2009-08-10 Paul Pluzhnikov <ppluzhnikov@google.com>

[deliverable/binutils-gdb.git] / config / tls.m4

diff --git a/config/tls.m4 b/config/tls.m4
index 69cf6d4f9d2b6096d87c83676cb1d5f834a55582..79cf382066483650e2c6c7e9ba5de849deca72f5 100644 (file)
--- a/config/tls.m4
+++ b/config/tls.m4
@@ -1,8 +1,9 @@
 dnl Check whether the target supports TLS.
 AC_DEFUN([GCC_CHECK_TLS], [
+  AC_REQUIRE([AC_CANONICAL_HOST])
   GCC_ENABLE(tls, yes, [], [Use thread-local storage])
   AC_CACHE_CHECK([whether the target supports thread-local storage],
-                have_tls, [
+                gcc_cv_have_tls, [
     AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
       [dnl If the test case passed with dynamic linking, try again with
        dnl static linking, but only if static linking is supported (not
@@ -10,11 +11,11 @@ AC_DEFUN([GCC_CHECK_TLS], [
       chktls_save_LDFLAGS="$LDFLAGS"
       LDFLAGS="-static $LDFLAGS"
       AC_LINK_IFELSE([int main() { return 0; }],
-       AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
-                     [have_tls=yes], [have_tls=no],[]),
-       [have_tls=yes])
+       [AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
+                      [gcc_cv_have_tls=yes], [gcc_cv_have_tls=no],[])],
+       [gcc_cv_have_tls=yes])
       LDFLAGS="$chktls_save_LDFLAGS"
-      if test $have_tls = yes; then
+      if test $gcc_cv_have_tls = yes; then
        dnl So far, the binutils and the compiler support TLS.
        dnl Also check whether the libc supports TLS, i.e. whether a variable
        dnl with __thread linkage has a different address in different threads.
@@ -58,18 +59,35 @@ AC_DEFUN([GCC_CHECK_TLS], [
                if (pthread_join (thread, &thread_retval))
                  return 0;
                return (a_in_other_thread == a_in_main_thread);])],
-            [have_tls=yes], [have_tls=no], [])
+            [gcc_cv_have_tls=yes], [gcc_cv_have_tls=no], [])
          CFLAGS="$chktls_save_CFLAGS"
        fi
       fi],
-      [have_tls=no],
+      [gcc_cv_have_tls=no],
       [dnl This is the cross-compiling case. Assume libc supports TLS if the
        dnl binutils and the compiler do.
        AC_LINK_IFELSE([__thread int a; int b; int main() { return a = b; }],
-                     [have_tls=yes], [have_tls=no])
+        [chktls_save_LDFLAGS="$LDFLAGS"
+         dnl Shared library options may depend on the host; this check
+         dnl is only known to be needed for GNU/Linux.
+         case $host in
+           *-*-linux*)
+             LDFLAGS="-shared -Wl,--no-undefined $LDFLAGS"
+             ;;
+         esac
+         chktls_save_CFLAGS="$CFLAGS"
+         CFLAGS="-fPIC $CFLAGS"
+         dnl If -shared works, test if TLS works in a shared library.
+         AC_LINK_IFELSE([int f() { return 0; }],
+           [AC_LINK_IFELSE([__thread int a; int b; int f() { return a = b; }],
+             [gcc_cv_have_tls=yes],
+             [gcc_cv_have_tls=no])],
+           [gcc_cv_have_tls=yes])
+         CFLAGS="$chktls_save_CFLAGS"
+         LDFLAGS="$chktls_save_LDFLAGS"], [gcc_cv_have_tls=no])
       ]
     )])
-  if test "$enable_tls $have_tls" = "yes yes"; then
+  if test "$enable_tls $gcc_cv_have_tls" = "yes yes"; then
     AC_DEFINE(HAVE_TLS, 1,
              [Define to 1 if the target supports thread-local storage.])
   fi])
@@ -77,12 +95,12 @@ AC_DEFUN([GCC_CHECK_TLS], [
 dnl Check whether the target assembler supports TLS.
 AC_DEFUN([GCC_CHECK_CC_TLS], [
   GCC_ENABLE(tls, yes, [], [Use thread-local storage])
-  AC_CACHE_CHECK([whether the target asssembler upports thread-local storage],
-                have_cc_tls, [
+  AC_CACHE_CHECK([whether the target assembler supports thread-local storage],
+                gcc_cv_have_cc_tls, [
     AC_COMPILE_IFELSE([__thread int a; int b; int main() { return a = b; }],
-      [have_cc_tls=yes], [have_cc_tls=no])]
+      [gcc_cv_have_cc_tls=yes], [gcc_cv_have_cc_tls=no])]
     )])
-  if test "$enable_tls $have_cc_tls" = "yes yes"; then
+  if test "$enable_tls $gcc_cv_have_cc_tls" = "yes yes"; then
     AC_DEFINE(HAVE_CC_TLS, 1,
              [Define to 1 if the target assembler supports thread-local storage.])
   fi])