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File 0632-erts-Fix-const-Term-for-maps-in-matchspecs.patch of Package erlang (Revision 02775a1e4b9808dffc0e5f09fec6e4ec)

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From 5b4f32fb23e09efa15b369ad8d597bb75bb19edd Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Wed, 11 Aug 2021 17:04:37 +0200
Subject: [PATCH 2/6] erts: Fix {const,Term} for maps in matchspecs

Strip any {const,Term} tags from map values in guards
and bodies of match specs.

We do not strip them from keys as match spec functions
cannot be run on keys.

This commit also makes flatmaps and hashmaps consistent
in that they do not allow expressions in keys. Before this
change hashmaps allowed expressions in keys, while flatmaps
did not.
---
 erts/emulator/beam/erl_db_util.c        | 155 +++++++++++++++++++-----
 erts/emulator/test/match_spec_SUITE.erl |  21 ++++
 2 files changed, 143 insertions(+), 33 deletions(-)

diff --git a/erts/emulator/beam/erl_db_util.c b/erts/emulator/beam/erl_db_util.c
index 70b300c69a..5c1530304b 100644
--- a/erts/emulator/beam/erl_db_util.c
+++ b/erts/emulator/beam/erl_db_util.c
@@ -3920,6 +3920,10 @@ dmc_tuple(DMCContext *context, DMCHeap *heap, DMC_STACK_TYPE(UWord) *text,
     return retOk;
 }
 
+/*
+ * For maps we only expand the values of the map. The keys remain as they are.
+ * So the map #{ {const,a} => {const,b} } will be transformed to #{ {const,a} => b }.
+ */
 static DMCRet
 dmc_map(DMCContext *context, DMCHeap *heap, DMC_STACK_TYPE(UWord) *text,
         Eterm t, int *constant)
@@ -3941,6 +3945,7 @@ dmc_map(DMCContext *context, DMCHeap *heap, DMC_STACK_TYPE(UWord) *text,
             *constant = 1;
             return retOk;
         }
+        /* Only copy the keys */
         DMC_PUSH2(*text, matchPushC, dmc_private_copy(context, m->keys));
         if (++context->stack_used > context->stack_need) {
             context->stack_need = context->stack_used;
@@ -3981,13 +3986,10 @@ dmc_map(DMCContext *context, DMCHeap *heap, DMC_STACK_TYPE(UWord) *text,
 
         while ((kv=hashmap_iterator_prev(&wstack)) != NULL) {
             /* push key */
-            if ((ret = dmc_expr(context, heap, text, CAR(kv), &c)) != retOk) {
-                DESTROY_WSTACK(wstack);
-                return ret;
-            }
-            if (c) {
-                do_emit_constant(context, text, CAR(kv));
-            }
+            DMC_PUSH2(*text, matchPushC, dmc_private_copy(context, CAR(kv)));
+            if (++context->stack_used > context->stack_need)
+                context->stack_need = context->stack_used;
+
             /* push value */
             if ((ret = dmc_expr(context, heap, text, CDR(kv), &c)) != retOk) {
                 DESTROY_WSTACK(wstack);
@@ -5159,8 +5161,8 @@ static int match_compact(ErlHeapFragment *expr, DMCErrInfo *err_info)
 }
 
 /*
-** Simple size object that takes care of function calls and constant tuples
-*/
+ ** Simple size object that takes care of function calls and constant tuples
+ */
 static Uint my_size_object(Eterm t) 
 {
     Uint sum = 0;
@@ -5172,30 +5174,65 @@ static Uint my_size_object(Eterm t)
 	    my_size_object(CDR(list_val(t)));
 	break;
     case TAG_PRIMARY_BOXED:
-	if ((((*boxed_val(t)) & 
-	      _TAG_HEADER_MASK) >> _TAG_PRIMARY_SIZE) !=
-	    (_TAG_HEADER_ARITYVAL >> _TAG_PRIMARY_SIZE)) {
-	    goto simple_term;
-	}
-
-	if (tuple_val(t)[0] == make_arityval(1) && is_tuple(tmp = tuple_val(t)[1])) {
-	    Uint i,n;
-	    p = tuple_val(tmp);
-	    n = arityval(p[0]);
-	    sum += 1 + n;
-	    for (i = 1; i <= n; ++i)
-		sum += my_size_object(p[i]);
-	} else if (tuple_val(t)[0] == make_arityval(2) &&
-		   is_atom(tmp = tuple_val(t)[1]) &&
-		   tmp == am_const) {
-	    sum += size_object(tuple_val(t)[2]);
-	} else {
-	    erts_exit(ERTS_ERROR_EXIT,"Internal error, sizing unrecognized object in "
-		     "(d)ets:match compilation.");
-	}
-	break;
+        if (is_tuple(t)) {
+            if (tuple_val(t)[0] == make_arityval(1) && is_tuple(tmp = tuple_val(t)[1])) {
+                Uint i,n;
+                p = tuple_val(tmp);
+                n = arityval(p[0]);
+                sum += 1 + n;
+                for (i = 1; i <= n; ++i)
+                    sum += my_size_object(p[i]);
+            } else if (tuple_val(t)[0] == make_arityval(2) &&
+                       is_atom(tmp = tuple_val(t)[1]) &&
+                       tmp == am_const) {
+                sum += size_object(tuple_val(t)[2]);
+            } else {
+                erts_exit(ERTS_ERROR_EXIT,"Internal error, sizing unrecognized object in "
+                          "(d)ets:match compilation.");
+            }
+            break;
+        } else if (is_map(t)) {
+            if (is_flatmap(t)) {
+                Uint n;
+                flatmap_t *mp;
+                mp  = (flatmap_t*)flatmap_val(t);
+
+                /* Calculate size of keys */
+                sum += size_object(mp->keys);
+
+                /* Calculate size of values */
+                p = (Eterm *)mp;
+                n   = flatmap_get_size(mp);
+                sum += n + 3;
+                p += 3; /* hdr + size + keys words */
+                while (n--) {
+                    sum += my_size_object(*p++);
+                }
+            } else {
+                Eterm *head = (Eterm *)hashmap_val(t);
+                Eterm hdr = *head;
+                Uint sz;
+                sz    = hashmap_bitcount(MAP_HEADER_VAL(hdr));
+                sum  += 1 + sz + header_arity(hdr);
+                head += 1 + header_arity(hdr);
+
+                while(sz-- > 0) {
+                    Eterm obj = head[sz];
+                    if (is_list(obj)) {
+                        Eterm key = CAR(list_val(obj));
+                        Eterm val = CDR(list_val(obj));
+                        sum += 2;
+                        sum += size_object(key);
+                        sum += my_size_object(val);
+                    } else {
+                        sum += my_size_object(obj);
+                    }
+                }
+            }
+            break;
+        }
+        /* fall through */
     default:
-    simple_term:
 	sum += size_object(t);
 	break;
     }
@@ -5225,7 +5262,7 @@ static Eterm my_copy_struct(Eterm t, Eterm **hp, ErlOffHeap* off_heap)
 		n = arityval(p[0]);
 		*hp += n + 1;
 		*savep++ = make_arityval(n);
-		for(i = 1; i <= n; ++i) 
+		for(i = 1; i <= n; ++i)
 		    *savep++ = my_copy_struct(p[i], hp, off_heap);
 	    }
             else if (tuple_val(t)[0] == make_arityval(2) &&
@@ -5238,6 +5275,58 @@ static Eterm my_copy_struct(Eterm t, Eterm **hp, ErlOffHeap* off_heap)
 		erts_exit(ERTS_ERROR_EXIT, "Trying to constant-copy non constant expression "
 			 "0x%bex in (d)ets:match compilation.", t);
 	    }
+        } else if (is_map(t)) {
+            if (is_flatmap(t)) {
+                Uint i,n;
+                flatmap_t *mp;
+                Eterm *savep;
+                Eterm keys;
+
+                mp  = (flatmap_t*)flatmap_val(t);
+
+                /* Copy keys */
+                keys = copy_struct(mp->keys,size_object(mp->keys),hp,off_heap);
+
+                savep = *hp;
+                ret = make_flatmap(savep);
+                n = flatmap_get_size(mp);
+                p = (Eterm *)mp;
+                *hp += n + 3;
+                *savep++ = mp->thing_word;
+                *savep++ = mp->size;
+                *savep++ = keys;
+                p += 3; /* hdr + size + keys words */
+                for (i = 0; i < n; i++)
+                    *savep++ = my_copy_struct(p[i], hp, off_heap);
+            } else {
+                Eterm *head = hashmap_val(t);
+                Eterm hdr = *head;
+                Uint sz;
+                Eterm *savep = *hp;
+                sz   = hashmap_bitcount(MAP_HEADER_VAL(hdr));
+                *hp += 1 + sz + header_arity(hdr);
+
+                ret = make_hashmap(savep);
+
+                *savep++ = *head++; /* map header */
+                if (header_arity(hdr) == 1)
+                    *savep++ = *head++;  /* map size */
+
+                for (int i = 0; i < sz; i++) {
+                    Eterm obj = head[i];
+                    if (is_list(obj)) {
+                        Eterm key = CAR(list_val(obj));
+                        Eterm val = CDR(list_val(obj));
+                        Eterm *kv = *hp;
+                        *hp += 2;
+                        *savep++ = make_list(kv);
+                        CAR(kv) = copy_struct(key,size_object(key),hp,off_heap);
+                        CDR(kv) = my_copy_struct(val,hp,off_heap);
+                    } else {
+                        *savep++ = my_copy_struct(obj,hp,off_heap);
+                    }
+                }
+            }
 	} else {
 	    sz = size_object(t);
 	    ret = copy_struct(t,sz,hp,off_heap);
diff --git a/erts/emulator/test/match_spec_SUITE.erl b/erts/emulator/test/match_spec_SUITE.erl
index ac132c1912..a7fd2b8526 100644
--- a/erts/emulator/test/match_spec_SUITE.erl
+++ b/erts/emulator/test/match_spec_SUITE.erl
@@ -918,6 +918,27 @@ maps(Config) when is_list(Config) ->
     ok = maps_check_loop(M0),
     M2 = maps:from_list([{integer_to_list(K),V} || {K,V} <- Ls0]),
     ok = maps_check_loop(M2),
+
+    %% Maps in guards
+    {ok,#{a:=1},[],[]} = erlang:match_spec_test(#{a=>1}, [{'$1',[{'==','$1',#{a=>1}}],['$1']}], table),
+    {ok,#{a:='$1'},[],[]} = erlang:match_spec_test(#{a=>'$1'}, [{'$1',[{'==','$1',#{a=>{const,'$1'}}}],['$1']}], table),
+    {ok,false,[],[]} = erlang:match_spec_test(#{a=>1}, [{'$1',[{'==','$1',#{{const,a}=>1}}],['$1']}], table),
+    {ok,#{a:=1,b:=2},[],[]} = erlang:match_spec_test({11,#{a=>1,b=>2}},[{{'$1','$2'},[{'==','$2',#{a=>{'-','$1',10},b=>{const,2}}}],['$2']}], table),
+    {ok,#{a:=1,b:=2},[],[]} = erlang:match_spec_test(#{a=>1},[{#{a=>'$1'},[],[#{a=>'$1',b=>{const,2}}]}], table),
+
+    %% Large maps in guards
+    {ok,#{a:=1},[],[]} = erlang:match_spec_test(M0#{a=>1}, [{'$1',[{'==','$1',M0#{a=>1}}],['$1']}], table),
+    {ok,#{a:='$1'},[],[]} = erlang:match_spec_test(M0#{a=>'$1'}, [{'$1',[{'==','$1',M0#{a=>{const,'$1'}}}],['$1']}], table),
+    {ok,#{a:=1,b:=2},[],[]} = erlang:match_spec_test({11,M0#{a=>1,b=>2}},[{{'$1','$2'},[{'==','$2',M0#{a=>{'-','$1',10},b=>{const,2}}}],['$2']}], table),
+
+    %% Maps in body
+    {ok,#{a:=1,b:=#{a:='$1'}},[],[]} = erlang:match_spec_test(#{a=>1},[{#{a=>'$1'},[],[#{a=>'$1',b=>#{a=>{const,'$1'}}}]}], table),
+    {ok,#{a:=1,{const,b}:=#{a:='$1'}},[],[]} = erlang:match_spec_test(#{a=>1},[{#{a=>'$1'},[],[#{a=>'$1',{const,b}=>#{a=>{const,'$1'}}}]}], table),
+
+    %% Large maps in body
+    {ok,#{a:=1,b:=#{a:='$1'}},[],[]} = erlang:match_spec_test(M0#{a=>1},[{#{a=>'$1'},[],[M0#{a=>'$1',b=>M0#{a=>{const,'$1'}}}]}], table),
+    {ok,#{a:=1,{const,b}:=#{a:='$1'}},[],[]} = erlang:match_spec_test(M0#{a=>1},[{#{a=>'$1'},[],[M0#{a=>'$1',{const,b}=>M0#{a=>{const,'$1'}}}]}], table),
+
     ok.
 
 maps_check_loop(M) ->
-- 
2.31.1

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File 0632-erts-Fix-const-Term-for-maps-in-matchspecs.patch of Package erlang (Revision 02775a1e4b9808dffc0e5f09fec6e4ec)

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