From 4c763443365591e170308a1c5f11a4586734ca4e Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Tue, 12 Jan 2016 16:57:59 +0100
Subject: erts: Optimize erlang:check_process_code

by ignoring literals.

erts_internal:check_process_code will be called again anyway
(with option {copy_literals, true}) before the module is actually purged.
No need to check literals twice.
---
 erts/emulator/beam/beam_bif_load.c | 61 +++++++++++++-------------------------
 1 file changed, 20 insertions(+), 41 deletions(-)

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

diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index 892b2d16c2..a000935388 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -38,7 +38,7 @@
 #include "erl_thr_progress.h"
 
 static void set_default_trace_pattern(Eterm module);
-static Eterm check_process_code(Process* rp, Module* modp, int allow_gc, int *redsp);
+static Eterm check_process_code(Process* rp, Module* modp, Uint flags, int *redsp);
 static void delete_code(Module* modp);
 static void decrement_refc(BeamCodeHeader*);
 static int any_heap_ref_ptrs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size);
@@ -426,7 +426,7 @@ check_old_code_1(BIF_ALIST_1)
 }
 
 Eterm
-erts_check_process_code(Process *c_p, Eterm module, int allow_gc, int *redsp)
+erts_check_process_code(Process *c_p, Eterm module, Uint flags, int *redsp)
 {
     Module* modp;
     Eterm res;
@@ -441,7 +441,8 @@ erts_check_process_code(Process *c_p, Eterm module, int allow_gc, int *redsp)
     if (!modp)
 	return am_false;
     erts_rlock_old_code(code_ix);
-    res = modp->old.code_hdr ? check_process_code(c_p, modp, allow_gc, redsp) : am_false;
+    res = (!modp->old.code_hdr ? am_false :
+           check_process_code(c_p, modp, flags, redsp));
     erts_runlock_old_code(code_ix);
 
     return res;
@@ -450,49 +451,21 @@ erts_check_process_code(Process *c_p, Eterm module, int allow_gc, int *redsp)
 BIF_RETTYPE erts_internal_check_process_code_2(BIF_ALIST_2)
 {
     int reds = 0;
+    Uint flags;
     Eterm res;
-    Eterm olist = BIF_ARG_2;
-    int allow_gc = 1;
 
     if (is_not_atom(BIF_ARG_1))
 	goto badarg;
 
-    while (is_list(olist)) {
-	Eterm *lp = list_val(olist);
-	Eterm opt = CAR(lp);
-	if (is_tuple(opt)) {
-	    Eterm* tp = tuple_val(opt);
-	    switch (arityval(tp[0])) {
-	    case 2:
-		switch (tp[1]) {
-		case am_allow_gc:
-		    switch (tp[2]) {
-		    case am_false:
-			allow_gc = 0;
-			break;
-		    case am_true:
-			allow_gc = 1;
-			break;
-		    default:
-			goto badarg;
-		    }
-		    break;
-		default:
-		    goto badarg;
-		}
-		break;
-	    default:
-		goto badarg;
-	    }
-	}
-	else
-	    goto badarg;
-	olist = CDR(lp);
+    if (is_not_small(BIF_ARG_2))
+        goto badarg;
+
+    flags = unsigned_val(BIF_ARG_2);
+    if (flags & ~ERTS_CPC_ALL) {
+        goto badarg;
     }
-    if (is_not_nil(olist))
-	goto badarg;
 
-    res = erts_check_process_code(BIF_P, BIF_ARG_1, allow_gc, &reds);
+    res = erts_check_process_code(BIF_P, BIF_ARG_1, flags, &reds);
 
     ASSERT(is_value(res));
 
@@ -739,7 +712,7 @@ check_mod_funs(Process *p, ErlOffHeap *off_heap, char *area, size_t area_size)
 
 
 static Eterm
-check_process_code(Process* rp, Module* modp, int allow_gc, int *redsp)
+check_process_code(Process* rp, Module* modp, Uint flags, int *redsp)
 {
     BeamInstr* start;
     char* literals;
@@ -852,6 +825,12 @@ check_process_code(Process* rp, Module* modp, int allow_gc, int *redsp)
 	/* Check heap, stack etc... */
 	if (check_mod_funs(rp, &rp->off_heap, mod_start, mod_size))
 	    goto try_gc;
+        if (!(flags & ERTS_CPC_COPY_LITERALS)) {
+            /* Process ok. May contain old literals but we will be called
+             * again before module is purged.
+             */
+            return am_false;
+        }
 	if (any_heap_ref_ptrs(&rp->fvalue, &rp->fvalue+1, literals, lit_bsize)) {
 	    rp->freason = EXC_NULL;
 	    rp->fvalue = NIL;
@@ -919,7 +898,7 @@ check_process_code(Process* rp, Module* modp, int allow_gc, int *redsp)
 	if ((done_gc & need_gc) == need_gc)
 	    return am_true;
 
-	if (!allow_gc)
+	if (!(flags & ERTS_CPC_ALLOW_GC))
 	    return am_aborted;
 
 	need_gc &= ~done_gc;
-- 
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