8254075: Shenandoah: Remove ShenandoahCodeRootsStyle diagnostic flag and related test

Reviewed-by: shade

Author: zhengyu123

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

@@ -112,50 +112,18 @@ void ShenandoahCodeRoots::initialize() {
 }
 
 void ShenandoahCodeRoots::register_nmethod(nmethod* nm) {
-  switch (ShenandoahCodeRootsStyle) {
-    case 0:
-    case 1:
-      break;
-    case 2: {
-      assert_locked_or_safepoint(CodeCache_lock);
-      _nmethod_table->register_nmethod(nm);
-      break;
-    }
-    default:
-      ShouldNotReachHere();
-  }
+  assert_locked_or_safepoint(CodeCache_lock);
+  _nmethod_table->register_nmethod(nm);
 }
 
 void ShenandoahCodeRoots::unregister_nmethod(nmethod* nm) {
-  switch (ShenandoahCodeRootsStyle) {
-    case 0:
-    case 1: {
-      break;
-    }
-    case 2: {
-      assert_locked_or_safepoint(CodeCache_lock);
-      _nmethod_table->unregister_nmethod(nm);
-      break;
-    }
-    default:
-      ShouldNotReachHere();
-  }
+  assert_locked_or_safepoint(CodeCache_lock);
+  _nmethod_table->unregister_nmethod(nm);
 }
 
 void ShenandoahCodeRoots::flush_nmethod(nmethod* nm) {
-  switch (ShenandoahCodeRootsStyle) {
-    case 0:
-    case 1: {
-      break;
-    }
-    case 2: {
-      assert_locked_or_safepoint(CodeCache_lock);
-      _nmethod_table->flush_nmethod(nm);
-      break;
-    }
-    default:
-      ShouldNotReachHere();
-  }
+  assert_locked_or_safepoint(CodeCache_lock);
+  _nmethod_table->flush_nmethod(nm);
 }
 
 void ShenandoahCodeRoots::arm_nmethods() {
@@ -389,64 +357,18 @@ ShenandoahCodeRootsIterator::ShenandoahCodeRootsIterator() :
         _table_snapshot(NULL) {
   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
   assert(!Thread::current()->is_Worker_thread(), "Should not be acquired by workers");
-  switch (ShenandoahCodeRootsStyle) {
-    case 0:
-    case 1: {
-      // No need to do anything here
-      break;
-    }
-    case 2: {
-      CodeCache_lock->lock_without_safepoint_check();
-      _table_snapshot = ShenandoahCodeRoots::table()->snapshot_for_iteration();
-      break;
-    }
-    default:
-      ShouldNotReachHere();
-  }
+  CodeCache_lock->lock_without_safepoint_check();
+  _table_snapshot = ShenandoahCodeRoots::table()->snapshot_for_iteration();
 }
 
 ShenandoahCodeRootsIterator::~ShenandoahCodeRootsIterator() {
-  switch (ShenandoahCodeRootsStyle) {
-    case 0:
-    case 1: {
-      // No need to do anything here
-      break;
-    }
-    case 2: {
-      ShenandoahCodeRoots::table()->finish_iteration(_table_snapshot);
-      _table_snapshot = NULL;
-      CodeCache_lock->unlock();
-      break;
-    }
-    default:
-      ShouldNotReachHere();
-  }
+  ShenandoahCodeRoots::table()->finish_iteration(_table_snapshot);
+  _table_snapshot = NULL;
+  CodeCache_lock->unlock();
 }
 
 void ShenandoahCodeRootsIterator::possibly_parallel_blobs_do(CodeBlobClosure *f) {
-  switch (ShenandoahCodeRootsStyle) {
-    case 0: {
-      if (_seq_claimed.try_set()) {
-        CodeCache::blobs_do(f);
-      }
-      break;
-    }
-    case 1: {
-      _par_iterator.parallel_blobs_do(f);
-      break;
-    }
-    case 2: {
-      ShenandoahCodeRootsIterator::fast_parallel_blobs_do(f);
-      break;
-    }
-    default:
-      ShouldNotReachHere();
-  }
-}
-
-void ShenandoahCodeRootsIterator::fast_parallel_blobs_do(CodeBlobClosure *f) {
   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint");
   assert(_table_snapshot != NULL, "Sanity");
   _table_snapshot->parallel_blobs_do(f);
 }
-

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

@@ -78,7 +78,6 @@ class ShenandoahCodeRootsIterator {
   ~ShenandoahCodeRootsIterator();
 
   void possibly_parallel_blobs_do(CodeBlobClosure *f);
-  void fast_parallel_blobs_do(CodeBlobClosure *f);
 };
 
 class ShenandoahCodeRoots : public AllStatic {

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

@@ -37,12 +37,7 @@ bool ShenandoahConcurrentRoots::should_do_concurrent_roots() {
 }
 
 bool ShenandoahConcurrentRoots::can_do_concurrent_class_unloading() {
-#if (defined(X86) || defined(AARCH64))
-  return ShenandoahCodeRootsStyle == 2 &&
-         ClassUnloading;
-#else
-  return false;
-#endif
+  return ClassUnloading;
 }
 
 bool ShenandoahConcurrentRoots::should_do_concurrent_class_unloading() {

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

@@ -336,12 +336,6 @@
   product(bool, ShenandoahLoadRefBarrier, true, DIAGNOSTIC,                 \
           "Turn on/off load-reference barriers in Shenandoah")              \
                                                                             \
-  product(uintx, ShenandoahCodeRootsStyle, 2, DIAGNOSTIC,                   \
-          "Use this style to scan the code cache roots:"                    \
-          " 0 - sequential iterator;"                                       \
-          " 1 - parallel iterator;"                                         \
-          " 2 - parallel iterator with cset filters;")                      \
-                                                                            \
   develop(bool, ShenandoahVerifyOptoBarriers, false,                        \
           "Verify no missing barriers in C2.")                              \
                                                                             \