From: Explorer09 <explore...@gmail.com>
(This is my first time submitting a patch for GCC)
I found the logic of use_cxa_atexit in configure script a little
bit weird.
It first looks up the default_use_cxa_atexit value for the target,
then, for building the native compiler, checks for __cxa_atexit
in libc. But, from what I read about __cxa_atexit, it should be the
recommended way for registering destructors, and in other words, GCC
shall --enable-__cxa_atexit whenever libc has it, or when _we_ have its
implementation for the target.
The logic should be:
When building native compiler, check for libc's function despite
default_use_cxa_atexit defined for the target, and
default_use_cxa_atexit be used only when building a cross.
Do I understand it wrong?
Below is the patch for the proposed logic change. Thank you.
2017-04-19 Kang-Che Sung <explore...@gmail.com>
* configure.ac (use_cxa_atexit): When building native compiler,
ignore $default_use_cxa_atexit and check for libc's __cxa_atexit.
* configure: Regenerate.
---
gcc/ChangeLog | 6 ++++++
gcc/configure.ac | 24 ++++++++++++++----------
gcc/configure | 27 ++++++++++++++++-----------
3 files changed, 36 insertions(+), 21 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d52db8a3609..e93789faf9c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-04-19 Kang-Che Sung <explore...@gmail.com>
+
+ * configure.ac (use_cxa_atexit): When building native compiler,
+ ignore $default_use_cxa_atexit and check for libc's __cxa_atexit.
+ * configure: Regenerate.
+
2017-04-19 Eric Botcazou <ebotca...@adacore.com>
Vladimir Makarov <vmaka...@redhat.com>
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 9d4c792a33f..cf7ddce79c1 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -1632,9 +1632,8 @@ fi
# --------
use_cxa_atexit=no
-if test x$enable___cxa_atexit = xyes || \
- test x$enable___cxa_atexit = x -a x$default_use_cxa_atexit = xyes; then
- if test x$host = x$target; then
+if test x$host = x$target; then
+ if test x$enable___cxa_atexit != xno; then
case $host in
# mingw32 doesn't have __cxa_atexit but uses atexit registration
# keyed to flag_use_cxa_atexit
@@ -1645,22 +1644,27 @@ if test x$enable___cxa_atexit = xyes || \
use_cxa_atexit=yes
;;
*)
- AC_CHECK_FUNC(__cxa_atexit,[use_cxa_atexit=yes],
- [echo "__cxa_atexit can't be enabled on this target"])
+ AC_CHECK_FUNC(__cxa_atexit, [use_cxa_atexit=yes],[
+ if test x$enable___cxa_atexit = xyes; then
+ AC_MSG_ERROR([__cxa_atexit can't be enabled on this target])
+ fi])
;;
esac
- else
- # We can't check for __cxa_atexit when building a cross, so assume
- # it is available
+ fi
+else
+ # Can't check presence of libc functions during cross-compile, so respect
+ # user or use our default.
+ if test x$enable___cxa_atexit = xyes || \
+ test x$enable___cxa_atexit = x -a x$default_use_cxa_atexit = xyes; then
use_cxa_atexit=yes
fi
- if test x$use_cxa_atexit = xyes; then
+fi
+if test x$use_cxa_atexit = xyes; then
AC_DEFINE(DEFAULT_USE_CXA_ATEXIT, 2,
[Define if you want to use __cxa_atexit, rather than atexit, to
register C++ destructors for local statics and global objects.
This is essential for fully standards-compliant handling of
destructors, but requires __cxa_atexit in libc.])
- fi
fi
# Look for a file containing extra machine modes.
--
2.11.0
