jdk8-mips64-public/hotspot: src/share/vm/memory/memRegion.hpp@749b1464aa81

     1 /*

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     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

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    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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    25 #ifndef SHARE_VM_MEMORY_MEMREGION_HPP

    26 #define SHARE_VM_MEMORY_MEMREGION_HPP

    28 #include "memory/allocation.hpp"

    29 #include "utilities/debug.hpp"

    30 #include "utilities/globalDefinitions.hpp"

    32 // A very simple data structure representing a contigous region

    33 // region of address space.

    35 // Note that MemRegions are passed by value, not by reference.

    36 // The intent is that they remain very small and contain no

    37 // objects.

    39 class MemRegion VALUE_OBJ_CLASS_SPEC {

    40   friend class VMStructs;

    41 private:

    42   HeapWord* _start;

    43   size_t    _word_size;

    45 public:

    46   MemRegion() : _start(NULL), _word_size(0) {};

    47   MemRegion(HeapWord* start, size_t word_size) :

    48     _start(start), _word_size(word_size) {};

    49   MemRegion(HeapWord* start, HeapWord* end) :

    50     _start(start), _word_size(pointer_delta(end, start)) {

    51     assert(end >= start, "incorrect constructor arguments");

    52   }

    54   MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}

    56   MemRegion intersection(const MemRegion mr2) const;

    57   // regions must overlap or be adjacent

    58   MemRegion _union(const MemRegion mr2) const;

    59   // minus will fail a guarantee if mr2 is interior to this,

    60   // since there's no way to return 2 disjoint regions.

    61   MemRegion minus(const MemRegion mr2) const;

    63   HeapWord* start() const { return _start; }

    64   HeapWord* end() const   { return _start + _word_size; }

    65   HeapWord* last() const  { return _start + _word_size - 1; }

    67   void set_start(HeapWord* start) { _start = start; }

    68   void set_end(HeapWord* end)     { _word_size = pointer_delta(end, _start); }

    69   void set_word_size(size_t word_size) {

    70     _word_size = word_size;

    71   }

    73   bool contains(const MemRegion mr2) const {

    74     return _start <= mr2._start && end() >= mr2.end();

    75   }

    76   bool contains(const void* addr) const {

    77     return addr >= (void*)_start && addr < (void*)end();

    78   }

    79   bool equals(const MemRegion mr2) const {

    80     // first disjunct since we do not have a canonical empty set

    81     return ((is_empty() && mr2.is_empty()) ||

    82             (start() == mr2.start() && end() == mr2.end()));

    83   }

    85   size_t byte_size() const { return _word_size * sizeof(HeapWord); }

    86   size_t word_size() const { return _word_size; }

    88   bool is_empty() const { return word_size() == 0; }

    89 };

    91 // For iteration over MemRegion's.

    93 class MemRegionClosure : public StackObj {

    94 public:

    95   virtual void do_MemRegion(MemRegion mr) = 0;

    96 };

    98 // A ResourceObj version of MemRegionClosure

   100 class MemRegionClosureRO: public MemRegionClosure {

   101 public:

   102   void* operator new(size_t size, ResourceObj::allocation_type type) {

   103         return ResourceObj::operator new(size, type);

   104   }

   105   void* operator new(size_t size, Arena *arena) {

   106         return ResourceObj::operator new(size, arena);

   107   }

   108   void* operator new(size_t size) {

   109         return ResourceObj::operator new(size);

   110   }

   112   void  operator delete(void* p) {} // nothing to do

   113 };

   115 #endif // SHARE_VM_MEMORY_MEMREGION_HPP

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