From 6cf7f9c4a76b99ed7aa4dc7ee54692331fc73408 Mon Sep 17 00:00:00 2001
From: Aleksey Shipilev <shade@openjdk.org>
Date: Thu, 22 Aug 2024 11:39:47 +0000
Subject: [PATCH] 8338662: Shenandoah: Remove excessive
 ShenandoahVerifier::verify_during_evacuation

Reviewed-by: wkemper, ysr
---
 .../gc/shenandoah/shenandoahConcurrentGC.cpp  |  6 ------
 .../gc/shenandoah/shenandoahDegeneratedGC.cpp |  8 ++++----
 .../gc/shenandoah/shenandoahVerifier.cpp      | 20 -------------------
 .../gc/shenandoah/shenandoahVerifier.hpp      |  6 +-----
 4 files changed, 5 insertions(+), 35 deletions(-)

diff --git a/src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp b/src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp
index 0e18b591037..ed40fecfc1d 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp
@@ -613,12 +613,6 @@ void ShenandoahConcurrentGC::op_final_mark() {
       // From here on, we need to update references.
       heap->set_has_forwarded_objects(true);
 
-      // Verify before arming for concurrent processing.
-      // Otherwise, verification can trigger stack processing.
-      if (ShenandoahVerify) {
-        heap->verifier()->verify_during_evacuation();
-      }
-
       // Arm nmethods/stack for concurrent processing
       ShenandoahCodeRoots::arm_nmethods_for_evac();
       ShenandoahStackWatermark::change_epoch_id();
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahDegeneratedGC.cpp b/src/hotspot/share/gc/shenandoah/shenandoahDegeneratedGC.cpp
index 6b597d9b2d7..81d07a414cd 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahDegeneratedGC.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahDegeneratedGC.cpp
@@ -276,12 +276,12 @@ void ShenandoahDegenGC::op_prepare_evacuation() {
   }
 
   if (!heap->collection_set()->is_empty()) {
+    if (ShenandoahVerify) {
+      heap->verifier()->verify_before_evacuation();
+    }
+
     heap->set_evacuation_in_progress(true);
     heap->set_has_forwarded_objects(true);
-
-    if(ShenandoahVerify) {
-      heap->verifier()->verify_during_evacuation();
-    }
   } else {
     if (ShenandoahVerify) {
       heap->verifier()->verify_after_concmark();
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahVerifier.cpp b/src/hotspot/share/gc/shenandoah/shenandoahVerifier.cpp
index e5db7a9b392..51878772889 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahVerifier.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahVerifier.cpp
@@ -661,14 +661,6 @@ void ShenandoahVerifier::verify_at_safepoint(const char *label,
         enabled = true;
         expected = ShenandoahHeap::HAS_FORWARDED;
         break;
-      case _verify_gcstate_evacuation:
-        enabled = true;
-        expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
-        if (!_heap->is_stw_gc_in_progress()) {
-          // Only concurrent GC sets this.
-          expected |= ShenandoahHeap::WEAK_ROOTS;
-        }
-        break;
       case _verify_gcstate_stable:
         enabled = true;
         expected = ShenandoahHeap::STABLE;
@@ -851,18 +843,6 @@ void ShenandoahVerifier::verify_before_evacuation() {
   );
 }
 
-void ShenandoahVerifier::verify_during_evacuation() {
-  verify_at_safepoint(
-          "During Evacuation",
-          _verify_forwarded_allow,    // some forwarded references are allowed
-          _verify_marked_disable,     // walk only roots
-          _verify_cset_disable,       // some cset references are not forwarded yet
-          _verify_liveness_disable,   // liveness data might be already stale after pre-evacs
-          _verify_regions_disable,    // trash regions not yet recycled
-          _verify_gcstate_evacuation  // evacuation is in progress
-  );
-}
-
 void ShenandoahVerifier::verify_before_updaterefs() {
   verify_at_safepoint(
           "Before Updating References",
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahVerifier.hpp b/src/hotspot/share/gc/shenandoah/shenandoahVerifier.hpp
index dd4eb901a33..1617678d928 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahVerifier.hpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahVerifier.hpp
@@ -133,10 +133,7 @@ public:
     _verify_gcstate_stable_weakroots,
 
     // Nothing is in progress, some objects are forwarded
-    _verify_gcstate_forwarded,
-
-    // Evacuation is in progress, some objects are forwarded
-    _verify_gcstate_evacuation
+    _verify_gcstate_forwarded
   } VerifyGCState;
 
   struct VerifyOptions {
@@ -175,7 +172,6 @@ public:
   void verify_before_concmark();
   void verify_after_concmark();
   void verify_before_evacuation();
-  void verify_during_evacuation();
   void verify_before_updaterefs();
   void verify_after_updaterefs();
   void verify_before_fullgc();