Block the GC while executing a proxied method

Proxy runs methods on the target with the target's interp. If GC is triggered during this run, the foreign interp's GC could find our PMCs on the call stack. It would also not find any PMCs which are on the foreign interp's callstack. And most of all it could be that the foreign interp also starts collecting garbage at the same time... So we block the foreign GC to prevent this from happening.
parrot · Mar 11, 2012 · 97254da · 97254da
1 parent 5165f6a
commit 97254da
Showing 1 changed file with 8 additions and 1 deletion.
diff --git a/lib/Parrot/Pmc2c/PMC/Proxy.pm b/lib/Parrot/Pmc2c/PMC/Proxy.pm
@@ -89,7 +89,14 @@ sub _generate_proxy_method {
 
     my $body = $method->return_type eq 'PMC*'
         ? <<BODY
-    PMC * result = $call;
+    PMC * result;
+   
+    /* otherwise the GC could find foreign PMCs on the stack */
+    Parrot_block_GC_mark(proxied_interp);
+
+    result = $call;
+
+    Parrot_unblock_GC_mark(proxied_interp);
 
     return (PMC_IS_NULL(result)
         ? PMCNULL