From 20b8ade8ce6a46485bdb0ac4508293440e25db05 Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Sat, 3 May 2014 16:16:17 +0000
Subject: [PATCH]   * added readbarriers as counterparts for the writebarriers
 (see     "SMP BARRIER PAIRING"     in
 https://www.kernel.org/doc/Documentation/memory-barriers.txt ), should    
 fix sporadic crashes of the test

git-svn-id: trunk@27726 -
---
 tests/test/theapthread.pp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/test/theapthread.pp b/tests/test/theapthread.pp
index 9839929b75..1dde316e89 100644
--- a/tests/test/theapthread.pp
+++ b/tests/test/theapthread.pp
@@ -130,6 +130,10 @@ begin
   begin
     if ((pair.writeindex+1) mod fifolength) <> pair.readindex then
     begin
+      { counterpart for the writebarrier in the consumer: ensure that we see
+        the write to pair.fifo[pair.readindex] now that we've seen the write
+        to pair.readindex }
+      readbarrier;
       freemem(pair.fifo[pair.writeindex]);
       pair.fifo[pair.writeindex] := getmem(((pair.writeindex*17) mod 520)+8);
       writebarrier;
@@ -167,6 +171,10 @@ begin
   begin
     if pair.readindex <> pair.writeindex then
     begin
+      { counterpart for the writebarrier in the producer: ensure that we see
+        the write to pair.fifo[pair.writeindex] now that we've seen the write
+        to pair.writeindex }
+      readbarrier;
       freemem(pair.fifo[pair.readindex]);
       pair.fifo[pair.readindex] := getmem(((pair.writeindex*17) mod 520)+8);
       writebarrier;