1 files changed, 17 insertions, 7 deletions

diff --git a/src/share/vm/memory/space.cpp b/src/share/vm/memory/space.cpp
index b4fe565fd..7f9647f2e 100644
--- a/src/share/vm/memory/space.cpp
+++ b/src/share/vm/memory/space.cpp
@@ -790,7 +790,9 @@ ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN)
 
 // Very general, slow implementation.
 HeapWord* ContiguousSpace::block_start_const(const void* p) const {
-  assert(MemRegion(bottom(), end()).contains(p), "p not in space");
+  assert(MemRegion(bottom(), end()).contains(p),
+         err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
+                  p, bottom(), end()));
   if (p >= top()) {
     return top();
   } else {
@@ -800,19 +802,27 @@ HeapWord* ContiguousSpace::block_start_const(const void* p) const {
       last = cur;
       cur += oop(cur)->size();
     }
-    assert(oop(last)->is_oop(), "Should be an object start");
+    assert(oop(last)->is_oop(),
+           err_msg(PTR_FORMAT " should be an object start", last));
     return last;
   }
 }
 
 size_t ContiguousSpace::block_size(const HeapWord* p) const {
-  assert(MemRegion(bottom(), end()).contains(p), "p not in space");
+  assert(MemRegion(bottom(), end()).contains(p),
+         err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
+                  p, bottom(), end()));
   HeapWord* current_top = top();
-  assert(p <= current_top, "p is not a block start");
-  assert(p == current_top || oop(p)->is_oop(), "p is not a block start");
-  if (p < current_top)
+  assert(p <= current_top,
+         err_msg("p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT,
+                  p, current_top));
+  assert(p == current_top || oop(p)->is_oop(),
+         err_msg("p (" PTR_FORMAT ") is not a block start - "
+                 "current_top: " PTR_FORMAT ", is_oop: %s",
+                 p, current_top, BOOL_TO_STR(oop(p)->is_oop())));
+  if (p < current_top) {
     return oop(p)->size();
-  else {
+  } else {
     assert(p == current_top, "just checking");
     return pointer_delta(end(), (HeapWord*) p);
   }