Store pointers to heap data in 32-bit words

Store Erlang terms in 32-bit entities on the heap, expanding the
pointers to 64-bit when needed. This works because all terms are stored
on addresses in the 32-bit address range (the 32 most significant bits
of pointers to term data are always 0).

Introduce a new datatype called UWord (along with its companion SWord),
which is an integer having the exact same size as the machine word
(a void *), but might be larger than Eterm/Uint.

Store code as machine words, as the instructions are pointers to
executable code which might reside outside the 32-bit address range.

Continuation pointers are stored on the 32-bit stack and hence must
point to addresses in the low range, which means that loaded beam code
much be placed in the low 32-bit address range (but, as said earlier,
the instructions themselves are full words).

No Erlang term data can be stored on C stacks (enforced by an
earlier commit).

This version gives a prompt, but test cases still fail (and dump core).

The loader (and emulator loop) has instruction packing disabled.

The main issues has been in rewriting loader and actual virtual
machine. Subsystems (like distribution) does not work yet.

1 files changed, 19 insertions, 19 deletions

diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index b1feec7074..db557c27a5 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -39,10 +39,10 @@ static Eterm check_process_code(Process* rp, Module* modp);
 static void delete_code(Process *c_p, ErtsProcLocks c_p_locks, Module* modp);
 static void delete_export_references(Eterm module);
 static int purge_module(int module);
-static int is_native(Eterm* code);
+static int is_native(UWord* code);
 static int any_heap_ref_ptrs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size);
 static int any_heap_refs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size);
-static void remove_from_address_table(Eterm* code);
+static void remove_from_address_table(UWord* code);
 
 Eterm
 load_module_2(BIF_ALIST_2)
@@ -344,8 +344,8 @@ BIF_RETTYPE finish_after_on_load_2(BIF_ALIST_2)
 	modp->code[MI_ON_LOAD_FUNCTION_PTR] = 0;
 	set_default_trace_pattern(BIF_ARG_1);
     } else if (BIF_ARG_2 == am_false) {
-	Eterm* code;
-	Eterm* end;
+	UWord* code;
+	UWord* end;
 
 	/*
 	 * The on_load function failed. Remove the loaded code.
@@ -354,7 +354,7 @@ BIF_RETTYPE finish_after_on_load_2(BIF_ALIST_2)
 	 */
 	erts_total_code_size -= modp->code_length;
 	code = modp->code;
-	end = (Eterm *)((char *)code + modp->code_length);
+	end = (UWord *)((char *)code + modp->code_length);
 	erts_cleanup_funs_on_purge(code, end);
 	beam_catches_delmod(modp->catches, code, modp->code_length);
 	erts_free(ERTS_ALC_T_CODE, (void *) code);
@@ -397,10 +397,10 @@ set_default_trace_pattern(Eterm module)
 static Eterm
 check_process_code(Process* rp, Module* modp)
 {
-    Eterm* start;
+    UWord* start;
     char* mod_start;
     Uint mod_size;
-    Eterm* end;
+    UWord* end;
     Eterm* sp;
 #ifndef HYBRID /* FIND ME! */
     ErlFunThing* funp;
@@ -418,7 +418,7 @@ check_process_code(Process* rp, Module* modp)
      * Pick up limits for the module.
      */
     start = modp->old_code;
-    end = (Eterm *)((char *)start + modp->old_code_length);
+    end = (UWord *)((char *)start + modp->old_code_length);
     mod_start = (char *) start;
     mod_size = modp->old_code_length;
 
@@ -472,11 +472,11 @@ check_process_code(Process* rp, Module* modp)
 #ifndef HYBRID /* FIND ME! */
  rescan:
     for (funp = MSO(rp).funs; funp; funp = funp->next) {
-	Eterm* fun_code;
+	UWord* fun_code;
 
 	fun_code = funp->fe->address;
 
-	if (INSIDE((Eterm *) funp->fe->address)) {
+	if (INSIDE((UWord *) funp->fe->address)) {
 	    if (done_gc) {
 		return am_true;
 	    } else {
@@ -576,7 +576,7 @@ any_heap_ref_ptrs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size)
 	switch (primary_tag(val)) {
 	case TAG_PRIMARY_BOXED:
 	case TAG_PRIMARY_LIST:
-	    if (in_area(val, mod_start, mod_size)) {
+	    if (in_area(EXPAND_POINTER(val), mod_start, mod_size)) {
 		return 1;
 	    }
 	    break;
@@ -596,7 +596,7 @@ any_heap_refs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size)
 	switch (primary_tag(val)) {
 	case TAG_PRIMARY_BOXED:
 	case TAG_PRIMARY_LIST:
-	    if (in_area(val, mod_start, mod_size)) {
+	    if (in_area(EXPAND_POINTER(val), mod_start, mod_size)) {
 		return 1;
 	    }
 	    break;
@@ -617,8 +617,8 @@ any_heap_refs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size)
 static int
 purge_module(int module)
 {
-    Eterm* code;
-    Eterm* end;
+    UWord* code;
+    UWord* end;
     Module* modp;
 
     /*
@@ -653,7 +653,7 @@ purge_module(int module)
     ASSERT(erts_total_code_size >= modp->old_code_length);
     erts_total_code_size -= modp->old_code_length;
     code = modp->old_code;
-    end = (Eterm *)((char *)code + modp->old_code_length);
+    end = (UWord *)((char *)code + modp->old_code_length);
     erts_cleanup_funs_on_purge(code, end);
     beam_catches_delmod(modp->old_catches, code, modp->old_code_length);
     erts_free(ERTS_ALC_T_CODE, (void *) code);
@@ -665,7 +665,7 @@ purge_module(int module)
 }
 
 static void
-remove_from_address_table(Eterm* code)
+remove_from_address_table(UWord* code)
 {
     int i;
 
@@ -738,11 +738,11 @@ delete_export_references(Eterm module)
 	Export *ep = export_list(i);
         if (ep != NULL && (ep->code[0] == module)) {
 	    if (ep->address == ep->code+3 &&
-		(ep->code[3] == (Eterm) em_apply_bif)) {
+		(ep->code[3] == (UWord) em_apply_bif)) {
 		continue;
 	    }
 	    ep->address = ep->code+3;
-	    ep->code[3] = (Uint) em_call_error_handler;
+	    ep->code[3] = (UWord) em_call_error_handler;
 	    ep->code[4] = 0;
 	    MatchSetUnref(ep->match_prog_set);
 	    ep->match_prog_set = NULL;
@@ -774,7 +774,7 @@ beam_make_current_old(Process *c_p, ErtsProcLocks c_p_locks, Eterm module)
 }
 
 static int
-is_native(Eterm* code)
+is_native(UWord* code)
 {
     return ((Eterm *)code[MI_FUNCTIONS])[1] != 0;
 }