1 /*
2 * Copyright (c) 1997, 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25 #ifndef SHARE_VM_CODE_STUBS_HPP
26 #define SHARE_VM_CODE_STUBS_HPP
27
28 #include "memory/allocation.hpp"
29 #ifdef TARGET_OS_FAMILY_linux
30 # include "os_linux.inline.hpp"
31 #endif
32 #ifdef TARGET_OS_FAMILY_solaris
33 # include "os_solaris.inline.hpp"
34 #endif
35 #ifdef TARGET_OS_FAMILY_windows
36 # include "os_windows.inline.hpp"
37 #endif
38 #ifdef TARGET_OS_FAMILY_bsd
39 # include "os_bsd.inline.hpp"
40 #endif
41
42 // The classes in this file provide a simple framework for the
43 // management of little pieces of machine code - or stubs -
44 // created on the fly and frequently discarded. In this frame-
45 // work stubs are stored in a queue.
46
47
48 // Stub serves as abstract base class. A concrete stub
49 // implementation is a subclass of Stub, implementing
50 // all (non-virtual!) functions required sketched out
51 // in the Stub class.
52 //
53 // A concrete stub layout may look like this (both data
54 // and code sections could be empty as well):
55 //
56 // ________
57 // stub -->| | <--+
58 // | data | |
59 // |________| |
60 // code_begin -->| | |
61 // | | |
62 // | code | | size
63 // | | |
64 // |________| |
65 // code_end -->| | |
66 // | data | |
67 // |________| |
68 // <--+
69
70
71 class Stub VALUE_OBJ_CLASS_SPEC {
72 public:
73 // Initialization/finalization
74 void initialize(int size) { ShouldNotCallThis(); } // called to initialize/specify the stub's size
75 void finalize() { ShouldNotCallThis(); } // called before the stub is deallocated
76
77 // General info/converters
78 int size() const { ShouldNotCallThis(); return 0; } // must return the size provided by initialize
79 static int code_size_to_size(int code_size) { ShouldNotCallThis(); return 0; } // computes the size given the code size
80
81 // Code info
82 address code_begin() const { ShouldNotCallThis(); return NULL; } // points to the first byte of the code
83 address code_end() const { ShouldNotCallThis(); return NULL; } // points to the first byte after the code
84
85 // Debugging
86 void verify() { ShouldNotCallThis(); } // verifies the Stub
87 void print() { ShouldNotCallThis(); } // prints some information about the stub
88 };
89
90
91 // A stub interface defines the interface between a stub queue
92 // and the stubs it queues. In order to avoid a vtable and
93 // (and thus the extra word) in each stub, a concrete stub
94 // interface object is created and associated with a stub
95 // buffer which in turn uses the stub interface to interact
96 // with its stubs.
97 //
98 // StubInterface serves as an abstract base class. A concrete
99 // stub interface implementation is a subclass of StubInterface,
100 // forwarding its virtual function calls to non-virtual calls
101 // of the concrete stub (see also macro below). There's exactly
102 // one stub interface instance required per stub queue.
103
104 class StubInterface: public CHeapObj {
105 public:
106 // Initialization/finalization
107 virtual void initialize(Stub* self, int size) = 0; // called after creation (called twice if allocated via (request, commit))
108 virtual void finalize(Stub* self) = 0; // called before deallocation
109
110 // General info/converters
111 virtual int size(Stub* self) const = 0; // the total size of the stub in bytes (must be a multiple of CodeEntryAlignment)
112 virtual int code_size_to_size(int code_size) const = 0; // computes the total stub size in bytes given the code size in bytes
113
114 // Code info
115 virtual address code_begin(Stub* self) const = 0; // points to the first code byte
116 virtual address code_end(Stub* self) const = 0; // points to the first byte after the code
117
118 // Debugging
119 virtual void verify(Stub* self) = 0; // verifies the stub
120 virtual void print(Stub* self) = 0; // prints information about the stub
121 };
122
123
124 // DEF_STUB_INTERFACE is used to create a concrete stub interface
125 // class, forwarding stub interface calls to the corresponding
126 // stub calls.
127
128 #define DEF_STUB_INTERFACE(stub) \
129 class stub##Interface: public StubInterface { \
130 private: \
131 static stub* cast(Stub* self) { return (stub*)self; } \
132 \
133 public: \
134 /* Initialization/finalization */ \
135 virtual void initialize(Stub* self, int size) { cast(self)->initialize(size); } \
136 virtual void finalize(Stub* self) { cast(self)->finalize(); } \
137 \
138 /* General info */ \
139 virtual int size(Stub* self) const { return cast(self)->size(); } \
140 virtual int code_size_to_size(int code_size) const { return stub::code_size_to_size(code_size); } \
141 \
142 /* Code info */ \
143 virtual address code_begin(Stub* self) const { return cast(self)->code_begin(); } \
144 virtual address code_end(Stub* self) const { return cast(self)->code_end(); } \
145 \
146 /* Debugging */ \
147 virtual void verify(Stub* self) { cast(self)->verify(); } \
148 virtual void print(Stub* self) { cast(self)->print(); } \
149 };
150
151
152 // A StubQueue maintains a queue of stubs.
153 // Note: All sizes (spaces) are given in bytes.
154
155 class StubQueue: public CHeapObj {
156 friend class VMStructs;
157 private:
158 StubInterface* _stub_interface; // the interface prototype
159 address _stub_buffer; // where all stubs are stored
160 int _buffer_size; // the buffer size in bytes
161 int _buffer_limit; // the (byte) index of the actual buffer limit (_buffer_limit <= _buffer_size)
162 int _queue_begin; // the (byte) index of the first queue entry (word-aligned)
163 int _queue_end; // the (byte) index of the first entry after the queue (word-aligned)
164 int _number_of_stubs; // the number of buffered stubs
165 Mutex* const _mutex; // the lock used for a (request, commit) transaction
166
167 void check_index(int i) const { assert(0 <= i && i < _buffer_limit && i % CodeEntryAlignment == 0, "illegal index"); }
168 bool is_contiguous() const { return _queue_begin <= _queue_end; }
169 int index_of(Stub* s) const { int i = (address)s - _stub_buffer; check_index(i); return i; }
170 Stub* stub_at(int i) const { check_index(i); return (Stub*)(_stub_buffer + i); }
171 Stub* current_stub() const { return stub_at(_queue_end); }
172
173 // Stub functionality accessed via interface
174 void stub_initialize(Stub* s, int size) { assert(size % CodeEntryAlignment == 0, "size not aligned"); _stub_interface->initialize(s, size); }
175 void stub_finalize(Stub* s) { _stub_interface->finalize(s); }
176 int stub_size(Stub* s) const { return _stub_interface->size(s); }
177 bool stub_contains(Stub* s, address pc) const { return _stub_interface->code_begin(s) <= pc && pc < _stub_interface->code_end(s); }
178 int stub_code_size_to_size(int code_size) const { return _stub_interface->code_size_to_size(code_size); }
179 void stub_verify(Stub* s) { _stub_interface->verify(s); }
180 void stub_print(Stub* s) { _stub_interface->print(s); }
181
182 static void register_queue(StubQueue*);
183
184 public:
185 StubQueue(StubInterface* stub_interface, int buffer_size, Mutex* lock,
186 const char* name);
187 ~StubQueue();
188
189 // General queue info
190 bool is_empty() const { return _queue_begin == _queue_end; }
191 int total_space() const { return _buffer_size - 1; }
192 int available_space() const { int d = _queue_begin - _queue_end - 1; return d < 0 ? d + _buffer_size : d; }
193 int used_space() const { return total_space() - available_space(); }
194 int number_of_stubs() const { return _number_of_stubs; }
195 bool contains(address pc) const { return _stub_buffer <= pc && pc < _stub_buffer + _buffer_limit; }
196 Stub* stub_containing(address pc) const;
197 address code_start() const { return _stub_buffer; }
198 address code_end() const { return _stub_buffer + _buffer_limit; }
199
200 // Stub allocation (atomic transactions)
201 Stub* request_committed(int code_size); // request a stub that provides exactly code_size space for code
202 Stub* request(int requested_code_size); // request a stub with a (maximum) code space - locks the queue
203 void commit (int committed_code_size); // commit the previously requested stub - unlocks the queue
204
205 // Stub deallocation
206 void remove_first(); // remove the first stub in the queue
207 void remove_first(int n); // remove the first n stubs in the queue
208 void remove_all(); // remove all stubs in the queue
209
210 // Iteration
211 static void queues_do(void f(StubQueue* s)); // call f with each StubQueue
212 void stubs_do(void f(Stub* s)); // call f with all stubs
213 Stub* first() const { return number_of_stubs() > 0 ? stub_at(_queue_begin) : NULL; }
214 Stub* next(Stub* s) const { int i = index_of(s) + stub_size(s);
215 if (i == _buffer_limit) i = 0;
216 return (i == _queue_end) ? NULL : stub_at(i);
217 }
218
219 address stub_code_begin(Stub* s) const { return _stub_interface->code_begin(s); }
220 address stub_code_end(Stub* s) const { return _stub_interface->code_end(s); }
221
222 // Debugging/printing
223 void verify(); // verifies the stub queue
224 void print(); // prints information about the stub queue
225 };
226
227 #endif // SHARE_VM_CODE_STUBS_HPP