifuncs; case "$enableval" in
+ yes) enable_libatomic_ifuncs=yes ;;
+ no)  enable_libatomic_ifuncs=no ;;
+ *)   enable_libatomic_ifuncs=yes;;
+ esac
+else
+  enable_libatomic_ifuncs=yes
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $enable_libatomic_ifuncs" >&5
+$as_echo "$enable_libatomic_ifuncs" >&6; }
+
 # Record target_configdirs and the configure arguments for target and
 # build configuration in Makefile.
 target_configdirs=`echo "${target_configdirs}" | sed -e 's/target-//g'`
diff --git a/gcc-4.9/configure.ac b/gcc-4.9/configure.ac
index e04fdfe6e..b78629a75 100644
--- a/gcc-4.9/configure.ac
+++ b/gcc-4.9/configure.ac
@@ -2556,6 +2556,18 @@ AC_ARG_ENABLE(bionic-libs,
 [enable_bionic_libs=no])
 AC_MSG_RESULT($enable_bionic_libs)
 
+# Use same top-level configure hooks in libatomic.
+AC_MSG_CHECKING([for --enable-libatomic-ifuncs])
+AC_ARG_ENABLE(libatomic-ifuncs,
+[  --enable-bionic-libs    Enable/disable IFUNCs in libatomic library ],
+[case "$enableval" in
+ yes) enable_libatomic_ifuncs=yes ;;
+ no)  enable_libatomic_ifuncs=no ;;
+ *)   enable_libatomic_ifuncs=yes;;
+ esac],
+[enable_libatomic_ifuncs=yes])
+AC_MSG_RESULT($enable_libatomic_ifuncs)
+
 # Record target_configdirs and the configure arguments for target and
 # build configuration in Makefile.
 target_configdirs=`echo "${target_configdirs}" | sed -e 's/target-//g'`
diff --git a/gcc-4.9/libatomic/acinclude.m4 b/gcc-4.9/libatomic/acinclude.m4
index a86e52b4f..34db650be 100644
--- a/gcc-4.9/libatomic/acinclude.m4
+++ b/gcc-4.9/libatomic/acinclude.m4
@@ -197,6 +197,11 @@ AC_DEFUN([LIBAT_CHECK_IFUNC], [
     void *foo_sel(void) { return foo_alt; }
     int foo(void) __attribute__((ifunc("foo_sel")));],
     [return foo();], libat_cv_have_ifunc=yes, libat_cv_have_ifunc=no)])
+
+  if test $enable_libatomic_ifuncs = no; then
+    libat_cv_have_ifunc=no
+  fi
+
   LIBAT_DEFINE_YESNO([HAVE_IFUNC], [$libat_cv_have_ifunc],
       [Define to 1 if the target supports __attribute__((ifunc(...))).])
 ])
-- 
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