jdk8-mips64-public/hotspot: src/share/vm/code/location.hpp@9f4457a14b58

     1 /*

     2  * Copyright 1997-2006 Sun Microsystems, Inc.  All Rights Reserved.

     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

    16  * 2 along with this work; if not, write to the Free Software Foundation,

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

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    25 // A Location describes a concrete machine variable location

    26 // (such as integer or floating point register or a stack-held

    27 // variable). Used when generating debug-information for nmethods.

    28 //

    29 // Encoding:

    30 //

    31 // bits:

    32 //  Where:  [15]

    33 //  Type:   [14..12]

    34 //  Offset: [11..0]

    36 class Location VALUE_OBJ_CLASS_SPEC {

    37   friend class VMStructs;

    38  public:

    39   enum Where {

    40     on_stack,

    41     in_register

    42   };

    44   enum Type {

    45     normal,                     // Ints, floats, double halves

    46     oop,                        // Oop (please GC me!)

    47     int_in_long,                // Integer held in long register

    48     lng,                        // Long held in one register

    49     float_in_dbl,               // Float held in double register

    50     dbl,                        // Double held in one register

    51     addr,                       // JSR return address

    52     invalid                     // Invalid location

    53   };

    56  private:

    57   enum {

    58     OFFSET_MASK  = (jchar) 0x0FFF,

    59     OFFSET_SHIFT = 0,

    60     TYPE_MASK    = (jchar) 0x7000,

    61     TYPE_SHIFT   = 12,

    62     WHERE_MASK   = (jchar) 0x8000,

    63     WHERE_SHIFT  = 15

    64   };

    66   uint16_t _value;

    68   // Create a bit-packed Location

    69   Location(Where where_, Type type_, unsigned offset_) {

    70     set(where_, type_, offset_);

    71     assert( where () == where_ , "" );

    72     assert( type  () == type_  , "" );

    73     assert( offset() == offset_, "" );

    74   }

    76   inline void set(Where where_, Type type_, unsigned offset_) {

    77     _value = (uint16_t) ((where_  << WHERE_SHIFT) |

    78                          (type_   << TYPE_SHIFT)  |

    79                          ((offset_ << OFFSET_SHIFT) & OFFSET_MASK));

    80   }

    82  public:

    84   // Stack location Factory.  Offset is 4-byte aligned; remove low bits

    85   static Location new_stk_loc( Type t, int offset ) { return Location(on_stack,t,offset>>LogBytesPerInt); }

    86   // Register location Factory

    87   static Location new_reg_loc( Type t, VMReg reg ) { return Location(in_register, t, reg->value()); }

    88   // Default constructor

    89   Location() { set(on_stack,invalid,(unsigned) -1); }

    91   // Bit field accessors

    92   Where where()  const { return (Where)       ((_value & WHERE_MASK)  >> WHERE_SHIFT);}

    93   Type  type()   const { return (Type)        ((_value & TYPE_MASK)   >> TYPE_SHIFT); }

    94   unsigned offset() const { return (unsigned) ((_value & OFFSET_MASK) >> OFFSET_SHIFT); }

    96   // Accessors

    97   bool is_register() const    { return where() == in_register; }

    98   bool is_stack() const       { return where() == on_stack;    }

   100   int stack_offset() const    { assert(where() == on_stack,    "wrong Where"); return offset()<<LogBytesPerInt; }

   101   int register_number() const { assert(where() == in_register, "wrong Where"); return offset()   ; }

   103   VMReg reg() const { assert(where() == in_register, "wrong Where"); return VMRegImpl::as_VMReg(offset())   ; }

   105   // Printing

   106   void print_on(outputStream* st) const;

   108   // Serialization of debugging information

   109   Location(DebugInfoReadStream* stream);

   110   void write_on(DebugInfoWriteStream* stream);

   112   // check

   113   static bool legal_offset_in_bytes(int offset_in_bytes);

   114 };

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