8290715: Fix incorrect uses of G1CollectedHeap::heap_region_containing()

Reviewed-by: kbarrett, sangheki

Author: Thomas Schatzl

src/hotspot/share/gc/g1/g1CollectedHeap.inline.hpp

@@ -97,12 +97,10 @@ inline HeapWord* G1CollectedHeap::bottom_addr_for_region(uint index) const {
   return _hrm.reserved().start() + index * HeapRegion::GrainWords;
 }
 
+
 inline HeapRegion* G1CollectedHeap::heap_region_containing(const void* addr) const {
-  assert(addr != nullptr, "invariant");
-  assert(is_in_reserved(addr),
-         "Address " PTR_FORMAT " is outside of the heap ranging from [" PTR_FORMAT " to " PTR_FORMAT ")",
-         p2i((void*)addr), p2i(reserved().start()), p2i(reserved().end()));
-  return _hrm.addr_to_region((HeapWord*)addr);
+  uint const region_idx = addr_to_region(addr);
+  return region_at(region_idx);
 }
 
 inline HeapRegion* G1CollectedHeap::heap_region_containing_or_null(const void* addr) const {

src/hotspot/share/gc/g1/g1ConcurrentMark.cpp

@@ -1889,16 +1889,16 @@ HeapRegion* G1ConcurrentMark::claim_region(uint worker_id) {
   while (finger < _heap.end()) {
     assert(_g1h->is_in_reserved(finger), "invariant");
 
-    HeapRegion* curr_region = _g1h->heap_region_containing(finger);
+    HeapRegion* curr_region = _g1h->heap_region_containing_or_null(finger);
     // Make sure that the reads below do not float before loading curr_region.
     OrderAccess::loadload();
     // Above heap_region_containing may return NULL as we always scan claim
     // until the end of the heap. In this case, just jump to the next region.
-    HeapWord* end = curr_region != NULL ? curr_region->end() : finger + HeapRegion::GrainWords;
+    HeapWord* end = curr_region != nullptr ? curr_region->end() : finger + HeapRegion::GrainWords;
 
     // Is the gap between reading the finger and doing the CAS too long?
     HeapWord* res = Atomic::cmpxchg(&_finger, finger, end);
-    if (res == finger && curr_region != NULL) {
+    if (res == finger && curr_region != nullptr) {
       // we succeeded
       HeapWord* bottom = curr_region->bottom();
       HeapWord* limit = curr_region->top_at_mark_start();
@@ -1915,7 +1915,7 @@ HeapRegion* G1ConcurrentMark::claim_region(uint worker_id) {
                "the region limit should be at bottom");
         // we return NULL and the caller should try calling
         // claim_region() again.
-        return NULL;
+        return nullptr;
       }
     } else {
       assert(_finger > finger, "the finger should have moved forward");
@@ -1924,7 +1924,7 @@ HeapRegion* G1ConcurrentMark::claim_region(uint worker_id) {
     }
   }
 
-  return NULL;
+  return nullptr;
 }
 
 #ifndef PRODUCT
@@ -1972,11 +1972,11 @@ void G1ConcurrentMark::verify_no_collection_set_oops() {
 
   // Verify the global finger
   HeapWord* global_finger = finger();
-  if (global_finger != NULL && global_finger < _heap.end()) {
-    // Since we always iterate over all regions, we might get a NULL HeapRegion
+  if (global_finger != nullptr && global_finger < _heap.end()) {
+    // Since we always iterate over all regions, we might get a nullptr HeapRegion
     // here.
-    HeapRegion* global_hr = _g1h->heap_region_containing(global_finger);
-    guarantee(global_hr == NULL || global_finger == global_hr->bottom(),
+    HeapRegion* global_hr = _g1h->heap_region_containing_or_null(global_finger);
+    guarantee(global_hr == nullptr || global_finger == global_hr->bottom(),
               "global finger: " PTR_FORMAT " region: " HR_FORMAT,
               p2i(global_finger), HR_FORMAT_PARAMS(global_hr));
   }
@@ -1986,10 +1986,10 @@ void G1ConcurrentMark::verify_no_collection_set_oops() {
   for (uint i = 0; i < _num_concurrent_workers; ++i) {
     G1CMTask* task = _tasks[i];
     HeapWord* task_finger = task->finger();
-    if (task_finger != NULL && task_finger < _heap.end()) {
+    if (task_finger != nullptr && task_finger < _heap.end()) {
       // See above note on the global finger verification.
-      HeapRegion* r = _g1h->heap_region_containing(task_finger);
-      guarantee(r == NULL || task_finger == r->bottom() ||
+      HeapRegion* r = _g1h->heap_region_containing_or_null(task_finger);
+      guarantee(r == nullptr || task_finger == r->bottom() ||
                 !r->in_collection_set() || !r->has_index_in_opt_cset(),
                 "task finger: " PTR_FORMAT " region: " HR_FORMAT,
                 p2i(task_finger), HR_FORMAT_PARAMS(r));

src/hotspot/share/gc/g1/g1OopClosures.inline.hpp

@@ -122,7 +122,6 @@ inline static void check_obj_during_refinement(T* p, oop const obj) {
 
   HeapRegion* from = g1h->heap_region_containing(p);
 
-  assert(from != NULL, "from region must be non-NULL");
   assert(from->is_in_reserved(p) ||
          (from->is_humongous() &&
           g1h->heap_region_containing(p)->is_humongous() &&

src/hotspot/share/gc/g1/g1SATBMarkQueueSet.cpp

@@ -86,7 +86,6 @@ static inline bool requires_marking(const void* entry, G1CollectedHeap* g1h) {
          "Non-heap pointer in SATB buffer: " PTR_FORMAT, p2i(entry));
 
   HeapRegion* region = g1h->heap_region_containing(entry);
-  assert(region != NULL, "No region for " PTR_FORMAT, p2i(entry));
   if (entry >= region->top_at_mark_start()) {
     return false;
   }

src/hotspot/share/prims/whitebox.cpp

@@ -383,9 +383,6 @@ WB_ENTRY(jboolean, WB_isObjectInOldGen(JNIEnv* env, jobject o, jobject obj))
   if (UseG1GC) {
     G1CollectedHeap* g1h = G1CollectedHeap::heap();
     const HeapRegion* hr = g1h->heap_region_containing(p);
-    if (hr == NULL) {
-      return false;
-    }
     return !(hr->is_young());
   }
 #endif