Mps br/unfixed-summary: (debug only): on entering et (emergency tracing),

SegDescribe the seg being scanned, and the seg being Fixed (ie. holding 
the referent object that we have just failed to forward).

Copied from Perforce
 Change: 161979
 ServerID: perforce.ravenbrook.com

2 files changed, 25 insertions, 1 deletions

diff --git a/mps/code/poolamc.c b/mps/code/poolamc.c
index 496e4876801..57e4472eec0 100644
--- a/mps/code/poolamc.c
+++ b/mps/code/poolamc.c
@@ -1282,6 +1282,15 @@ static Res AMCScan(Bool *totalReturn, ScanState ss, Pool pool, Seg seg)
 
   format = pool->format;
   arena = pool->arena;
+  
+  /* what is a typical buffer state? */
+  if (SegBuffer(seg) != NULL) {
+    static int lots = 5;
+    if (lots > 0) {
+      lots -= 1;
+      SegDescribe(seg, mps_lib_get_stdout());
+    }
+  }
 
   if (amcSegHasNailboard(seg)) {
     return amcScanNailed(totalReturn, ss, pool, seg, amc);
@@ -1507,8 +1516,16 @@ Res AMCFix(Pool pool, ScanState ss, Seg seg, Ref *refIO)
     ss->forwardedSize += length;
     do {
       res = BUFFER_RESERVE(&newRef, buffer, length, FALSE);
-      if (res != ResOK)
+      if (res != ResOK) {
+        WriteF(mps_lib_get_stdout(),
+               "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\n"
+               "AMCFix forwarding buffer: BUFFER_RESERVE failed,\n"
+               "Referent object is in this seg:\n",
+               NULL
+              );
+        SegDescribe(seg, mps_lib_get_stdout());
         goto returnRes;
+      }
 
       toSeg = BufferSeg(buffer);
       ShieldExpose(arena, toSeg);
diff --git a/mps/code/trace.c b/mps/code/trace.c
index ff76600689b..eaf948c6fa5 100644
--- a/mps/code/trace.c
+++ b/mps/code/trace.c
@@ -1093,6 +1093,13 @@ static Res traceScanSegRes(TraceSet ts, Rank rank, Arena arena, Seg seg)
     /* Expose the segment to make sure we can scan it. */
     ShieldExpose(arena, seg);
     res = PoolScan(&wasTotal, &ss, SegPool(seg), seg);
+    if (res != ResOK) {
+        WriteF(mps_lib_get_stdout(),
+               "PoolScan failed on this seg:\n",
+               NULL
+              );
+        SegDescribe(seg, mps_lib_get_stdout());
+    }
     /* Cover, regardless of result */
     ShieldCover(arena, seg);