From: Nicholas Clark <nick@ccl4.org>
Date: Mon, 30 Jan 2006 12:59:12 +0000 (+0000)
Subject: Use a union for storing the shared hash key reference count, rather
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=de61663159118b735969bec9539d9251323990fa;p=p5sagit%2Fp5-mst-13.2.git

Use a union for storing the shared hash key reference count, rather
than messy pointer hacks.

p4raw-id: //depot/perl@27000
---

diff --git a/ext/XS/APItest/APItest.xs b/ext/XS/APItest/APItest.xs
index c2a6478..c8391c6 100644
--- a/ext/XS/APItest/APItest.xs
+++ b/ext/XS/APItest/APItest.xs
@@ -86,7 +86,7 @@ test_freeent(freeent_function *f) {
 
     test_scalar = newSV(0);
     SvREFCNT_inc(test_scalar);
-    victim->hent_val = test_scalar;
+    HeVAL(victim) = test_scalar;
 
     /* Need this little game else we free the temps on the return stack.  */
     results[0] = SvREFCNT(test_scalar);
diff --git a/hv.c b/hv.c
index c458f56..0ab2558 100644
--- a/hv.c
+++ b/hv.c
@@ -2279,8 +2279,8 @@ S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
 	assert (he->shared_he_he.hent_hek == hek);
 
 	LOCK_STRTAB_MUTEX;
-	if (he->shared_he_he.hent_val - 1) {
-	    --he->shared_he_he.hent_val;
+	if (he->shared_he_he.he_valu.hent_refcount - 1) {
+	    --he->shared_he_he.he_valu.hent_refcount;
 	    UNLOCK_STRTAB_MUTEX;
 	    return;
 	}
@@ -2299,7 +2299,7 @@ S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
             k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
     }
 
-    /* what follows is the moral equivalent of:
+    /* what follows was the moral equivalent of:
     if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
 	if (--*Svp == Nullsv)
 	    hv_delete(PL_strtab, str, len, G_DISCARD, hash);
@@ -2333,7 +2333,7 @@ S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
     }
 
     if (found) {
-        if (--HeVAL(entry) == Nullsv) {
+        if (--he->shared_he_he.he_valu.hent_refcount == 0) {
             *oentry = HeNEXT(entry);
             if (!*first) {
 		/* There are now no entries in our slot.  */
@@ -2449,7 +2449,7 @@ S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
 	/* Still "point" to the HEK, so that other code need not know what
 	   we're up to.  */
 	HeKEY_hek(entry) = hek;
-	HeVAL(entry) = Nullsv;
+	entry->he_valu.hent_refcount = 0;
 	HeNEXT(entry) = next;
 	*head = entry;
 
@@ -2461,7 +2461,7 @@ S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
 	}
     }
 
-    ++HeVAL(entry);				/* use value slot as REFCNT */
+    ++entry->he_valu.hent_refcount;
     UNLOCK_STRTAB_MUTEX;
 
     if (flags & HVhek_FREEKEY)
diff --git a/hv.h b/hv.h
index d0ac0e8..fd0cf2e 100644
--- a/hv.h
+++ b/hv.h
@@ -15,7 +15,10 @@ struct he {
        body arenas  */
     HE		*hent_next;	/* next entry in chain */
     HEK		*hent_hek;	/* hash key */
-    SV		*hent_val;	/* scalar value that was hashed */
+    union {
+	SV	*hent_val;	/* scalar value that was hashed */
+	Size_t	hent_refcount;	/* references for this shared hash key */
+    } he_valu;
 };
 
 /* hash key -- defined separately for use as shared pointer */
@@ -291,7 +294,7 @@ C<SV*>.
 #define HeKREHASH(he)  HEK_REHASH(HeKEY_hek(he))
 #define HeKLEN_UTF8(he)  (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
 #define HeKFLAGS(he)  HEK_FLAGS(HeKEY_hek(he))
-#define HeVAL(he)		(he)->hent_val
+#define HeVAL(he)		(he)->he_valu.hent_val
 #define HeHASH(he)		HEK_HASH(HeKEY_hek(he))
 #define HePV(he,lp)		((HeKLEN(he) == HEf_SVKEY) ?		\
 				 SvPV(HeKEY_sv(he),lp) :		\
@@ -372,7 +375,7 @@ C<SV*>.
     (++(((struct shared_he *)(((char *)hek)				\
 			      - STRUCT_OFFSET(struct shared_he,		\
 					      shared_he_hek)))		\
-	->shared_he_he.hent_val),					\
+	->shared_he_he.he_valu.hent_refcount),				\
      hek)
 
 /*
diff --git a/perl.c b/perl.c
index 82960f3..e9f7795 100644
--- a/perl.c
+++ b/perl.c
@@ -1100,7 +1100,7 @@ perl_destruct(pTHXx)
 		HE * const next = HeNEXT(hent);
 		Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
 		     "Unbalanced string table refcount: (%ld) for \"%s\"",
-		     (long)(HeVAL(hent) - Nullsv), HeKEY(hent));
+		     (long)hent->he_valu.hent_refcount, HeKEY(hent));
 		Safefree(hent);
 		hent = next;
 	    }