Revert "[perl #126410] keep the DESTROY cache in mro_meta"

This reverts commit 971809a61a634661b679cfedb722bf989b33d0d5.

4 files changed, 20 insertions, 30 deletions

diff --git a/ext/B/t/sv_stash.t b/ext/B/t/sv_stash.t
index e9abf4d55d..eaaabcf8fe 100644
--- a/ext/B/t/sv_stash.t
+++ b/ext/B/t/sv_stash.t
@@ -14,6 +14,7 @@ plan 1;
 # RT #126410 = used to coredump when doing SvSTASH on %version::
 
 TODO: {
+    local $TODO = 'Broken since c07f9fb2c7 - revert of a revert: slowed down detruction with no DESTROY';
     fresh_perl_is(
         'use B; version->new("v5.22.0"); $s = B::svref_2object(\%version::); $s->SvSTASH; print "ok\n"',
         "ok\n", { stderr => 1 }, 'RT #126410 - SvSTASH against %version::'
diff --git a/hv.h b/hv.h
index 1d873f4e2e..9533af58f2 100644
--- a/hv.h
+++ b/hv.h
@@ -82,7 +82,6 @@ struct mro_meta {
     const struct mro_alg *mro_which; /* which mro alg is in use? */
     HV      *isa;            /* Everything this class @ISA */
     HV      *super;          /* SUPER method cache */
-    CV      *destroy;        /* DESTROY method if destroy_gen non-zero */
     U32     destroy_gen;     /* Generation number of DESTROY cache */
 };
 
diff --git a/mro_core.c b/mro_core.c
index e15d47fea3..25d30d9067 100644
--- a/mro_core.c
+++ b/mro_core.c
@@ -191,10 +191,6 @@ Perl_mro_meta_dup(pTHX_ struct mro_meta* smeta, CLONE_PARAMS* param)
 
     newmeta->super = NULL;
 
-    /* clear the destructor cache */
-    newmeta->destroy = NULL;
-    newmeta->destroy_gen = 0;
-
     return newmeta;
 }
 
@@ -542,8 +538,8 @@ Perl_mro_isa_changed_in(pTHX_ HV* stash)
     /* pessimise derefs for now. Will get recalculated by Gv_AMupdate() */
     HvAUX(stash)->xhv_aux_flags &= ~HvAUXf_NO_DEREF;
 
-    /* DESTROY can be cached in meta. */
-    meta->destroy_gen = 0;
+    /* DESTROY can be cached in SvSTASH. */
+    if (!SvOBJECT(stash)) SvSTASH(stash) = NULL;
 
     /* Iterate the isarev (classes that are our children),
        wiping out their linearization, method and isa caches
@@ -1324,8 +1320,8 @@ Perl_mro_method_changed_in(pTHX_ HV *stash)
     /* Inc the package generation, since a local method changed */
     HvMROMETA(stash)->pkg_gen++;
 
-    /* DESTROY can be cached in meta */
-    HvMROMETA(stash)->destroy_gen = 0;
+    /* DESTROY can be cached in SvSTASH. */
+    if (!SvOBJECT(stash)) SvSTASH(stash) = NULL;
 
     /* If stash is UNIVERSAL, or one of UNIVERSAL's parents,
        invalidate all method caches globally */
@@ -1350,7 +1346,7 @@ Perl_mro_method_changed_in(pTHX_ HV *stash)
             mrometa->cache_gen++;
             if(mrometa->mro_nextmethod)
                 hv_clear(mrometa->mro_nextmethod);
-            mrometa->destroy_gen = 0;
+            if (!SvOBJECT(revstash)) SvSTASH(revstash) = NULL;
         }
     }
 
diff --git a/sv.c b/sv.c
index 4d80d6d775..263d27bedc 100644
--- a/sv.c
+++ b/sv.c
@@ -6890,31 +6890,25 @@ S_curse(pTHX_ SV * const sv, const bool check_refcnt) {
 	  assert(SvTYPE(stash) == SVt_PVHV);
 	  if (HvNAME(stash)) {
 	    CV* destructor = NULL;
-            struct mro_meta *meta;
 	    assert (SvOOK(stash));
-
-            DEBUG_o( Perl_deb(aTHX_ "Looking for DESTROY method for %s\n",
-                         HvNAME(stash)) );
-
-            /* don't make this an initialization above the assert, since it needs
-               an AUX structure */
-            meta = HvMROMETA(stash);
-            if (meta->destroy_gen && meta->destroy_gen == PL_sub_generation) {
-                destructor = meta->destroy;
-                DEBUG_o( Perl_deb(aTHX_ "Using cached DESTROY method %p for %s\n",
-                             (void *)destructor, HvNAME(stash)) );
-            }
-            else {
+	    if (!SvOBJECT(stash)) destructor = (CV *)SvSTASH(stash);
+	    if (!destructor || HvMROMETA(stash)->destroy_gen
+				!= PL_sub_generation)
+	    {
 		GV * const gv =
 		    gv_fetchmeth_autoload(stash, "DESTROY", 7, 0);
 		if (gv) destructor = GvCV(gv);
-                meta->destroy_gen = PL_sub_generation;
-                meta->destroy = destructor;
-                DEBUG_o( Perl_deb(aTHX_ "Set cached DESTROY method %p for %s\n",
-                             (void *)destructor, HvNAME(stash)) );
+		if (!SvOBJECT(stash))
+		{
+		    SvSTASH(stash) =
+			destructor ? (HV *)destructor : ((HV *)0)+1;
+		    HvAUX(stash)->xhv_mro_meta->destroy_gen =
+			PL_sub_generation;
+		}
 	    }
-	    assert(!destructor || SvTYPE(destructor) == SVt_PVCV);
-	    if (destructor
+	    assert(!destructor || destructor == ((CV *)0)+1
+		|| SvTYPE(destructor) == SVt_PVCV);
+	    if (destructor && destructor != ((CV *)0)+1
 		/* A constant subroutine can have no side effects, so
 		   don't bother calling it.  */
 		&& !CvCONST(destructor)