[PATCH] libgomp: Add RTEMS support

[Sebastian Huber]

I would like to commit this patch to GCC 4.9 and 5.0.

libgomp/ChangeLog
2015-03-13  Sebastian Huber  <sebastian.huber at embedded-brains.de>

	* configure.tgt (*-*-rtems*): Use local-exec TLS model.
	* configure.ac (*-*-rtems*): Assume Pthread is supported.
	(pthread.h): Check for this header file.
	* configure: Regenerate.
---
 libgomp/configure     | 22 ++++++++++++++--------
 libgomp/configure.ac  | 42 ++++++++++++++++++++++++------------------
 libgomp/configure.tgt |  4 ++++
 3 files changed, 42 insertions(+), 26 deletions(-)

diff --git a/libgomp/configure b/libgomp/configure
index 0818707..e39787c 100755
--- a/libgomp/configure
+++ b/libgomp/configure
@@ -14611,7 +14611,7 @@ $as_echo "#define STRING_WITH_STRINGS 1" >>confdefs.h
 
 fi
 
-for ac_header in unistd.h semaphore.h sys/loadavg.h sys/time.h sys/time.h
+for ac_header in pthread.h unistd.h semaphore.h sys/loadavg.h sys/time.h sys/time.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -15033,14 +15033,19 @@ ac_config_commands="$ac_config_commands gstdint.h"
 
 
 
-# Check to see if -pthread or -lpthread is needed.  Prefer the former.
-# In case the pthread.h system header is not found, this test will fail.
 XPCFLAGS=""
-CFLAGS="$CFLAGS -pthread"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+case "$host" in
+  *-*-rtems*)
+    # RTEMS supports Pthreads, but the library is not available at GCC build time.
+    ;;
+  *)
+    # Check to see if -pthread or -lpthread is needed.  Prefer the former.
+    # In case the pthread.h system header is not found, this test will fail.
+    CFLAGS="$CFLAGS -pthread"
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <pthread.h>
-   void *g(void *d) { return NULL; }
+       void *g(void *d) { return NULL; }
 int
 main ()
 {
@@ -15053,10 +15058,10 @@ if ac_fn_c_try_link "$LINENO"; then :
   XPCFLAGS=" -Wc,-pthread"
 else
   CFLAGS="$save_CFLAGS" LIBS="-lpthread $LIBS"
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <pthread.h>
-     void *g(void *d) { return NULL; }
+         void *g(void *d) { return NULL; }
 int
 main ()
 {
@@ -15075,6 +15080,7 @@ rm -f core conftest.err conftest.$ac_objext \
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
+esac
 
 # Plugins for offload execution, configure.ac fragment.  -*- mode: autoconf -*-
 #
diff --git a/libgomp/configure.ac b/libgomp/configure.ac
index 4687b01..51e646d 100644
--- a/libgomp/configure.ac
+++ b/libgomp/configure.ac
@@ -170,28 +170,34 @@ AC_SUBST(libtool_VERSION)
 AC_STDC_HEADERS
 AC_HEADER_TIME
 ACX_HEADER_STRING
-AC_CHECK_HEADERS(unistd.h semaphore.h sys/loadavg.h sys/time.h sys/time.h)
+AC_CHECK_HEADERS(pthread.h unistd.h semaphore.h sys/loadavg.h sys/time.h sys/time.h)
 
 GCC_HEADER_STDINT(gstdint.h)
 
-# Check to see if -pthread or -lpthread is needed.  Prefer the former.
-# In case the pthread.h system header is not found, this test will fail.
 XPCFLAGS=""
-CFLAGS="$CFLAGS -pthread"
-AC_LINK_IFELSE(
- [AC_LANG_PROGRAM(
-  [#include <pthread.h>
-   void *g(void *d) { return NULL; }],
-  [pthread_t t; pthread_create(&t,NULL,g,NULL);])],
- [XPCFLAGS=" -Wc,-pthread"],
- [CFLAGS="$save_CFLAGS" LIBS="-lpthread $LIBS"
-  AC_LINK_IFELSE(
-   [AC_LANG_PROGRAM(
-    [#include <pthread.h>
-     void *g(void *d) { return NULL; }],
-    [pthread_t t; pthread_create(&t,NULL,g,NULL);])],
-   [],
-   [AC_MSG_ERROR([Pthreads are required to build libgomp])])])
+case "$host" in
+  *-*-rtems*)
+    # RTEMS supports Pthreads, but the library is not available at GCC build time.
+    ;;
+  *)
+    # Check to see if -pthread or -lpthread is needed.  Prefer the former.
+    # In case the pthread.h system header is not found, this test will fail.
+    CFLAGS="$CFLAGS -pthread"
+    AC_LINK_IFELSE(
+     [AC_LANG_PROGRAM(
+      [#include <pthread.h>
+       void *g(void *d) { return NULL; }],
+      [pthread_t t; pthread_create(&t,NULL,g,NULL);])],
+     [XPCFLAGS=" -Wc,-pthread"],
+     [CFLAGS="$save_CFLAGS" LIBS="-lpthread $LIBS"
+      AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+        [#include <pthread.h>
+         void *g(void *d) { return NULL; }],
+        [pthread_t t; pthread_create(&t,NULL,g,NULL);])],
+       [],
+       [AC_MSG_ERROR([Pthreads are required to build libgomp])])])
+esac
 
 m4_include([plugin/configfrag.ac])
 
diff --git a/libgomp/configure.tgt b/libgomp/configure.tgt
index ad98de1..2970f6f 100644
--- a/libgomp/configure.tgt
+++ b/libgomp/configure.tgt
@@ -20,6 +20,10 @@ if test $gcc_cv_have_tls = yes ; then
     *-*-linux* | *-*-gnu*)
 	XCFLAGS="${XCFLAGS} -ftls-model=initial-exec"
 	;;
+
+    *-*-rtems*)
+	XCFLAGS="${XCFLAGS} -ftls-model=local-exec"
+	;;
   esac
 fi
 
-- 
1.8.4.5