jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/objectStartArray.hpp@2d8a650513c2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/objectStartArray.hpp@2d8a650513c2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/objectStartArray.hpp

Fri, 29 Apr 2016 00:06:10 +0800

author: aoqi
date: Fri, 29 Apr 2016 00:06:10 +0800
changeset 1: 2d8a650513c2
parent 0: f90c822e73f8
child 25: 873fd82b133d
permissions: -rw-r--r--

Added MIPS 64-bit port.

 /*
  * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 /*
  * This file has been modified by Loongson Technology in 2015. These
  * modifications are Copyright (c) 2015 Loongson Technology, and are made
  * available on the same license terms set forth above.
  */
 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_OBJECTSTARTARRAY_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_OBJECTSTARTARRAY_HPP
 #include "gc_implementation/parallelScavenge/psVirtualspace.hpp"
 #include "memory/allocation.hpp"
 #include "memory/memRegion.hpp"
 #include "oops/oop.hpp"
 //
 // This class can be used to locate the beginning of an object in the
 // covered region.
 //
 class ObjectStartArray : public CHeapObj<mtGC> {
  friend class VerifyObjectStartArrayClosure;
  private:
   PSVirtualSpace  _virtual_space;
   MemRegion       _reserved_region;
   MemRegion       _covered_region;
   MemRegion       _blocks_region;
   jbyte*          _raw_base;
   jbyte*          _offset_base;
  public:
   enum BlockValueConstants {
     clean_block                  = -1
   };
   enum BlockSizeConstants {
     block_shift                  = 9,
     block_size                   = 1 << block_shift,
     block_size_in_words          = block_size / sizeof(HeapWord)
   };
  protected:
   // Mapping from address to object start array entry
   jbyte* block_for_addr(void* p) const {
     assert(_covered_region.contains(p),
            "out of bounds access to object start array");
     jbyte* result = &_offset_base[uintptr_t(p) >> block_shift];
     assert(_blocks_region.contains(result),
            "out of bounds result in byte_for");
     return result;
   }
   // Mapping from object start array entry to address of first word
   HeapWord* addr_for_block(jbyte* p) {
     assert(_blocks_region.contains(p),
            "out of bounds access to object start array");
     size_t delta = pointer_delta(p, _offset_base, sizeof(jbyte));
     HeapWord* result = (HeapWord*) (delta << block_shift);
     assert(_covered_region.contains(result),
            "out of bounds accessor from card marking array");
     return result;
   }
   // Mapping that includes the derived offset.
   // If the block is clean, returns the last address in the covered region.
   // If the block is < index 0, returns the start of the covered region.
   HeapWord* offset_addr_for_block (jbyte* p) const {
     // We have to do this before the assert
     if (p < _raw_base) {
       return _covered_region.start();
     }
     assert(_blocks_region.contains(p),
            "out of bounds access to object start array");
     if (*p == clean_block) {
       return _covered_region.end();
     }
     size_t delta = pointer_delta(p, _offset_base, sizeof(jbyte));
     HeapWord* result = (HeapWord*) (delta << block_shift);
     result += *p;
     assert(_covered_region.contains(result),
            "out of bounds accessor from card marking array");
     return result;
   }
  public:
   // This method is in lieu of a constructor, so that this class can be
   // embedded inline in other classes.
   void initialize(MemRegion reserved_region);
   void set_covered_region(MemRegion mr);
   void reset();
   MemRegion covered_region() { return _covered_region; }
   void allocate_block(HeapWord* p) {
     assert(_covered_region.contains(p), "Must be in covered region");
     jbyte* block = block_for_addr(p);
     HeapWord* block_base = addr_for_block(block);
     size_t offset = pointer_delta(p, block_base, sizeof(HeapWord*));
     assert(offset < 128, "Sanity");
     // When doing MT offsets, we can't assert this.
     //assert(offset > *block, "Found backwards allocation");
     *block = (jbyte)offset;
     // tty->print_cr("[%p]", p);
   }
   // Optimized for finding the first object that crosses into
   // a given block. The blocks contain the offset of the last
   // object in that block. Scroll backwards by one, and the first
   // object hit should be at the beginning of the block
   HeapWord* object_start(HeapWord* addr) const {
     assert(_covered_region.contains(addr), "Must be in covered region");
     jbyte* block = block_for_addr(addr);
     HeapWord* scroll_forward = offset_addr_for_block(block--);
     while (scroll_forward > addr) {
       scroll_forward = offset_addr_for_block(block--);
     }
     HeapWord* next = scroll_forward;
     while (next <= addr) {
       scroll_forward = next;
       next += oop(next)->size();
     }
     assert(scroll_forward <= addr, "wrong order for current and arg");
     assert(addr <= next, "wrong order for arg and next");
     return scroll_forward;
   }
   HeapWord* object_start_oldnuma(HeapWord* addr, HeapWord* bottom) const {
     assert(_covered_region.contains(addr), "Must be in covered region");
     jbyte* block = block_for_addr(addr);
     HeapWord* scroll_forward;
     if(bottom == addr)
       return bottom;
     else
       scroll_forward = offset_addr_for_block(block--);
     while (scroll_forward > addr) {
       scroll_forward = offset_addr_for_block(block--);
     }
     HeapWord* next = scroll_forward;
     while (next <= addr) {
       if(oop(next)->is_oop_or_null()) {
         scroll_forward = next;
         next += oop(next)->size();
       }
       else
         next++;
     }
     assert(scroll_forward <= addr, "wrong order for current and arg");
     assert(addr <= next, "wrong order for arg and next");
     return scroll_forward;
   }
   bool is_block_allocated(HeapWord* addr) {
     assert(_covered_region.contains(addr), "Must be in covered region");
     jbyte* block = block_for_addr(addr);
     if (*block == clean_block)
       return false;
     return true;
   }
   // Return true if an object starts in the range of heap addresses.
   // If an object starts at an address corresponding to
   // "start", the method will return true.
   bool object_starts_in_range(HeapWord* start_addr, HeapWord* end_addr) const;
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_OBJECTSTARTARRAY_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/objectStartArray.hpp@2d8a650513c2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/objectStartArray.hpp