aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_CODE_LOCATION_HPP
aoqi@0: #define SHARE_VM_CODE_LOCATION_HPP
aoqi@0: 
aoqi@0: #include "asm/assembler.hpp"
aoqi@0: #include "code/vmreg.hpp"
aoqi@0: #include "memory/allocation.hpp"
aoqi@0: 
aoqi@0: // A Location describes a concrete machine variable location
aoqi@0: // (such as integer or floating point register or a stack-held
aoqi@0: // variable). Used when generating debug-information for nmethods.
aoqi@0: //
aoqi@0: // Encoding:
aoqi@0: //
aoqi@0: // bits (use low bits for best compression):
aoqi@0: //  Type:   [3..0]
aoqi@0: //  Where:  [4]
aoqi@0: //  Offset: [31..5]
aoqi@0: 
aoqi@0: class Location VALUE_OBJ_CLASS_SPEC {
aoqi@0:   friend class VMStructs;
aoqi@0:  public:
aoqi@0:   enum Where {
aoqi@0:     on_stack,
aoqi@0:     in_register
aoqi@0:   };
aoqi@0: 
aoqi@0:   enum Type {
aoqi@0:     invalid,                    // Invalid location
aoqi@0:     normal,                     // Ints, floats, double halves
aoqi@0:     oop,                        // Oop (please GC me!)
aoqi@0:     int_in_long,                // Integer held in long register
aoqi@0:     lng,                        // Long held in one register
aoqi@0:     float_in_dbl,               // Float held in double register
aoqi@0:     dbl,                        // Double held in one register
aoqi@0:     addr,                       // JSR return address
aoqi@0:     narrowoop                   // Narrow Oop (please GC me!)
aoqi@0:   };
aoqi@0: 
aoqi@0: 
aoqi@0:  private:
aoqi@0:   enum {
aoqi@0:     TYPE_MASK    = (juint) 0x0F,
aoqi@0:     TYPE_SHIFT   = 0,
aoqi@0:     WHERE_MASK   = (juint) 0x10,
aoqi@0:     WHERE_SHIFT  = 4,
aoqi@0:     OFFSET_MASK  = (juint) 0xFFFFFFE0,
aoqi@0:     OFFSET_SHIFT = 5
aoqi@0:   };
aoqi@0: 
aoqi@0:   juint _value;
aoqi@0: 
aoqi@0:   // Create a bit-packed Location
aoqi@0:   Location(Where where_, Type type_, unsigned offset_) {
aoqi@0:     set(where_, type_, offset_);
aoqi@0:     assert( where () == where_ , "" );
aoqi@0:     assert( type  () == type_  , "" );
aoqi@0:     assert( offset() == offset_, "" );
aoqi@0:   }
aoqi@0: 
aoqi@0:   inline void set(Where where_, Type type_, unsigned offset_) {
aoqi@0:     _value = (juint) ((where_  << WHERE_SHIFT) |
aoqi@0:                       (type_   << TYPE_SHIFT)  |
aoqi@0:                       ((offset_ << OFFSET_SHIFT) & OFFSET_MASK));
aoqi@0:   }
aoqi@0: 
aoqi@0:  public:
aoqi@0: 
aoqi@0:   // Stack location Factory.  Offset is 4-byte aligned; remove low bits
aoqi@0:   static Location new_stk_loc( Type t, int offset ) { return Location(on_stack,t,offset>>LogBytesPerInt); }
aoqi@0:   // Register location Factory
aoqi@0:   static Location new_reg_loc( Type t, VMReg reg ) { return Location(in_register, t, reg->value()); }
aoqi@0:   // Default constructor
aoqi@0:   Location() { set(on_stack,invalid,0); }
aoqi@0: 
aoqi@0:   // Bit field accessors
aoqi@0:   Where where()  const { return (Where)       ((_value & WHERE_MASK)  >> WHERE_SHIFT);}
aoqi@0:   Type  type()   const { return (Type)        ((_value & TYPE_MASK)   >> TYPE_SHIFT); }
aoqi@0:   unsigned offset() const { return (unsigned) ((_value & OFFSET_MASK) >> OFFSET_SHIFT); }
aoqi@0: 
aoqi@0:   // Accessors
aoqi@0:   bool is_register() const    { return where() == in_register; }
aoqi@0:   bool is_stack() const       { return where() == on_stack;    }
aoqi@0: 
aoqi@0:   int stack_offset() const    { assert(where() == on_stack,    "wrong Where"); return offset()<<LogBytesPerInt; }
aoqi@0:   int register_number() const { assert(where() == in_register, "wrong Where"); return offset()   ; }
aoqi@0: 
aoqi@0:   VMReg reg() const { assert(where() == in_register, "wrong Where"); return VMRegImpl::as_VMReg(offset())   ; }
aoqi@0: 
aoqi@0:   // Printing
aoqi@0:   void print_on(outputStream* st) const;
aoqi@0: 
aoqi@0:   // Serialization of debugging information
aoqi@0:   Location(DebugInfoReadStream* stream);
aoqi@0:   void write_on(DebugInfoWriteStream* stream);
aoqi@0: 
aoqi@0:   // check
aoqi@0:   static bool legal_offset_in_bytes(int offset_in_bytes);
aoqi@0: };
aoqi@0: 
aoqi@0: #endif // SHARE_VM_CODE_LOCATION_HPP