1 /*
2 * Copyright (c) 2000, 2010, 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.
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23 */
24
25 #ifndef SHARE_VM_RUNTIME_VMSTRUCTS_HPP
26 #define SHARE_VM_RUNTIME_VMSTRUCTS_HPP
27
28 #ifndef KERNEL
29 #include "utilities/debug.hpp"
30 #endif
31 #ifdef COMPILER1
32 #include "c1/c1_Runtime1.hpp"
33 #endif
34
35 // This table encapsulates the debugging information required by the
36 // serviceability agent in order to run. Specifically, we need to
37 // understand the layout of certain C data structures (offsets, in
38 // bytes, of their fields.)
39 //
40 // There are alternatives for the design of this mechanism, including
41 // parsing platform-specific debugging symbols from a debug build into
42 // a program database. While this current mechanism can be considered
43 // to be a workaround for the inability to debug arbitrary C and C++
44 // programs at the present time, it does have certain advantages.
45 // First, it is platform-independent, which will vastly simplify the
46 // initial bringup of the system both now and on future platforms.
47 // Second, it is embedded within the VM, as opposed to being in a
48 // separate program database; experience has shown that whenever
49 // portions of a system are decoupled, version skew is problematic.
50 // Third, generating a program database, for example for a product
51 // build, would probably require two builds to be done: the desired
52 // product build as well as an intermediary build with the PRODUCT
53 // flag turned on but also compiled with -g, leading to a doubling of
54 // the time required to get a serviceability agent-debuggable product
55 // build. Fourth, and very significantly, this table probably
56 // preserves more information about field types than stabs do; for
57 // example, it preserves the fact that a field is a "jlong" rather
58 // than transforming the type according to the typedef in jni_md.h,
59 // which allows the Java-side code to identify "Java-sized" fields in
60 // C++ data structures. If the symbol parsing mechanism was redone
61 // using stabs, it might still be necessary to have a table somewhere
62 // containing this information.
63 //
64 // Do not change the sizes or signedness of the integer values in
65 // these data structures; they are fixed over in the serviceability
66 // agent's Java code (for bootstrapping).
67
68 typedef struct {
69 const char* typeName; // The type name containing the given field (example: "Klass")
70 const char* fieldName; // The field name within the type (example: "_name")
71 const char* typeString; // Quoted name of the type of this field (example: "symbolOopDesc*";
72 // parsed in Java to ensure type correctness
73 int32_t isStatic; // Indicates whether following field is an offset or an address
74 uint64_t offset; // Offset of field within structure; only used for nonstatic fields
75 void* address; // Address of field; only used for static fields
76 // ("offset" can not be reused because of apparent SparcWorks compiler bug
77 // in generation of initializer data)
78 } VMStructEntry;
79
80 typedef struct {
81 const char* typeName; // Type name (example: "methodOopDesc")
82 const char* superclassName; // Superclass name, or null if none (example: "oopDesc")
83 int32_t isOopType; // Does this type represent an oop typedef? (i.e., "methodOop" or
84 // "klassOop", but NOT "methodOopDesc")
85 int32_t isIntegerType; // Does this type represent an integer type (of arbitrary size)?
86 int32_t isUnsigned; // If so, is it unsigned?
87 uint64_t size; // Size, in bytes, of the type
88 } VMTypeEntry;
89
90 typedef struct {
91 const char* name; // Name of constant (example: "_thread_in_native")
92 int32_t value; // Value of constant
93 } VMIntConstantEntry;
94
95 typedef struct {
96 const char* name; // Name of constant (example: "_thread_in_native")
97 uint64_t value; // Value of constant
98 } VMLongConstantEntry;
99
100 // This class is a friend of most classes, to be able to access
101 // private fields
102 class VMStructs {
103 public:
104 // The last entry is identified over in the serviceability agent by
105 // the fact that it has a NULL fieldName
106 static VMStructEntry localHotSpotVMStructs[];
107
108 // The last entry is identified over in the serviceability agent by
109 // the fact that it has a NULL typeName
110 static VMTypeEntry localHotSpotVMTypes[];
111
112 // Table of integer constants required by the serviceability agent.
113 // The last entry is identified over in the serviceability agent by
114 // the fact that it has a NULL typeName
115 static VMIntConstantEntry localHotSpotVMIntConstants[];
116
117 // Table of long constants required by the serviceability agent.
118 // The last entry is identified over in the serviceability agent by
119 // the fact that it has a NULL typeName
120 static VMLongConstantEntry localHotSpotVMLongConstants[];
121
122 // This is used to run any checking code necessary for validation of
123 // the data structure (debug build only)
124 static void init();
125
126 private:
127 // Look up a type in localHotSpotVMTypes using strcmp() (debug build only).
128 // Returns 1 if found, 0 if not.
129 // debug_only(static int findType(const char* typeName);)
130 static int findType(const char* typeName);
131 };
132
133 #endif // SHARE_VM_RUNTIME_VMSTRUCTS_HPP