From a3981bb0d5742098e484e49661b7f378f18069d5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Wed, 8 Dec 2010 06:55:37 +0100
Subject: beam_emu: Clean up calling of the error_handler module

There were two separate functions (call_error_handler() and
call_breakpoint_handler()) that were identical except for
the name of the function in the error_handler module being
called. Generalize call_error_handler() by adding a function
name argument so that it can be used for both purposes.

Also let the call_error_handler() return the new program
counter instead of passing it in c_p->i. That slightly decrease
the code size at the call site.

There is also no need to use the Dispatch() macro to yet again
decrease the reduction counter, because that has just been done by
the call instruction that caused the execution of the
call_error_handler or i_debug_breakpoint instruction.
---
 erts/emulator/beam/beam_emu.c | 79 +++++++------------------------------------
 1 file changed, 13 insertions(+), 66 deletions(-)

(limited to 'erts/emulator/beam/beam_emu.c')

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index e36ac1f1e6..2f90f67351 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -998,8 +998,8 @@ static void save_stacktrace(Process* c_p, BeamInstr* pc, Eterm* reg,
 			     BifFunction bf, Eterm args);
 static struct StackTrace * get_trace_from_exc(Eterm exc);
 static Eterm make_arglist(Process* c_p, Eterm* reg, int a);
-static Eterm call_error_handler(Process* p, BeamInstr* ip, Eterm* reg);
-static Eterm call_breakpoint_handler(Process* p, BeamInstr* fi, Eterm* reg);
+static BeamInstr* call_error_handler(Process* p, BeamInstr* ip,
+				     Eterm* reg, Eterm func);
 static BeamInstr* fixed_apply(Process* p, Eterm* reg, Uint arity);
 static BeamInstr* apply(Process* p, Eterm module, Eterm function,
 		     Eterm args, Eterm* reg);
@@ -2976,12 +2976,11 @@ void process_main(void)
      */
     SWAPOUT;
     reg[0] = r(0);
-    tmp_arg1 = call_error_handler(c_p, I-3, reg);
+    I = call_error_handler(c_p, I-3, reg, am_undefined_function);
     r(0) = reg[0];
     SWAPIN;
-    if (tmp_arg1) {
-	SET_I(c_p->i);
-	Dispatch();
+    if (I) {
+	Goto(*I);
     }
 
  /* Fall through */
@@ -4884,12 +4883,11 @@ apply_bif_or_nif_epilogue:
  OpCase(i_debug_breakpoint): {
      SWAPOUT;
      reg[0] = r(0);
-     tmp_arg1 = call_breakpoint_handler(c_p, I-3, reg);
+     I = call_error_handler(c_p, I-3, reg, am_breakpoint);
      r(0) = reg[0];
      SWAPIN;
-     if (tmp_arg1) {
-	 SET_I(c_p->i);
-	 Dispatch();
+     if (I) {
+	 Goto(*I);
      }
      goto no_error_handler;
  }
@@ -5639,8 +5637,8 @@ build_stacktrace(Process* c_p, Eterm exc) {
 }
 
 
-static Eterm
-call_error_handler(Process* p, BeamInstr* fi, Eterm* reg)
+static BeamInstr*
+call_error_handler(Process* p, BeamInstr* fi, Eterm* reg, Eterm func)
 {
     Eterm* hp;
     Export* ep;
@@ -5652,62 +5650,12 @@ call_error_handler(Process* p, BeamInstr* fi, Eterm* reg)
     /*
      * Search for the error_handler module.
      */
-    ep = erts_find_function(erts_proc_get_error_handler(p),
-			    am_undefined_function, 3);
-    if (ep == NULL) {		/* No error handler */
-	p->current = fi;
-	p->freason = EXC_UNDEF;
-	return 0;
-    }
-    p->i = ep->address;
-
-    /*
-     * Create a list with all arguments in the x registers.
-     */
-
-    arity = fi[2];
-    sz = 2 * arity;
-    if (HeapWordsLeft(p) < sz) {
-	erts_garbage_collect(p, sz, reg, arity);
-    }
-    hp = HEAP_TOP(p);
-    HEAP_TOP(p) += sz;
-    args = NIL;
-    for (i = arity-1; i >= 0; i--) {
-	args = CONS(hp, reg[i], args);
-	hp += 2;
-    }
-
-    /*
-     * Set up registers for call to error_handler:undefined_function/3.
-     */
-    reg[0] = fi[0];
-    reg[1] = fi[1];
-    reg[2] = args;
-    return 1;
-}
-
-static Eterm
-call_breakpoint_handler(Process* p, BeamInstr* fi, Eterm* reg)
-{
-    Eterm* hp;
-    Export* ep;
-    int arity;
-    Eterm args;
-    Uint sz;
-    int i;
-
-    /*
-     * Search for error handler module.
-     */
-    ep = erts_find_function(erts_proc_get_error_handler(p),
-			    am_breakpoint, 3);
+    ep = erts_find_function(erts_proc_get_error_handler(p), func, 3);
     if (ep == NULL) {		/* No error handler */
 	p->current = fi;
 	p->freason = EXC_UNDEF;
 	return 0;
     }
-    p->i = ep->address;
 
     /*
      * Create a list with all arguments in the x registers.
@@ -5727,15 +5675,14 @@ call_breakpoint_handler(Process* p, BeamInstr* fi, Eterm* reg)
     }
 
     /*
-     * Set up registers for call to error_handler:breakpoint/3.
+     * Set up registers for call to error_handler:<func>/3.
      */
     reg[0] = fi[0];
     reg[1] = fi[1];
     reg[2] = args;
-    return 1;
+    return ep->address;
 }
 
-
 
 static Export*
 apply_setup_error_handler(Process* p, Eterm module, Eterm function, Uint arity, Eterm* reg)
-- 
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