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comparison src/share/vm/code/location.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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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 */
24
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]
35
36 class Location VALUE_OBJ_CLASS_SPEC {
37 friend class VMStructs;
38 public:
39 enum Where {
40 on_stack,
41 in_register
42 };
43
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 };
54
55
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 };
65
66 uint16_t _value;
67
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 }
75
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 }
81
82 public:
83
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); }
90
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); }
95
96 // Accessors
97 bool is_register() const { return where() == in_register; }
98 bool is_stack() const { return where() == on_stack; }
99
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() ; }
102
103 VMReg reg() const { assert(where() == in_register, "wrong Where"); return VMRegImpl::as_VMReg(offset()) ; }
104
105 // Printing
106 void print_on(outputStream* st) const;
107
108 // Serialization of debugging information
109 Location(DebugInfoReadStream* stream);
110 void write_on(DebugInfoWriteStream* stream);
111
112 // check
113 static bool legal_offset_in_bytes(int offset_in_bytes);
114 };