Make refcounts atomic for threading (dependent on appropriate

arch-dependent and compiler-dependent definitions in atomic.h
or else falls back to a global mutex to protect refcounts).

p4raw-id: //depot/perl@598

1 files changed, 5 insertions, 2 deletions

diff --git a/sv.c b/sv.c
index 0edfdb2453..af74e28e0c 100644
--- a/sv.c
+++ b/sv.c
@@ -2870,13 +2870,15 @@ SV *
 sv_newref(SV *sv)
 {
     if (sv)
-	SvREFCNT(sv)++;
+	ATOMIC_INC(SvREFCNT(sv));
     return sv;
 }
 
 void
 sv_free(SV *sv)
 {
+    int refcount_is_zero;
+
     if (!sv)
 	return;
     if (SvREADONLY(sv)) {
@@ -2891,7 +2893,8 @@ sv_free(SV *sv)
 	warn("Attempt to free unreferenced scalar");
 	return;
     }
-    if (--SvREFCNT(sv) > 0)
+    ATOMIC_DEC_AND_TEST(refcount_is_zero, SvREFCNT(sv));
+    if (!refcount_is_zero)
 	return;
 #ifdef DEBUGGING
     if (SvTEMP(sv)) {