From 8bfd101b3454e841b36b2bb952319624fea1c088 Mon Sep 17 00:00:00 2001
From: Richard Brooksby <rb@ravenbrook.com>
Date: Wed, 23 Mar 2016 14:23:14 +0000
Subject: [PATCH] Responding to review by gdr
 <https://info.ravenbrook.com/mail/2016/03/21/21-05-49/0/>.

Copied from Perforce
 Change: 190336
 ServerID: perforce.ravenbrook.com
---
 mps/code/mpmst.h  | 2 +-
 mps/code/seg.c    | 3 ++-
 mps/code/shield.c | 6 ++++++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/mps/code/mpmst.h b/mps/code/mpmst.h
index b7e338c1319..99c63458825 100644
--- a/mps/code/mpmst.h
+++ b/mps/code/mpmst.h
@@ -699,7 +699,7 @@ typedef struct SortStruct {
 #define ShieldSig      ((Sig)0x519581E1) /* SIGnature SHEILd */
 
 typedef struct ShieldStruct {
-  Sig sig;
+  Sig sig;           /* design.mps.sig */
   Bool inside;       /* design.mps.shield.def.inside */
   Seg *queue;        /* queue of unsynced segs */
   Count length;      /* number of elements in shield queue */
diff --git a/mps/code/seg.c b/mps/code/seg.c
index e7c43c31ddf..bd0abeb018b 100644
--- a/mps/code/seg.c
+++ b/mps/code/seg.c
@@ -224,7 +224,7 @@ static void SegFinish(Seg seg)
   AVER(seg->depth == 0);
   if (seg->queued)
     ShieldFlush(PoolArena(SegPool(seg)));
-  AVER(seg->queued == FALSE);
+  AVER(!seg->queued);
 
   limit = SegLimit(seg);
   
@@ -686,6 +686,7 @@ Bool SegCheck(Seg seg)
   CHECKL(AddrIsArenaGrain(TractBase(seg->firstTract), arena));
   CHECKL(AddrIsArenaGrain(seg->limit, arena));
   CHECKL(seg->limit > TractBase(seg->firstTract));
+  CHECKL(BoolCheck(seg->queued));
 
   /* Each tract of the segment must agree about white traces. Note
    * that even if the CHECKs are compiled away there is still a
diff --git a/mps/code/shield.c b/mps/code/shield.c
index 0a00ae8f740..61976403a5c 100644
--- a/mps/code/shield.c
+++ b/mps/code/shield.c
@@ -46,6 +46,12 @@ void ShieldDestroyQueue(Shield shield, Arena arena)
 
 void ShieldFinish(Shield shield)
 {
+  /* The queue should already have been destroyed by
+     GlobalsPrepareToDestroy calling ShieldDestroyQueue. */
+  AVER(shield->length == 0);
+  AVER(shield->limit == 0);
+  AVER(shield->queue == NULL);
+
   AVER(shield->depth == 0);
   AVER(shield->unsynced == 0);
   AVER(shield->holds == 0);