From d5ba65f0aa25768c1af7a1639eb73298b029eaf3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 23 Aug 2016 07:46:43 +0200
Subject: Slightly reduce code size of process_main()

clang will generate smaller code if we avoid reassigning the
reg and freg arrays. That can be easily arranged by passing them
as arguments to process_main().
---
 erts/emulator/beam/beam_emu.c    | 10 ++++------
 erts/emulator/beam/erl_init.c    |  2 +-
 erts/emulator/beam/erl_process.c |  3 ++-
 erts/emulator/beam/global.h      |  2 +-
 4 files changed, 8 insertions(+), 9 deletions(-)

(limited to 'erts/emulator')

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index c704323bb2..0ba06058a5 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -1078,7 +1078,7 @@ static Eterm make_arglist(Process* c_p, Eterm* reg, int a);
 void
 init_emulator(void)
 {
-    process_main();
+    process_main(0, 0);
 }
 
 /*
@@ -1225,7 +1225,7 @@ init_emulator(void)
  * the instructions' C labels to the loader.
  * The second call starts execution of BEAM code. This call never returns.
  */
-void process_main(void)
+void process_main(Eterm * x_reg_array, FloatDef* f_reg_array)
 {
     static int init_done = 0;
     Process* c_p = NULL;
@@ -1237,7 +1237,7 @@ void process_main(void)
     /* Pointer to X registers: x(1)..x(N); reg[0] is used when doing GC,
      * in all other cases x0 is used.
      */
-    register Eterm* reg REG_xregs = NULL;
+    register Eterm* reg REG_xregs = x_reg_array;
 
     /*
      * Top of heap (next free location); grows upwards.
@@ -1264,7 +1264,7 @@ void process_main(void)
      * X registers and floating point registers are located in
      * scheduler specific data.
      */
-    register FloatDef *freg;
+    register FloatDef *freg = f_reg_array;
 
     /*
      * For keeping the negative old value of 'reds' when call saving is active.
@@ -1350,8 +1350,6 @@ void process_main(void)
 	start_time_i = c_p->i;
     }
 
-    reg = erts_proc_sched_data(c_p)->x_reg_array;
-    freg = erts_proc_sched_data(c_p)->f_reg_array;
     ERL_BITS_RELOAD_STATEP(c_p);
     {
 	int reds;
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 781bf024dd..2f68ece37b 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -2302,7 +2302,7 @@ erl_start(int argc, char **argv)
 #endif
 	set_main_stack_size();
 	erts_sched_init_time_sup(esdp);
-	process_main();
+	process_main(esdp->x_reg_array, esdp->f_reg_array);
     }
 #endif
 }
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index bcbb9b3115..b577ae95b0 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -8169,7 +8169,8 @@ sched_thread_func(void *vesdp)
     ERTS_VERIFY_UNUSED_TEMP_ALLOC(NULL);
 #endif
 
-    process_main();
+    process_main(esdp->x_reg_array, esdp->f_reg_array);
+
     /* No schedulers should *ever* terminate */
     erts_exit(ERTS_ABORT_EXIT,
 	     "Scheduler thread number %beu terminated\n",
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index d7dd6371b7..3030a095a8 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1200,7 +1200,7 @@ void print_pass_through(int, byte*, int);
 /* beam_emu.c */
 int catchlevel(Process*);
 void init_emulator(void);
-void process_main(void);
+void process_main(Eterm* x_reg_array, FloatDef* f_reg_array);
 void erts_dirty_process_main(ErtsSchedulerData *);
 Eterm build_stacktrace(Process* c_p, Eterm exc);
 Eterm expand_error_value(Process* c_p, Uint freason, Eterm Value);
-- 
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