[perl #117855] Store CopFILEGV in a pad under ithreads

This saves having to allocate a separate string buffer for every cop
(control op; every statement has one).

Under non-threaded builds, every cop has a pointer to the GV for that
source file, namely *{"_<filename"}.

Under threaded builds, the name of the GV used to be stored instead.

Now we store an offset into the per-interpreter PL_filegvpad, which
points to the GV.

This makes no significant speed difference, but it reduces mem-
ory usage.

1 files changed, 5 insertions, 0 deletions

diff --git a/scope.c b/scope.c
index 3ac3990fff..24645909d7 100644
--- a/scope.c
+++ b/scope.c
@@ -1231,6 +1231,11 @@ Perl_leave_scope(pTHX_ I32 base)
 	case SAVEt_READONLY_OFF:
 	    SvREADONLY_off(ARG0_SV);
 	    break;
+#ifdef USE_ITHREADS
+	case SAVEt_COPFILEFREE:
+	    CopFILE_free((COP *)ARG0_PTR);
+	    break;
+#endif
 	default:
 	    Perl_croak(aTHX_ "panic: leave_scope inconsistency %u", type);
 	}