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[perl5.git] / hv.c
diff --git a/hv.c b/hv.c
index 09b1b3f..9523fb0 100644 (file)
--- a/hv.c
+++ b/hv.c
@@ -1,7 +1,7 @@
 /*    hv.c
  *
  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- *    2000, 2001, 2002, 2003, 2004, 2005, 2006, by Larry Wall and others
+ *    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, by Larry Wall and others
  *
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
@@ -40,12 +40,9 @@ STATIC void
 S_more_he(pTHX)
 {
     dVAR;
-    HE* he;
-    HE* heend;
-
-    he = (HE*) Perl_get_arena(aTHX_ PERL_ARENA_SIZE);
+    HE* he = (HE*) Perl_get_arena(aTHX_ PERL_ARENA_SIZE, HE_SVSLOT);
+    HE * const heend = &he[PERL_ARENA_SIZE / sizeof(HE) - 1];
 
-    heend = &he[PERL_ARENA_SIZE / sizeof(HE) - 1];
     PL_body_roots[HE_SVSLOT] = he;
     while (he < heend) {
        HeNEXT(he) = (HE*)(he + 1);
@@ -68,23 +65,19 @@ S_new_he(pTHX)
     HE* he;
     void ** const root = &PL_body_roots[HE_SVSLOT];
 
-    LOCK_SV_MUTEX;
     if (!*root)
        S_more_he(aTHX);
-    he = *root;
+    he = (HE*) *root;
     assert(he);
     *root = HeNEXT(he);
-    UNLOCK_SV_MUTEX;
     return he;
 }
 
 #define new_HE() new_he()
 #define del_HE(p) \
     STMT_START { \
-       LOCK_SV_MUTEX; \
        HeNEXT(p) = (HE*)(PL_body_roots[HE_SVSLOT]);    \
        PL_body_roots[HE_SVSLOT] = p; \
-       UNLOCK_SV_MUTEX; \
     } STMT_END
 
 
@@ -104,7 +97,7 @@ S_save_hek_flags(const char *str, I32 len, U32 hash, int flags)
     HEK_KEY(hek)[len] = 0;
     HEK_LEN(hek) = len;
     HEK_HASH(hek) = hash;
-    HEK_FLAGS(hek) = (unsigned char)flags_masked;
+    HEK_FLAGS(hek) = (unsigned char)flags_masked | HVhek_UNSHARED;
 
     if (flags & HVhek_FREEKEY)
        Safefree(str);
@@ -214,17 +207,12 @@ S_hv_notallowed(pTHX_ int flags, const char *key, I32 klen,
     if (flags & HVhek_UTF8) {
        SvUTF8_on(sv);
     }
-    Perl_croak(aTHX_ msg, sv);
+    Perl_croak(aTHX_ msg, SVfARG(sv));
 }
 
 /* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
  * contains an SV* */
 
-#define HV_FETCH_ISSTORE   0x01
-#define HV_FETCH_ISEXISTS  0x02
-#define HV_FETCH_LVALUE    0x04
-#define HV_FETCH_JUST_SV   0x08
-
 /*
 =for apidoc hv_store
 
@@ -248,39 +236,6 @@ hv_store_ent.
 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
 information on how to use this function on tied hashes.
 
-=cut
-*/
-
-SV**
-Perl_hv_store(pTHX_ HV *hv, const char *key, I32 klen_i32, SV *val, U32 hash)
-{
-    HE *hek;
-    STRLEN klen;
-    int flags;
-
-    if (klen_i32 < 0) {
-       klen = -klen_i32;
-       flags = HVhek_UTF8;
-    } else {
-       klen = klen_i32;
-       flags = 0;
-    }
-    hek = hv_fetch_common (hv, NULL, key, klen, flags,
-                          (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
-    return hek ? &HeVAL(hek) : NULL;
-}
-
-/* XXX This looks like an ideal candidate to inline */
-SV**
-Perl_hv_store_flags(pTHX_ HV *hv, const char *key, I32 klen, SV *val,
-                 register U32 hash, int flags)
-{
-    HE * const hek = hv_fetch_common (hv, NULL, key, klen, flags,
-                              (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
-    return hek ? &HeVAL(hek) : NULL;
-}
-
-/*
 =for apidoc hv_store_ent
 
 Stores C<val> in a hash.  The hash key is specified as C<key>.  The C<hash>
@@ -306,43 +261,11 @@ hv_store in preference to hv_store_ent.
 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
 information on how to use this function on tied hashes.
 
-=cut
-*/
-
-/* XXX This looks like an ideal candidate to inline */
-HE *
-Perl_hv_store_ent(pTHX_ HV *hv, SV *keysv, SV *val, U32 hash)
-{
-  return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISSTORE, val, hash);
-}
-
-/*
 =for apidoc hv_exists
 
 Returns a boolean indicating whether the specified hash key exists.  The
 C<klen> is the length of the key.
 
-=cut
-*/
-
-bool
-Perl_hv_exists(pTHX_ HV *hv, const char *key, I32 klen_i32)
-{
-    STRLEN klen;
-    int flags;
-
-    if (klen_i32 < 0) {
-       klen = -klen_i32;
-       flags = HVhek_UTF8;
-    } else {
-       klen = klen_i32;
-       flags = 0;
-    }
-    return hv_fetch_common(hv, NULL, key, klen, flags, HV_FETCH_ISEXISTS, 0, 0)
-       ? TRUE : FALSE;
-}
-
-/*
 =for apidoc hv_fetch
 
 Returns the SV which corresponds to the specified key in the hash.  The
@@ -353,30 +276,6 @@ dereferencing it to an C<SV*>.
 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
 information on how to use this function on tied hashes.
 
-=cut
-*/
-
-SV**
-Perl_hv_fetch(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 lval)
-{
-    HE *hek;
-    STRLEN klen;
-    int flags;
-
-    if (klen_i32 < 0) {
-       klen = -klen_i32;
-       flags = HVhek_UTF8;
-    } else {
-       klen = klen_i32;
-       flags = 0;
-    }
-    hek = hv_fetch_common (hv, NULL, key, klen, flags,
-                          lval ? (HV_FETCH_JUST_SV | HV_FETCH_LVALUE) : HV_FETCH_JUST_SV,
-                          NULL, 0);
-    return hek ? &HeVAL(hek) : NULL;
-}
-
-/*
 =for apidoc hv_exists_ent
 
 Returns a boolean indicating whether the specified hash key exists. C<hash>
@@ -386,14 +285,6 @@ computed.
 =cut
 */
 
-/* XXX This looks like an ideal candidate to inline */
-bool
-Perl_hv_exists_ent(pTHX_ HV *hv, SV *keysv, U32 hash)
-{
-    return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISEXISTS, 0, hash)
-       ? TRUE : FALSE;
-}
-
 /* returns an HE * structure with the all fields set */
 /* note that hent_val will be a mortal sv for MAGICAL hashes */
 /*
@@ -413,16 +304,27 @@ information on how to use this function on tied hashes.
 =cut
 */
 
-HE *
-Perl_hv_fetch_ent(pTHX_ HV *hv, SV *keysv, I32 lval, register U32 hash)
+/* Common code for hv_delete()/hv_exists()/hv_fetch()/hv_store()  */
+void *
+Perl_hv_common_key_len(pTHX_ HV *hv, const char *key, I32 klen_i32,
+                      const int action, SV *val, const U32 hash)
 {
-    return hv_fetch_common(hv, keysv, NULL, 0, 0, 
-                          (lval ? HV_FETCH_LVALUE : 0), NULL, hash);
+    STRLEN klen;
+    int flags;
+
+    if (klen_i32 < 0) {
+       klen = -klen_i32;
+       flags = HVhek_UTF8;
+    } else {
+       klen = klen_i32;
+       flags = 0;
+    }
+    return hv_common(hv, NULL, key, klen, flags, action, val, hash);
 }
 
-STATIC HE *
-S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
-                 int flags, int action, SV *val, register U32 hash)
+void *
+Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
+              int flags, int action, SV *val, register U32 hash)
 {
     dVAR;
     XPVHV* xhv;
@@ -431,10 +333,40 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
     SV *sv;
     bool is_utf8;
     int masked_flags;
+    const int return_svp = action & HV_FETCH_JUST_SV;
 
     if (!hv)
        return NULL;
+    if (SvTYPE(hv) == SVTYPEMASK)
+       return NULL;
+
+    assert(SvTYPE(hv) == SVt_PVHV);
+
+    if (SvSMAGICAL(hv) && SvGMAGICAL(hv) && !(action & HV_DISABLE_UVAR_XKEY)) {
+       MAGIC* mg;
+       if ((mg = mg_find((SV*)hv, PERL_MAGIC_uvar))) {
+           struct ufuncs * const uf = (struct ufuncs *)mg->mg_ptr;
+           if (uf->uf_set == NULL) {
+               SV* obj = mg->mg_obj;
 
+               if (!keysv) {
+                   keysv = sv_2mortal(newSVpvn(key, klen));
+                   if (flags & HVhek_UTF8)
+                       SvUTF8_on(keysv);
+               }
+               
+               mg->mg_obj = keysv;         /* pass key */
+               uf->uf_index = action;      /* pass action */
+               magic_getuvar((SV*)hv, mg);
+               keysv = mg->mg_obj;         /* may have changed */
+               mg->mg_obj = obj;
+
+               /* If the key may have changed, then we need to invalidate
+                  any passed-in computed hash value.  */
+               hash = 0;
+           }
+       }
+    }
     if (keysv) {
        if (flags & HVhek_FREEKEY)
            Safefree(key);
@@ -445,15 +377,19 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
        is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
     }
 
+    if (action & HV_DELETE) {
+       return (void *) hv_delete_common(hv, keysv, key, klen,
+                                        flags | (is_utf8 ? HVhek_UTF8 : 0),
+                                        action, hash);
+    }
+
     xhv = (XPVHV*)SvANY(hv);
     if (SvMAGICAL(hv)) {
        if (SvRMAGICAL(hv) && !(action & (HV_FETCH_ISSTORE|HV_FETCH_ISEXISTS))) {
-           if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
-               sv = sv_newmortal();
-
-               /* XXX should be able to skimp on the HE/HEK here when
+           if ( mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv))
+           {
+               /* FIXME should be able to skimp on the HE/HEK here when
                   HV_FETCH_JUST_SV is true.  */
-
                if (!keysv) {
                    keysv = newSVpvn(key, klen);
                    if (is_utf8) {
@@ -462,7 +398,8 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
                } else {
                    keysv = newSVsv(keysv);
                }
-               mg_copy((SV*)hv, sv, (char *)keysv, HEf_SVKEY);
+                sv = sv_newmortal();
+                mg_copy((SV*)hv, sv, (char *)keysv, HEf_SVKEY);
 
                /* grab a fake HE/HEK pair from the pool or make a new one */
                entry = PL_hv_fetch_ent_mh;
@@ -486,7 +423,10 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
                if (flags & HVhek_FREEKEY)
                    Safefree(key);
 
-               return entry;
+               if (return_svp) {
+                   return entry ? (void *) &HeVAL(entry) : NULL;
+               }
+               return (void *) entry;
            }
 #ifdef ENV_IS_CASELESS
            else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
@@ -498,23 +438,27 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
                        const char * const nkey = strupr(savepvn(key,klen));
                        /* Note that this fetch is for nkey (the uppercased
                           key) whereas the store is for key (the original)  */
-                       entry = hv_fetch_common(hv, NULL, nkey, klen,
-                                               HVhek_FREEKEY, /* free nkey */
-                                               0 /* non-LVAL fetch */,
-                                               NULL /* no value */,
-                                               0 /* compute hash */);
-                       if (!entry && (action & HV_FETCH_LVALUE)) {
+                       void *result = hv_common(hv, NULL, nkey, klen,
+                                                HVhek_FREEKEY, /* free nkey */
+                                                0 /* non-LVAL fetch */
+                                                | HV_DISABLE_UVAR_XKEY
+                                                | return_svp,
+                                                NULL /* no value */,
+                                                0 /* compute hash */);
+                       if (!result && (action & HV_FETCH_LVALUE)) {
                            /* This call will free key if necessary.
                               Do it this way to encourage compiler to tail
                               call optimise.  */
-                           entry = hv_fetch_common(hv, keysv, key, klen,
-                                                   flags, HV_FETCH_ISSTORE,
-                                                   newSV(0), hash);
+                           result = hv_common(hv, keysv, key, klen, flags,
+                                              HV_FETCH_ISSTORE
+                                              | HV_DISABLE_UVAR_XKEY
+                                              | return_svp,
+                                              newSV(0), hash);
                        } else {
                            if (flags & HVhek_FREEKEY)
                                Safefree(key);
                        }
-                       return entry;
+                       return result;
                    }
            }
 #endif
@@ -543,7 +487,7 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
                /* This cast somewhat evil, but I'm merely using NULL/
                   not NULL to return the boolean exists.
                   And I know hv is not NULL.  */
-               return SvTRUE(svret) ? (HE *)hv : NULL;
+               return SvTRUE(svret) ? (void *)hv : NULL;
                }
 #ifdef ENV_IS_CASELESS
            else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
@@ -632,7 +576,7 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
             if (flags & HVhek_FREEKEY)
                 Safefree(key);
 
-           return 0;
+           return NULL;
        }
     }
 
@@ -748,6 +692,9 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
        }
        if (flags & HVhek_FREEKEY)
            Safefree(key);
+       if (return_svp) {
+           return entry ? (void *) &HeVAL(entry) : NULL;
+       }
        return entry;
     }
 #ifdef DYNAMIC_ENV_FETCH  /* %ENV lookup?  If so, try to fetch the value now */
@@ -758,8 +705,9 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
        if (env) {
            sv = newSVpvn(env,len);
            SvTAINTED_on(sv);
-           return hv_fetch_common(hv,keysv,key,klen,flags,HV_FETCH_ISSTORE,sv,
-                                  hash);
+           return hv_common(hv, keysv, key, klen, flags,
+                            HV_FETCH_ISSTORE|HV_DISABLE_UVAR_XKEY|return_svp,
+                            sv, hash);
        }
     }
 #endif
@@ -773,7 +721,7 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
        /* Not doing some form of store, so return failure.  */
        if (flags & HVhek_FREEKEY)
            Safefree(key);
-       return 0;
+       return NULL;
     }
     if (action & HV_FETCH_LVALUE) {
        val = newSV(0);
@@ -782,8 +730,15 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
               which in turn might do some tied magic. So we need to make that
               magic check happen.  */
            /* gonna assign to this, so it better be there */
-           return hv_fetch_common(hv, keysv, key, klen, flags,
-                                  HV_FETCH_ISSTORE, val, hash);
+           /* If a fetch-as-store fails on the fetch, then the action is to
+              recurse once into "hv_store". If we didn't do this, then that
+              recursive call would call the key conversion routine again.
+              However, as we replace the original key with the converted
+              key, this would result in a double conversion, which would show
+              up as a bug if the conversion routine is not idempotent.  */
+           return hv_common(hv, keysv, key, klen, flags,
+                            HV_FETCH_ISSTORE|HV_DISABLE_UVAR_XKEY|return_svp,
+                            val, hash);
            /* XXX Surely that could leak if the fetch-was-store fails?
               Just like the hv_fetch.  */
        }
@@ -854,7 +809,10 @@ S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
        }
     }
 
-    return entry;
+    if (return_svp) {
+       return entry ? (void *) &HeVAL(entry) : NULL;
+    }
+    return (void *) entry;
 }
 
 STATIC void
@@ -912,26 +870,6 @@ hash and returned to the caller.  The C<klen> is the length of the key.
 The C<flags> value will normally be zero; if set to G_DISCARD then NULL
 will be returned.
 
-=cut
-*/
-
-SV *
-Perl_hv_delete(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 flags)
-{
-    STRLEN klen;
-    int k_flags;
-
-    if (klen_i32 < 0) {
-       klen = -klen_i32;
-       k_flags = HVhek_UTF8;
-    } else {
-       klen = klen_i32;
-       k_flags = 0;
-    }
-    return hv_delete_common(hv, NULL, key, klen, k_flags, flags, 0);
-}
-
-/*
 =for apidoc hv_delete_ent
 
 Deletes a key/value pair in the hash.  The value SV is removed from the
@@ -942,13 +880,6 @@ precomputed hash value, or 0 to ask for it to be computed.
 =cut
 */
 
-/* XXX This looks like an ideal candidate to inline */
-SV *
-Perl_hv_delete_ent(pTHX_ HV *hv, SV *keysv, I32 flags, U32 hash)
-{
-    return hv_delete_common(hv, keysv, NULL, 0, 0, flags, hash);
-}
-
 STATIC SV *
 S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
                   int k_flags, I32 d_flags, U32 hash)
@@ -958,22 +889,9 @@ S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
     register HE *entry;
     register HE **oentry;
     HE *const *first_entry;
-    bool is_utf8;
+    bool is_utf8 = (k_flags & HVhek_UTF8) ? TRUE : FALSE;
     int masked_flags;
 
-    if (!hv)
-       return NULL;
-
-    if (keysv) {
-       if (k_flags & HVhek_FREEKEY)
-           Safefree(key);
-       key = SvPV_const(keysv, klen);
-       k_flags = 0;
-       is_utf8 = (SvUTF8(keysv) != 0);
-    } else {
-       is_utf8 = ((k_flags & HVhek_UTF8) ? TRUE : FALSE);
-    }
-
     if (SvRMAGICAL(hv)) {
        bool needs_copy;
        bool needs_store;
@@ -981,9 +899,10 @@ S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
 
        if (needs_copy) {
            SV *sv;
-           entry = hv_fetch_common(hv, keysv, key, klen,
-                                   k_flags & ~HVhek_FREEKEY, HV_FETCH_LVALUE,
-                                   NULL, hash);
+           entry = (HE *) hv_common(hv, keysv, key, klen,
+                                    k_flags & ~HVhek_FREEKEY,
+                                    HV_FETCH_LVALUE|HV_DISABLE_UVAR_XKEY,
+                                    NULL, hash);
            sv = entry ? HeVAL(entry) : NULL;
            if (sv) {
                if (SvMAGICAL(sv)) {
@@ -1130,7 +1049,7 @@ STATIC void
 S_hsplit(pTHX_ HV *hv)
 {
     dVAR;
-    register XPVHV* xhv = (XPVHV*)SvANY(hv);
+    register XPVHV* const xhv = (XPVHV*)SvANY(hv);
     const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
     register I32 newsize = oldsize * 2;
     register I32 i;
@@ -1141,7 +1060,7 @@ S_hsplit(pTHX_ HV *hv)
     int was_shared;
 
     /*PerlIO_printf(PerlIO_stderr(), "hsplit called for %p which had %d\n",
-      hv, (int) oldsize);*/
+      (void*)hv, (int) oldsize);*/
 
     if (HvPLACEHOLDERS_get(hv) && !SvREADONLY(hv)) {
       /* Can make this clear any placeholders first for non-restricted hashes,
@@ -1237,7 +1156,7 @@ S_hsplit(pTHX_ HV *hv)
     }
 
     /* Awooga. Awooga. Pathological data.  */
-    /*PerlIO_printf(PerlIO_stderr(), "%p %d of %d with %d/%d buckets\n", hv,
+    /*PerlIO_printf(PerlIO_stderr(), "%p %d of %d with %d/%d buckets\n", (void*)hv,
       longest_chain, HvTOTALKEYS(hv), HvFILL(hv),  1+HvMAX(hv));*/
 
     ++newsize;
@@ -1386,33 +1305,6 @@ Perl_hv_ksplit(pTHX_ HV *hv, IV newmax)
     }
 }
 
-/*
-=for apidoc newHV
-
-Creates a new HV.  The reference count is set to 1.
-
-=cut
-*/
-
-HV *
-Perl_newHV(pTHX)
-{
-    register XPVHV* xhv;
-    HV * const hv = (HV*)newSV(0);
-
-    sv_upgrade((SV *)hv, SVt_PVHV);
-    xhv = (XPVHV*)SvANY(hv);
-    SvPOK_off(hv);
-    SvNOK_off(hv);
-#ifndef NODEFAULT_SHAREKEYS
-    HvSHAREKEYS_on(hv);         /* key-sharing on by default */
-#endif
-
-    xhv->xhv_max    = 7;       /* HvMAX(hv) = 7 (start with 8 buckets) */
-    xhv->xhv_fill   = 0;       /* HvFILL(hv) = 0 */
-    return hv;
-}
-
 HV *
 Perl_newHVhv(pTHX_ HV *ohv)
 {
@@ -1481,9 +1373,9 @@ Perl_newHVhv(pTHX_ HV *ohv)
 
        hv_iterinit(ohv);
        while ((entry = hv_iternext_flags(ohv, 0))) {
-           hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
-                           newSVsv(HeVAL(entry)), HeHASH(entry),
-                           HeKFLAGS(entry));
+           (void)hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
+                                newSVsv(HeVAL(entry)), HeHASH(entry),
+                                HeKFLAGS(entry));
        }
        HvRITER_set(ohv, riter);
        HvEITER_set(ohv, eiter);
@@ -1515,8 +1407,8 @@ Perl_hv_copy_hints_hv(pTHX_ HV *const ohv)
            SV *const sv = newSVsv(HeVAL(entry));
            sv_magic(sv, NULL, PERL_MAGIC_hintselem,
                     (char *)newSVhek (HeKEY_hek(entry)), HEf_SVKEY);
-           hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
-                          sv, HeHASH(entry), HeKFLAGS(entry));
+           (void)hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
+                                sv, HeHASH(entry), HeKFLAGS(entry));
        }
        HvRITER_set(ohv, riter);
        HvEITER_set(ohv, eiter);
@@ -1534,8 +1426,8 @@ Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
     if (!entry)
        return;
     val = HeVAL(entry);
-    if (val && isGV(val) && GvCVu(val) && HvNAME_get(hv))
-       PL_sub_generation++;    /* may be deletion of method from stash */
+    if (val && isGV(val) && isGV_with_GP(val) && GvCVu(val) && HvNAME_get(hv))
+        mro_method_changed_in(hv);     /* deletion of method from stash */
     SvREFCNT_dec(val);
     if (HeKLEN(entry) == HEf_SVKEY) {
        SvREFCNT_dec(HeKEY_sv(entry));
@@ -1593,8 +1485,8 @@ Perl_hv_clear(pTHX_ HV *hv)
                    if (HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
                        SV* const keysv = hv_iterkeysv(entry);
                        Perl_croak(aTHX_
-       "Attempt to delete readonly key '%"SVf"' from a restricted hash",
-                                  keysv);
+                                  "Attempt to delete readonly key '%"SVf"' from a restricted hash",
+                                  (void*)keysv);
                    }
                    SvREFCNT_dec(HeVAL(entry));
                    HeVAL(entry) = &PL_sv_placeholder;
@@ -1608,8 +1500,7 @@ Perl_hv_clear(pTHX_ HV *hv)
     hfreeentries(hv);
     HvPLACEHOLDERS_set(hv, 0);
     if (HvARRAY(hv))
-       (void)memzero(HvARRAY(hv),
-                     (xhv->xhv_max+1 /* HvMAX(hv)+1 */) * sizeof(HE*));
+       Zero(HvARRAY(hv), xhv->xhv_max+1 /* HvMAX(hv)+1 */, HE*);
 
     if (SvRMAGICAL(hv))
        mg_clear((SV*)hv);
@@ -1618,6 +1509,8 @@ Perl_hv_clear(pTHX_ HV *hv)
     HvREHASH_off(hv);
     reset:
     if (SvOOK(hv)) {
+        if(HvNAME_get(hv))
+            mro_isa_changed_in(hv);
        HvEITER_set(hv, NULL);
     }
 }
@@ -1695,11 +1588,11 @@ STATIC void
 S_hfreeentries(pTHX_ HV *hv)
 {
     /* This is the array that we're going to restore  */
-    HE **orig_array;
+    HE **const orig_array = HvARRAY(hv);
     HEK *name;
     int attempts = 100;
 
-    if (!HvARRAY(hv))
+    if (!orig_array)
        return;
 
     if (SvOOK(hv)) {
@@ -1713,7 +1606,6 @@ S_hfreeentries(pTHX_ HV *hv)
        name = NULL;
     }
 
-    orig_array = HvARRAY(hv);
     /* orig_array remains unchanged throughout the loop. If after freeing all
        the entries it turns out that one of the little blighters has triggered
        an action that has caused HvARRAY to be re-allocated, then we set
@@ -1732,6 +1624,7 @@ S_hfreeentries(pTHX_ HV *hv)
 
        if (SvOOK(hv)) {
            HE *entry;
+            struct mro_meta *meta;
            struct xpvhv_aux *iter = HvAUX(hv);
            /* If there are weak references to this HV, we need to avoid
               freeing them up here.  In particular we need to keep the AV
@@ -1763,6 +1656,14 @@ S_hfreeentries(pTHX_ HV *hv)
            iter->xhv_riter = -1;       /* HvRITER(hv) = -1 */
            iter->xhv_eiter = NULL;     /* HvEITER(hv) = NULL */
 
+            if((meta = iter->xhv_mro_meta)) {
+                if(meta->mro_linear_dfs) SvREFCNT_dec(meta->mro_linear_dfs);
+                if(meta->mro_linear_c3)  SvREFCNT_dec(meta->mro_linear_c3);
+                if(meta->mro_nextmethod) SvREFCNT_dec(meta->mro_nextmethod);
+                Safefree(meta);
+                iter->xhv_mro_meta = NULL;
+            }
+
            /* There are now no allocated pointers in the aux structure.  */
 
            SvFLAGS(hv) &= ~SVf_OOK; /* Goodbye, aux structure.  */
@@ -1846,10 +1747,14 @@ Perl_hv_undef(pTHX_ HV *hv)
        return;
     DEBUG_A(Perl_hv_assert(aTHX_ hv));
     xhv = (XPVHV*)SvANY(hv);
+
+    if ((name = HvNAME_get(hv)) && !PL_dirty)
+        mro_isa_changed_in(hv);
+
     hfreeentries(hv);
-    if ((name = HvNAME_get(hv))) {
-        if(PL_stashcache)
-           hv_delete(PL_stashcache, name, HvNAMELEN_get(hv), G_DISCARD);
+    if (name) {
+        if (PL_stashcache)
+           (void)hv_delete(PL_stashcache, name, HvNAMELEN_get(hv), G_DISCARD);
        hv_name_set(hv, NULL, 0, 0);
     }
     SvFLAGS(hv) &= ~SVf_OOK;
@@ -1884,6 +1789,7 @@ S_hv_auxinit(HV *hv) {
     iter->xhv_eiter = NULL;    /* HvEITER(hv) = NULL */
     iter->xhv_name = 0;
     iter->xhv_backreferences = 0;
+    iter->xhv_mro_meta = NULL;
     return iter;
 }
 
@@ -2009,7 +1915,7 @@ Perl_hv_name_set(pTHX_ HV *hv, const char *name, U32 len, U32 flags)
        iter = hv_auxinit(hv);
     }
     PERL_HASH(hash, name, len);
-    iter->xhv_name = name ? share_hek(name, len, hash) : 0;
+    iter->xhv_name = name ? share_hek(name, len, hash) : NULL;
 }
 
 AV **
@@ -2075,6 +1981,7 @@ Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
 
     if (!hv)
        Perl_croak(aTHX_ "Bad hash");
+
     xhv = (XPVHV*)SvANY(hv);
 
     if (!SvOOK(hv)) {
@@ -2086,37 +1993,38 @@ Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
     iter = HvAUX(hv);
 
     oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
-
-    if ((mg = SvTIED_mg((SV*)hv, PERL_MAGIC_tied))) {
-       SV * const key = sv_newmortal();
-       if (entry) {
-           sv_setsv(key, HeSVKEY_force(entry));
-           SvREFCNT_dec(HeSVKEY(entry));       /* get rid of previous key */
-       }
-       else {
-           char *k;
-           HEK *hek;
-
-           /* one HE per MAGICAL hash */
-           iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
-           Zero(entry, 1, HE);
-           Newxz(k, HEK_BASESIZE + sizeof(SV*), char);
-           hek = (HEK*)k;
-           HeKEY_hek(entry) = hek;
-           HeKLEN(entry) = HEf_SVKEY;
-       }
-       magic_nextpack((SV*) hv,mg,key);
-       if (SvOK(key)) {
-           /* force key to stay around until next time */
-           HeSVKEY_set(entry, SvREFCNT_inc_simple_NN(key));
-           return entry;               /* beware, hent_val is not set */
-       }
-       if (HeVAL(entry))
-           SvREFCNT_dec(HeVAL(entry));
-       Safefree(HeKEY_hek(entry));
-       del_HE(entry);
-       iter->xhv_eiter = NULL; /* HvEITER(hv) = NULL */
-       return NULL;
+    if (SvMAGICAL(hv) && SvRMAGICAL(hv)) {
+       if ( ( mg = mg_find((SV*)hv, PERL_MAGIC_tied) ) ) {
+            SV * const key = sv_newmortal();
+            if (entry) {
+                sv_setsv(key, HeSVKEY_force(entry));
+                SvREFCNT_dec(HeSVKEY(entry));       /* get rid of previous key */
+            }
+            else {
+                char *k;
+                HEK *hek;
+
+                /* one HE per MAGICAL hash */
+                iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
+                Zero(entry, 1, HE);
+                Newxz(k, HEK_BASESIZE + sizeof(SV*), char);
+                hek = (HEK*)k;
+                HeKEY_hek(entry) = hek;
+                HeKLEN(entry) = HEf_SVKEY;
+            }
+            magic_nextpack((SV*) hv,mg,key);
+            if (SvOK(key)) {
+                /* force key to stay around until next time */
+                HeSVKEY_set(entry, SvREFCNT_inc_simple_NN(key));
+                return entry;               /* beware, hent_val is not set */
+            }
+            if (HeVAL(entry))
+                SvREFCNT_dec(HeVAL(entry));
+            Safefree(HeKEY_hek(entry));
+            del_HE(entry);
+            iter->xhv_eiter = NULL; /* HvEITER(hv) = NULL */
+            return NULL;
+        }
     }
 #if defined(DYNAMIC_ENV_FETCH) && !defined(__riscos__)  /* set up %ENV for iteration */
     if (!entry && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
@@ -2177,7 +2085,7 @@ Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
     }
 
     /*if (HvREHASH(hv) && entry && !HeKREHASH(entry))
-      PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", hv, entry);*/
+      PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", (void*)hv, (void*)entry);*/
 
     iter->xhv_eiter = entry; /* HvEITER(hv) = entry */
     return entry;
@@ -2293,6 +2201,7 @@ Perl_unsharepvn(pTHX_ const char *str, I32 len, U32 hash)
 void
 Perl_unshare_hek(pTHX_ HEK *hek)
 {
+    assert(hek);
     unshare_hek_or_pvn(hek, NULL, 0, 0);
 }
 
@@ -2553,10 +2462,49 @@ Perl_hv_placeholders_set(pTHX_ HV *hv, I32 ph)
     /* else we don't need to add magic to record 0 placeholders.  */
 }
 
+STATIC SV *
+S_refcounted_he_value(pTHX_ const struct refcounted_he *he)
+{
+    dVAR;
+    SV *value;
+    switch(he->refcounted_he_data[0] & HVrhek_typemask) {
+    case HVrhek_undef:
+       value = newSV(0);
+       break;
+    case HVrhek_delete:
+       value = &PL_sv_placeholder;
+       break;
+    case HVrhek_IV:
+       value = newSViv(he->refcounted_he_val.refcounted_he_u_iv);
+       break;
+    case HVrhek_UV:
+       value = newSVuv(he->refcounted_he_val.refcounted_he_u_uv);
+       break;
+    case HVrhek_PV:
+    case HVrhek_PV_UTF8:
+       /* Create a string SV that directly points to the bytes in our
+          structure.  */
+       value = newSV_type(SVt_PV);
+       SvPV_set(value, (char *) he->refcounted_he_data + 1);
+       SvCUR_set(value, he->refcounted_he_val.refcounted_he_u_len);
+       /* This stops anything trying to free it  */
+       SvLEN_set(value, 0);
+       SvPOK_on(value);
+       SvREADONLY_on(value);
+       if ((he->refcounted_he_data[0] & HVrhek_typemask) == HVrhek_PV_UTF8)
+           SvUTF8_on(value);
+       break;
+    default:
+       Perl_croak(aTHX_ "panic: refcounted_he_value bad flags %x",
+                  he->refcounted_he_data[0]);
+    }
+    return value;
+}
+
 /*
 =for apidoc refcounted_he_chain_2hv
 
-Generates an returns a C<HV *> by walking up the tree starting at the passed
+Generates and returns a C<HV *> by walking up the tree starting at the passed
 in C<struct refcounted_he *>.
 
 =cut
@@ -2564,6 +2512,7 @@ in C<struct refcounted_he *>.
 HV *
 Perl_refcounted_he_chain_2hv(pTHX_ const struct refcounted_he *chain)
 {
+    dVAR;
     HV *hv = newHV();
     U32 placeholders = 0;
     /* We could chase the chain once to get an idea of the number of keys,
@@ -2589,7 +2538,26 @@ Perl_refcounted_he_chain_2hv(pTHX_ const struct refcounted_he *chain)
 
        for (; entry; entry = HeNEXT(entry)) {
            if (HeHASH(entry) == hash) {
-               goto next_please;
+               /* We might have a duplicate key here.  If so, entry is older
+                  than the key we've already put in the hash, so if they are
+                  the same, skip adding entry.  */
+#ifdef USE_ITHREADS
+               const STRLEN klen = HeKLEN(entry);
+               const char *const key = HeKEY(entry);
+               if (klen == chain->refcounted_he_keylen
+                   && (!!HeKUTF8(entry)
+                       == !!(chain->refcounted_he_data[0] & HVhek_UTF8))
+                   && memEQ(key, REF_HE_KEY(chain), klen))
+                   goto next_please;
+#else
+               if (HeKEY_hek(entry) == chain->refcounted_he_hek)
+                   goto next_please;
+               if (HeKLEN(entry) == HEK_LEN(chain->refcounted_he_hek)
+                   && HeKUTF8(entry) == HEK_UTF8(chain->refcounted_he_hek)
+                   && memEQ(HeKEY(entry), HEK_KEY(chain->refcounted_he_hek),
+                            HeKLEN(entry)))
+                   goto next_please;
+#endif
            }
        }
        assert (!entry);
@@ -2597,11 +2565,7 @@ Perl_refcounted_he_chain_2hv(pTHX_ const struct refcounted_he *chain)
 
 #ifdef USE_ITHREADS
        HeKEY_hek(entry)
-           = share_hek_flags(/* A big expression to find the key offset */
-                             (((chain->refcounted_he_data[0]
-                                & HVrhek_typemask) == HVrhek_PV)
-                              ? chain->refcounted_he_val.refcounted_he_u_len
-                              + 1 : 0) + 1 + chain->refcounted_he_data,
+           = share_hek_flags(REF_HE_KEY(chain),
                              chain->refcounted_he_keylen,
                              chain->refcounted_he_hash,
                              (chain->refcounted_he_data[0]
@@ -2609,38 +2573,9 @@ Perl_refcounted_he_chain_2hv(pTHX_ const struct refcounted_he *chain)
 #else
        HeKEY_hek(entry) = share_hek_hek(chain->refcounted_he_hek);
 #endif
-
-       switch(chain->refcounted_he_data[0] & HVrhek_typemask) {
-       case HVrhek_undef:
-           value = newSV(0);
-           break;
-       case HVrhek_delete:
-           value = &PL_sv_placeholder;
+       value = refcounted_he_value(chain);
+       if (value == &PL_sv_placeholder)
            placeholders++;
-           break;
-       case HVrhek_IV:
-           value = (chain->refcounted_he_data[0] & HVrhek_UV)
-               ? newSVuv(chain->refcounted_he_val.refcounted_he_u_iv)
-               : newSViv(chain->refcounted_he_val.refcounted_he_u_uv);
-           break;
-       case HVrhek_PV:
-           /* Create a string SV that directly points to the bytes in our
-              structure.  */
-           value = newSV(0);
-           sv_upgrade(value, SVt_PV);
-           SvPV_set(value, (char *) chain->refcounted_he_data + 1);
-           SvCUR_set(value, chain->refcounted_he_val.refcounted_he_u_len);
-           /* This stops anything trying to free it  */
-           SvLEN_set(value, 0);
-           SvPOK_on(value);
-           SvREADONLY_on(value);
-           if (chain->refcounted_he_data[0] & HVrhek_UTF8)
-               SvUTF8_on(value);
-           break;
-       default:
-           Perl_croak(aTHX_ "panic: refcounted_he_chain_2hv bad flags %x",
-                      chain->refcounted_he_data[0]);
-       }
        HeVAL(entry) = value;
 
        /* Link it into the chain.  */
@@ -2671,13 +2606,71 @@ Perl_refcounted_he_chain_2hv(pTHX_ const struct refcounted_he *chain)
     return hv;
 }
 
+SV *
+Perl_refcounted_he_fetch(pTHX_ const struct refcounted_he *chain, SV *keysv,
+                        const char *key, STRLEN klen, int flags, U32 hash)
+{
+    dVAR;
+    /* Just to be awkward, if you're using this interface the UTF-8-or-not-ness
+       of your key has to exactly match that which is stored.  */
+    SV *value = &PL_sv_placeholder;
+    bool is_utf8;
+
+    if (keysv) {
+       if (flags & HVhek_FREEKEY)
+           Safefree(key);
+       key = SvPV_const(keysv, klen);
+       flags = 0;
+       is_utf8 = (SvUTF8(keysv) != 0);
+    } else {
+       is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
+    }
+
+    if (!hash) {
+       if (keysv && (SvIsCOW_shared_hash(keysv))) {
+            hash = SvSHARED_HASH(keysv);
+        } else {
+            PERL_HASH(hash, key, klen);
+        }
+    }
+
+    for (; chain; chain = chain->refcounted_he_next) {
+#ifdef USE_ITHREADS
+       if (hash != chain->refcounted_he_hash)
+           continue;
+       if (klen != chain->refcounted_he_keylen)
+           continue;
+       if (memNE(REF_HE_KEY(chain),key,klen))
+           continue;
+       if (!!is_utf8 != !!(chain->refcounted_he_data[0] & HVhek_UTF8))
+           continue;
+#else
+       if (hash != HEK_HASH(chain->refcounted_he_hek))
+           continue;
+       if (klen != (STRLEN)HEK_LEN(chain->refcounted_he_hek))
+           continue;
+       if (memNE(HEK_KEY(chain->refcounted_he_hek),key,klen))
+           continue;
+       if (!!is_utf8 != !!HEK_UTF8(chain->refcounted_he_hek))
+           continue;
+#endif
+
+       value = sv_2mortal(refcounted_he_value(chain));
+       break;
+    }
+
+    if (flags & HVhek_FREEKEY)
+       Safefree(key);
+
+    return value;
+}
+
 /*
 =for apidoc refcounted_he_new
 
-Creates a new C<struct refcounted_he>. Assumes ownership of one reference
-to I<value>. As S<key> is copied into a shared hash key, all references remain
-the property of the caller. The C<struct refcounted_he> is returned with a
-reference count of 1.
+Creates a new C<struct refcounted_he>. As S<key> is copied, and value is
+stored in a compact form, all references remain the property of the caller.
+The C<struct refcounted_he> is returned with a reference count of 1.
 
 =cut
 */
@@ -2685,16 +2678,17 @@ reference count of 1.
 struct refcounted_he *
 Perl_refcounted_he_new(pTHX_ struct refcounted_he *const parent,
                       SV *const key, SV *const value) {
+    dVAR;
     struct refcounted_he *he;
     STRLEN key_len;
     const char *key_p = SvPV_const(key, key_len);
     STRLEN value_len = 0;
-    const char *value_p;
+    const char *value_p = NULL;
     char value_type;
     char flags;
     STRLEN key_offset;
     U32 hash;
-    bool is_utf8 = SvUTF8(key);
+    bool is_utf8 = SvUTF8(key) ? TRUE : FALSE;
 
     if (SvPOK(value)) {
        value_type = HVrhek_PV;
@@ -2715,15 +2709,16 @@ Perl_refcounted_he_new(pTHX_ struct refcounted_he *const parent,
        value_len = 0;
        key_offset = 1;
     }
-    flags = value_type;
 
 #ifdef USE_ITHREADS
-    he = PerlMemShared_malloc(sizeof(struct refcounted_he) - 1
-                             + key_len
-                             + key_offset);
+    he = (struct refcounted_he*)
+       PerlMemShared_malloc(sizeof(struct refcounted_he) - 1
+                            + key_len
+                            + key_offset);
 #else
-    he = PerlMemShared_malloc(sizeof(struct refcounted_he) - 1
-                             + key_offset);
+    he = (struct refcounted_he*)
+       PerlMemShared_malloc(sizeof(struct refcounted_he) - 1
+                            + key_offset);
 #endif
 
 
@@ -2732,17 +2727,19 @@ Perl_refcounted_he_new(pTHX_ struct refcounted_he *const parent,
     if (value_type == HVrhek_PV) {
        Copy(value_p, he->refcounted_he_data + 1, value_len + 1, char);
        he->refcounted_he_val.refcounted_he_u_len = value_len;
-       if (SvUTF8(value)) {
-           flags |= HVrhek_UTF8;
-       }
+       /* Do it this way so that the SvUTF8() test is after the SvPV, in case
+          the value is overloaded, and doesn't yet have the UTF-8flag set.  */
+       if (SvUTF8(value))
+           value_type = HVrhek_PV_UTF8;
     } else if (value_type == HVrhek_IV) {
        if (SvUOK(value)) {
            he->refcounted_he_val.refcounted_he_u_uv = SvUVX(value);
-           flags |= HVrhek_UV;
+           value_type = HVrhek_UV;
        } else {
            he->refcounted_he_val.refcounted_he_u_iv = SvIVX(value);
        }
     }
+    flags = value_type;
 
     if (is_utf8) {
        /* Hash keys are always stored normalised to (yes) ISO-8859-1.
@@ -2785,6 +2782,7 @@ and C<refcounted_he_free> iterates onto the parent node.
 
 void
 Perl_refcounted_he_free(pTHX_ struct refcounted_he *he) {
+    dVAR;
     PERL_UNUSED_CONTEXT;
 
     while (he) {
@@ -2840,12 +2838,12 @@ Perl_hv_assert(pTHX_ HV *hv)
            real++;
        /* sanity check the keys */
        if (HeSVKEY(entry)) {
-           /*EMPTY*/ /* Don't know what to check on SV keys.  */
+           NOOP;   /* Don't know what to check on SV keys.  */
        } else if (HeKUTF8(entry)) {
            withflags++;
            if (HeKWASUTF8(entry)) {
                PerlIO_printf(Perl_debug_log,
-                           "hash key has both WASUFT8 and UTF8: '%.*s'\n",
+                           "hash key has both WASUTF8 and UTF8: '%.*s'\n",
                            (int) HeKLEN(entry),  HeKEY(entry));
                bad = 1;
            }