A Configure test for C11 thread local storage specificer, _Thread_local

We also provbe for gcc's earlier syntax, __thread.

1 files changed, 127 insertions, 0 deletions

diff --git a/Configure b/Configure
index 08f2445a40..5879d7a233 100755
--- a/Configure
+++ b/Configure
@@ -860,6 +860,8 @@ d_statfs_f_flags=''
 d_statfs_s=''
 d_static_inline=''
 perl_static_inline=''
+d_thread_local=''
+perl_thread_local=''
 d_fstatvfs=''
 d_statvfs=''
 d_stdio_cnt_lval=''
@@ -19231,6 +19233,129 @@ eval $setvar
 $rm -f a.[co] b.[co]
 $rm_try
 
+: see what flavor, if any, of thread local storage is supported
+echo " "
+echo "Checking to see if your system supports C11 thread local storage..."
+$cat > try.c <<'EOCP'
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+static int plus_one = 1;
+static int minus_one = -1;
+
+PROBE_MACRO int *minion;
+
+int callback (const void *a, const void *b) {
+    int val_a = *minion * *(const int *)a;
+    int val_b = *minion * *(const int *)b;
+    return val_a < val_b ? -1 : val_a > val_b;
+}
+
+#define SIZE 8
+
+void *thread_function(void *arg) {
+    /* thread local variables should start zeroed in each thread. */
+    if (minion != NULL) {
+        fprintf(stderr, "__thread variable started with %p, should be NULL\n",
+                minion);
+        exit(2);
+    }
+    minion = &minus_one;
+
+    int array[SIZE];
+    unsigned int i;
+    for (i = 0; i < SIZE; ++i) {
+        /* "Hash randomisation" - this array isn't in sorted order: */
+        array[i ^ 5] = i * i;
+    }
+
+    qsort(array, SIZE, sizeof(int), callback);
+
+    int bad = 0;
+    for (i = 0; i < SIZE; ++i) {
+        int want = (SIZE - 1 - i) * (SIZE - 1 - i);
+        int have = array[i];
+        if (want != have) {
+            ++bad;
+            fprintf(stderr, "array[%u] - want %i, have %i\n", i, want, have);
+        }
+    }
+    if (bad)
+        exit(3);
+
+    return NULL;
+}
+
+int main(int argc, char **argv) {
+    if (minion != NULL) {
+        fprintf(stderr, "__thread variable started with %p, should be NULL\n",
+                minion);
+        exit(4);
+    }
+
+    minion = &plus_one;
+
+    pthread_t tid;
+    int result = pthread_create(&tid, NULL, thread_function, NULL);
+    if (result) {
+        fprintf(stderr, "pthread_create failed (%d)\n", result);
+        exit(5);
+    }
+
+    result = pthread_join(tid, NULL);
+    if (result) {
+        fprintf(stderr, "pthread_join failed (%d)\n", result);
+        exit(6);
+    }
+
+    if (minion == NULL) {
+        fprintf(stderr, "__thread variable should not be NULL\n");
+        exit(7);
+    }
+    if (!(minion == &plus_one && *minion == 1)) {
+        fprintf(stderr, "__thread variable should be %d @ %p, not %d @ %p\n",
+                1, &plus_one, *minion, minion);
+        exit(8);
+    }
+
+    return 0;
+}
+EOCP
+
+# Respect a hint (or previous) value for perl_thread_local, if there is one.
+case "$perl_thread_local" in
+'')	# Check the various possibilities, and break out on success.
+	for thread_local in _Thread_local __thread; do
+		set try -DPROBE_MACRO=$thread_local
+		if eval $compile && $run ./try; then
+			$echo "Your compiler supports $thread_local." >&4
+			val=$define
+			perl_thread_local="$thread_local";
+			break;
+		fi
+		$echo "Your compiler does NOT support $thread_local." >&4
+		val="$undef"
+	done
+	;;
+*thread*|*Thread*) # Some variant of thread local exists.
+	echo "Keeping your $hint value of $perl_thread_local."
+	val=$define
+	;;
+*)  # Unrecognized previous value -- blindly trust the supplied
+	# value and hope it makes sense.  Use old value for
+	# d_thread_local, if there is one.
+	echo "Keeping your $hint value of $perl_thread_local."
+	case "$d_thread_local" in
+		'') val=$define ;;
+		*)  val=$d_thread_local ;;
+	esac
+	;;
+esac
+set d_thread_local
+eval $setvar
+$rm_try
+
 : Check stream access
 $cat >&4 <<EOM
 Checking how to access stdio streams by file descriptor number...
@@ -24883,6 +25008,7 @@ d_tcsetpgrp='$d_tcsetpgrp'
 d_telldir='$d_telldir'
 d_telldirproto='$d_telldirproto'
 d_tgamma='$d_tgamma'
+d_thread_local='$d_thread_local'
 d_thread_safe_nl_langinfo_l='$d_thread_safe_nl_langinfo_l'
 d_time='$d_time'
 d_timegm='$d_timegm'
@@ -25258,6 +25384,7 @@ perl5='$perl5'
 perl='$perl'
 perl_patchlevel='$perl_patchlevel'
 perl_static_inline='$perl_static_inline'
+perl_thread_local='$perl_thread_local'
 perladmin='$perladmin'
 perllibs='$perllibs'
 perlpath='$perlpath'