Merge branch 'bg/opt-receive' into dev

* bg/opt-receive:
  Test that gen_server:call/2,3 are fast even with a huge message queue
  erts: Add tests for the receive optimization
  Update primary bootstrap
  erts: Implement recv_mark/1 and recv_set/1 for real
  compiler tests: Cover the error handling code in beam_receive
  compiler test: Test optimization of receive statements
  Optimize selective receives in the presence of a large message queue
  Introduce the new recv_mark/1 and recv_mark/1 instructions
  Compile tests that communicate with R12 nodes with the r12 option
  Move p_run/2 to test_lib
  gen: Inline wait_resp_mon/2 to help the compiler optimize

OTP-8623 bg/opt-receive

reveive statements that can only read out a newly created reference are now
specially optimized so that it will execute in constant time regardless of
the number of messages in the receive queue for the process. That
optimization will benefit calls to gen_server:call(). (See gen:do_call/4
for an example of a receive statement that will be optimized.)

1 files changed, 32 insertions, 0 deletions

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index 5b2f032afc..ee8ba54cb8 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -1539,6 +1539,10 @@ void process_main(void)
  /*
   * Skeleton for receive statement:
   *
+  *             recv_mark L1                     Optional
+  *             call make_ref/monitor            Optional
+  *             ...
+  *             recv_set L1                      Optional
   *      L1:          <-------------------+
   *                   <-----------+       |
   *     	     	       	  |   	  |
@@ -1557,6 +1561,34 @@ void process_main(void)
   *
   */
 
+ OpCase(recv_mark_f): {
+     /*
+      * Save the current position in message buffer and the
+      * the label for the loop_rec/2 instruction for the
+      * the receive statement.
+      */
+     c_p->msg.mark = (BeamInstr *) Arg(0);
+     c_p->msg.saved_last = c_p->msg.last;
+     Next(1);
+ }
+
+ OpCase(i_recv_set): {
+     /*
+      * If the mark is valid (points to the loop_rec/2
+      * instruction that follows), we know that the saved
+      * position points to the first message that could
+      * possibly be matched out.
+      *
+      * If the mark is invalid, we do nothing, meaning that
+      * we will look through all messages in the message queue.
+      */
+     if (c_p->msg.mark == (BeamInstr *) (I+1)) {
+	 c_p->msg.save = c_p->msg.saved_last;
+     }
+     I++;
+     /* Fall through to the loop_rec/2 instruction */
+ }
+
     /*
      * Pick up the next message and place it in x(0).
      * If no message, jump to a wait or wait_timeout instruction.