8264908: Investigate adding BOT range check in G1BlockOffsetTablePart…

…::block_at_or_preceding Reviewed-by: ayang, tschatzl
openjdk · Jul 15, 2021 · 99d7f9a · 99d7f9a · openjdk-notifier · Jul 15, 2021
1 parent e92e2fd
commit 99d7f9a
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Showing 2 changed files with 2 additions and 58 deletions.
diff --git a/src/hotspot/share/gc/g1/g1BlockOffsetTable.inline.hpp b/src/hotspot/share/gc/g1/g1BlockOffsetTable.inline.hpp
@@ -115,9 +115,8 @@ inline HeapWord* G1BlockOffsetTablePart::block_at_or_preceding(const void* addr)
          "Object crossed region boundary, found offset %u instead of 0",
          (uint) _bot->offset_array(_bot->index_for(_hr->bottom())));
   size_t index = _bot->index_for(addr);
-  // We must make sure that the offset table entry we use is valid.  If
-  // "addr" is past the end, start at the last valid index.
-  index = MIN2(index, _next_offset_index - 1);
+  // We must make sure that the offset table entry we use is valid.
+  assert(index < _next_offset_index, "Precondition");
 
   HeapWord* q = _bot->address_for_index(index);
 

diff --git a/src/hotspot/share/gc/g1/heapRegion.cpp b/src/hotspot/share/gc/g1/heapRegion.cpp
@@ -734,61 +734,6 @@ void HeapRegion::verify(VerifyOption vo,
     return;
   }
 
-  HeapWord* the_end = end();
-  // Do some extra BOT consistency checking for addresses in the
-  // range [top, end). BOT look-ups in this range should yield
-  // top. No point in doing that if top == end (there's nothing there).
-  if (p < the_end) {
-    // Look up top
-    HeapWord* addr_1 = p;
-    HeapWord* b_start_1 = block_start_const(addr_1);
-    if (b_start_1 != p) {
-      log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
-                            " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
-                            p2i(addr_1), p2i(b_start_1), p2i(p));
-      *failures = true;
-      return;
-    }
-
-    // Look up top + 1
-    HeapWord* addr_2 = p + 1;
-    if (addr_2 < the_end) {
-      HeapWord* b_start_2 = block_start_const(addr_2);
-      if (b_start_2 != p) {
-        log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
-                              " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
-                              p2i(addr_2), p2i(b_start_2), p2i(p));
-        *failures = true;
-        return;
-      }
-    }
-
-    // Look up an address between top and end
-    size_t diff = pointer_delta(the_end, p) / 2;
-    HeapWord* addr_3 = p + diff;
-    if (addr_3 < the_end) {
-      HeapWord* b_start_3 = block_start_const(addr_3);
-      if (b_start_3 != p) {
-        log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
-                              " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
-                              p2i(addr_3), p2i(b_start_3), p2i(p));
-        *failures = true;
-        return;
-      }
-    }
-
-    // Look up end - 1
-    HeapWord* addr_4 = the_end - 1;
-    HeapWord* b_start_4 = block_start_const(addr_4);
-    if (b_start_4 != p) {
-      log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
-                            " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
-                            p2i(addr_4), p2i(b_start_4), p2i(p));
-      *failures = true;
-      return;
-    }
-  }
-
   verify_strong_code_roots(vo, failures);
 }