From aa468af0a4ee66a5da429f63b70222fe74f461e2 Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Thu, 22 Aug 2024 11:37:25 -0700
Subject: [PATCH] WIP: possible fix

---
 packages/swingset-liveslots/src/liveslots.js | 24 +++++++++++++++-----
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/packages/swingset-liveslots/src/liveslots.js b/packages/swingset-liveslots/src/liveslots.js
index 4490679c4d56..20de4cf302a5 100644
--- a/packages/swingset-liveslots/src/liveslots.js
+++ b/packages/swingset-liveslots/src/liveslots.js
@@ -284,19 +284,31 @@ function build(
 
       for (const vref of possiblyRetiredSet) {
         // eslint-disable-next-line no-use-before-define
-        if (!getValForSlot(vref) && !deadSet.has(vref)) {
-          // Don't retire things that haven't yet made the transition to dead,
-          // i.e., always drop before retiring
-          // eslint-disable-next-line no-use-before-define
-          if (!vrm.isVrefRecognizable(vref)) {
-            importsToRetire.add(vref);
+        if (getValForSlot(vref)) {
+          continue; // reachable by RAM pillar inhibits retirement
+        }
+        const { virtual, durable, allocatedByVat, type } = parseVatSlot(vref);
+        if (type !== 'object') {
+          continue; // we only retire objects
+        }
+        if (!virtual && !durable && !allocatedByVat) {
+          if (vrm.isPresenceReachable(vref)) {
+            continue; // reachable by vdata pillar inhibits retirement
           }
         }
+        // TODO: what was the deadSet check for? it wasn't sufficient.
+        // if (deadSet.has(vref)) {
+        //     continue;
+        // }
+        if (!vrm.isVrefRecognizable(vref)) {
+          importsToRetire.add(vref);
+        }
       }
       possiblyRetiredSet.clear();
 
       const deadBaseRefs = Array.from(deadSet);
       deadBaseRefs.sort();
+      console.log(`== sFDO scanning deadBaseRefs`, deadBaseRefs);
       for (const baseRef of deadBaseRefs) {
         const { virtual, durable, allocatedByVat, type } =
           parseVatSlot(baseRef);