Re: [gomp4 7/8] libgomp: work around missing pthread_attr_t on nvptx

[Alexander Monakov <amonakov at ispras dot ru>]

> I'd prefer here the https://gcc.gnu.org/ml/gcc-patches/2015-04/msg01418.html
> changes to libgomp.h and associated configury changes.

OK, like the following?

[gomp4] libgomp: guard pthreads usage by LIBGOMP_USE_PTHREADS

This allows to avoid referencing pthread types and functions on nvptx.

	* configure.ac [nvptx*-*-*] (libgomp_use_pthreads): Set and use it...
        (LIBGOMP_USE_PTHREADS): ...here; new define.
        * configure: Regenerate.
        * config.h.in: Likewise.
        * libgomp.h: Guard pthread.h inclusion.
        (gomp_thread_attr): Guard by LIBGOMP_USE_PTHREADS.
        (gomp_init_thread_affinity): Ditto.
---
 libgomp/config.h.in  | 3 +++
 libgomp/configure    | 7 +++++++
 libgomp/configure.ac | 6 ++++++
 libgomp/libgomp.h    | 6 ++++++
 4 files changed, 22 insertions(+)

diff --git a/libgomp/config.h.in b/libgomp/config.h.in
index 7685bfb..ba64fd7 100644
--- a/libgomp/config.h.in
+++ b/libgomp/config.h.in
@@ -91,6 +91,9 @@
 /* Define to 1 if GNU symbol versioning is used for libgomp. */
 #undef LIBGOMP_GNU_SYMBOL_VERSIONING
 
+/* Define to 1 if libgomp should use POSIX threads. */
+#undef LIBGOMP_USE_PTHREADS
+
 /* Define to the sub-directory in which libtool stores uninstalled libraries.
    */
 #undef LT_OBJDIR
diff --git a/libgomp/configure b/libgomp/configure
index 7407b4c..de87d4a 100755
--- a/libgomp/configure
+++ b/libgomp/configure
@@ -15043,6 +15043,7 @@ case "$host" in
     ;;
   nvptx*-*-*)
     # NVPTX does not support Pthreads, has its own code replacement.
+    libgomp_use_pthreads=no
     ;;
   *)
     # Check to see if -pthread or -lpthread is needed.  Prefer the former.
@@ -15088,6 +15089,12 @@ rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 esac
 
+if test x$libgomp_use_pthreads != xno; then
+
+$as_echo "#define LIBGOMP_USE_PTHREADS 1" >>confdefs.h
+
+fi
+
 # Plugins for offload execution, configure.ac fragment.  -*- mode: autoconf -*-
 #
 # Copyright (C) 2014-2015 Free Software Foundation, Inc.
diff --git a/libgomp/configure.ac b/libgomp/configure.ac
index b1696d0..3bce745 100644
--- a/libgomp/configure.ac
+++ b/libgomp/configure.ac
@@ -181,6 +181,7 @@ case "$host" in
     ;;
   nvptx*-*-*)
     # NVPTX does not support Pthreads, has its own code replacement.
+    libgomp_use_pthreads=no
     ;;
   *)
     # Check to see if -pthread or -lpthread is needed.  Prefer the former.
@@ -202,6 +203,11 @@ case "$host" in
        [AC_MSG_ERROR([Pthreads are required to build libgomp])])])
 esac
 
+if test x$libgomp_use_pthreads != xno; then
+  AC_DEFINE(LIBGOMP_USE_PTHREADS, 1,
+            [Define to 1 if libgomp should use POSIX threads.])
+fi
+
 m4_include([plugin/configfrag.ac])
 
 # Check for functions needed.
diff --git a/libgomp/libgomp.h b/libgomp/libgomp.h
index d51b08b..1454adf 100644
--- a/libgomp/libgomp.h
+++ b/libgomp/libgomp.h
@@ -40,7 +40,9 @@
 #include "gstdint.h"
 #include "libgomp-plugin.h"
 
+#ifdef HAVE_PTHREAD_H
 #include <pthread.h>
+#endif
 #include <stdbool.h>
 #include <stdlib.h>
 #include <stdarg.h>
@@ -510,15 +512,19 @@ static inline struct gomp_task_icv *gomp_icv (bool write)
     return &gomp_global_icv;
 }
 
+#ifdef LIBGOMP_USE_PTHREADS
 /* The attributes to be used during thread creation.  */
 extern pthread_attr_t gomp_thread_attr;
+#endif
 
 /* Function prototypes.  */
 
 /* affinity.c */
 
 extern void gomp_init_affinity (void);
+#ifdef LIBGOMP_USE_PTHREADS
 extern void gomp_init_thread_affinity (pthread_attr_t *, unsigned int);
+#endif
 extern void **gomp_affinity_alloc (unsigned long, bool);
 extern void gomp_affinity_init_place (void *);
 extern bool gomp_affinity_add_cpus (void *, unsigned long, unsigned long,
-- 
1.8.3.1