UTF-8 support for distribution

19 files changed, 440 insertions, 194 deletions

diff --git a/erts/emulator/beam/atom.c b/erts/emulator/beam/atom.c
index b41a98f2a2..82dd320ea9 100644
--- a/erts/emulator/beam/atom.c
+++ b/erts/emulator/beam/atom.c
@@ -162,6 +162,7 @@ atom_alloc(Atom* tmpl)
     obj->name = atom_text_alloc(tmpl->len);
     sys_memcpy(obj->name, tmpl->name, tmpl->len);
     obj->len = tmpl->len;
+    obj->latin1_chars = tmpl->latin1_chars;
     obj->slot.index = -1;
 
     /*
@@ -192,48 +193,6 @@ atom_free(Atom* obj)
     erts_free(ERTS_ALC_T_ATOM, (void*) obj);
 }
 
-Eterm
-am_atom_put(const char* name, int len)
-{
-    Atom a;
-    Eterm ret;
-    int aix;
-#ifdef DEBUG
-    byte* err_pos;
-    Uint num_chars;
-    ASSERT(erts_analyze_utf8(name, len, &err_pos, &num_chars, NULL) == ERTS_UTF8_OK);
-#endif
-    /*
-     * Silently truncate the atom if it is too long. Overlong atoms
-     * could occur in situations where we have no good way to return
-     * an error, such as in the I/O system. (Unfortunately, many
-     * drivers don't check for errors.)
-     *
-     * If an error should be produced for overlong atoms (such in
-     * list_to_atom/1), the caller should check the length before
-     * calling this function.
-     */
-    if (len > MAX_ATOM_SZ_LIMIT) {
-	len = MAX_ATOM_SZ_LIMIT;  /*SVERK Urk... */
-    }
-#ifdef ERTS_ATOM_PUT_OPS_STAT
-    erts_smp_atomic_inc_nob(&atom_put_ops);
-#endif
-    a.len = len;
-    a.name = (byte*)name;
-    atom_read_lock();
-    aix = index_get(&erts_atom_table, (void*) &a);
-    atom_read_unlock();
-    if (aix >= 0)
-	ret = make_atom(aix);
-    else {
-	atom_write_lock();
-	ret = make_atom(index_put(&erts_atom_table, (void*) &a));
-	atom_write_unlock();
-    }
-    return ret;
-}
-
 static void latin1_to_utf8(byte* conv_buf, const byte** srcp, int* lenp)
 {
     byte* dst;
@@ -264,19 +223,116 @@ need_convertion:
     *lenp = dst - conv_buf;
 }
 
-
+/*
+ * erts_atom_put() may fail. If it fails THE_NON_VALUE is returned!
+ */
 Eterm
-am_atom_put2(const byte* name, int len, int is_latin1)
+erts_atom_put(const byte *name, int len, ErtsAtomEncoding enc, int trunc)
 {
     byte utf8_copy[MAX_ATOM_SZ_FROM_LATIN1];
+    const byte *text = name;
+    int tlen = len;
+    Sint no_latin1_chars;
+    Atom a;
+    int aix;
 
-    if (is_latin1) {
-	latin1_to_utf8(utf8_copy, &name, &len);
+#ifdef ERTS_ATOM_PUT_OPS_STAT
+    erts_smp_atomic_inc_nob(&atom_put_ops);
+#endif
+
+    if (tlen < 0) {
+	if (trunc)
+	    tlen = 0;
+	else
+	    return THE_NON_VALUE;
     }
-    return am_atom_put((const char*)name, len);
-}
 
+    switch (enc) {
+    case ERTS_ATOM_ENC_7BIT_ASCII:
+	if (tlen > MAX_ATOM_CHARACTERS) {
+	    if (trunc)
+		tlen = MAX_ATOM_CHARACTERS;
+	    else
+		return THE_NON_VALUE;
+	}
+#ifdef DEBUG
+	for (aix = 0; aix < len; aix++) {
+	    ASSERT((name[aix] & 0x80) == 0);
+	}
+#endif
+	no_latin1_chars = tlen;
+	break;
+    case ERTS_ATOM_ENC_LATIN1:
+	if (tlen > MAX_ATOM_CHARACTERS) {
+	    if (trunc)
+		tlen = MAX_ATOM_CHARACTERS;
+	    else
+		return THE_NON_VALUE;
+	}
+	no_latin1_chars = tlen;
+	latin1_to_utf8(utf8_copy, &text, &tlen);
+	break;
+    case ERTS_ATOM_ENC_UTF8:
+	/* First sanity check; need to verify later */
+	if (tlen > MAX_ATOM_SZ_LIMIT && !trunc)
+	    return THE_NON_VALUE;
+	break;
+    }
 
+    a.len = tlen;
+    a.name = (byte *) text;
+    atom_read_lock();
+    aix = index_get(&erts_atom_table, (void*) &a);
+    atom_read_unlock();
+    if (aix >= 0) {
+	/* Already in table no need to verify it */
+	return make_atom(aix);
+    }
+
+    if (enc == ERTS_ATOM_ENC_UTF8) {
+	/* Need to verify encoding and length */
+	byte *err_pos;
+	Uint no_chars;
+	switch (erts_analyze_utf8_x((byte *) text,
+				    (Uint) tlen,
+				    &err_pos,
+				    &no_chars, NULL,
+				    &no_latin1_chars,
+				    MAX_ATOM_CHARACTERS)) {
+	case ERTS_UTF8_OK:
+	    ASSERT(no_chars <= MAX_ATOM_CHARACTERS);
+	    break;
+	case ERTS_UTF8_OK_MAX_CHARS:
+	    /* Truncated... */
+	    if (!trunc)
+		return THE_NON_VALUE;
+	    ASSERT(no_chars == MAX_ATOM_CHARACTERS);
+	    tlen = err_pos - text;
+	    break;
+	default:
+	    /* Bad utf8... */
+	    return THE_NON_VALUE;
+	}
+    }
+
+    ASSERT(tlen <= MAX_ATOM_SZ_LIMIT);
+    ASSERT(-1 <= no_latin1_chars && no_latin1_chars <= MAX_ATOM_CHARACTERS);
+
+    a.len = tlen;
+    a.latin1_chars = (Sint16) no_latin1_chars;
+    a.name = (byte *) text;
+    atom_write_lock();
+    aix = index_put(&erts_atom_table, (void*) &a);
+    atom_write_unlock();
+    return make_atom(aix);
+}
+
+Eterm
+am_atom_put(const char* name, int len)
+{
+    /* Assumes 7-bit ascii; use erts_atom_put() for other encodings... */
+    return erts_atom_put((byte *) name, len, ERTS_ATOM_ENC_7BIT_ASCII, 1);
+}
 
 int atom_table_size(void)
 {
@@ -318,10 +374,11 @@ erts_atom_get(const char *name, int len, Eterm* ap, int is_latin1)
     int i;
     int res;
 
-    a.len = len;
+    a.len = (Sint16) len;
     a.name = (byte *)name;
     if (is_latin1) {
-	latin1_to_utf8(utf8_copy, (const byte**)&a.name, &a.len);
+	latin1_to_utf8(utf8_copy, (const byte**)&a.name, &len);
+	a.len = (Sint16) len;
     }
     atom_read_lock();
     i = index_get(&erts_atom_table, (void*) &a);
@@ -384,8 +441,15 @@ init_atom_table(void)
     for (i = 0; erl_atom_names[i] != 0; i++) {
 	int ix;
 	a.len = strlen(erl_atom_names[i]);
+	a.latin1_chars = a.len;
 	a.name = (byte*)erl_atom_names[i];
 	a.slot.index = i;
+#ifdef DEBUG
+	/* Verify 7-bit ascii */
+	for (ix = 0; ix < a.len; ix++) {
+	    ASSERT((a.name[ix] & 0x80) == 0);
+	}
+#endif
 	ix = index_put(&erts_atom_table, (void*) &a);
 	atom_text_pos -= a.len;
 	atom_space -= a.len;
diff --git a/erts/emulator/beam/atom.h b/erts/emulator/beam/atom.h
index 84dd6d8901..f721999a4c 100644
--- a/erts/emulator/beam/atom.h
+++ b/erts/emulator/beam/atom.h
@@ -47,7 +47,8 @@
  */
 typedef struct atom {
     IndexSlot slot;  /* MUST BE LOCATED AT TOP OF STRUCT!!! */
-    int len;         /* length of atom name */
+    Sint16 len;      /* length of atom name (UTF-8 encoded) */
+    Sint16 latin1_chars; /* 0-255 if atom can be encoded in latin1; otherwise, -1 */
     int ord0;        /* ordinal value of first 3 bytes + 7 bits */
     byte* name;      /* name of atom */
 } Atom;
@@ -113,6 +114,12 @@ ERTS_GLB_INLINE int erts_is_atom_str(const char *str, Eterm term, int is_latin1)
 
 #endif
 
+typedef enum {
+    ERTS_ATOM_ENC_7BIT_ASCII,
+    ERTS_ATOM_ENC_LATIN1,
+    ERTS_ATOM_ENC_UTF8
+} ErtsAtomEncoding;
+
 /*
  * Note, ERTS_IS_ATOM_STR() expects the first argument to be a
  * 7-bit ASCII string literal.
@@ -125,8 +132,8 @@ ERTS_GLB_INLINE int erts_is_atom_str(const char *str, Eterm term, int is_latin1)
 int atom_table_size(void);	/* number of elements */
 int atom_table_sz(void);	/* table size in bytes, excluding stored objects */
 
-Eterm am_atom_put(const char*, int); /* most callers pass plain char*'s */
-Eterm am_atom_put2(const byte*, int, int is_latin1);
+Eterm am_atom_put(const char*, int); /* ONLY 7-bit ascii! */
+Eterm erts_atom_put(const byte *name, int len, ErtsAtomEncoding enc, int trunc);
 int atom_erase(byte*, int);
 int atom_static_put(byte*, int);
 void init_atom_table(void);
diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index afcbd732df..59c9f39e7b 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -18,6 +18,8 @@
 #
 
 #
+# IMPORTANT! All atoms defined here *need* to be in 7-bit ascii!
+#
 # File format:
 #
 # Lines starting with '#' are ignored.
diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index 7bb964d5aa..8b4135e21d 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -1230,7 +1230,7 @@ load_atom_table(LoaderState* stp)
 
 	GetByte(stp, n);
 	GetString(stp, atom, n);
-	stp->atom[i] = am_atom_put2(atom, n, 1);
+	stp->atom[i] = erts_atom_put(atom, n, ERTS_ATOM_ENC_LATIN1, 1);
     }
 
     /*
@@ -1620,7 +1620,7 @@ read_line_table(LoaderState* stp)
 
 	    GetInt(stp, 2, n);
 	    GetString(stp, fname, n);
-	    stp->fname[i] = am_atom_put((char*)fname, n); /*SVERK ? */
+	    stp->fname[i] = erts_atom_put(fname, n, ERTS_ATOM_ENC_LATIN1, 1);
 	}
     }
 
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 89157068c0..a0b4a8c049 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -2536,11 +2536,13 @@ BIF_RETTYPE append_element_2(BIF_ALIST_2)
 
 BIF_RETTYPE atom_to_list_1(BIF_ALIST_1)
 {
-    Eterm do_utf8_to_list(Process*, Uint num, byte *bytes, Uint sz, Uint left,
-			  Uint *num_built, Uint *num_eaten, Eterm tail); /*SVERK */
     Atom* ap;
     Uint num_chars, num_built, num_eaten;
+    byte* err_pos;
     Eterm res;
+#ifdef DEBUG
+    int ares;
+#endif
 
     if (is_not_atom(BIF_ARG_1))
 	BIF_ERROR(BIF_P, BADARG);
@@ -2549,16 +2551,15 @@ BIF_RETTYPE atom_to_list_1(BIF_ALIST_1)
     ap = atom_tab(atom_val(BIF_ARG_1));
     if (ap->len == 0)
 	BIF_RET(NIL);	/* the empty atom */
-    {
-	byte* err_pos;
-	if (erts_analyze_utf8(ap->name, ap->len, &err_pos, &num_chars, NULL)
-	    != ERTS_UTF8_OK) {
-	    BIF_ERROR(BIF_P, BADARG);
-	}
-    }
+
+#ifdef DEBUG
+    ares =
+#endif
+	erts_analyze_utf8(ap->name, ap->len, &err_pos, &num_chars, NULL);
+    ASSERT(ares == ERTS_UTF8_OK);
     
-    res = do_utf8_to_list(BIF_P, num_chars, ap->name, ap->len, ap->len,
-			  &num_built, &num_eaten, NIL);
+    res = erts_utf8_to_list(BIF_P, num_chars, ap->name, ap->len, ap->len,
+			    &num_built, &num_eaten, NIL);
     ASSERT(num_built == num_chars);
     ASSERT(num_eaten == ap->len);
     BIF_RET(res);
@@ -2582,7 +2583,8 @@ BIF_RETTYPE list_to_atom_1(BIF_ALIST_1)
 	}
 	BIF_ERROR(BIF_P, BADARG);
     }
-    res = am_atom_put2((byte*)buf, i, 1);
+    res = erts_atom_put((byte *) buf, i, ERTS_ATOM_ENC_LATIN1, 1);
+    ASSERT(is_atom(res));
     erts_free(ERTS_ALC_T_TMP, (void *) buf);
     BIF_RET(res);
 }
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index 28c4621ff2..8c3bcd1de4 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -1646,7 +1646,7 @@ dsig_send(ErtsDSigData *dsdp, Eterm ctl, Eterm msg, int force_busy)
     data_size += erts_encode_dist_ext_size(ctl, flags, acmp);
     if (is_value(msg))
 	data_size += erts_encode_dist_ext_size(msg, flags, acmp);
-    erts_finalize_atom_cache_map(acmp);
+    erts_finalize_atom_cache_map(acmp, flags);
 
     dhdr_ext_size = erts_encode_ext_dist_header_size(acmp);
     data_size += dhdr_ext_size;
@@ -1996,7 +1996,8 @@ erts_dist_command(Port *prt, int reds_limit)
 	    ASSERT(ob);
 	    do {
 		ob->extp = erts_encode_ext_dist_header_finalize(ob->extp,
-								dep->cache);
+								dep->cache,
+								flags);
 		if (!(flags & DFLAG_DIST_HDR_ATOM_CACHE))
 		    *--ob->extp = PASS_THROUGH; /* Old node; 'pass through'
 						   needed */
@@ -2040,7 +2041,8 @@ erts_dist_command(Port *prt, int reds_limit)
 	    Uint size;
 	    oq.first->extp
 		= erts_encode_ext_dist_header_finalize(oq.first->extp,
-						       dep->cache);
+						       dep->cache,
+						       flags);
 	    reds += ERTS_PORT_REDS_DIST_CMD_FINALIZE;
 	    if (!(flags & DFLAG_DIST_HDR_ATOM_CACHE))
 		*--oq.first->extp = PASS_THROUGH; /* Old node; 'pass through'
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 0a4407f009..2b649b589b 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -49,6 +49,8 @@
 #   true after a "+enable X" statement or if it has been passed as a
 #   command line argument to make_alloc_types. The variable X is false
 #   after a "+disable X" statement or if it has never been mentioned.
+#
+# IMPORTANT! Only use 7-bit ascii text in this file!
 
 +if smp
 +disable threads_no_smp
diff --git a/erts/emulator/beam/erl_bif_ddll.c b/erts/emulator/beam/erl_bif_ddll.c
index 7f7c975e78..59a53870f3 100644
--- a/erts/emulator/beam/erl_bif_ddll.c
+++ b/erts/emulator/beam/erl_bif_ddll.c
@@ -1869,7 +1869,10 @@ static Eterm build_load_error_hp(Eterm *hp, int code)
 
 static Eterm mkatom(char *str)
 {
-    return am_atom_put(str, sys_strlen(str));
+    return erts_atom_put((byte *) str,
+			 sys_strlen(str),
+			 ERTS_ATOM_ENC_LATIN1,
+			 1);
 }
 
 static char *pick_list_or_atom(Eterm name_term)
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index a3811ccdb0..c910bd0cb6 100755
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -2296,8 +2296,10 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 	for (i = num_instructions-1; i >= 0; i--) {
 	    res = erts_bld_cons(hpp, hszp,
 				erts_bld_tuple(hpp, hszp, 2,
-					       am_atom_put(opc[i].name,
-							   strlen(opc[i].name)),
+					       erts_atom_put(opc[i].name,
+							     strlen(opc[i].name),
+							     ERTS_ATOM_ENC_LATIN1,
+							     1),
 					       erts_bld_uint(hpp, hszp,
 							     opc[i].count)),
 				res);
@@ -3901,7 +3903,7 @@ static Eterm lcnt_build_lock_stats_term(Eterm **hpp, Uint *szp, erts_lcnt_lock_s
     timer_ns = stats->timer.ns;
     timer_n  = stats->timer_n;
    
-    af    = am_atom_put(stats->file, strlen(stats->file)); 
+    af    = erts_atom_put(stats->file, strlen(stats->file), ERTS_ATOM_ENC_LATIN1, 1); 
     uil   = erts_bld_uint( hpp, szp, line);
     tloc  = erts_bld_tuple(hpp, szp, 2, af, uil);
     
@@ -3938,13 +3940,13 @@ static Eterm lcnt_build_lock_term(Eterm **hpp, Uint *szp, erts_lcnt_lock_t *lock
     
     ASSERT(ltype);
     
-    type  = am_atom_put(ltype, strlen(ltype));           
-    name  = am_atom_put(lock->name, strlen(lock->name)); 
+    type  = erts_atom_put(ltype, strlen(ltype), ERTS_ATOM_ENC_LATIN1, 1);           
+    name  = erts_atom_put(lock->name, strlen(lock->name), ERTS_ATOM_ENC_LATIN1, 1); 
 
     if (lock->flag & ERTS_LCNT_LT_ALLOC) {
 	/* use allocator types names as id's for allocator locks */
 	ltype = (char *) ERTS_ALC_A2AD(signed_val(lock->id));
-	id    = am_atom_put(ltype, strlen(ltype));
+	id    = erts_atom_put(ltype, strlen(ltype), ERTS_ATOM_ENC_LATIN1, 1);
     } else if (lock->flag & ERTS_LCNT_LT_PROCLOCK) {
 	/* use registered names as id's for process locks if available */
 	proc  = erts_proc_lookup(lock->id);
@@ -3984,12 +3986,12 @@ static Eterm lcnt_build_result_term(Eterm **hpp, Uint *szp, erts_lcnt_data_t *da
     dtns = erts_bld_uint( hpp, szp, data->duration.ns);
     tdt  = erts_bld_tuple(hpp, szp, 2, dts, dtns);
     
-    adur = am_atom_put(str_duration, strlen(str_duration));
+    adur = erts_atom_put(str_duration, strlen(str_duration), ERTS_ATOM_ENC_LATIN1, 1);
     tdur = erts_bld_tuple(hpp, szp, 2, adur, tdt);
    
     /* lock tuple */
     
-    aloc = am_atom_put(str_locks, strlen(str_locks));
+    aloc = erts_atom_put(str_locks, strlen(str_locks), ERTS_ATOM_ENC_LATIN1, 1);
     	
     for (lock = data->current_locks->head; lock != NULL ; lock = lock->next ) {
 	lloc = lcnt_build_lock_term(hpp, szp, lock, lloc);
@@ -4125,14 +4127,14 @@ BIF_RETTYPE erts_debug_lock_counters_1(BIF_ALIST_1)
 
 static void os_info_init(void)
 {
-    Eterm type = am_atom_put(os_type, strlen(os_type));
+    Eterm type = erts_atom_put((byte *) os_type, strlen(os_type), ERTS_ATOM_ENC_LATIN1, 1);
     Eterm flav;
     int major, minor, build;
     char* buf = erts_alloc(ERTS_ALC_T_TMP, 1024); /* More than enough */
     Eterm* hp;
 
     os_flavor(buf, 1024);
-    flav = am_atom_put(buf, strlen(buf));
+    flav = erts_atom_put((byte *) buf, strlen(buf), ERTS_ATOM_ENC_LATIN1, 1);
     erts_free(ERTS_ALC_T_TMP, (void *) buf);
     hp = erts_alloc(ERTS_ALC_T_LL_TEMP_TERM, (3+4)*sizeof(Eterm));
     os_type_tuple = TUPLE2(hp, type, flav);
diff --git a/erts/emulator/beam/erl_bif_port.c b/erts/emulator/beam/erl_bif_port.c
index f9009166c0..4b270414cb 100644
--- a/erts/emulator/beam/erl_bif_port.c
+++ b/erts/emulator/beam/erl_bif_port.c
@@ -68,7 +68,7 @@ BIF_RETTYPE open_port_2(BIF_ALIST_2)
 	} else {
 	    str = "einval";
 	}
-	BIF_P->fvalue = am_atom_put(str, strlen(str));
+	BIF_P->fvalue = erts_atom_put((byte *) str, strlen(str), ERTS_ATOM_ENC_LATIN1, 1);
 	BIF_ERROR(BIF_P, EXC_ERROR);
     }
 
diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c
index 1ba1048afa..f8a4882ec0 100644
--- a/erts/emulator/beam/erl_db.c
+++ b/erts/emulator/beam/erl_db.c
@@ -3815,7 +3815,7 @@ erts_ets_colliding_names(Process* p, Eterm name, Uint cnt)
             while (index >= atom_table_size()) {
                 char tmp[20];
                 erts_snprintf(tmp, sizeof(tmp), "am%x", atom_table_size());
-                am_atom_put(tmp,strlen(tmp));
+                erts_atom_put((byte *) tmp, strlen(tmp), ERTS_ATOM_ENC_LATIN1, 1);
             }
             list = CONS(hp, make_atom(index), list);
             hp += 2;
diff --git a/erts/emulator/beam/erl_db_util.c b/erts/emulator/beam/erl_db_util.c
index 0c9ca83ce4..407a55a3d7 100644
--- a/erts/emulator/beam/erl_db_util.c
+++ b/erts/emulator/beam/erl_db_util.c
@@ -4768,7 +4768,8 @@ static int match_compact(ErlHeapFragment *expr, DMCErrInfo *err_info)
 	    ASSERT(j < x);
 	    erts_snprintf(buff+1, sizeof(buff) - 1, "%u", (unsigned) j);
 	    /* Yes, writing directly into terms, they ARE off heap */
-	    *p = am_atom_put(buff, strlen(buff));
+	    *p = erts_atom_put((byte *) buff, strlen(buff),
+			       ERTS_ATOM_ENC_LATIN1, 1);
 	}
 	++p;
     }
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 4b90e5394a..369eab5980 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -344,7 +344,7 @@ erl_first_process_otp(char* modname, void* code, unsigned size, int argc, char**
     ErlSpawnOpts so;
     Eterm env;
     
-    start_mod = am_atom_put(modname, sys_strlen(modname));
+    start_mod = erts_atom_put((byte *) modname, sys_strlen(modname), ERTS_ATOM_ENC_LATIN1, 1);
     if (erts_find_function(start_mod, am_start, 2,
 			   erts_active_code_ix()) == NULL) {
 	erl_exit(5, "No function %s:start/2\n", modname);
@@ -441,7 +441,7 @@ load_preloaded(void)
     i = 0;
     while ((name = preload_p[i].name) != NULL) {
 	length = preload_p[i].size;
-	module_name = am_atom_put(name, sys_strlen(name));
+	module_name = erts_atom_put((byte *) name, sys_strlen(name), ERTS_ATOM_ENC_LATIN1, 1);
 	if ((code = sys_preload_begin(&preload_p[i])) == 0)
 	    erl_exit(1, "Failed to find preloaded code for module %s\n", 
 		     name);
diff --git a/erts/emulator/beam/erl_unicode.c b/erts/emulator/beam/erl_unicode.c
index e24b6f1458..6600ce4a4a 100644
--- a/erts/emulator/beam/erl_unicode.c
+++ b/erts/emulator/beam/erl_unicode.c
@@ -1154,15 +1154,24 @@ BIF_RETTYPE unicode_characters_to_list_2(BIF_ALIST_2)
  * When input to characters_to_list is a plain binary and the format is 'unicode', we do
  * a faster analyze and size count with this function.
  */
-int erts_analyze_utf8(byte *source, Uint size, 
-		      byte **err_pos, Uint *num_chars, int *left)
+static ERTS_INLINE int
+analyze_utf8(byte *source, Uint size, byte **err_pos, Uint *num_chars, int *left,
+	     Sint *num_latin1_chars, Uint max_chars)
 {
+    Uint latin1_count;
+    int is_latin1;
     *err_pos = source;
+    if (num_latin1_chars) {
+	is_latin1 = 1;
+	latin1_count = 0;
+    }
     *num_chars = 0;
     while (size) {
 	if (((*source) & ((byte) 0x80)) == 0) {
 	    source++;
-	    --size; 
+	    --size;
+	    if (num_latin1_chars)
+		latin1_count++;
 	} else if (((*source) & ((byte) 0xE0)) == 0xC0) {
 	    if (size < 2) {
 		return ERTS_UTF8_INCOMPLETE;
@@ -1173,6 +1182,11 @@ int erts_analyze_utf8(byte *source, Uint size,
 	    }
 	    source += 2;
 	    size -= 2;
+	    if (num_latin1_chars) {
+		latin1_count++;
+		if ((source[0] & ((byte) 0xFC)) != ((byte) 0xC0))
+		    is_latin1 = 0;
+	    }
 	} else if (((*source) & ((byte) 0xF0)) == 0xE0) {
 	    if (size < 3) {
 		return ERTS_UTF8_INCOMPLETE;
@@ -1188,6 +1202,8 @@ int erts_analyze_utf8(byte *source, Uint size,
 	    }
 	    source += 3;
 	    size -= 3;
+	    if (num_latin1_chars)
+		is_latin1 = 0;
 	} else if (((*source) & ((byte) 0xF8)) == 0xF0) {
 	    if (size < 4) {
 		return ERTS_UTF8_INCOMPLETE;
@@ -1205,22 +1221,41 @@ int erts_analyze_utf8(byte *source, Uint size,
 	    }
 	    source += 4;
 	    size -= 4; 
+	    if (num_latin1_chars)
+		is_latin1 = 0;
 	} else {
 	    return ERTS_UTF8_ERROR;
 	}
 	++(*num_chars);
 	*err_pos = source;
+	if (max_chars && size > 0 && *num_chars == max_chars)
+	    return ERTS_UTF8_OK_MAX_CHARS;
 	if (left && --(*left) <= 0 && size) {
 	    return ERTS_UTF8_ANALYZE_MORE;
 	}
     }
+    if (num_latin1_chars)
+	*num_latin1_chars = is_latin1 ? latin1_count : -1;
     return ERTS_UTF8_OK;
 }
 
+int erts_analyze_utf8(byte *source, Uint size, 
+		      byte **err_pos, Uint *num_chars, int *left)
+{
+    return analyze_utf8(source, size, err_pos, num_chars, left, NULL, 0);
+}
+
+int erts_analyze_utf8_x(byte *source, Uint size, 
+			byte **err_pos, Uint *num_chars, int *left,
+			Sint *num_latin1_chars, Uint max_chars)
+{
+    return analyze_utf8(source, size, err_pos, num_chars, left, num_latin1_chars, max_chars);
+}
+
 /*
  * No errors should be able to occur - no overlongs, no malformed, no nothing
- */    
-Eterm do_utf8_to_list(Process *p, Uint num, byte *bytes, Uint sz, 
+ */
+static Eterm do_utf8_to_list(Process *p, Uint num, byte *bytes, Uint sz, 
 			     Uint left,
 			     Uint *num_built, Uint *num_eaten, Eterm tail)
 {
@@ -1275,6 +1310,12 @@ Eterm do_utf8_to_list(Process *p, Uint num, byte *bytes, Uint sz,
     return ret;
 }
 
+Eterm erts_utf8_to_list(Process *p, Uint num, byte *bytes, Uint sz, Uint left,
+			Uint *num_built, Uint *num_eaten, Eterm tail)
+{
+    return do_utf8_to_list(p, num, bytes, sz, left, num_built, num_eaten, tail);
+}
+
 static int is_candidate(Uint cp)
 {
     int index,pos;
@@ -1849,14 +1890,14 @@ BIF_RETTYPE atom_to_binary_2(BIF_ALIST_2)
 }
 
 static BIF_RETTYPE
-binary_to_atom(Process* p, Eterm bin, Eterm enc, int must_exist)
+binary_to_atom(Process* proc, Eterm bin, Eterm enc, int must_exist)
 {
     byte* bytes;
     byte *temp_alloc = NULL;
     Uint bin_size;
 
     if ((bytes = erts_get_aligned_binary_bytes(bin, &temp_alloc)) == 0) {
-	BIF_ERROR(p, BADARG);
+	BIF_ERROR(proc, BADARG);
     }
     bin_size = binary_size(bin);
     if (enc == am_latin1) {
@@ -1864,11 +1905,16 @@ binary_to_atom(Process* p, Eterm bin, Eterm enc, int must_exist)
 	if (bin_size > MAX_ATOM_CHARACTERS) {
 	system_limit:
 	    erts_free_aligned_binary_bytes(temp_alloc);
-	    BIF_ERROR(p, SYSTEM_LIMIT);
+	    BIF_ERROR(proc, SYSTEM_LIMIT);
 	}
 	if (!must_exist) {
-	    a = am_atom_put2(bytes, bin_size, 1);
-	    erts_free_aligned_binary_bytes(temp_alloc);
+	    a = erts_atom_put((byte *) bytes,
+			      bin_size,
+			      ERTS_ATOM_ENC_LATIN1,
+			      0);
+    	    erts_free_aligned_binary_bytes(temp_alloc);
+	    if (is_non_value(a))
+		goto badarg;
 	    BIF_RET(a);
 	} else if (erts_atom_get((char *)bytes, bin_size, &a, 1)) {
 	    erts_free_aligned_binary_bytes(temp_alloc);
@@ -1900,17 +1946,22 @@ binary_to_atom(Process* p, Eterm bin, Eterm enc, int must_exist)
 	}
 
 	if (!must_exist) {
-	    res = am_atom_put((char*)bytes, bin_size);
+	    res = erts_atom_put((byte *) bytes,
+				bin_size,
+				ERTS_ATOM_ENC_UTF8,
+				0);
 	}
 	else if (!erts_atom_get((char*)bytes, bin_size, &res, 0)) {
 	    goto badarg;
 	}
 	erts_free_aligned_binary_bytes(temp_alloc);
+	if (is_non_value(res))
+	    goto badarg;
 	BIF_RET(res);
     } else {
     badarg:
 	erts_free_aligned_binary_bytes(temp_alloc);
-	BIF_ERROR(p, BADARG);
+	BIF_ERROR(proc, BADARG);
     }
 }
 
@@ -2625,30 +2676,70 @@ BIF_RETTYPE file_native_name_encoding_0(BIF_ALIST_0)
     }
 }
 
-/* Assumes 'dest' has enough room.
- */
-int erts_utf8_to_latin1(byte* dest, const byte* source, unsigned slen)
+int erts_utf8_is_latin1_string(const byte *string, int len)
+{
+    /* Assumes string is encoded in valid UTF-8 */
+    int i;
+    while (i < len) {
+	if ((string[i] & 0x80) == 0)
+	    i++;
+	else if (i+1 < len
+		 && (string[i] & 0xFE) == 0xC2
+		 && (string[i+1] & 0xC0) == 0x80)
+	    i +=2;
+	else
+	    return 0;
+    }
+    return 1;
+}
+
+int erts_utf8_to_latin1(byte* dest, const byte* source, int slen)
 {
+    /*
+     * Assumes source contains valid utf8 that can be encoded as latin1,
+     * and that dest has enough room.
+     */
     byte* dp = dest;
     while (slen > 0) {
 	if ((source[0] & 0x80) == 0) {
 	    *dp++ = *source++;
 	    --slen;
 	}
-	else if (slen > 1 &&
-		 (source[0] & 0xFE) == 0xC2 &&
-		 (source[1] & 0xC0) == 0x80) {
+	else {
+	    ASSERT(slen > 1);
+	    ASSERT((source[0] & 0xFE) == 0xC2);
+	    ASSERT((source[1] & 0xC0) == 0x80);
 	    *dp++ = (char) ((source[0] << 6) | (source[1] & 0x3F));
 	    source += 2;
 	    slen -= 2;
 	}
-	else {
-	    /* Just let unconvertable octets through. This should not happen
-	       in a correctly upgraded system */
-	    *dp++ = *source++;
-	    --slen;
-	}
     }
     return dp - dest;
 }
 
+int erts_utf8_to_latin1_backwards(byte *dest, const byte *source, int slen)
+{
+    /*
+     * Assumes source contains valid utf8 that can be encoded as latin1,
+     * and that dest has enough room.
+     */
+    int dix = 0;
+    int six = slen;
+    while (six > 0) {
+	six--;
+	dix--;
+	if ((source[six] & 0x80) == 0)
+	    dest[dix] = source[six];
+	else {
+	    byte c;
+	    ASSERT(six > 0);
+	    ASSERT((source[six] & 0xC0) == 0x80);
+	    ASSERT((source[six-1] & 0xFE) == 0xC2);
+ 	    c = source[six] & 0x3F;
+	    six--;
+	    c |= source[six] << 6;
+	    dest[dix] = c;
+	}
+    }
+    return -dix;
+}
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index 68edcd0fa6..8c4d9108d4 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -142,6 +142,7 @@ erts_init_atom_cache_map(ErtsAtomCacheMap *acmp)
 {
     if (acmp) {
 	int ix;
+	acmp->long_atoms = 0;
 	for (ix = 0; ix < ERTS_ATOM_CACHE_SIZE; ix++)
 	    acmp->cache[ix].iix = -1;
 	acmp->sz = 0;
@@ -154,6 +155,7 @@ erts_reset_atom_cache_map(ErtsAtomCacheMap *acmp)
 {
     if (acmp) {
 	int i;
+	acmp->long_atoms = 0;
 	for (i = 0; i < acmp->sz; i++) {
 	    ASSERT(0 <= acmp->cix[i] && acmp->cix[i] < ERTS_ATOM_CACHE_SIZE);
 	    acmp->cache[acmp->cix[i]].iix = -1;
@@ -175,9 +177,23 @@ erts_destroy_atom_cache_map(ErtsAtomCacheMap *acmp)
 }
 
 static ERTS_INLINE void
-insert_acache_map(ErtsAtomCacheMap *acmp, Eterm atom)
+insert_acache_map(ErtsAtomCacheMap *acmp, Eterm atom, Uint32 dflags)
 {
-    if (acmp && acmp->sz < ERTS_MAX_INTERNAL_ATOM_CACHE_ENTRIES) {
+    /*
+     * If the receiver do not understand utf8 atoms
+     * and this atom cannot be represented in latin1,
+     * we are not allowed to cache it.
+     *
+     * In this case all atoms are assumed to have
+     * latin1 encoding in the cache. By refusing it
+     * in the cache we will instead encode it using
+     * ATOM_UTF8_EXT/SMALL_ATOM_UTF8_EXT which the
+     * receiver do not recognize and tear down the
+     * connection.
+     */
+    if (acmp && acmp->sz < ERTS_MAX_INTERNAL_ATOM_CACHE_ENTRIES
+	&& ((dflags & DFLAG_UTF8_ATOMS)
+	    || atom_tab(atom_val(atom))->latin1_chars >= 0)) {
 	int ix;
 	ASSERT(acmp->hdr_sz < 0);
 	ix = atom2cix(atom);
@@ -190,7 +206,7 @@ insert_acache_map(ErtsAtomCacheMap *acmp, Eterm atom)
 }
 
 static ERTS_INLINE int
-get_iix_acache_map(ErtsAtomCacheMap *acmp, Eterm atom)
+get_iix_acache_map(ErtsAtomCacheMap *acmp, Eterm atom, Uint32 dflags)
 {
     if (!acmp)
 	return -1;
@@ -199,7 +215,9 @@ get_iix_acache_map(ErtsAtomCacheMap *acmp, Eterm atom)
 	ASSERT(is_atom(atom));
 	ix = atom2cix(atom);
 	if (acmp->cache[ix].iix < 0) {
-	    ASSERT(acmp->sz == ERTS_MAX_INTERNAL_ATOM_CACHE_ENTRIES);
+	    ASSERT(acmp->sz == ERTS_MAX_INTERNAL_ATOM_CACHE_ENTRIES
+		   || (!(dflags & DFLAG_UTF8_ATOMS)
+		       && atom_tab(atom_val(atom))->latin1_chars < 0));
 	    return -1;
 	}
 	else {
@@ -210,18 +228,17 @@ get_iix_acache_map(ErtsAtomCacheMap *acmp, Eterm atom)
 }
 
 void
-erts_finalize_atom_cache_map(ErtsAtomCacheMap *acmp)
+erts_finalize_atom_cache_map(ErtsAtomCacheMap *acmp, Uint32 dflags)
 {
     if (acmp) {
-#if MAX_ATOM_LENGTH > 255
-#error "This code is not complete; long_atoms info need to be passed to the following stages."
-	int long_atoms = 0; /* !0 if one or more atoms are long than 255. */
-#endif
+	int utf8_atoms = (int) (dflags & DFLAG_UTF8_ATOMS);
+	int long_atoms = 0; /* !0 if one or more atoms are longer than 255. */
 	int i;
 	int sz;
 	int fix_sz
 	    = 1 /* VERSION_MAGIC */
 	    + 1 /* DIST_HEADER */
+	    + 1 /* dist header flags */
 	    + 1 /* number of internal cache entries */
 	    ;
 	int min_sz;
@@ -230,22 +247,23 @@ erts_finalize_atom_cache_map(ErtsAtomCacheMap *acmp)
 	min_sz = fix_sz+(2+4)*acmp->sz;
 	sz = fix_sz;
 	for (i = 0; i < acmp->sz; i++) {
+	    Atom *a;
 	    Eterm atom;
 	    int len;
 	    atom = acmp->cache[acmp->cix[i]].atom;
 	    ASSERT(is_atom(atom));
-	    len = atom_tab(atom_val(atom))->len;
-#if MAX_ATOM_LENGTH > 255
+	    a = atom_tab(atom_val(atom));
+	    len = (int) (utf8_atoms ? a->len : a->latin1_chars);
+	    ASSERT(len >= 0);
 	    if (!long_atoms && len > 255)
 		long_atoms = 1;
-#endif
 	    /* Enough for a new atom cache value */
 	    sz += 1 /* cix */ + 1 /* length */ + len /* text */;
 	}
-#if MAX_ATOM_LENGTH > 255
-	if (long_atoms)
+	if (long_atoms) {
+	    acmp->long_atoms = 1;
 	    sz += acmp->sz; /* we need 2 bytes per atom for length */
-#endif
+	}
 	/* Dynamically sized flag field */
 	sz += ERTS_DIST_HDR_ATOM_CACHE_FLAG_BYTES(acmp->sz);
 	if (sz < min_sz)
@@ -274,6 +292,7 @@ byte *erts_encode_ext_dist_header_setup(byte *ctl_ext, ErtsAtomCacheMap *acmp)
     else {
 	int i;
 	byte *ep = ctl_ext;
+	byte dist_hdr_flags = acmp->long_atoms ? ERTS_DIST_HDR_LONG_ATOMS_FLG : 0;
 	ASSERT(acmp->hdr_sz >= 0);
 	/*
 	 * Write cache update instructions. Note that this is a purely
@@ -296,28 +315,36 @@ byte *erts_encode_ext_dist_header_setup(byte *ctl_ext, ErtsAtomCacheMap *acmp)
 	}
 	--ep;
 	put_int8(acmp->sz, ep);
+	--ep;
+	put_int8(dist_hdr_flags, ep);
 	*--ep = DIST_HEADER;
 	*--ep = VERSION_MAGIC;
 	return ep;
     }
 }
 
-byte *erts_encode_ext_dist_header_finalize(byte *ext, ErtsAtomCache *cache)
+byte *erts_encode_ext_dist_header_finalize(byte *ext, ErtsAtomCache *cache, Uint32 dflags)
 {
     byte *ip;
     byte instr_buf[(2+4)*ERTS_ATOM_CACHE_SIZE];
     int ci, sz;
+    byte dist_hdr_flags;
+    int long_atoms;
+    int utf8_atoms = (int) (dflags & DFLAG_UTF8_ATOMS);
     register byte *ep = ext;
     ASSERT(ep[0] == VERSION_MAGIC);
     if (ep[1] != DIST_HEADER)
 	return ext;
 
+    dist_hdr_flags = ep[2];
+    long_atoms = ERTS_DIST_HDR_LONG_ATOMS_FLG & ((int) dist_hdr_flags);
+
     /*
      * Update output atom cache and write the external version of
      * the dist header. We write the header backwards just
      * before the actual term(s).
      */
-    ep += 2;
+    ep += 3;
     ci = (int) get_int8(ep);
     ASSERT(0 <= ci && ci < ERTS_ATOM_CACHE_SIZE);
     ep += 1;
@@ -342,12 +369,7 @@ byte *erts_encode_ext_dist_header_finalize(byte *ext, ErtsAtomCache *cache)
 	flgs_bytes = ERTS_DIST_HDR_ATOM_CACHE_FLAG_BYTES(ci);
 
 	ASSERT(flgs_bytes <= sizeof(flgs_buf));
-#if MAX_ATOM_LENGTH > 255
-	/* long_atoms info needs to be passed from previous stages */
-	if (long_atoms)
-	    flgs |= ERTS_DIST_HDR_LONG_ATOMS_FLG;
-#endif
-	flgs = 0;
+	flgs = (Uint32) dist_hdr_flags;
 	flgs_buf_ix = 0;
 	if ((ci & 1) == 0)
 	    used_half_bytes = 2;
@@ -382,17 +404,22 @@ byte *erts_encode_ext_dist_header_finalize(byte *ext, ErtsAtomCache *cache)
 		Atom *a;
 		cache->out_arr[cix] = atom;
 		a = atom_tab(atom_val(atom));
-		sz = a->len;
-		ep -= sz;
-		sys_memcpy((void *) ep, (void *) a->name, sz);
-#if MAX_ATOM_LENGTH > 255
+		if (utf8_atoms) {
+		    sz = a->len;
+		    ep -= sz;
+		    sys_memcpy((void *) ep, (void *) a->name, sz);
+		}
+		else {
+		    ASSERT(0 <= a->latin1_chars && a->latin1_chars <= MAX_ATOM_CHARACTERS);
+		    ep -= a->latin1_chars;
+		    sz = erts_utf8_to_latin1(ep, a->name, a->len);
+		    ASSERT(a->latin1_chars == sz);
+		}
 		if (long_atoms) {
 		    ep -= 2;
 		    put_int16(sz, ep);
 		}
-		else
-#endif
-		{
+		else {
 		    ASSERT(0 <= sz && sz <= 255);
 		    --ep;
 		    put_int8(sz, ep);
@@ -553,6 +580,7 @@ erts_prepare_dist_ext(ErtsDistExternal *edep,
 #endif
 
     register byte *ep = ext;
+    int utf8_atoms = (int) (dep->flags & DFLAG_UTF8_ATOMS);
 
     edep->heap_size = -1;
     edep->ext_endp = ext+size;
@@ -611,9 +639,7 @@ erts_prepare_dist_ext(ErtsDistExternal *edep,
 	    ERTS_EXT_HDR_FAIL;
 	ep++;
 	if (no_atoms) {
-#if MAX_ATOM_LENGTH > 255
 	    int long_atoms = 0;
-#endif
 #ifdef DEBUG
 	    byte *flgs_buf = ep;
 #endif
@@ -632,14 +658,8 @@ erts_prepare_dist_ext(ErtsDistExternal *edep,
 	     */
 	    byte_ix = ERTS_DIST_HDR_ATOM_CACHE_FLAG_BYTE_IX(no_atoms);
 	    bit_ix = ERTS_DIST_HDR_ATOM_CACHE_FLAG_BIT_IX(no_atoms);
-	    if (flgsp[byte_ix] & (((byte) ERTS_DIST_HDR_LONG_ATOMS_FLG)
-				  << bit_ix)) {
-#if MAX_ATOM_LENGTH > 255
+	    if (flgsp[byte_ix] & (((byte) ERTS_DIST_HDR_LONG_ATOMS_FLG) << bit_ix))
 		long_atoms = 1;
-#else
-		ERTS_EXT_HDR_FAIL; /* Long atoms not supported yet */
-#endif
-	    }
 
 #ifdef DEBUG
 	    byte_ix = 0;
@@ -707,23 +727,25 @@ erts_prepare_dist_ext(ErtsDistExternal *edep,
 		    if (cix >= ERTS_ATOM_CACHE_SIZE)
 			ERTS_EXT_HDR_FAIL;
 		    ep++;
-#if MAX_ATOM_CHARACTERS > 255
 		    if (long_atoms) {
 			CHKSIZE(2);
 			len = get_int16(ep);
 			ep += 2;
 		    }
-		    else
-#endif
-		    {
+		    else {
 			CHKSIZE(1);
 			len = get_int8(ep);
 			ep++;
 		    }
-		    if (len > MAX_ATOM_CHARACTERS)
-			ERTS_EXT_HDR_FAIL; /* Too long atom */
 		    CHKSIZE(len);
-		    atom = am_atom_put((char *) ep, len);
+		    atom = erts_atom_put((byte *) ep,
+					 len,
+					 (utf8_atoms
+					  ? ERTS_ATOM_ENC_UTF8
+					  : ERTS_ATOM_ENC_LATIN1),
+					 0);
+		    if (is_non_value(atom))
+			ERTS_EXT_HDR_FAIL;
 		    ep += len;
 		    cache->in_arr[cix] = atom;
 		    edep->attab.atom[tix] = atom;
@@ -1404,7 +1426,8 @@ static byte*
 enc_atom(ErtsAtomCacheMap *acmp, Eterm atom, byte *ep, Uint32 dflags)
 {
     int iix;
-    int i, j;
+    int len;
+    int utf8_atoms = (int) (dflags & DFLAG_UTF8_ATOMS);
 
     ASSERT(is_atom(atom));
 
@@ -1423,42 +1446,46 @@ enc_atom(ErtsAtomCacheMap *acmp, Eterm atom, byte *ep, Uint32 dflags)
 	}
 	return ep;
     }
+
     /*
      * term_to_binary/1,2 and the initial distribution message
      * don't use the cache.
      */
-    iix = get_iix_acache_map(acmp, atom);
-    if (iix < 0) { 
-	i = atom_val(atom);
-	j = atom_tab(i)->len;
-	if (dflags & DFLAG_UTF8_ATOMS) {
-	    if (j <= 255) {
+
+    iix = get_iix_acache_map(acmp, atom, dflags);
+    if (iix < 0) {
+	Atom *a = atom_tab(atom_val(atom));
+	if (utf8_atoms || a->latin1_chars < 0) {
+	    len = a->len;
+	    if (len > 255) {
 		*ep++ = ATOM_UTF8_EXT;
-		put_int16(j, ep);
+		put_int16(len, ep);
 		ep += 2;
 	    }
 	    else {
 		*ep++ = SMALL_ATOM_UTF8_EXT;
-		put_int8(j, ep);
-		ep += 2;
+		put_int8(len, ep);
+		ep += 1;
 	    }
-	    sys_memcpy((char *) ep, (char*)atom_tab(i)->name, (int) j);
+	    sys_memcpy((char *) ep, (char *) a->name, len);
 	}
 	else {
-	    if (j <= 255 && (dflags & DFLAG_SMALL_ATOM_TAGS)) {
+	    if (a->latin1_chars <= 255 && (dflags & DFLAG_SMALL_ATOM_TAGS)) {
 		*ep++ = SMALL_ATOM_EXT;
-		j = erts_utf8_to_latin1(ep+1, atom_tab(i)->name, j);
-		put_int8(j, ep);
+		len = erts_utf8_to_latin1(ep+1, a->name, a->len);
+		ASSERT(len == a->latin1_chars);
+		put_int8(len, ep);
 		ep++;
 	    }
 	    else {
 		*ep++ = ATOM_EXT;
-		j = erts_utf8_to_latin1(ep+2, atom_tab(i)->name, j);
-		put_int16(j, ep);
+		len = erts_utf8_to_latin1(ep+2, a->name, a->len);
+		ASSERT(len == a->latin1_chars);
+		put_int16(len, ep);
 		ep += 2;
 	    }	    
 	}
-	ep += j;
+	ep += len;
 	return ep;
     }
 
@@ -1535,7 +1562,15 @@ dec_atom(ErtsDistExternal *edep, byte* ep, Eterm* objp)
                 goto error;
 	    }
         } else {
-            *objp = am_atom_put2(ep, len, is_latin1);
+	    Eterm atom = erts_atom_put(ep,
+				       len,
+				       (is_latin1
+					? ERTS_ATOM_ENC_LATIN1
+					: ERTS_ATOM_ENC_UTF8),
+				       0);
+	    if (is_non_value(atom))
+		goto error;
+            *objp = atom;
         }
 	ep += len;
 	break;
@@ -2248,7 +2283,15 @@ dec_term_atom_common:
 		    goto error;
 		}
 	    } else {
-	        *objp = am_atom_put2(ep, n, is_latin1);
+		Eterm atom = erts_atom_put(ep,
+					   n,
+					   (is_latin1
+					    ? ERTS_ATOM_ENC_LATIN1
+					    : ERTS_ATOM_ENC_UTF8),
+					   0);
+		if (is_non_value(atom))
+		    goto error;
+	        *objp = atom;
 	    }
 	    ep += n;
 	    break;
@@ -2917,18 +2960,22 @@ encode_size_struct2(ErtsAtomCacheMap *acmp, Eterm obj, unsigned dflags)
 		}
 	    }
 	    else {
-		int alen = atom_tab(atom_val(obj))->len;
-		result += 1 + 1 + alen;
-		if (dflags & DFLAG_UTF8_ATOMS) {
+		Atom *a = atom_tab(atom_val(obj));
+		int alen;
+		if ((dflags & DFLAG_UTF8_ATOMS) || a->latin1_chars < 0) {
+		    alen = a->len;
+		    result += 1 + 1 + alen;
 		    if (alen > 255) {
 			result++; /* ATOM_UTF8_EXT (not small) */
 		    }
-		    /*SVERK we use utf8 length which is an over estimation */
-		}		    
-		else if (alen > 255 || !(dflags & DFLAG_SMALL_ATOM_TAGS)) {
-		    result++; /* ATOM_EXT (not small) */
 		}
-		insert_acache_map(acmp, obj);
+		else {
+		    alen = a->latin1_chars;
+		    result += 1 + 1 + alen;
+		    if (alen > 255 || !(dflags & DFLAG_SMALL_ATOM_TAGS))
+			result++; /* ATOM_EXT (not small) */
+		}
+		insert_acache_map(acmp, obj, dflags);
 	    }
 	    break;
 	case SMALL_DEF:
diff --git a/erts/emulator/beam/external.h b/erts/emulator/beam/external.h
index 50eea62225..ad430117c8 100644
--- a/erts/emulator/beam/external.h
+++ b/erts/emulator/beam/external.h
@@ -92,6 +92,7 @@ typedef struct cache {
 typedef struct {
     int hdr_sz;
     int sz;
+    int long_atoms;
     int cix[ERTS_ATOM_CACHE_SIZE];
     struct {
 	Eterm atom;
@@ -152,12 +153,12 @@ typedef struct {
 void erts_init_atom_cache_map(ErtsAtomCacheMap *);
 void erts_reset_atom_cache_map(ErtsAtomCacheMap *);
 void erts_destroy_atom_cache_map(ErtsAtomCacheMap *);
-void erts_finalize_atom_cache_map(ErtsAtomCacheMap *);
+void erts_finalize_atom_cache_map(ErtsAtomCacheMap *, Uint32);
 Uint erts_encode_ext_dist_header_size(ErtsAtomCacheMap *);
 
 Uint erts_encode_ext_dist_header_size(ErtsAtomCacheMap *);
 byte *erts_encode_ext_dist_header_setup(byte *, ErtsAtomCacheMap *);
-byte *erts_encode_ext_dist_header_finalize(byte *, ErtsAtomCache *);
+byte *erts_encode_ext_dist_header_finalize(byte *, ErtsAtomCache *, Uint32);
 Uint erts_encode_dist_ext_size(Eterm, Uint32, ErtsAtomCacheMap *);
 void erts_encode_dist_ext(Eterm, byte **, Uint32, ErtsAtomCacheMap *);
 
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 1500424d3e..eccdf10c75 100755
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1519,17 +1519,25 @@ Sint erts_native_filename_need(Eterm ioterm, int encoding);
 void erts_copy_utf8_to_utf16_little(byte *target, byte *bytes, int num_chars);
 int erts_analyze_utf8(byte *source, Uint size, 
 			byte **err_pos, Uint *num_chars, int *left);
+int erts_analyze_utf8_x(byte *source, Uint size, 
+			byte **err_pos, Uint *num_chars, int *left,
+			Sint *num_latin1_chars, Uint max_chars);
 char *erts_convert_filename_to_native(Eterm name, char *statbuf, 
 				      size_t statbuf_size, 
 				      ErtsAlcType_t alloc_type, 
 				      int allow_empty, int allow_atom,
 				      Sint *used /* out */);
 Eterm erts_convert_native_to_filename(Process *p, byte *bytes);
-int erts_utf8_to_latin1(byte* dest, const byte* source, unsigned slen);
+Eterm erts_utf8_to_list(Process *p, Uint num, byte *bytes, Uint sz, Uint left,
+			Uint *num_built, Uint *num_eaten, Eterm tail);
+int erts_utf8_is_latin1_string(const byte *string, int len);
+int erts_utf8_to_latin1(byte* dest, const byte* source, int slen);
+int erts_utf8_to_latin1_backwards(byte* dest, const byte* source, int slen);
 #define ERTS_UTF8_OK 0
 #define ERTS_UTF8_INCOMPLETE 1
 #define ERTS_UTF8_ERROR 2
 #define ERTS_UTF8_ANALYZE_MORE 3
+#define ERTS_UTF8_OK_MAX_CHARS 4
 
 /* erl_trace.c */
 void erts_init_trace(void);
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index 60b9238d38..b1eb75bede 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -646,8 +646,11 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
     
     if (IS_TRACED_FL(port, F_TRACE_PORTS)) {
 	trace_port_open(port,
-		pid,		
-		am_atom_put(port->name, strlen(port->name)));
+			pid,
+			erts_atom_put((byte *) port->name,
+				      strlen(port->name),
+				      ERTS_ATOM_ENC_LATIN1,
+				      1));
     }
     
     if (driver->start) {
@@ -4765,7 +4768,8 @@ int driver_exit(ErlDrvPort ix, int err)
         return driver_failure_term(ix, am_normal, 0);
     else {
         char* err_str = erl_errno_id(err);
-        Eterm am_err = am_atom_put(err_str, sys_strlen(err_str));
+        Eterm am_err = erts_atom_put((byte *) err_str, sys_strlen(err_str),
+				     ERTS_ATOM_ENC_LATIN1, 1);
         return driver_failure_term(ix, am_err, 0);
     }
 }
@@ -4778,8 +4782,12 @@ int driver_failure(ErlDrvPort ix, int code)
 
 int driver_failure_atom(ErlDrvPort ix, char* string)
 {
-    Eterm am = am_atom_put(string, strlen(string));
-    return driver_failure_term(ix, am, 0);
+    return driver_failure_term(ix,
+			       erts_atom_put((byte *) string,
+					     strlen(string),
+					     ERTS_ATOM_ENC_LATIN1,
+					     1),
+			       0);
 }
 
 int driver_failure_posix(ErlDrvPort ix, int err)
@@ -4796,7 +4804,10 @@ int driver_failure_eof(ErlDrvPort ix)
 
 ErlDrvTermData driver_mk_atom(char* string)
 {
-    Eterm am = am_atom_put(string, sys_strlen(string));
+    Eterm am = erts_atom_put((byte *) string,
+			     sys_strlen(string),
+			     ERTS_ATOM_ENC_LATIN1,
+			     1);
     ERTS_SMP_CHK_NO_PROC_LOCKS;
     return (ErlDrvTermData) am;
 }
@@ -5091,7 +5102,10 @@ init_driver(erts_driver_t *drv, ErlDrvEntry *de, DE_Handle *handle)
 	erts_smp_mtx_init_x(drv->lock,
 			    "driver_lock",
 #if defined(ERTS_ENABLE_LOCK_CHECK) || defined(ERTS_ENABLE_LOCK_COUNT)
-			    am_atom_put(drv->name, sys_strlen(drv->name))
+			    erts_atom_put((byte *) drv->name,
+					  sys_strlen(drv->name),
+					  ERTS_ATOM_ENC_LATIN1,
+					  1)
 #else
 			    NIL
 #endif
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index 1969fc762c..97b6d01207 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -370,7 +370,7 @@ Eterm
 erts_bld_atom(Uint **hpp, Uint *szp, char *str)
 {
     if (hpp)
-	return am_atom_put(str, sys_strlen(str));
+	return erts_atom_put((byte *) str, sys_strlen(str), ERTS_ATOM_ENC_LATIN1, 1);
     else
 	return THE_NON_VALUE;
 }