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-rw-r--r--ChangeLog4
-rwxr-xr-xconfigure45
-rw-r--r--configure.ac37
3 files changed, 80 insertions, 6 deletions
diff --git a/ChangeLog b/ChangeLog
index 66a500b78c..aa7e9a96c5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2017-10-20  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
+	* configure.ac (libc_cv_gcc_incompatbile_alias): New define:
+	indicates whether compiler emits an warning for alias for
+	functions with incompatible types.
+
 	[BZ #22273]
 	* sysdeps/unix/sysv/linux/spawni.c (__spawnix): Handle the case where
 	the auxiliary process is terminated by a signal before calling _exit
diff --git a/configure b/configure
index c2c9c72d5a..6010977c58 100755
--- a/configure
+++ b/configure
@@ -3996,6 +3996,32 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_gcc_indirect_function" >&5
 $as_echo "$libc_cv_gcc_indirect_function" >&6; }
 
+# Check if gcc warns about alias for function with incompatible types.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if compiler warns about alias for function with incompatible types" >&5
+$as_echo_n "checking if compiler warns about alias for function with incompatible types... " >&6; }
+if ${libc_cv_gcc_incompatible_alias+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.c <<EOF
+int __redirect_foo (const void *s, int c);
+
+__typeof (__redirect_foo) *foo_impl (void) __asm__ ("foo");
+__typeof (__redirect_foo) *foo_impl (void)
+{
+  return 0;
+}
+
+extern __typeof (__redirect_foo) foo_alias __attribute__ ((alias ("foo")));
+EOF
+libc_cv_gcc_incompatible_alias=yes
+if ${CC-cc} -Werror -c conftest.c -o conftest.o 1>&5 2>&5 ; then
+  libc_cv_gcc_incompatible_alias=no
+fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_gcc_incompatible_alias" >&5
+$as_echo "$libc_cv_gcc_incompatible_alias" >&6; }
+
 if test x"$libc_cv_ld_gnu_indirect_function" != xyes; then
   if test x"$multi_arch" = xyes; then
     as_fn_error $? "--enable-multi-arch support requires assembler and linker support" "$LINENO" 5
@@ -4003,12 +4029,25 @@ if test x"$libc_cv_ld_gnu_indirect_function" != xyes; then
     multi_arch=no
   fi
 fi
-if test x"$libc_cv_gcc_indirect_function" != xyes &&
-   test x"$multi_arch" = xyes; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: --enable-multi-arch support recommends a gcc with gnu-indirect-function support.
+if test x"$libc_cv_gcc_indirect_function" != xyes; then
+  # GCC 8+ emits a warning for alias with incompatible types and it might
+  # fail to build ifunc resolvers aliases to either weak or internal
+  # symbols.  Disables multiarch build in this case.
+  if test x"$libc_cv_gcc_incompatible_alias" == xyes; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: gcc emits a warning for alias between functions of incompatible types" >&5
+$as_echo "$as_me: WARNING: gcc emits a warning for alias between functions of incompatible types" >&2;}
+    if test x"$multi_arch" = xyes; then
+      as_fn_error $? "--enable-multi-arch support requires a gcc with gnu-indirect-function support" "$LINENO" 5
+    fi
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Multi-arch is disabled." >&5
+$as_echo "$as_me: WARNING: Multi-arch is disabled." >&2;}
+    multi_arch=no
+  elif test x"$multi_arch" = xyes; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: --enable-multi-arch support recommends a gcc with gnu-indirect-function support.
 Please use a gcc which supports it by default or configure gcc with --enable-gnu-indirect-function" >&5
 $as_echo "$as_me: WARNING: --enable-multi-arch support recommends a gcc with gnu-indirect-function support.
 Please use a gcc which supports it by default or configure gcc with --enable-gnu-indirect-function" >&2;}
+  fi
 fi
 multi_arch_d=
 if test x"$multi_arch" != xno; then
diff --git a/configure.ac b/configure.ac
index 195e81acfd..148f7d1682 100644
--- a/configure.ac
+++ b/configure.ac
@@ -634,6 +634,26 @@ if ${CC-cc} -c conftest.c -o conftest.o 1>&AS_MESSAGE_LOG_FD \
 fi
 rm -f conftest*])
 
+# Check if gcc warns about alias for function with incompatible types.
+AC_CACHE_CHECK([if compiler warns about alias for function with incompatible types],
+	       libc_cv_gcc_incompatible_alias, [dnl
+cat > conftest.c <<EOF
+int __redirect_foo (const void *s, int c);
+
+__typeof (__redirect_foo) *foo_impl (void) __asm__ ("foo");
+__typeof (__redirect_foo) *foo_impl (void)
+{
+  return 0;
+}
+
+extern __typeof (__redirect_foo) foo_alias __attribute__ ((alias ("foo")));
+EOF
+libc_cv_gcc_incompatible_alias=yes
+if ${CC-cc} -Werror -c conftest.c -o conftest.o 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD ; then
+  libc_cv_gcc_incompatible_alias=no
+fi
+rm -f conftest*])
+
 if test x"$libc_cv_ld_gnu_indirect_function" != xyes; then
   if test x"$multi_arch" = xyes; then
     AC_MSG_ERROR([--enable-multi-arch support requires assembler and linker support])
@@ -641,10 +661,21 @@ if test x"$libc_cv_ld_gnu_indirect_function" != xyes; then
     multi_arch=no
   fi
 fi
-if test x"$libc_cv_gcc_indirect_function" != xyes &&
-   test x"$multi_arch" = xyes; then
-  AC_MSG_WARN([--enable-multi-arch support recommends a gcc with gnu-indirect-function support.
+if test x"$libc_cv_gcc_indirect_function" != xyes; then
+  # GCC 8+ emits a warning for alias with incompatible types and it might
+  # fail to build ifunc resolvers aliases to either weak or internal
+  # symbols.  Disables multiarch build in this case.
+  if test x"$libc_cv_gcc_incompatible_alias" == xyes; then
+    AC_MSG_WARN([gcc emits a warning for alias between functions of incompatible types])
+    if test x"$multi_arch" = xyes; then
+      AC_MSG_ERROR([--enable-multi-arch support requires a gcc with gnu-indirect-function support])
+    fi
+    AC_MSG_WARN([Multi-arch is disabled.])
+    multi_arch=no
+  elif test x"$multi_arch" = xyes; then
+    AC_MSG_WARN([--enable-multi-arch support recommends a gcc with gnu-indirect-function support.
 Please use a gcc which supports it by default or configure gcc with --enable-gnu-indirect-function])
+  fi
 fi
 multi_arch_d=
 if test x"$multi_arch" != xno; then