try to fix Linux build problems related to pthreads

svn: r18776

src/configure

@@ -2258,6 +2258,7 @@ show_explicitly_disabled "${enable_foreign}" Foreign
 
 show_explicitly_enabled "${enable_places}" Places
 show_explicitly_enabled "${enable_futures}" Futures
+show_explicitly_disabled "${enable_futures}" Futures
 
 show_explicitly_enabled "${enable_sgc}" SGC
 show_explicitly_enabled "${enable_sgcdebug}" "SGC debug mode"
@@ -10760,6 +10761,67 @@ cat >>confdefs.h <<\_ACEOF
 #define USE_PTHREAD_INSTEAD_OF_ITIMER 1
 _ACEOF
 
+
+ msg="whether pthread_rwlock is available"
+  { echo "$as_me:$LINENO: checking $msg" >&5
+echo $ECHO_N "checking $msg... $ECHO_C" >&6; }
+  if test "$cross_compiling" = yes; then
+  rwlockavail=no
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+  #include <pthread.h>
+   pthread_rwlock_t l;
+   int main() {
+     return pthread_rwlock_init(&l, NULL);
+   }
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  rwlockavail=yes
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+rwlockavail=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+  { echo "$as_me:$LINENO: result: $rwlockavail" >&5
+echo "${ECHO_T}$rwlockavail" >&6; }
+  if test "$rwlockavail" = "yes" ; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_PTHREAD_RWLOCK 1
+_ACEOF
+
+  fi
 fi
 
 ################ Xrender ##################

src/mzscheme/configure.ac

@@ -296,6 +296,7 @@ show_explicitly_disabled "${enable_foreign}" Foreign
 
 show_explicitly_enabled "${enable_places}" Places
 show_explicitly_enabled "${enable_futures}" Futures
+show_explicitly_disabled "${enable_futures}" Futures
 
 show_explicitly_enabled "${enable_sgc}" SGC
 show_explicitly_enabled "${enable_sgcdebug}" "SGC debug mode"
@@ -1178,6 +1179,19 @@ if test "${enable_pthread}" = "yes" ; then
   PREFLAGS="$PREFLAGS -pthread"
   LDFLAGS="$LDFLAGS -pthread"
   AC_DEFINE(USE_PTHREAD_INSTEAD_OF_ITIMER, 1, [Pthread timer enabled])
+
+[ msg="whether pthread_rwlock is available"   ]
+  AC_MSG_CHECKING($msg)
+  AC_TRY_RUN(
+[  #include <pthread.h>]
+   pthread_rwlock_t l;
+   int main() {
+     return pthread_rwlock_init(&l, NULL);
+   }, rwlockavail=yes, rwlockavail=no, rwlockavail=no)
+  AC_MSG_RESULT($rwlockavail)
+  if test "$rwlockavail" = "yes" ; then
+    AC_DEFINE(HAVE_PTHREAD_RWLOCK,1,[Have pthread_rwlock])
+  fi
 fi
 
 ################ Xrender ##################

src/mzscheme/include/schthread.h

@@ -30,7 +30,7 @@ extern "C" {
 # if _MSC_VER
 #  define THREAD_LOCAL /* empty */
 #  define IMPLEMENT_THREAD_LOCAL_VIA_WIN_TLS
-# elif defined(OS_X) || (defined(linux) && defined(MZ_USES_SHARED_LIB))
+# elif defined(OS_X)
 #  define IMPLEMENT_THREAD_LOCAL_VIA_PTHREADS
 #  if defined(__x86_64__) || defined(__i386__)
 #   define INLINE_GETSPECIFIC_ASSEMBLY_CODE
@@ -306,7 +306,7 @@ static inline Thread_Local_Variables *scheme_get_thread_local_variables() {
 #   else
   asm volatile("movl %%gs:0x48(,%1,4), %0" : "=r"(x) : "r"(scheme_thread_local_key));
 #   endif
-#  elif defined(linux) && defined(MZ_USES_SHARED_LIB)
+#  elif defined(linux)
 #   if defined(__x86_64__)
   asm volatile( "mov %1, %%eax;" 
   "shl $0x4, %%rax;"

src/mzscheme/mzconfig.h.in

@@ -35,6 +35,9 @@
 /* Whether __attribute__ ((noinline)) works */
 #undef MZ_USE_NOINLINE
 
+/* Whether pthread_rwlock is availabale: */
+#undef HAVE_PTHREAD_RWLOCK
+
 /* Enable futures and/or places: */
 #undef MZ_USE_FUTURES
 #undef MZ_USE_PLACES

src/mzscheme/src/mzrt.c

@@ -290,6 +290,8 @@ void mz_proc_thread_exit(void *rc) {
 
 #ifndef WIN32
 
+# ifdef HAVE_PTHREAD_RWLOCK
+
 struct mzrt_rwlock {
   pthread_rwlock_t lock;
 };
@@ -322,6 +324,142 @@ int mzrt_rwlock_destroy(mzrt_rwlock *lock) {
   return pthread_rwlock_destroy(&lock->lock);
 }
 
+# else
+
+struct mzrt_rwlock {
+  pthread_mutex_t m;
+  pthread_cond_t cr, cw;
+  int readers, writers, write_waiting;
+};
+
+static mzrt_rwlock *locks[2];
+
+static void *go(void *id)
+{
+  int i = *(int *)id, j, amt;
+
+  for (j = 0; j < 3; j++) {
+    amt = (random() % 400) + 100;
+    usleep(amt - 100);
+    if (!(i % 3)) {
+      mzrt_rwlock_wrlock(locks[0]);
+      printf("writing %d\n", i);
+      usleep(amt);
+      mzrt_rwlock_unlock(locks[0]);
+    } else {
+      mzrt_rwlock_rdlock(locks[0]);
+      printf("reading %d\n", i);
+      usleep(amt);
+      mzrt_rwlock_unlock(locks[0]);
+    }
+    printf("done %d\n", i);
+  }
+
+  return NULL;
+}
+
+int mzrt_rwlock_create(mzrt_rwlock **lock) {
+  int err;
+
+  *lock = malloc(sizeof(mzrt_rwlock));
+  err = pthread_mutex_init(&(*lock)->m, NULL);
+  if (err) { free(*lock); return err; }
+  err = pthread_cond_init(&(*lock)->cr, NULL);
+  if (err) { free(*lock); return err; }
+  err = pthread_cond_init(&(*lock)->cw, NULL);
+  if (err) { free(*lock); return err; }
+  return err;
+}
+
+static int rwlock_rdlock(mzrt_rwlock *lock, int just_try) {
+  int err;
+
+  err = pthread_mutex_lock(&lock->m);
+  if (err) return err;
+  while (lock->writers || lock->write_waiting) {
+    if (just_try) {
+      err = pthread_mutex_unlock(&lock->m);
+      if (err) return err;
+      return EBUSY;
+    } else {
+      err = pthread_cond_wait(&lock->cr, &lock->m);
+      if (err)
+        return err;
+    }
+  }
+  lock->readers++;
+  return pthread_mutex_unlock(&lock->m);
+}
+
+int mzrt_rwlock_rdlock(mzrt_rwlock *lock) {
+  return rwlock_rdlock(lock, 0);
+}
+
+static int rwlock_wrlock(mzrt_rwlock *lock, int just_try) {
+  int err;
+
+  err = pthread_mutex_lock(&lock->m);
+  if (err) return err;
+  while (lock->writers || lock->readers) {
+    if (just_try) {
+      err = pthread_mutex_unlock(&lock->m);
+      if (err) return err;
+      return EBUSY;
+    } else {
+      lock->write_waiting++;
+      err = pthread_cond_wait(&lock->cw, &lock->m);
+      --lock->write_waiting;
+      if (err)
+        return err;
+    }
+  }
+  lock->writers++;
+  return pthread_mutex_unlock(&lock->m);
+}
+
+int mzrt_rwlock_wrlock(mzrt_rwlock *lock) {
+  return rwlock_wrlock(lock, 0);
+}
+
+int mzrt_rwlock_tryrdlock(mzrt_rwlock *lock) {
+  return rwlock_rdlock(lock, 1);
+}
+
+int mzrt_rwlock_trywrlock(mzrt_rwlock *lock) {
+  return rwlock_wrlock(lock, 1);
+}
+
+int mzrt_rwlock_unlock(mzrt_rwlock *lock) {
+  int err;
+
+  err = pthread_mutex_lock(&lock->m);
+  if (err) return err;
+
+  if (lock->readers)
+    --lock->readers; /* must have been a read lock */
+  else
+    --lock->writers;
+
+  if (lock->write_waiting)
+    err = pthread_cond_signal(&lock->cw);
+  else
+    err = pthread_cond_broadcast(&lock->cr);
+  if (err) return err;
+  
+  return pthread_mutex_unlock(&lock->m);
+}
+
+int mzrt_rwlock_destroy(mzrt_rwlock *lock) {
+  pthread_mutex_destroy(&lock->m);
+  pthread_cond_destroy(&lock->cr);
+  pthread_cond_destroy(&lock->cw);
+  free(lock);
+
+  return 0;
+}
+
+# endif
+
 struct mzrt_mutex {
   pthread_mutex_t mutex;
 };