Fix SEGVs and test failures for -DPERL_GLOBAL_STRUCT_PRIVATE

With PERL_GLOBAL_STRUCT_PRIVATE "global" variables are in a structure in
malloc()ed memory, not in global static variables or a global static
structure. Hence no global variables are implicitly initialised to zero.

* PL_curinterp and PL_op_sequence need initialising to NULL
* The global structure is free()d before handlers registered with atexit()
  run, so be defensive about this.
* Some C code checks SvOK(PL_sv_placeholder) so ensure that its SvFLAGS()
  are 0.
* Zero PL_hash_seed

1 files changed, 4 insertions, 0 deletions

diff --git a/util.c b/util.c
index ffd41b9044..f09cd92c1d 100644
--- a/util.c
+++ b/util.c
@@ -5456,6 +5456,10 @@ Perl_init_global_struct(pTHX)
 #  ifdef PERL_SET_VARS
     PERL_SET_VARS(plvarsp);
 #  endif
+#  ifdef PERL_GLOBAL_STRUCT_PRIVATE
+    plvarsp->Gsv_placeholder.sv_flags = 0;
+    memset(plvarsp->Ghash_seed, 0, sizeof(plvarsp->Ghash_seed));
+#  endif
 # undef PERL_GLOBAL_STRUCT_INIT
 # endif
     return plvarsp;