8328671: Mark allocate_new_tlab and unsafe_max_tlab_alloc of CollectedHeap as pure virtual

Reviewed-by: stefank, tschatzl

Author: lgxbslgx

src/hotspot/share/gc/shared/collectedHeap.cpp

@@ -518,13 +518,6 @@ void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool
   CollectedHeap::fill_with_object(start, end, zap);
 }
 
-HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
-                                           size_t requested_size,
-                                           size_t* actual_size) {
-  guarantee(false, "thread-local allocation buffers not supported");
-  return nullptr;
-}
-
 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
   assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
          "Should only be called at a safepoint or at start-up");

src/hotspot/share/gc/shared/collectedHeap.hpp

@@ -149,7 +149,7 @@ class CollectedHeap : public CHeapObj<mtGC> {
   // returned in actual_size.
   virtual HeapWord* allocate_new_tlab(size_t min_size,
                                       size_t requested_size,
-                                      size_t* actual_size);
+                                      size_t* actual_size) = 0;
 
   // Reinitialize tlabs before resuming mutators.
   virtual void resize_all_tlabs();
@@ -345,10 +345,7 @@ class CollectedHeap : public CHeapObj<mtGC> {
   // An estimate of the maximum allocation that could be performed
   // for thread-local allocation buffers without triggering any
   // collection or expansion activity.
-  virtual size_t unsafe_max_tlab_alloc(Thread *thr) const {
-    guarantee(false, "thread-local allocation buffers not supported");
-    return 0;
-  }
+  virtual size_t unsafe_max_tlab_alloc(Thread *thr) const = 0;
 
   // If a GC uses a stack watermark barrier, the stack processing is lazy, concurrent,
   // incremental and cooperative. In order for that to work well, mechanisms that stop