duke@435: /*
stefank@2314:  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #ifndef SHARE_VM_CODE_LOCATION_HPP
stefank@2314: #define SHARE_VM_CODE_LOCATION_HPP
stefank@2314: 
stefank@2314: #include "asm/assembler.hpp"
stefank@2314: #include "code/vmreg.hpp"
stefank@2314: #include "memory/allocation.hpp"
stefank@2314: 
duke@435: // A Location describes a concrete machine variable location
duke@435: // (such as integer or floating point register or a stack-held
duke@435: // variable). Used when generating debug-information for nmethods.
duke@435: //
duke@435: // Encoding:
duke@435: //
kvn@766: // bits (use low bits for best compression):
kvn@766: //  Type:   [3..0]
kvn@766: //  Where:  [4]
kvn@766: //  Offset: [31..5]
duke@435: 
duke@435: class Location VALUE_OBJ_CLASS_SPEC {
duke@435:   friend class VMStructs;
duke@435:  public:
duke@435:   enum Where {
duke@435:     on_stack,
duke@435:     in_register
duke@435:   };
duke@435: 
duke@435:   enum Type {
kvn@766:     invalid,                    // Invalid location
duke@435:     normal,                     // Ints, floats, double halves
duke@435:     oop,                        // Oop (please GC me!)
duke@435:     int_in_long,                // Integer held in long register
duke@435:     lng,                        // Long held in one register
duke@435:     float_in_dbl,               // Float held in double register
duke@435:     dbl,                        // Double held in one register
duke@435:     addr,                       // JSR return address
kvn@766:     narrowoop                   // Narrow Oop (please GC me!)
duke@435:   };
duke@435: 
duke@435: 
duke@435:  private:
duke@435:   enum {
kvn@766:     TYPE_MASK    = (juint) 0x0F,
kvn@766:     TYPE_SHIFT   = 0,
kvn@766:     WHERE_MASK   = (juint) 0x10,
kvn@766:     WHERE_SHIFT  = 4,
kvn@766:     OFFSET_MASK  = (juint) 0xFFFFFFE0,
kvn@766:     OFFSET_SHIFT = 5
duke@435:   };
duke@435: 
kvn@766:   juint _value;
duke@435: 
duke@435:   // Create a bit-packed Location
duke@435:   Location(Where where_, Type type_, unsigned offset_) {
duke@435:     set(where_, type_, offset_);
duke@435:     assert( where () == where_ , "" );
duke@435:     assert( type  () == type_  , "" );
duke@435:     assert( offset() == offset_, "" );
duke@435:   }
duke@435: 
duke@435:   inline void set(Where where_, Type type_, unsigned offset_) {
kvn@766:     _value = (juint) ((where_  << WHERE_SHIFT) |
kvn@766:                       (type_   << TYPE_SHIFT)  |
kvn@766:                       ((offset_ << OFFSET_SHIFT) & OFFSET_MASK));
duke@435:   }
duke@435: 
duke@435:  public:
duke@435: 
duke@435:   // Stack location Factory.  Offset is 4-byte aligned; remove low bits
duke@435:   static Location new_stk_loc( Type t, int offset ) { return Location(on_stack,t,offset>>LogBytesPerInt); }
duke@435:   // Register location Factory
duke@435:   static Location new_reg_loc( Type t, VMReg reg ) { return Location(in_register, t, reg->value()); }
duke@435:   // Default constructor
kvn@766:   Location() { set(on_stack,invalid,0); }
duke@435: 
duke@435:   // Bit field accessors
duke@435:   Where where()  const { return (Where)       ((_value & WHERE_MASK)  >> WHERE_SHIFT);}
duke@435:   Type  type()   const { return (Type)        ((_value & TYPE_MASK)   >> TYPE_SHIFT); }
duke@435:   unsigned offset() const { return (unsigned) ((_value & OFFSET_MASK) >> OFFSET_SHIFT); }
duke@435: 
duke@435:   // Accessors
duke@435:   bool is_register() const    { return where() == in_register; }
duke@435:   bool is_stack() const       { return where() == on_stack;    }
duke@435: 
duke@435:   int stack_offset() const    { assert(where() == on_stack,    "wrong Where"); return offset()<<LogBytesPerInt; }
duke@435:   int register_number() const { assert(where() == in_register, "wrong Where"); return offset()   ; }
duke@435: 
duke@435:   VMReg reg() const { assert(where() == in_register, "wrong Where"); return VMRegImpl::as_VMReg(offset())   ; }
duke@435: 
duke@435:   // Printing
duke@435:   void print_on(outputStream* st) const;
duke@435: 
duke@435:   // Serialization of debugging information
duke@435:   Location(DebugInfoReadStream* stream);
duke@435:   void write_on(DebugInfoWriteStream* stream);
duke@435: 
duke@435:   // check
duke@435:   static bool legal_offset_in_bytes(int offset_in_bytes);
duke@435: };
stefank@2314: 
stefank@2314: #endif // SHARE_VM_CODE_LOCATION_HPP