[VxWorks] Allow --enable-threads=posix

[rbmj <rbmj at verizon dot net>]

Some builds of VxWorks have a pthread compatibility layer.  This patch 
allows one to compile GCC to use the pthread compatibility layer instead 
of the native vxworks threads.

I wrote this patch to get the c++11 threads to work - the vxworks native 
support don't implement all the necessary features, and it was much 
easier to use posix threads rather than add the necessary native thread 
support.

I do not have commit access, so someone would have to apply this for me.

Everything builds correctly, and users report success.

It does dirty up ghtr-posix.h a bit, but it doesn't appear to be too 
bad, and there's other platform-specific hacks in that file already.

Thanks,

R Blair Mason

>From 2cf34e06f47345884f234bb870714ed2896745a6 Mon Sep 17 00:00:00 2001
From: rbmj <rbmj@verizon.net>
Date: Sat, 4 Jan 2014 09:11:02 -0500
Subject: [PATCH] Allowed posix as a thread option for vxworks

Note: VxWorks defines all of the _POSIX_TIMERS functions, but doesn't
define the macro.  Configure looks for the _POSIX_TIMERS macro when
checking for these functions.  This seems strange to me.  It seems like
if the try_compile can find them, then everything should be fine.
I'm not an expert though, and acinclude.m4 notes that there is a similar
situation for darwin, so I'll just let it be this way for now.
---
 gcc/config.gcc                              |  1 +
 libgcc/config.host                          |  8 ++++++
 libgcc/config/t-vxworks-pthread             | 14 +++++++++++
 libgcc/gthr-posix.h                         | 38 ++++++++++++++++++++++++++++-
 libstdc++-v3/config/os/vxworks/os_defines.h |  3 +++
 5 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 libgcc/config/t-vxworks-pthread

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 92d57dd..3fd9bb5 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -804,6 +804,7 @@ case ${target} in
   case ${enable_threads} in
     no) ;;
     "" | yes | vxworks) thread_file='vxworks' ;;
+    posix) thread_file='posix' ;;
     *) echo 'Unknown thread configuration for VxWorks'; exit 1 ;;
   esac
   ;;
diff --git a/libgcc/config.host b/libgcc/config.host
index 259c9a7..21471db 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -261,6 +261,14 @@ case ${host} in
   ;;
 *-*-vxworks*)
   tmake_file=t-vxworks
+  case ${target_thread_file} in
+    vxworks)
+      tmake_file=t-vxworks
+      ;;
+    posix)
+      tmake_file=t-vxworks-pthread
+	  ;;
+  esac
   ;;
 *-*-elf)
   extra_parts="crtbegin.o crtend.o"
diff --git a/libgcc/config/t-vxworks-pthread b/libgcc/config/t-vxworks-pthread
new file mode 100644
index 0000000..4e538f9
--- /dev/null
+++ b/libgcc/config/t-vxworks-pthread
@@ -0,0 +1,14 @@
+# Don't build libgcc.a with debug info
+LIBGCC2_DEBUG_CFLAGS =
+
+# No out-of line help needed
+LIB2ADD = 
+
+# This ensures that the correct target headers are used; some
+# VxWorks system headers have names that collide with GCC's
+# internal (host) headers, e.g. regs.h.
+LIBGCC2_INCLUDES = -nostdinc -I \
+  `case "/$$(MULTIDIR)" in \
+     */mrtp*) echo $(WIND_USR)/h ;; \
+     *) echo $(WIND_BASE)/target/h ;; \
+   esac`
diff --git a/libgcc/gthr-posix.h b/libgcc/gthr-posix.h
index f0d8cd7..b6a6069 100644
--- a/libgcc/gthr-posix.h
+++ b/libgcc/gthr-posix.h
@@ -33,6 +33,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define __GTHREADS_CXX0X 1
 
 #include <pthread.h>
+/* For timespec, in case pthread.h doesn't include this */
+#include <time.h>
+/* For sched_yield, in case pthread.h doesn't include this */
+#include <sched.h>
 
 #if ((defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)) \
      || !defined(_GTHREAD_USE_MUTEX_TIMEDLOCK))
@@ -130,10 +134,42 @@ __gthrw(pthread_cond_destroy)
 
 __gthrw(pthread_key_create)
 __gthrw(pthread_key_delete)
+
 __gthrw(pthread_mutexattr_init)
-__gthrw(pthread_mutexattr_settype)
 __gthrw(pthread_mutexattr_destroy)
 
+/* VxWorks does not define pthread_mutexattr_settype itself, and we need
+   the constants and a prototype to be defined somewhere so the rest of 
+   this file will compile (they will be ignored) */
+#ifdef __VXWORKS__
+
+#define ATTRIBUTE_UNUSED __attribute__((unused))
+
+static inline int
+__gthrw_pthread_mutexattr_settype (pthread_mutexattr_t *a ATTRIBUTE_UNUSED, int t ATTRIBUTE_UNUSED)
+{
+  /* TODO:  It might be possible to override the mutex machinery to
+     simulate non-recursive mutexes, but this doesn't seem to be
+     necessary because all vxworks mutexes are recursive, and recursive
+     mutexes cover the most general case. */
+  return 0;
+}
+
+#undef ATTRIBUTE_UNUSED
+
+#define PTHREAD_MUTEX_NORMAL 0
+#define PTHREAD_MUTEX_ERRORCHECK 0
+#define PTHREAD_MUTEX_RECURSIVE 0
+#define PTHREAD_MUTEX_DEFAULT 0
+
+#else
+
+__gthrw(pthread_mutexattr_settype)
+
+#endif 
+
+
+
 
 #if defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)
 /* Objective-C.  */
diff --git a/libstdc++-v3/config/os/vxworks/os_defines.h b/libstdc++-v3/config/os/vxworks/os_defines.h
index de2522e..edb6693 100644
--- a/libstdc++-v3/config/os/vxworks/os_defines.h
+++ b/libstdc++-v3/config/os/vxworks/os_defines.h
@@ -39,4 +39,7 @@
 #endif
 #define NOMINMAX 1
 
+#define _GLIBCXX_USE_NANOSLEEP 1
+#define _GLIBCXX_USE_CLOCK_REALTIME 1
+
 #endif
-- 
1.8.4.rc3