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-rw-r--r--erts/emulator/beam/beam_emu.c32
-rw-r--r--erts/emulator/beam/erl_message.h8
-rw-r--r--erts/emulator/beam/ops.tab7
3 files changed, 45 insertions, 2 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.
diff --git a/erts/emulator/beam/erl_message.h b/erts/emulator/beam/erl_message.h
index 459c6363aa..489dee7b37 100644
--- a/erts/emulator/beam/erl_message.h
+++ b/erts/emulator/beam/erl_message.h
@@ -75,6 +75,13 @@ typedef struct {
ErlMessage** last; /* point to the last next pointer */
ErlMessage** save;
int len; /* queue length */
+
+ /*
+ * The following two fields are used by the recv_mark/1 and
+ * recv_set/1 instructions.
+ */
+ BeamInstr* mark; /* address to rec_loop/2 instruction */
+ ErlMessage** saved_last; /* saved last pointer */
} ErlMessageQueue;
#ifdef ERTS_SMP
@@ -137,6 +144,7 @@ do { \
(p)->msg.len--; \
if (__mp == NULL) \
(p)->msg.last = (p)->msg.save; \
+ (p)->msg.mark = 0; \
} while(0)
/* Reset message save point (after receive match) */
diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab
index ef6062203e..49280a60e0 100644
--- a/erts/emulator/beam/ops.tab
+++ b/erts/emulator/beam/ops.tab
@@ -1425,5 +1425,8 @@ on_load
#
# R14A.
#
-recv_mark Lbl =>
-recv_set Lbl =>
+recv_mark f
+
+recv_set Fail | label Lbl | loop_rec Lf Reg => \
+ i_recv_set | label Lbl | loop_rec Lf Reg
+i_recv_set