Merge branch 'bjorn/better-fun-info/OTP-15837'

* bjorn/better-fun-info/OTP-15837:
  Create a shared wrapper function for all occurrences of 'fun F/A'
  Support sharing of fun entries in the runtime system
  erl_fun.c: Remove unused struct definition
  hipe: Use the new index when translating funs
  Stop supporting decoding of old funs in the external term format
  genop.tab: Insert an "OTP 23" comment for clarity

15 files changed, 203 insertions, 221 deletions

diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index 0de694f449..9add87d944 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -315,6 +315,7 @@ typedef struct LoaderState {
 				 * (or 0 if there is no on_load function)
 				 */
     int otp_20_or_higher;       /* Compiled with OTP 20 or higher */
+    unsigned max_opcode;        /* Highest opcode used in module */
 
     /*
      * Atom table.
@@ -1588,6 +1589,17 @@ static int
 read_lambda_table(LoaderState* stp)
 {
     unsigned int i;
+    unsigned int otp_22_or_lower;
+
+    /*
+     * Determine whether this module was compiled with OTP 22 or lower
+     * by looking at the max opcode number. The compiler in OTP 23 will
+     * always set the max opcode to the opcode for `swap` (whether
+     * actually used or not) so that a module compiled for OTP 23
+     * cannot be loaded in earlier versions.
+     */
+
+    otp_22_or_lower = stp->max_opcode < genop_swap_2;
 
     GetInt(stp, 4, stp->num_lambdas);
     if (stp->num_lambdas > stp->lambdas_allocated) {
@@ -1619,6 +1631,29 @@ read_lambda_table(LoaderState* stp)
 	GetInt(stp, 4, Index);
 	GetInt(stp, 4, stp->lambdas[i].num_free);
 	GetInt(stp, 4, OldUniq);
+
+        /*
+         * Fun entries are now keyed by the explicit ("new") index in
+         * the fun entry. That allows multiple make_fun2 instructions
+         * to share the same fun entry (when the `fun F/A` syntax is
+         * used). Before OTP 23, fun entries were keyed by the old
+         * index, which is the order of the entries in the fun
+         * chunk. Each make_fun2 needed to refer to its own fun entry.
+         *
+         * Modules compiled before OTP 23 can safely be loaded if the
+         * old index and the new index are equal. That is true for all
+         * modules compiled with OTP R15 and later.
+         */
+        if (otp_22_or_lower && i != Index) {
+            /*
+             * Compiled with a compiler before OTP R15B. The new indices
+             * are not reliable, so it is not safe to load this module.
+             */
+            LoadError2(stp, "please re-compile this module with an "
+                       ERLANG_OTP_RELEASE " compiler "
+                       "(old-style fun with indices: %d/%d)",
+                       i, Index);
+        }
 	fe = erts_put_fun_entry2(stp->module, OldUniq, i, stp->mod_md5,
 				 Index, arity-stp->lambdas[i].num_free);
 	stp->lambdas[i].fe = fe;
@@ -1839,7 +1874,6 @@ read_code_header(LoaderState* stp)
 {
     unsigned head_size;
     unsigned version;
-    unsigned opcode_max;
     int i;
 
     /*
@@ -1871,8 +1905,8 @@ read_code_header(LoaderState* stp)
     /*
      * Verify the number of the highest opcode used.
      */
-    GetInt(stp, 4, opcode_max);
-    if (opcode_max > MAX_GENERIC_OPCODE) {
+    GetInt(stp, 4, stp->max_opcode);
+    if (stp->max_opcode > MAX_GENERIC_OPCODE) {
 	LoadError2(stp,
 		   "This BEAM file was compiled for a later version"
 		   " of the run-time system than " ERLANG_OTP_RELEASE ".\n"
@@ -1880,7 +1914,7 @@ read_code_header(LoaderState* stp)
 		   ERLANG_OTP_RELEASE " compiler.\n"
 		   "  (Use of opcode %d; this emulator supports "
 		   "only up to %d.)",
-		   opcode_max, MAX_GENERIC_OPCODE);
+		   stp->max_opcode, MAX_GENERIC_OPCODE);
     }
 
     GetInt(stp, 4, stp->num_labels);
diff --git a/erts/emulator/beam/erl_fun.c b/erts/emulator/beam/erl_fun.c
index 9c866250bb..257f9bf5b3 100644
--- a/erts/emulator/beam/erl_fun.c
+++ b/erts/emulator/beam/erl_fun.c
@@ -100,27 +100,6 @@ int erts_fun_table_sz(void)
 }
 
 ErlFunEntry*
-erts_put_fun_entry(Eterm mod, int uniq, int index)
-{
-    ErlFunEntry template;
-    ErlFunEntry* fe;
-    erts_aint_t refc;
-    ASSERT(is_atom(mod));
-    template.old_uniq = uniq;
-    template.old_index = index;
-    template.module = mod;
-    erts_fun_write_lock();
-    fe = (ErlFunEntry *) hash_put(&erts_fun_table, (void*) &template);
-    sys_memset(fe->uniq, 0, sizeof(fe->uniq));
-    fe->index = 0;
-    refc = erts_refc_inctest(&fe->refc, 0);
-    if (refc < 2) /* New or pending delete */
-	erts_refc_inc(&fe->refc, 1);
-    erts_fun_write_unlock();
-    return fe;
-}
-
-ErlFunEntry*
 erts_put_fun_entry2(Eterm mod, int old_uniq, int old_index,
 		    byte* uniq, int index, int arity)
 {
@@ -130,12 +109,12 @@ erts_put_fun_entry2(Eterm mod, int old_uniq, int old_index,
 
     ASSERT(is_atom(mod));
     template.old_uniq = old_uniq;
-    template.old_index = old_index;
+    template.index = index;
     template.module = mod;
     erts_fun_write_lock();
     fe = (ErlFunEntry *) hash_put(&erts_fun_table, (void*) &template);
     sys_memcpy(fe->uniq, uniq, sizeof(fe->uniq));
-    fe->index = index;
+    fe->old_index = old_index;
     fe->arity = arity;
     refc = erts_refc_inctest(&fe->refc, 0);
     if (refc < 2) /* New or pending delete */
@@ -144,13 +123,6 @@ erts_put_fun_entry2(Eterm mod, int old_uniq, int old_index,
     return fe;
 }
 
-struct my_key {
-    Eterm mod;
-    byte* uniq;
-    int index;
-    ErlFunEntry* fe;
-};
-
 ErlFunEntry*
 erts_get_fun_entry(Eterm mod, int uniq, int index)
 {
@@ -159,7 +131,7 @@ erts_get_fun_entry(Eterm mod, int uniq, int index)
 
     ASSERT(is_atom(mod));
     template.old_uniq = uniq;
-    template.old_index = index;
+    template.index = index;
     template.module = mod;
     erts_fun_read_lock();
     ret = (ErlFunEntry *) hash_get(&erts_fun_table, (void*) &template);
@@ -315,15 +287,27 @@ erts_dump_fun_entries(fmtfn_t to, void *to_arg)
 static HashValue
 fun_hash(ErlFunEntry* obj)
 {
-    return (HashValue) (obj->old_uniq ^ obj->old_index ^ atom_val(obj->module));
+    return (HashValue) (obj->old_uniq ^ obj->index ^ atom_val(obj->module));
 }
 
 static int
 fun_cmp(ErlFunEntry* obj1, ErlFunEntry* obj2)
 {
-    return !(obj1->module == obj2->module && 
+    /*
+     * OTP 23: Use 'index' (instead of 'old_index') when comparing fun
+     * entries. In OTP 23, multiple make_fun2 instructions may refer to the
+     * the same 'index' (for the wrapper function generated for the
+     * 'fun F/A' syntax).
+     *
+     * This is safe when loading code compiled with OTP R15 and later,
+     * because since R15 (2011), the 'index' has been reliably equal
+     * to 'old_index'. The loader refuses to load modules compiled before
+     * OTP R15.
+     */
+
+    return !(obj1->module == obj2->module &&
 	     obj1->old_uniq == obj2->old_uniq &&
-	     obj1->old_index == obj2->old_index);
+	     obj1->index == obj2->index);
 }
 
 static ErlFunEntry*
@@ -333,7 +317,7 @@ fun_alloc(ErlFunEntry* template)
 						  sizeof(ErlFunEntry));
 
     obj->old_uniq = template->old_uniq;
-    obj->old_index = template->old_index;
+    obj->index = template->index;
     obj->module = template->module;
     erts_refc_init(&obj->refc, -1);
     obj->address = unloaded_fun;
diff --git a/erts/emulator/beam/erl_fun.h b/erts/emulator/beam/erl_fun.h
index fb2901d866..eefc7a95bb 100644
--- a/erts/emulator/beam/erl_fun.h
+++ b/erts/emulator/beam/erl_fun.h
@@ -74,7 +74,6 @@ void erts_init_fun_table(void);
 void erts_fun_info(fmtfn_t, void *);
 int erts_fun_table_sz(void);
 
-ErlFunEntry* erts_put_fun_entry(Eterm mod, int uniq, int index);
 ErlFunEntry* erts_get_fun_entry(Eterm mod, int uniq, int index);
 
 ErlFunEntry* erts_put_fun_entry2(Eterm mod, int old_uniq, int old_index,
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index ec67ab2aed..8a8e62a608 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -4011,73 +4011,6 @@ dec_term_atom_common:
 		next = &(funp->creator);
 		break;
 	    }
-	case FUN_EXT:
-	    {
-		ErlFunThing* funp = (ErlFunThing *) hp;
-		Eterm module;
-		Sint old_uniq;
-		Sint old_index;
-		unsigned num_free;
-		int i;
-		Eterm temp;
-
-		num_free = get_int32(ep);
-		ep += 4;
-		hp += ERL_FUN_SIZE;
-		hp += num_free;
-		factory->hp = hp;
-		funp->thing_word = HEADER_FUN;
-		funp->num_free = num_free;
-		*objp = make_fun(funp);
-
-		/* Creator pid */
-		if ((*ep != PID_EXT && *ep != NEW_PID_EXT)
-		    || (ep = dec_pid(edep, factory, ep+1,
-				     &funp->creator, *ep))==NULL) {
-		    goto error;
-		}
-
-		/* Module */
-		if ((ep = dec_atom(edep, ep, &module)) == NULL) {
-		    goto error;
-		}
-
-		/* Index */
-		if ((ep = dec_term(edep, factory, ep, &temp, NULL)) == NULL) {
-		    goto error;
-		}
-		if (!is_small(temp)) {
-		    goto error;
-		}
-		old_index = unsigned_val(temp);
-
-		/* Uniq */
-		if ((ep = dec_term(edep, factory, ep, &temp, NULL)) == NULL) {
-		    goto error;
-		}
-		if (!is_small(temp)) {
-		    goto error;
-		}
-		
-		/*
-		 * It is safe to link the fun into the fun list only when
-		 * no more validity tests can fail.
-		 */
-		funp->next = factory->off_heap->first;
-		factory->off_heap->first = (struct erl_off_heap_header*)funp;
-		old_uniq = unsigned_val(temp);
-
-		funp->fe = erts_put_fun_entry(module, old_uniq, old_index);
-		funp->arity = funp->fe->address[-1] - num_free;
-		hp = factory->hp;
-
-		/* Environment */
-		for (i = num_free-1; i >= 0; i--) {
-		    funp->env[i] = (Eterm) next;
-		    next = funp->env + i;
-		}
-		break;
-	    }
 	case ATOM_INTERNAL_REF2:
 	    n = get_int16(ep);
 	    ep += 2;
@@ -4836,9 +4769,6 @@ init_done:
 		total_size = get_int32(ep);
 		CHKSIZE(total_size);		
 		ep += 1+16+4+4;
-		/*FALLTHROUGH*/
-
-	    case FUN_EXT:
 		CHKSIZE(4);
 		num_free = get_int32(ep);
 		ep += 4;
@@ -4849,6 +4779,12 @@ init_done:
 		heap_size += ERL_FUN_SIZE + num_free;
 		break;
 	    }
+	case FUN_EXT:
+            /*
+             * OTP 23: No longer support decoding the old fun
+             * representation.
+             */
+            goto error;
 	case ATOM_INTERNAL_REF2:
 	    SKIP(2+atom_extra_skip);
 	    atom_extra_skip = 0;
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index 88cdcc2675..ad71828d72 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -907,7 +907,7 @@ tail_recur:
 	    hash = hash * FUNNY_NUMBER10 + num_free;
 	    hash = hash*FUNNY_NUMBER1 +
 		(atom_tab(atom_val(funp->fe->module))->slot.bucket.hvalue);
-	    hash = hash*FUNNY_NUMBER2 + funp->fe->old_index;
+	    hash = hash*FUNNY_NUMBER2 + funp->fe->index;
 	    hash = hash*FUNNY_NUMBER2 + funp->fe->old_uniq;
 	    if (num_free > 0) {
 		if (num_free > 1) {
@@ -1636,7 +1636,7 @@ make_hash2_helper(Eterm term_param, const int can_trap, Eterm* state_mref_write_
 		     atom_tab(atom_val(funp->fe->module))->slot.bucket.hvalue,
 		     HCONST);
 		UINT32_HASH_2
-		    (funp->fe->old_index, funp->fe->old_uniq, HCONST);
+		    (funp->fe->index, funp->fe->old_uniq, HCONST);
 		if (ctx.num_free == 0) {
 		    goto hash2_common;
 		} else {
@@ -2160,7 +2160,7 @@ make_internal_hash(Eterm term, Uint32 salt)
 		ErlFunThing* funp = (ErlFunThing *) fun_val(term);
 		Uint num_free = funp->num_free;
                 UINT32_HASH_2(num_free, funp->fe->module, HCONST_20);
-                UINT32_HASH_2(funp->fe->old_index, funp->fe->old_uniq, HCONST_21);
+                UINT32_HASH_2(funp->fe->index, funp->fe->old_uniq, HCONST_21);
 		if (num_free == 0) {
 		    goto pop_next;
 		} else {
@@ -2810,7 +2810,7 @@ tailrecur_ne:
 		    f1 = (ErlFunThing *) fun_val(a);
 		    f2 = (ErlFunThing *) fun_val(b);
 		    if (f1->fe->module != f2->fe->module ||
-			f1->fe->old_index != f2->fe->old_index ||
+			f1->fe->index != f2->fe->index ||
 			f1->fe->old_uniq != f2->fe->old_uniq ||
 			f1->num_free != f2->num_free) {
 			goto not_equal;
@@ -3405,7 +3405,7 @@ tailrecur_ne:
 		    if (diff != 0) {
 			RETURN_NEQ(diff);
 		    }
-		    diff = f1->fe->old_index - f2->fe->old_index;
+		    diff = f1->fe->index - f2->fe->index;
 		    if (diff != 0) {
 			RETURN_NEQ(diff);
 		    }
diff --git a/erts/emulator/test/hash_SUITE.erl b/erts/emulator/test/hash_SUITE.erl
index 1bf9e033bf..dd71c3da58 100644
--- a/erts/emulator/test/hash_SUITE.erl
+++ b/erts/emulator/test/hash_SUITE.erl
@@ -223,26 +223,17 @@ basic_test() ->
 				    16#77777777777777],16#FFFFFFFF),
     ExternalReference = <<131,114,0,3,100,0,13,110,111,110,111,100,101,64,
 			 110,111,104,111,115,116,0,0,0,0,122,0,0,0,0,0,0,0,0>>,
-    1113403635 = erlang:phash(binary_to_term(ExternalReference),
-				    16#FFFFFFFF),
-    ExternalFun = <<131,117,0,0,0,3,103,100,0,13,110,111,110,111,100,101,64,
-		   110,111,104,111,115,116,0,0,0,38,0,0,0,0,0,100,0,8,101,
-		   114,108,95,101,118,97,108,97,20,98,5,182,139,98,108,0,0,
-		   0,3,104,2,100,0,1,66,109,0,0,0,33,131,114,0,3,100,0,13,
-		   110,111,110,111,100,101,64,110,111,104,111,115,116,0,0,
-		   0,0,122,0,0,0,0,0,0,0,0,104,2,100,0,1,76,107,0,33,131,
-		   114,0,3,100,0,13,110,111,110,111,100,101,64,110,111,104,
-		   111,115,116,0,0,0,0,122,0,0,0,0,0,0,0,0,104,2,100,0,1,82,
-		   114,0,3,100,0,13,110,111,110,111,100,101,64,110,111,104,
-		   111,115,116,0,0,0,0,122,0,0,0,0,0,0,0,0,106,108,0,0,0,1,
-		   104,5,100,0,6,99,108,97,117,115,101,97,1,106,106,108,0,0,
-		   0,1,104,3,100,0,7,105,110,116,101,103,101,114,97,1,97,1,
-		   106,106,104,3,100,0,4,101,118,97,108,104,2,100,0,5,115,
-		   104,101,108,108,100,0,10,108,111,99,97,108,95,102,117,
-		   110,99,108,0,0,0,1,103,100,0,13,110,111,110,111,100,101,
-		   64,110,111,104,111,115,116,0,0,0,22,0,0,0,0,0,106>>,
-    170987488 = erlang:phash(binary_to_term(ExternalFun),
-				   16#FFFFFFFF),
+    ExternalReference = <<131,114,0,3,100,0,13,110,111,110,111,100,101,64,
+			 110,111,104,111,115,116,0,0,0,0,122,0,0,0,0,0,0,0,0>>,
+    1113403635 = phash_from_external(ExternalReference),
+
+    ExternalFun = <<131,112,0,0,0,70,1,212,190,220,28,179,144,194,131,
+                    19,215,105,97,77,251,125,93,0,0,0,0,0,0,0,2,100,0,1,
+                    116,97,0,98,6,165,246,224,103,100,0,13,110,111,
+                    110,111,100,101,64,110,111,104,111,115,116,0,0,0,91,
+                    0,0,0,0,0,97,2,97,1>>,
+    25769064 = phash_from_external(ExternalFun),
+
     case (catch erlang:phash(1,0)) of
 	{'EXIT',{badarg, _}} ->
 	    ok;
@@ -250,6 +241,8 @@ basic_test() ->
 	    exit(phash_accepted_zero_as_range)
     end.
 
+phash_from_external(Ext) ->
+    erlang:phash(binary_to_term(Ext), 16#FFFFFFFF).
 
 range_test() ->
     F = fun(From,From,_FF) ->
diff --git a/lib/compiler/src/beam_asm.erl b/lib/compiler/src/beam_asm.erl
index df09dcb06c..60e19ec596 100644
--- a/lib/compiler/src/beam_asm.erl
+++ b/lib/compiler/src/beam_asm.erl
@@ -64,11 +64,30 @@ module(Code, ExtraChunks, CompileInfo, CompilerOpts) ->
 assemble({Mod,Exp0,Attr0,Asm0,NumLabels}, ExtraChunks, CompileInfo, CompilerOpts) ->
     {1,Dict0} = beam_dict:atom(Mod, beam_dict:new()),
     {0,Dict1} = beam_dict:fname(atom_to_list(Mod) ++ ".erl", Dict0),
+    Dict2 = shared_fun_wrappers(CompilerOpts, Dict1),
     NumFuncs = length(Asm0),
     {Asm,Attr} = on_load(Asm0, Attr0),
     Exp = cerl_sets:from_list(Exp0),
-    {Code,Dict2} = assemble_1(Asm, Exp, Dict1, []),
-    build_file(Code, Attr, Dict2, NumLabels, NumFuncs, ExtraChunks, CompileInfo, CompilerOpts).
+    {Code,Dict} = assemble_1(Asm, Exp, Dict2, []),
+    build_file(Code, Attr, Dict, NumLabels, NumFuncs,
+               ExtraChunks, CompileInfo, CompilerOpts).
+
+shared_fun_wrappers(Opts, Dict) ->
+    case proplists:get_bool(no_shared_fun_wrappers, Opts) of
+        false ->
+            %% The compiler in OTP 23 depends on the on the loader
+            %% using the new indices in funs and being able to have
+            %% multiple make_fun2 instructions referring to the same
+            %% fun entry. Artificially set the highest opcode for the
+            %% module to ensure that it cannot be loaded in OTP 22
+            %% and earlier.
+            Swap = beam_opcodes:opcode(swap, 2),
+            beam_dict:opcode(Swap, Dict);
+        true ->
+            %% Fun wrappers are not shared for compatibility with a
+            %% previous OTP release.
+            Dict
+    end.
 
 on_load(Fs0, Attr0) ->
     case proplists:get_value(on_load, Attr0) of
diff --git a/lib/compiler/src/beam_dict.erl b/lib/compiler/src/beam_dict.erl
index b2056332e6..4d0cec857d 100644
--- a/lib/compiler/src/beam_dict.erl
+++ b/lib/compiler/src/beam_dict.erl
@@ -40,6 +40,7 @@
 
 -type lambda_info() :: {label(),{index(),label(),non_neg_integer()}}.
 -type lambda_tab() :: {non_neg_integer(),[lambda_info()]}.
+-type wrapper() :: #{label() => index()}.
 
 -record(asm,
 	{atoms = #{}                :: atom_tab(),
@@ -48,6 +49,7 @@
 	 imports = gb_trees:empty() :: import_tab(),
 	 strings = <<>>		    :: binary(),	%String pool
 	 lambdas = {0,[]}           :: lambda_tab(),
+         wrappers = #{}             :: wrapper(),
 	 literals = dict:new()	    :: literal_tab(),
 	 fnames = #{}               :: fname_tab(),
 	 lines = #{}                :: line_tab(),
@@ -147,11 +149,21 @@ string(BinString, Dict) when is_binary(BinString) ->
 -spec lambda(label(), non_neg_integer(), bdict()) ->
         {non_neg_integer(), bdict()}.
 
-lambda(Lbl, NumFree, #asm{lambdas={OldIndex,Lambdas0}}=Dict) ->
-    %% Set Index the same as OldIndex.
-    Index = OldIndex,
-    Lambdas = [{Lbl,{Index,Lbl,NumFree}}|Lambdas0],
-    {OldIndex,Dict#asm{lambdas={OldIndex+1,Lambdas}}}.
+lambda(Lbl, NumFree, #asm{wrappers=Wrappers0,
+                          lambdas={OldIndex,Lambdas0}}=Dict) ->
+    case Wrappers0 of
+        #{Lbl:=Index} ->
+            %% OTP 23: There old is a fun entry for this wrapper function.
+            %% Share the fun entry.
+            {Index,Dict};
+        #{} ->
+            %% Set Index the same as OldIndex.
+            Index = OldIndex,
+            Wrappers = Wrappers0#{Lbl=>Index},
+            Lambdas = [{Lbl,{Index,Lbl,NumFree}}|Lambdas0],
+            {OldIndex,Dict#asm{wrappers=Wrappers,
+                               lambdas={OldIndex+1,Lambdas}}}
+    end.
 
 %% Returns the index for a literal (adding it to the literal table if necessary).
 %%    literal(Literal, Dict) -> {Index,Dict'}
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index 098f82fdc0..42f9e8b902 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -265,9 +265,10 @@ expand_opt(r19, Os) ->
 expand_opt(r20, Os) ->
     expand_opt_before_21(Os);
 expand_opt(r21, Os) ->
-    [no_swap, no_put_tuple2 | expand_opt(no_bsm3, Os)];
+    [no_shared_fun_wrappers,
+     no_swap, no_put_tuple2 | expand_opt(no_bsm3, Os)];
 expand_opt(r22, Os) ->
-    [no_swap | Os];
+    [no_shared_fun_wrappers, no_swap | Os];
 expand_opt({debug_info_key,_}=O, Os) ->
     [encrypt_debug_info,O|Os];
 expand_opt(no_type_opt, Os) ->
@@ -277,7 +278,8 @@ expand_opt(no_type_opt, Os) ->
 expand_opt(O, Os) -> [O|Os].
 
 expand_opt_before_21(Os) ->
-    [no_swap, no_put_tuple2, no_get_hd_tl, no_ssa_opt_record,
+    [no_shared_fun_wrappers, no_swap,
+     no_put_tuple2, no_get_hd_tl, no_ssa_opt_record,
      no_utf8_atoms | expand_opt(no_bsm3, Os)].
 
 %% format_error(ErrorDescriptor) -> string()
diff --git a/lib/compiler/src/genop.tab b/lib/compiler/src/genop.tab
index 03507bafb3..0a38d17857 100755
--- a/lib/compiler/src/genop.tab
+++ b/lib/compiler/src/genop.tab
@@ -597,6 +597,8 @@ BEAM_FORMAT_NUMBER=0
 ## @doc  Sets the current position of Ctx to Pos
 168: bs_set_position/2
 
+# OTP 23
+
 ## @spec swap Register1 Register2
 ## @doc  Swaps the contents of two registers.
 169: swap/2
diff --git a/lib/compiler/src/v3_kernel.erl b/lib/compiler/src/v3_kernel.erl
index e2b8787224..6fd1790c1a 100644
--- a/lib/compiler/src/v3_kernel.erl
+++ b/lib/compiler/src/v3_kernel.erl
@@ -81,8 +81,11 @@
 
 -export([module/2,format_error/1]).
 
--import(lists, [map/2,foldl/3,foldr/3,mapfoldl/3,splitwith/2,member/2,
-		keyfind/3,partition/2,droplast/1,last/1,sort/1,reverse/1]).
+-import(lists, [droplast/1,flatten/1,foldl/3,foldr/3,
+                map/2,mapfoldl/3,member/2,
+		keyfind/3,keyreplace/4,
+                last/1,partition/2,reverse/1,
+                splitwith/2,sort/1]).
 -import(ordsets, [add_element/2,del_element/2,union/2,union/1,subtract/2]).
 -import(cerl, [c_tuple/1]).
 
@@ -120,15 +123,19 @@ copy_anno(Kdst, Ksrc) ->
 	       funs=[],				%Fun functions
 	       free=#{},			%Free variables
 	       ws=[]   :: [warning()],		%Warnings.
-	       guard_refc=0}).			%> 0 means in guard
+	       guard_refc=0, 			%> 0 means in guard
+               no_shared_fun_wrappers=false :: boolean()
+              }).
 
 -spec module(cerl:c_module(), [compile:option()]) ->
 	{'ok', #k_mdef{}, [warning()]}.
 
-module(#c_module{anno=A,name=M,exports=Es,attrs=As,defs=Fs}, _Options) ->
+module(#c_module{anno=A,name=M,exports=Es,attrs=As,defs=Fs}, Options) ->
     Kas = attributes(As),
     Kes = map(fun (#c_var{name={_,_}=Fname}) -> Fname end, Es),
-    St0 = #kern{},
+    NoSharedFunWrappers = proplists:get_bool(no_shared_fun_wrappers,
+                                             Options),
+    St0 = #kern{no_shared_fun_wrappers=NoSharedFunWrappers},
     {Kfs,St} = mapfoldl(fun function/2, St0, Fs),
     {ok,#k_mdef{anno=A,name=M#c_literal.val,exports=Kes,attributes=Kas,
 		body=Kfs ++ St#kern.funs},lists:sort(St#kern.ws)}.
@@ -716,16 +723,27 @@ gexpr_test_add(Ke, St0) ->
 %% expr(Cexpr, Sub, State) -> {Kexpr,[PreKexpr],State}.
 %%  Convert a Core expression, flattening it at the same time.
 
-expr(#c_var{anno=A,name={_Name,Arity}}=Fname, Sub, St) ->
-    %% A local in an expression.
-    %% For now, these are wrapped into a fun by reverse
-    %% eta-conversion, but really, there should be exactly one
-    %% such "lambda function" for each escaping local name,
-    %% instead of one for each occurrence as done now.
+expr(#c_var{anno=A0,name={Name,Arity}}=Fname, Sub, St) ->
     Vs = [#c_var{name=list_to_atom("V" ++ integer_to_list(V))} ||
-	     V <- integers(1, Arity)],
-    Fun = #c_fun{anno=A,vars=Vs,body=#c_apply{anno=A,op=Fname,args=Vs}},
-    expr(Fun, Sub, St);
+             V <- integers(1, Arity)],
+    case St#kern.no_shared_fun_wrappers of
+        false ->
+            %% Generate a (possibly shared) wrapper function for calling
+            %% this function.
+            Wrapper0 = ["-fun.",atom_to_list(Name),"/",integer_to_list(Arity),"-"],
+            Wrapper = list_to_atom(flatten(Wrapper0)),
+            Id = {id,{0,0,Wrapper}},
+            A = keyreplace(id, 1, A0, Id),
+            Fun = #c_fun{anno=A,vars=Vs,body=#c_apply{anno=A,op=Fname,args=Vs}},
+            expr(Fun, Sub, St);
+        true ->
+            %% For backward compatibility with OTP 22 and earlier,
+            %% use the pre-generated name for the fun wrapper.
+            %% There will be one wrapper function for each occurrence
+            %% of `fun F/A`.
+            Fun = #c_fun{anno=A0,vars=Vs,body=#c_apply{anno=A0,op=Fname,args=Vs}},
+            expr(Fun, Sub, St)
+    end;
 expr(#c_var{anno=A,name=V}, Sub, St) ->
     {#k_var{anno=A,name=get_vsub(V, Sub)},[],St};
 expr(#c_literal{anno=A,val=V}, _Sub, St) ->
@@ -2446,8 +2464,21 @@ uexpr(Lit, {break,Rs0}, St0) ->
     {#k_put{anno=#k{us=Used,ns=lit_list_vars(Rs),a=get_kanno(Lit)},
 	    arg=Lit,ret=Rs},Used,St1}.
 
-add_local_function(_, #kern{funs=ignore}=St) -> St;
-add_local_function(F, #kern{funs=Funs}=St) -> St#kern{funs=[F|Funs]}.
+add_local_function(_, #kern{funs=ignore}=St) ->
+    St;
+add_local_function(#k_fdef{func=Name,arity=Arity}=F, #kern{funs=Funs}=St) ->
+    case is_defined(Name, Arity, Funs) of
+        false ->
+            St#kern{funs=[F|Funs]};
+        true ->
+            St
+    end.
+
+is_defined(Name, Arity, [#k_fdef{func=Name,arity=Arity}|_]) ->
+    true;
+is_defined(Name, Arity, [#k_fdef{}|T]) ->
+    is_defined(Name, Arity, T);
+is_defined(_, _, []) -> false.
 
 %% Make a #k_fdef{}, making sure that the body is always a #k_match{}.
 make_fdef(Anno, Name, Arity, Vs, #k_match{}=Body) ->
diff --git a/lib/compiler/test/compile_SUITE.erl b/lib/compiler/test/compile_SUITE.erl
index 7e9e641478..453debc0c1 100644
--- a/lib/compiler/test/compile_SUITE.erl
+++ b/lib/compiler/test/compile_SUITE.erl
@@ -1382,27 +1382,33 @@ env_compiler_options(_Config) ->
 bc_options(Config) ->
     DataDir = proplists:get_value(data_dir, Config),
 
-    L = [{101, small_float, [no_get_hd_tl,no_line_info]},
-         {103, big, [no_put_tuple2,no_get_hd_tl,no_ssa_opt_record,
+    L = [{101, small_float, [no_shared_fun_wrappers,
+                             no_get_hd_tl,no_line_info]},
+         {103, big, [no_shared_fun_wrappers,
+                     no_put_tuple2,no_get_hd_tl,no_ssa_opt_record,
                      no_line_info,no_stack_trimming]},
-         {125, small_float, [no_get_hd_tl,no_line_info,no_ssa_opt_float]},
+         {125, small_float, [no_shared_fun_wrappers,no_get_hd_tl,
+                             no_line_info,
+                             no_ssa_opt_float]},
 
-         {132, small, [no_put_tuple2,no_get_hd_tl,no_ssa_opt_record,
+         {132, small, [no_shared_fun_wrappers,
+                       no_put_tuple2,no_get_hd_tl,no_ssa_opt_record,
                        no_ssa_opt_float,no_line_info,no_bsm3]},
 
+         {136, big, [no_shared_fun_wrappers,no_put_tuple2,no_get_hd_tl,
+                     no_ssa_opt_record,no_line_info]},
+
          {153, small, [r20]},
          {153, small, [r21]},
 
-         {136, big, [no_put_tuple2,no_get_hd_tl,
-                     no_ssa_opt_record,no_line_info]},
-
-         {153, big, [no_put_tuple2,no_get_hd_tl, no_ssa_opt_record]},
+         {153, big, [no_shared_fun_wrappers,
+                     no_put_tuple2,no_get_hd_tl, no_ssa_opt_record]},
          {153, big, [r16]},
          {153, big, [r17]},
          {153, big, [r18]},
          {153, big, [r19]},
          {153, small_float, [r16]},
-         {153, small_float, []},
+         {153, small_float, [no_shared_fun_wrappers]},
 
          {158, small_maps, [r17]},
          {158, small_maps, [r18]},
@@ -1412,11 +1418,15 @@ bc_options(Config) ->
 
          {164, small_maps, [r22]},
          {164, big, [r22]},
-         {164, small_maps, []},
-         {164, big, []},
+         {164, small_maps, [no_shared_fun_wrappers]},
+         {164, big, [no_shared_fun_wrappers]},
 
          {168, small, [r22]},
-         {168, small, []}
+         {168, small, [no_shared_fun_wrappers]},
+
+         {169, small_maps, []},
+         {169, big, []},
+         {169, small, []}
         ],
 
     Test = fun({Expected,Mod,Options}) ->
diff --git a/lib/compiler/test/test_lib.erl b/lib/compiler/test/test_lib.erl
index 98210a351c..a468482acb 100644
--- a/lib/compiler/test/test_lib.erl
+++ b/lib/compiler/test/test_lib.erl
@@ -79,6 +79,7 @@ opt_opts(Mod) ->
                      (no_put_tuple2) -> true;
                      (no_recv_opt) -> true;
                      (no_share_opt) -> true;
+                     (no_shared_fun_wrappers) -> true;
                      (no_ssa_float) -> true;
                      (no_ssa_opt) -> true;
                      (no_stack_trimming) -> true;
diff --git a/lib/hipe/icode/hipe_beam_to_icode.erl b/lib/hipe/icode/hipe_beam_to_icode.erl
index 42e4ead169..1246af1da3 100644
--- a/lib/hipe/icode/hipe_beam_to_icode.erl
+++ b/lib/hipe/icode/hipe_beam_to_icode.erl
@@ -689,8 +689,8 @@ trans_fun([{call_fun,N}|Instructions], Env) ->
   Dst = [mk_var({r,0})],
   [hipe_icode:mk_comment('call_fun'),
    hipe_icode:mk_primop(Dst,call_fun,Args) | trans_fun(Instructions,Env)];
-%%--- patched_make_fun --- make_fun/make_fun2 after fixes
-trans_fun([{patched_make_fun,MFA,Magic,FreeVarNum,Index}|Instructions], Env) ->
+%%--- make_fun2 ---
+trans_fun([{make_fun2,MFA,Index,Magic,FreeVarNum}|Instructions], Env) ->
   Args = extract_fun_args(FreeVarNum),
   Dst = [mk_var({r,0})],
   Fun = hipe_icode:mk_primop(Dst,
@@ -1957,7 +1957,7 @@ mod_find_closure_info([FunCode|Fs], CI) ->
 mod_find_closure_info([], CI) ->
   CI.
 
-find_closure_info([{patched_make_fun,MFA={_M,_F,A},_Magic,FreeVarNum,_Index}|BeamCode],
+find_closure_info([{make_fun2,{_M,_F,A}=MFA,_Index,_Magic,FreeVarNum}|BeamCode],
 		  ClosureInfo) ->
   NewClosure = %% A-FreeVarNum+1 (The real arity + 1 for the closure)
     #closure_info{mfa=MFA, arity=A-FreeVarNum+1, fv_arity=FreeVarNum},
@@ -2035,41 +2035,8 @@ split_params(N, [ArgN|OrgArgs], Args) ->
 %%-----------------------------------------------------------------------
 
 preprocess_code(ModuleCode) ->
-  PatchedCode = patch_R7_funs(ModuleCode),
-  ClosureInfo = find_closure_info(PatchedCode),
-  {PatchedCode, ClosureInfo}.
-
-%%-----------------------------------------------------------------------
-%% Patches the "make_fun" BEAM instructions of R7 so that they also
-%% contain the index that the BEAM loader generates for funs.
-%% 
-%% The index starts from 0 and is incremented by 1 for each make_fun
-%% instruction encountered.
-%%
-%% Retained only for compatibility with BEAM code prior to R8.
-%%
-%% Temporarily, it also rewrites R8-PRE-RELEASE "make_fun2"
-%% instructions, since their embedded indices don't work.
-%%-----------------------------------------------------------------------
-
-patch_R7_funs(ModuleCode) ->
-  patch_make_funs(ModuleCode, 0).
-
-patch_make_funs([FunCode0|Fs], FunIndex0) ->
-  {PatchedFunCode,FunIndex} = patch_make_funs(FunCode0, FunIndex0, []),
-  [PatchedFunCode|patch_make_funs(Fs, FunIndex)];
-patch_make_funs([], _) -> [].
-
-patch_make_funs([{make_fun,MFA,Magic,FreeVarNum}|Is], FunIndex, Acc) ->
-  Patched = {patched_make_fun,MFA,Magic,FreeVarNum,FunIndex},
-  patch_make_funs(Is, FunIndex+1, [Patched|Acc]);
-patch_make_funs([{make_fun2,MFA,_BogusIndex,Magic,FreeVarNum}|Is], FunIndex, Acc) ->
-  Patched = {patched_make_fun,MFA,Magic,FreeVarNum,FunIndex},
-  patch_make_funs(Is, FunIndex+1, [Patched|Acc]);
-patch_make_funs([I|Is], FunIndex, Acc) ->
-  patch_make_funs(Is, FunIndex, [I|Acc]);
-patch_make_funs([], FunIndex, Acc) ->
-  {lists:reverse(Acc),FunIndex}.
+  ClosureInfo = find_closure_info(ModuleCode),
+  {ModuleCode, ClosureInfo}.
 
 %%-----------------------------------------------------------------------
 
diff --git a/lib/tools/test/cprof_SUITE.erl b/lib/tools/test/cprof_SUITE.erl
index 9cbc27fb17..39239a66a9 100644
--- a/lib/tools/test/cprof_SUITE.erl
+++ b/lib/tools/test/cprof_SUITE.erl
@@ -211,16 +211,12 @@ on_load_test(Config) ->
     Lr = seq_r(1, M, fun succ/1),
     N2 = cprof:pause(),
     {Module,0,[]} = cprof:analyse(Module),
-    M_1 = M - 1,
     M4__4 = M*4 - 4,
     M10_7 = M*10 - 7,
     {?MODULE,M10_7,[{{?MODULE,succ,1},M4__4},
+                    {{?MODULE,'-fun.succ/1-',1},M4__4},
                     {{?MODULE,seq_r,4},M},
                     {{?MODULE,seq,3},M},
-                    {{?MODULE,'-on_load_test/1-fun-5-',1},M_1},
-                    {{?MODULE,'-on_load_test/1-fun-4-',1},M_1},
-                    {{?MODULE,'-on_load_test/1-fun-3-',1},M_1},
-                    {{?MODULE,'-on_load_test/1-fun-2-',1},M_1},
                     {{?MODULE,seq_r,3},1}]}
     = cprof:analyse(?MODULE),
     N2 = cprof:stop(),
@@ -246,18 +242,14 @@ modules_test(Config) ->
     Lr = seq_r(1, M, fun succ/1),
     N = cprof:pause(),
     Lr = lists:reverse(L),
-    M_1 = M - 1,
     M4_4 = M*4 - 4,
     M10_7 = M*10 - 7,
     M2__1 = M*2 + 1,
     {Tot,ModList} = cprof:analyse(),
     {value,{?MODULE,M10_7,[{{?MODULE,succ,1},M4_4},
+                           {{?MODULE,'-fun.succ/1-',1},M4_4},
                            {{?MODULE,seq_r,4},M},
                            {{?MODULE,seq,3},M},
-                           {{?MODULE,'-modules_test/1-fun-3-',1},M_1},
-                           {{?MODULE,'-modules_test/1-fun-2-',1},M_1},
-                           {{?MODULE,'-modules_test/1-fun-1-',1},M_1},
-                           {{?MODULE,'-modules_test/1-fun-0-',1},M_1},
                            {{?MODULE,seq_r,3},1}]}} =
       lists:keysearch(?MODULE, 1, ModList),
     {value,{Module,M2__1,[{{Module,seq_r,4},M},