emulator: Add a fourth element in exception stacktraces

This commit is a preparation for introducing location information
(filename/line number) in stacktraces in exceptions. Currently
a stack trace looks like:

  [{Mod1,Function1,Arity1},
   .
   .
   .
   {ModN,FunctionN,ArityN}]

Add a forth element to each tuple that can be used indication
the filename and line number of the source file:

  [{Mod1,Function1,Arity1,Location1},
   .
   .
   .
   {ModN,FunctionN,ArityN,LocationN}]

In this commit, the fourth element will just be an empty list,
and we will change all code that look at or manipulate stacktraces.

1 files changed, 3 insertions, 3 deletions

diff --git a/erts/emulator/hipe/hipe_mode_switch.c b/erts/emulator/hipe/hipe_mode_switch.c
index e3e8367b62..0b35dbdf04 100644
--- a/erts/emulator/hipe/hipe_mode_switch.c
+++ b/erts/emulator/hipe/hipe_mode_switch.c
@@ -648,7 +648,7 @@ Eterm hipe_build_stacktrace(Process *p, struct StackTrace *s)
     if (depth < 1)
 	return NIL;
 
-    heap_size = 6 * depth;	/* each [{M,F,A}|_] is 2+4 == 6 words */
+    heap_size = 7 * depth;	/* each [{M,F,A,[]}|_] is 2+5 == 7 words */
     hp = HAlloc(p, heap_size);
     hp_end = hp + heap_size;
 
@@ -659,8 +659,8 @@ Eterm hipe_build_stacktrace(Process *p, struct StackTrace *s)
 	ra = (const void*)s->trace[i];
 	if (!hipe_find_mfa_from_ra(ra, &m, &f, &a))
 	    continue;
-	mfa = TUPLE3(hp, m, f, make_small(a));
-	hp += 4;
+	mfa = TUPLE4(hp, m, f, make_small(a), NIL);
+	hp += 5;
 	next = CONS(hp, mfa, NIL);
 	*next_p = next;
 	next_p = &CDR(list_val(next));