wip

Author: tstuefe

src/hotspot/share/gc/shenandoah/shenandoahAsserts.cpp

@@ -555,7 +555,6 @@ void ShenandoahAsserts::assert_generations_reconciled(const char* file, int line
   report_vm_error(file, line, msg.buffer());
 }
 
-// Given a possibly invalid oop, extract narrowKlass (if UCCP) and Klass* from it safely, with checks.
 bool ShenandoahAsserts::extract_klass_safely(oop obj, narrowKlass& nk, const Klass*& k) {
   nk = 0;
   k = nullptr;

src/hotspot/share/gc/shenandoah/shenandoahAsserts.hpp

@@ -80,11 +80,6 @@ class ShenandoahAsserts {
 
   // Given a possibly invalid oop, extract narrowKlass (if UCCP) and Klass*
   // from it safely.
-  // Returns:
-  // - false, nk=0 && k=0 if oop is unreadable or (+COH) is forwarded and forwardee is unreadable
-  //   or oop's narrowKlass was 0
-  // - false, nk>0 && k=0 if narrowKlass is garbage
-  // - true,  nk>0 && k!=0 if Klass* was successfully extracted. No further validity checks are done on the Klass*.
   // Note: For -UCCP, returned nk is always 0.
   static bool extract_klass_safely(oop obj, narrowKlass& nk, const Klass*& k);
 

test/hotspot/gtest/oops/test_compressedKlass.cpp

@@ -116,4 +116,7 @@ TEST_VM(CompressedKlass, test_is_valid_narrow_klass) {
   ASSERT_FALSE(CompressedKlassPointers::is_valid_narrow_klass_id(0));
   narrowKlass nk_jlC = CompressedKlassPointers::encode((Klass*)vmClasses::Class_klass());
   ASSERT_TRUE(CompressedKlassPointers::is_valid_narrow_klass_id(nk_jlC));
+  if (CompressedClassSpaceSize < 4 * G && CompressedKlassPointers::base() != nullptr) {
+    ASSERT_FALSE(CompressedKlassPointers::is_valid_narrow_klass_id(0xFFFFFFFF));
+  }
 }