erts: Refactor encode_size_struct_int

to handle the "start of list" case in one place and not seven.

Note that this commit reverts (47d6fd3ccf35) back to using WSTACK
and pushing raw pointers. We disable GC while yielding, so this should not
be a problem.

3 files changed, 73 insertions, 120 deletions

diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index bfecac1612..32f3cda4f5 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -712,7 +712,7 @@ void erts_dsend_context_dtor(Binary* ctx_bin)
     ErtsSendContext* ctx = ERTS_MAGIC_BIN_DATA(ctx_bin);
     switch (ctx->dss.phase) {
     case ERTS_DSIG_SEND_PHASE_MSG_SIZE:
-	DESTROY_SAVED_ESTACK(&ctx->dss.u.sc.estack);
+	DESTROY_SAVED_WSTACK(&ctx->dss.u.sc.wstack);
 	break;
     case ERTS_DSIG_SEND_PHASE_MSG_ENCODE:
 	DESTROY_SAVED_WSTACK(&ctx->dss.u.ec.wstack);
@@ -1800,7 +1800,7 @@ erts_dsig_send(ErtsDSigData *dsdp, struct erts_dsig_send_context* ctx)
 	    erts_encode_dist_ext_size(ctx->ctl, ctx->flags, ctx->acmp, &ctx->data_size);
 
 	    if (is_value(ctx->msg)) {
-		ctx->u.sc.estack.start = NULL;
+		ctx->u.sc.wstack.wstart = NULL;
 		ctx->u.sc.flags = ctx->flags;
 		ctx->u.sc.level = 0;
 		ctx->phase = ERTS_DSIG_SEND_PHASE_MSG_SIZE;
diff --git a/erts/emulator/beam/dist.h b/erts/emulator/beam/dist.h
index 2a2ba0c83f..cd2cc0ef4a 100644
--- a/erts/emulator/beam/dist.h
+++ b/erts/emulator/beam/dist.h
@@ -282,7 +282,7 @@ typedef struct TTBSizeContext_ {
     int level;
     Uint result;
     Eterm obj;
-    ErtsEStack estack;
+    ErtsWStack wstack;
 } TTBSizeContext;
 
 typedef struct TTBEncodeContext_ {
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index 2117dbec62..fe48298155 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -1779,7 +1779,7 @@ static void ttb_context_destructor(Binary *context_bin)
 	context->alive = 0;
 	switch (context->state) {
 	case TTBSize:
-	    DESTROY_SAVED_ESTACK(&context->s.sc.estack);
+	    DESTROY_SAVED_WSTACK(&context->s.sc.wstack);
 	    break;
 	case TTBEncode:
 	    DESTROY_SAVED_WSTACK(&context->s.ec.wstack);
@@ -1847,7 +1847,7 @@ static Eterm erts_term_to_binary_int(Process* p, Eterm Term, int level, Uint fla
 	/* Setup enough to get started */
 	context->state = TTBSize;
 	context->alive = 1;
-	context->s.sc.estack.start = NULL;
+	context->s.sc.wstack.wstart = NULL;
 	context->s.sc.flags = flags;
 	context->s.sc.level = level;
     } else {
@@ -3962,51 +3962,35 @@ static int
 encode_size_struct_int(TTBSizeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj,
 		       unsigned dflags, Sint *reds, Uint *res)
 {
-    DECLARE_ESTACK(s);
+    DECLARE_WSTACK(s);
     Uint m, i, arity;
     Uint result = 0;
     Sint r = 0;
 
     if (ctx) {
-	ESTACK_CHANGE_ALLOCATOR(s, ERTS_ALC_T_SAVED_ESTACK);
+	WSTACK_CHANGE_ALLOCATOR(s, ERTS_ALC_T_SAVED_ESTACK);
 	r = *reds;
 
-	if (ctx->estack.start) { /* restore saved stack */
-	    ESTACK_RESTORE(s, &ctx->estack);
+	if (ctx->wstack.wstart) { /* restore saved stack */
+	    WSTACK_RESTORE(s, &ctx->wstack);
 	    result = ctx->result;
 	    obj = ctx->obj;
 	}
     }
 
-    goto L_jump_start;
+#define LIST_TAIL_OP ((0 << _TAG_PRIMARY_SIZE) | TAG_PRIMARY_HEADER)
+#define TERM_ARRAY_OP(N) (((N) << _TAG_PRIMARY_SIZE) | TAG_PRIMARY_HEADER)
+#define TERM_ARRAY_OP_DEC(OP) ((OP) - (1 << _TAG_PRIMARY_SIZE))
+
+
+    for (;;) {
+	ASSERT(!is_header(obj));
 
- outer_loop:
-    while (!ESTACK_ISEMPTY(s)) {
-	obj = ESTACK_POP(s);
-    handle_popped_obj:
-	if (is_list(obj)) {
-	    Eterm* cons = list_val(obj);
-	    Eterm tl;
-
-	    tl = CDR(cons);
-	    obj = CAR(cons);
-	    ESTACK_PUSH(s, tl);
-	} else if (is_nil(obj)) {
-	    result++;
-	    goto outer_loop;
-	} else {
-	    /*
-	     * Other term (in the tail of a non-proper list or
-	     * in a fun's environment).
-	     */
-	}
-    
-    L_jump_start:
 	if (ctx && --r == 0) {
 	    *reds = r;
 	    ctx->obj = obj;
 	    ctx->result = result;
-	    ESTACK_SAVE(s, &ctx->estack);
+	    WSTACK_SAVE(s, &ctx->wstack);
 	    return -1;
 	}
 	switch (tag_val_def(obj)) {
@@ -4089,69 +4073,43 @@ encode_size_struct_int(TTBSizeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj,
 		result += m + 2 + 1;
 	    } else {
 		result += 5;
-		goto handle_popped_obj;
+		WSTACK_PUSH2(s, (UWord)CDR(list_val(obj)), (UWord)LIST_TAIL_OP);
+		obj = CAR(list_val(obj));
+		continue; /* big loop */
 	    }
 	    break;
 	case TUPLE_DEF:
 	    {
 		Eterm* ptr = tuple_val(obj);
-		Uint i;
 		arity = arityval(*ptr);
 		if (arity <= 0xff) {
 		    result += 1 + 1;
 		} else {
 		    result += 1 + 4;
 		}
-		for (i = 1; i <= arity; ++i) {
-		    if (is_list(ptr[i])) {
-			if ((m = is_string(ptr[i])) && (m < MAX_STRING_LEN)) {
-			    result += m + 2 + 1;
-			    continue;
-			} else {
-			    result += 5;
-			}
-		    }
-		    ESTACK_PUSH(s,ptr[i]);
+		if (arity > 1) {
+		    WSTACK_PUSH2(s, (UWord) (ptr + 2),
+				    (UWord) TERM_ARRAY_OP(arity-1));
 		}
-		goto outer_loop;
+                else if (arity == 0) {
+		    break;
+                }
+		obj = ptr[1];
+		continue; /* big loop */
 	    }
-	    break;
 	case MAP_DEF:
 	    if (is_flatmap(obj)) {
 		flatmap_t *mp = (flatmap_t*)flatmap_val(obj);
 		Uint size = flatmap_get_size(mp);
-		Uint i;
-		Eterm *ptr;
 
 		result += 1 + 4; /* tag + 4 bytes size */
 
-		/* push values first */
-		ptr = flatmap_get_values(mp);
-		for (i = size; i; i--, ptr++) {
-		    if (is_list(*ptr)) {
-			if ((m = is_string(*ptr)) && (m < MAX_STRING_LEN)) {
-			    result += m + 2 + 1;
-			    continue;
-			} else {
-			    result += 5;
-			}
-		    }
-		    ESTACK_PUSH(s,*ptr);
+                if (size) {
+		    WSTACK_PUSH4(s, (UWord) flatmap_get_values(mp),
+				    (UWord) TERM_ARRAY_OP(size),
+		                    (UWord) flatmap_get_keys(mp),
+				    (UWord) TERM_ARRAY_OP(size));
 		}
-
-		ptr = flatmap_get_keys(mp);
-		for (i = size; i; i--, ptr++) {
-		    if (is_list(*ptr)) {
-			if ((m = is_string(*ptr)) && (m < MAX_STRING_LEN)) {
-			    result += m + 2 + 1;
-			    continue;
-			} else {
-			    result += 5;
-			}
-		    }
-		    ESTACK_PUSH(s,*ptr);
-		}
-		goto outer_loop;
 	    } else {
 		Eterm *ptr;
 		Eterm hdr;
@@ -4178,35 +4136,13 @@ encode_size_struct_int(TTBSizeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj,
 		}
 
 		ptr++;
-		ESTACK_RESERVE(s, node_sz*2);
+		WSTACK_RESERVE(s, node_sz*2);
 		while(node_sz--) {
                     if (is_list(*ptr)) {
-			Eterm* leaf = list_val(*ptr);
-			if (is_not_list(CAR(leaf))) {
-			    ESTACK_FAST_PUSH(s, CAR(leaf));
-			}
-			else {
-			    if ((m = is_string(CAR(leaf))) && (m < MAX_STRING_LEN)) {
-				result += m + 2 + 1;
-			    } else {
-				result += 5;
-				ESTACK_FAST_PUSH(s, CAR(leaf));
-			    }
-			}
-			if (is_not_list(CDR(leaf))) {
-			    ESTACK_FAST_PUSH(s, CDR(leaf));
-			}
-			else {
-			    if ((m = is_string(CDR(leaf))) && (m < MAX_STRING_LEN)) {
-				result += m + 2 + 1;
-			    } else {
-				result += 5;
-				ESTACK_FAST_PUSH(s, CDR(leaf));
-			    }
-			}
-		    }
-		    else {
-			ESTACK_FAST_PUSH(s, *ptr);
+			WSTACK_FAST_PUSH(s, CAR(list_val(*ptr)));
+			WSTACK_FAST_PUSH(s, CDR(list_val(*ptr)));
+                    } else {
+			WSTACK_FAST_PUSH(s, *ptr);
 		    }
 		    ptr++;
 		}
@@ -4262,25 +4198,13 @@ encode_size_struct_int(TTBSizeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj,
 		    result += 2 * (1 + 4); /* Index + Uniq */
 		    result += 1 + (funp->num_free < 0x100 ? 1 : 4);
 		}
-		for (i = 1; i < funp->num_free; i++) {
-		    obj = funp->env[i];
-
-		    if (is_not_list(obj)) {
-			/* Push any non-list terms on the stack */
-			ESTACK_PUSH(s, obj);
-		    } else {
-			/* Lists must be handled specially. */
-			if ((m = is_string(obj)) && (m < MAX_STRING_LEN)) {
-			    result += m + 2 + 1;
-			} else {
-			    result += 5;
-			    ESTACK_PUSH(s, obj);
-			}
-		    }
+		if (funp->num_free > 1) {
+		    WSTACK_PUSH2(s, (UWord) (funp->env + 1),
+				    (UWord) TERM_ARRAY_OP(funp->num_free-1));
 		}
 		if (funp->num_free != 0) {
 		    obj = funp->env[0];
-		    goto L_jump_start;
+		    continue; /* big loop */
 		}
 		break;
 	    }
@@ -4303,11 +4227,40 @@ encode_size_struct_int(TTBSizeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj,
 	    erl_exit(1,"Internal data structure error (in encode_size_struct2)%x\n",
 		     obj);
 	}
+
+	if (WSTACK_ISEMPTY(s)) {
+	    break;
+	}
+	obj = (Eterm) WSTACK_POP(s);
+
+        if (is_header(obj)) {
+            switch (obj) {
+	    case LIST_TAIL_OP:
+		obj = (Eterm) WSTACK_POP(s);
+		if (is_list(obj)) {
+		    Eterm* cons = list_val(obj);
+
+		    WSTACK_PUSH2(s, (UWord)CDR(cons), (UWord)LIST_TAIL_OP);
+		    obj = CAR(cons);
+		}
+		break;
+
+	    case TERM_ARRAY_OP(1):
+		obj = *(Eterm*)WSTACK_POP(s);
+		break;
+	    default: { /* TERM_ARRAY_OP(N) when N > 1 */
+		Eterm* ptr = (Eterm*) WSTACK_POP(s);
+		WSTACK_PUSH2(s, (UWord) (ptr+1),
+			        (UWord) TERM_ARRAY_OP_DEC(obj));
+		obj = *ptr;
+	    }
+	    }
+	}
     }
 
-    DESTROY_ESTACK(s);
+    WSTACK_DESTROY(s);
     if (ctx) {
-	ASSERT(ctx->estack.start == NULL);
+	ASSERT(ctx->wstack.wstart == NULL);
 	*reds = r;
     }
     *res = result;