1 /*
2 * Copyright (c) 2002, 2007, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 class JavaThread;
26
27 //
28 // RegisterMap
29 //
30 // A companion structure used for stack traversal. The RegisterMap contains
31 // misc. information needed in order to do correct stack traversal of stack
32 // frames. Hence, it must always be passed in as an argument to
33 // frame::sender(RegisterMap*).
34 //
35 // In particular,
36 // 1) It provides access to the thread for which the stack belongs. The
37 // thread object is needed in order to get sender of a deoptimized frame.
38 //
39 // 2) It is used to pass information from a callee frame to its caller
40 // frame about how the frame should be traversed. This is used to let
41 // the caller frame take care of calling oops-do of out-going
42 // arguments, when the callee frame is not instantiated yet. This
43 // happens, e.g., when a compiled frame calls into
44 // resolve_virtual_call. (Hence, it is critical that the same
45 // RegisterMap object is used for the entire stack walk. Normally,
46 // this is hidden by using the StackFrameStream.) This is used when
47 // doing follow_oops and oops_do.
48 //
49 // 3) The RegisterMap keeps track of the values of callee-saved registers
50 // from frame to frame (hence, the name). For some stack traversal the
51 // values of the callee-saved registers does not matter, e.g., if you
52 // only need the static properies such as frame type, pc, and such.
53 // Updating of the RegisterMap can be turned off by instantiating the
54 // register map as: RegisterMap map(thread, false);
55
56 class RegisterMap : public StackObj {
57 public:
58 typedef julong LocationValidType;
59 enum {
60 reg_count = ConcreteRegisterImpl::number_of_registers,
61 location_valid_type_size = sizeof(LocationValidType)*8,
62 location_valid_size = (reg_count+location_valid_type_size-1)/location_valid_type_size
63 };
64 private:
65 intptr_t* _location[reg_count]; // Location of registers (intptr_t* looks better than address in the debugger)
66 LocationValidType _location_valid[location_valid_size];
67 bool _include_argument_oops; // Should include argument_oop marked locations for compiler
68 JavaThread* _thread; // Reference to current thread
69 bool _update_map; // Tells if the register map need to be
70 // updated when traversing the stack
71
72 #ifdef ASSERT
73 void check_location_valid();
74 #else
75 void check_location_valid() {}
76 #endif
77
78 public:
79 debug_only(intptr_t* _update_for_id;) // Assert that RegisterMap is not updated twice for same frame
80 RegisterMap(JavaThread *thread, bool update_map = true);
81 RegisterMap(const RegisterMap* map);
82
83 address location(VMReg reg) const {
84 int index = reg->value() / location_valid_type_size;
85 assert(0 <= reg->value() && reg->value() < reg_count, "range check");
86 assert(0 <= index && index < location_valid_size, "range check");
87 if (_location_valid[index] & ((LocationValidType)1 << (reg->value() % location_valid_type_size))) {
88 return (address) _location[reg->value()];
89 } else {
90 return pd_location(reg);
91 }
92 }
93
94 void set_location(VMReg reg, address loc) {
95 int index = reg->value() / location_valid_type_size;
96 assert(0 <= reg->value() && reg->value() < reg_count, "range check");
97 assert(0 <= index && index < location_valid_size, "range check");
98 assert(_update_map, "updating map that does not need updating");
99 _location[reg->value()] = (intptr_t*) loc;
100 _location_valid[index] |= ((LocationValidType)1 << (reg->value() % location_valid_type_size));
101 check_location_valid();
102 }
103
104 // Called by an entry frame.
105 void clear();
106
107 bool include_argument_oops() const { return _include_argument_oops; }
108 void set_include_argument_oops(bool f) { _include_argument_oops = f; }
109
110 JavaThread *thread() const { return _thread; }
111 bool update_map() const { return _update_map; }
112
113 void print_on(outputStream* st) const;
114 void print() const;
115
116 // the following contains the definition of pd_xxx methods
117 # include "incls/_registerMap_pd.hpp.incl"
118 };