erts: Support custom salt in enif_hash

14 files changed, 57 insertions, 47 deletions

diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 53b6fdeaa1..03c96dd3ca 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -827,11 +827,13 @@ typedef enum {
           </item>
           <tag><c>ERL_NIF_PHASH2</c></tag>
           <item>
-            <p>Portable hash function that gives the same hash for the same Erlang term
-              regardless of machine architecture and ERTS version. Corresponds to
-              <seealso marker="erlang#phash2-1"><c>erlang:phash2/1</c></seealso>.</p>
-            <p>Slower than <c>ERL_NIF_INTERNAL_HASH.</c></p>
+            <p>Portable hash function that gives the same hash for the
+              same Erlang term regardless of machine architecture and ERTS version.</p>
             <p>Generated hash values within <c>0..2^27-1</c>.</p>
+            <p>Slower than <c>ERL_NIF_INTERNAL_HASH.</c>
+              When used with <c>salt=0</c>,
+              it corresponds to
+              <seealso marker="erlang#phash2-1"><c>erlang:phash2/1</c></seealso>.</p>
           </item>
         </taglist>
       </item>
@@ -1411,12 +1413,15 @@ typedef enum {
     <func>
       <name>
         <ret>unsigned long</ret>
-        <nametext>enif_hash(ErlNifHash type, ERL_NIF_TERM term)</nametext>
+        <nametext>
+          enif_hash(ErlNifHash type, ERL_NIF_TERM term, unsigned long salt)
+        </nametext>
       </name>
       <fsummary>Hash terms.</fsummary>
       <desc>
-        <p>Hash terms according to the specified
-          <seealso marker="#ErlNifHash"><c>ErlNifHash</c></seealso> type.</p>
+        <p>Hash <c>term</c> according to the specified
+          <seealso marker="#ErlNifHash"><c>ErlNifHash</c></seealso> <c>type</c>
+          and using the least significant 32 bits of <c>salt</c>.</p>
         <p>Range of returned value depends on the hash type.</p>
       </desc>
     </func>
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 214de3652f..7473a8e43f 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -4881,7 +4881,7 @@ BIF_RETTYPE phash2_1(BIF_ALIST_1)
 {
     Uint32 hash;
 
-    hash = make_hash2(BIF_ARG_1);
+    hash = make_hash2(BIF_ARG_1, 0);
     BIF_RET(make_small(hash & ((1L << 27) - 1)));
 }
 
@@ -4901,7 +4901,7 @@ BIF_RETTYPE phash2_2(BIF_ALIST_2)
 	}
 	range = (Uint32) u;
     }
-    hash = make_hash2(BIF_ARG_1);
+    hash = make_hash2(BIF_ARG_1, 0);
     if (range) {
 	final_hash = hash % range; /* [0..range-1] */
     } else {
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 3a8687dc59..f2863f5d5b 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -3950,7 +3950,7 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 		BIF_RET(erts_debug_reader_groups_map(BIF_P, (int) groups));
 	    }
 	    else if (ERTS_IS_ATOM_STR("internal_hash", tp[1])) {
-		Uint hash = (Uint) make_internal_hash(tp[2]);
+		Uint hash = (Uint) make_internal_hash(tp[2], 0);
 		Uint hsz = 0;
 		Eterm* hp;
 		erts_bld_uint(NULL, &hsz, hash);
diff --git a/erts/emulator/beam/erl_db_hash.c b/erts/emulator/beam/erl_db_hash.c
index 7ab27df00c..07f6da7b6d 100644
--- a/erts/emulator/beam/erl_db_hash.c
+++ b/erts/emulator/beam/erl_db_hash.c
@@ -189,7 +189,7 @@ static ERTS_INLINE int add_fixed_deletion(DbTableHash* tb, int ix,
 /* optimised version of make_hash (normal case? atomic key) */
 #define MAKE_HASH(term) \
     ((is_atom(term) ? (atom_tab(atom_val(term))->slot.bucket.hvalue) : \
-      make_internal_hash(term)) % MAX_HASH)
+      make_internal_hash(term, 0)) % MAX_HASH)
 
 #ifdef ERTS_SMP
 #  define DB_HASH_LOCK_MASK (DB_HASH_LOCK_CNT-1)
diff --git a/erts/emulator/beam/erl_map.h b/erts/emulator/beam/erl_map.h
index 61a841f7f0..f7d0413685 100644
--- a/erts/emulator/beam/erl_map.h
+++ b/erts/emulator/beam/erl_map.h
@@ -57,7 +57,7 @@ typedef struct flatmap_s {
 
 
 #define hashmap_size(x)               (((hashmap_head_t*) hashmap_val(x))->size)
-#define hashmap_make_hash(Key)        make_internal_hash(Key)
+#define hashmap_make_hash(Key)        make_internal_hash(Key, 0)
 
 #define hashmap_restore_hash(Heap,Lvl,Key) \
     (((Lvl) < 8) ? hashmap_make_hash(Key) >> (4*(Lvl)) : hashmap_make_hash(CONS(Heap, make_small((Lvl)>>3), (Key))) >> (4*((Lvl) & 7)))
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 3470cf3fd5..bdfb7f3b8e 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -1214,7 +1214,7 @@ int enif_compare(Eterm lhs, Eterm rhs)
     return result;
 }
 
-unsigned long enif_hash(ErlNifHash type, Eterm term)
+unsigned long enif_hash(ErlNifHash type, Eterm term, unsigned long salt)
 {
 #if SIZEOF_LONG < 4
 /* This *really* shouldn't happen */
@@ -1222,9 +1222,9 @@ unsigned long enif_hash(ErlNifHash type, Eterm term)
 #endif
     switch (type) {
         case ERL_NIF_INTERNAL_HASH:
-            return make_internal_hash(term);
+            return make_internal_hash(term, salt);
         case ERL_NIF_PHASH2:
-            return make_hash2(term) & ((1 << 27) - 1);
+            return make_hash2(term, salt) & ((1 << 27) - 1);
         default:
             return 0;
     }
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index f52c841ed7..6b9f78d46b 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -47,7 +47,7 @@ ERL_NIF_API_FUNC_DECL(int,enif_get_list_cell,(ErlNifEnv* env, ERL_NIF_TERM term,
 ERL_NIF_API_FUNC_DECL(int,enif_get_tuple,(ErlNifEnv* env, ERL_NIF_TERM tpl, int* arity, const ERL_NIF_TERM** array));
 ERL_NIF_API_FUNC_DECL(int,enif_is_identical,(ERL_NIF_TERM lhs, ERL_NIF_TERM rhs));
 ERL_NIF_API_FUNC_DECL(int,enif_compare,(ERL_NIF_TERM lhs, ERL_NIF_TERM rhs));
-ERL_NIF_API_FUNC_DECL(unsigned long,enif_hash,(ErlNifHash type, ERL_NIF_TERM term));
+ERL_NIF_API_FUNC_DECL(unsigned long,enif_hash,(ErlNifHash type, ERL_NIF_TERM term, unsigned long salt));
 ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_make_binary,(ErlNifEnv* env, ErlNifBinary* bin));
 ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_make_badarg,(ErlNifEnv* env));
 ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_make_int,(ErlNifEnv* env, int i));
diff --git a/erts/emulator/beam/erl_process_dict.c b/erts/emulator/beam/erl_process_dict.c
index 7cfdf20341..01e240c65d 100644
--- a/erts/emulator/beam/erl_process_dict.c
+++ b/erts/emulator/beam/erl_process_dict.c
@@ -57,7 +57,7 @@
     ((is_small(Term)) ? (Uint32) unsigned_val(Term) :  \
      ((is_atom(Term)) ?                                \
       (Uint32) atom_val(Term) :                        \
-      make_internal_hash(Term)))
+      make_internal_hash(Term, 0)))
 
 #define PD_SZ2BYTES(Sz) (sizeof(ProcDict) + ((Sz) - 1)*sizeof(Eterm))
 
diff --git a/erts/emulator/beam/erl_trace.c b/erts/emulator/beam/erl_trace.c
index 04f3160d42..8855449ca1 100644
--- a/erts/emulator/beam/erl_trace.c
+++ b/erts/emulator/beam/erl_trace.c
@@ -3230,7 +3230,7 @@ static int tracer_cmp_fun(void* a, void* b)
 
 static HashValue tracer_hash_fun(void* obj)
 {
-    return make_internal_hash(((ErtsTracerNif*)obj)->module);
+    return make_internal_hash(((ErtsTracerNif*)obj)->module, 0);
 }
 
 static void *tracer_alloc_fun(void* tmpl)
diff --git a/erts/emulator/beam/erl_utils.h b/erts/emulator/beam/erl_utils.h
index 47289a0af1..b38beaf93d 100644
--- a/erts/emulator/beam/erl_utils.h
+++ b/erts/emulator/beam/erl_utils.h
@@ -118,9 +118,9 @@ int erts_fit_in_bits_uint(Uint);
 Sint erts_list_length(Eterm);
 int erts_is_builtin(Eterm, Eterm, int);
 Uint32 block_hash(byte *, unsigned, Uint32);
-Uint32 make_hash2(Eterm);
+Uint32 make_hash2(Eterm, Uint32 salt);
 Uint32 make_hash(Eterm);
-Uint32 make_internal_hash(Eterm);
+Uint32 make_internal_hash(Eterm, Uint32 salt);
 
 void erts_save_emu_args(int argc, char **argv);
 Eterm erts_get_emu_args(struct process *c_p);
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index 8f3f48f38f..2378c057dd 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -1003,7 +1003,7 @@ tail_recur:
 	    break;
 	}
     case MAP_DEF:
-        hash = hash*FUNNY_NUMBER13 + FUNNY_NUMBER14 + make_hash2(term);
+        hash = hash*FUNNY_NUMBER13 + FUNNY_NUMBER14 + make_hash2(term, 0);
         break;
     case TUPLE_DEF:
 	{
@@ -1109,7 +1109,7 @@ block_hash(byte *k, unsigned length, Uint32 initval)
 }
 
 Uint32
-make_hash2(Eterm term)
+make_hash2(Eterm term, Uint32 salt)
 {
     Uint32 hash;
     Uint32 hash_xor_pairs;
@@ -1179,7 +1179,7 @@ make_hash2(Eterm term)
 	    switch (term & _TAG_IMMED2_MASK) {
 	    case _TAG_IMMED2_ATOM:
 		/* Fast, but the poor hash value should be mixed. */
-		return atom_tab(atom_val(term))->slot.bucket.hvalue;
+		return atom_tab(atom_val(term))->slot.bucket.hvalue ^ salt;
 	    }
 	    break;
 	case _TAG_IMMED1_SMALL:
@@ -1190,7 +1190,7 @@ make_hash2(Eterm term)
 		  term = small_to_big(x, tmp_big);
 		  break;
 	      }
-	      hash = 0;
+	      hash = salt;
 	      SINT32_HASH(x, HCONST);
 	      return hash;
 	  }
@@ -1201,7 +1201,7 @@ make_hash2(Eterm term)
     DECLARE_ESTACK(s);
 
     UseTmpHeapNoproc(2);
-    hash = 0;
+    hash = salt;
     for (;;) {
 	switch (primary_tag(term)) {
 	case TAG_PRIMARY_LIST:
@@ -1277,7 +1277,7 @@ make_hash2(Eterm term)
                     ESTACK_PUSH(s, hash_xor_pairs);
                     ESTACK_PUSH(s, hash);
                     ESTACK_PUSH(s, HASH_MAP_TAIL);
-                    hash = 0;
+                    hash = salt;
                     hash_xor_pairs = 0;
                     for (i = size - 1; i >= 0; i--) {
                         ESTACK_PUSH(s, HASH_MAP_PAIR);
@@ -1296,7 +1296,7 @@ make_hash2(Eterm term)
                     ESTACK_PUSH(s, hash_xor_pairs);
                     ESTACK_PUSH(s, hash);
                     ESTACK_PUSH(s, HASH_MAP_TAIL);
-                    hash = 0;
+                    hash = salt;
                     hash_xor_pairs = 0;
                 }
                 switch (hdr & _HEADER_MAP_SUBTAG_MASK) {
@@ -1471,7 +1471,7 @@ make_hash2(Eterm term)
 	    break;
 
 	    default:
-		erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X)\n", term);
+		erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X, %lu)\n", term, salt);
 	    }
 	}
 	break;
@@ -1488,21 +1488,21 @@ make_hash2(Eterm term)
 	    case _TAG_IMMED1_IMMED2:
 		switch (term & _TAG_IMMED2_MASK) {
 		case _TAG_IMMED2_ATOM:
-		    if (hash == 0)
+		    if (hash == salt)
 			/* Fast, but the poor hash value should be mixed. */
-			hash = atom_tab(atom_val(term))->slot.bucket.hvalue;
+			hash = atom_tab(atom_val(term))->slot.bucket.hvalue ^ salt;
 		    else
 			UINT32_HASH(atom_tab(atom_val(term))->slot.bucket.hvalue,
 				    HCONST_3);
 		    goto hash2_common;
 		case _TAG_IMMED2_NIL:
-		    if (hash == 0)
-			hash = 3468870702UL;
+		    if (hash == salt)
+			hash = 3468870702UL ^ salt;
 		    else
 			UINT32_HASH(NIL_DEF, HCONST_2);
 		    goto hash2_common;
 		default:
-		    erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X)\n", term);
+		    erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X, %lu)\n", term, salt);
 		}
 	    case _TAG_IMMED1_SMALL:
 	      {
@@ -1518,7 +1518,7 @@ make_hash2(Eterm term)
 	    }
 	    break;
 	default:
-	    erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X)\n", term);
+	    erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X, %lu)\n", term, salt);
 	hash2_common:
 
 	    /* Uint32 hash always has the hash value of the previous term,
@@ -1542,7 +1542,7 @@ make_hash2(Eterm term)
 		}
 		case HASH_MAP_PAIR:
 		    hash_xor_pairs ^= hash;
-                    hash = 0;
+                    hash = salt;
 		    goto hash2_common;
 		default:
 		    break;
@@ -1578,7 +1578,7 @@ do {  /* Lightweight mixing of constant (type info) */  \
 } while (0)
 
 Uint32
-make_internal_hash(Eterm term)
+make_internal_hash(Eterm term, Uint32 salt)
 {
     Uint32 hash;
     Uint32 hash_xor_pairs;
@@ -1587,7 +1587,7 @@ make_internal_hash(Eterm term)
 
     /* Optimization. Simple cases before declaration of estack. */
     if (primary_tag(term) == TAG_PRIMARY_IMMED1) {
-        hash = 0;
+        hash = salt;
     #if ERTS_SIZEOF_ETERM == 8
         UINT32_HASH_2((Uint32)term, (Uint32)(term >> 32), HCONST);
     #elif ERTS_SIZEOF_ETERM == 4
@@ -1601,7 +1601,7 @@ make_internal_hash(Eterm term)
     Eterm tmp;
     DECLARE_ESTACK(s);
 
-    hash = 0;
+    hash = salt;
     for (;;) {
 	switch (primary_tag(term)) {
 	case TAG_PRIMARY_LIST:
@@ -1894,7 +1894,7 @@ make_internal_hash(Eterm term)
 		goto pop_next;
 	    }
 	    default:
-		erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X)\n", term);
+		erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_internal_hash(0x%X, %lu)\n", term, salt);
 	    }
 	}
 	break;
@@ -1907,7 +1907,7 @@ make_internal_hash(Eterm term)
             goto pop_next;
 
 	default:
-	    erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_hash2(0x%X)\n", term);
+	    erts_exit(ERTS_ERROR_EXIT, "Invalid tag in make_internal_hash(0x%X, %lu)\n", term, salt);
 
 	pop_next:
 	    if (ESTACK_ISEMPTY(s)) {
diff --git a/erts/emulator/hipe/hipe_bif0.c b/erts/emulator/hipe/hipe_bif0.c
index 8b420b9e9b..b7297043e5 100644
--- a/erts/emulator/hipe/hipe_bif0.c
+++ b/erts/emulator/hipe/hipe_bif0.c
@@ -496,7 +496,7 @@ static ErlOffHeap const_term_table_off_heap;
 
 static HashValue const_term_hash(void *tmpl)
 {
-    return make_hash2((Eterm)tmpl);
+    return make_hash2((Eterm)tmpl, 0);
 }
 
 static int const_term_cmp(void *tmpl, void *bucket)
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index e177fa4963..36af68be60 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -2628,7 +2628,7 @@ nif_internal_hash(Config) ->
     OnesPerBit =
         lists:foldl(
           fun (Term, Acc) ->
-                  NifHashValue = hash_nif(internal, Term),
+                  NifHashValue = hash_nif(internal, Term, 0),
                   lists:foldl(
                     fun (BitIndex, AccB) ->
                             BitValue = (NifHashValue band (1 bsl BitIndex)) bsr BitIndex,
@@ -2661,7 +2661,7 @@ nif_phash2(Config) ->
     lists:foreach(
       fun (Term) ->
               HashValue = erlang:phash2(Term),
-              NifHashValue = hash_nif(phash2, Term),
+              NifHashValue = hash_nif(phash2, Term, 0),
               (HashValue =:= NifHashValue
                orelse ct:fail("Expected: ~p\nActual:   ~p",
                               [HashValue, NifHashValue]))
@@ -2714,7 +2714,7 @@ type_test() -> ?nif_stub.
 tuple_2_list(_) -> ?nif_stub.    
 is_identical(_,_) -> ?nif_stub.
 compare(_,_) -> ?nif_stub.
-hash_nif(_, _) -> ?nif_stub.
+hash_nif(_Type, _Term, _Salt) -> ?nif_stub.
 many_args_100(_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_) -> ?nif_stub.
 clone_bin(_) -> ?nif_stub.
 make_sub_bin(_,_,_) -> ?nif_stub.
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index 9d65b9c09b..2a80d48b62 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -689,7 +689,7 @@ static ERL_NIF_TERM compare(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 
 static ERL_NIF_TERM hash_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 {
-    if (argc != 2) {
+    if (argc != 3) {
         return enif_make_badarg(env);
     }
 
@@ -704,7 +704,12 @@ static ERL_NIF_TERM hash_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]
         return enif_make_badarg(env);
     }
 
-    return enif_make_ulong(env, enif_hash(type, argv[1]));
+    unsigned long salt;
+    if (! enif_get_ulong(env, argv[2], &salt)) {
+        return enif_make_badarg(env);
+    }
+
+    return enif_make_ulong(env, enif_hash(type, argv[1], salt));
 }
 
 static ERL_NIF_TERM many_args_100(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
@@ -2884,7 +2889,7 @@ static ErlNifFunc nif_funcs[] =
     {"tuple_2_list", 1, tuple_2_list},
     {"is_identical",2,is_identical},
     {"compare",2,compare},
-    {"hash_nif",2,hash_nif},
+    {"hash_nif",3,hash_nif},
     {"many_args_100", 100, many_args_100},
     {"clone_bin", 1, clone_bin},
     {"make_sub_bin", 3, make_sub_bin},