1 /*
2 * Copyright (c) 1997, 2012, 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_CODE_STUBS_HPP
26 #define SHARE_VM_CODE_STUBS_HPP
27
28 #include "asm/codeBuffer.hpp"
29 #include "memory/allocation.hpp"
30 #ifdef TARGET_OS_FAMILY_linux
31 # include "os_linux.inline.hpp"
32 #endif
33 #ifdef TARGET_OS_FAMILY_solaris
34 # include "os_solaris.inline.hpp"
35 #endif
36 #ifdef TARGET_OS_FAMILY_windows
37 # include "os_windows.inline.hpp"
38 #endif
39 #ifdef TARGET_OS_FAMILY_aix
40 # include "os_aix.inline.hpp"
41 #endif
42 #ifdef TARGET_OS_FAMILY_bsd
43 # include "os_bsd.inline.hpp"
44 #endif
45
46 // The classes in this file provide a simple framework for the
47 // management of little pieces of machine code - or stubs -
48 // created on the fly and frequently discarded. In this frame-
49 // work stubs are stored in a queue.
50
51
52 // Stub serves as abstract base class. A concrete stub
53 // implementation is a subclass of Stub, implementing
54 // all (non-virtual!) functions required sketched out
55 // in the Stub class.
56 //
57 // A concrete stub layout may look like this (both data
58 // and code sections could be empty as well):
59 //
60 // ________
61 // stub -->| | <--+
62 // | data | |
63 // |________| |
64 // code_begin -->| | |
65 // | | |
66 // | code | | size
67 // | | |
68 // |________| |
69 // code_end -->| | |
70 // | data | |
71 // |________| |
72 // <--+
73
74
75 class Stub VALUE_OBJ_CLASS_SPEC {
76 public:
77 // Initialization/finalization
78 void initialize(int size,
79 CodeStrings& strings) { ShouldNotCallThis(); } // called to initialize/specify the stub's size
80 void finalize() { ShouldNotCallThis(); } // called before the stub is deallocated
81
82 // General info/converters
83 int size() const { ShouldNotCallThis(); return 0; } // must return the size provided by initialize
84 static int code_size_to_size(int code_size) { ShouldNotCallThis(); return 0; } // computes the size given the code size
85
86 // Code info
87 address code_begin() const { ShouldNotCallThis(); return NULL; } // points to the first byte of the code
88 address code_end() const { ShouldNotCallThis(); return NULL; } // points to the first byte after the code
89
90 // Debugging
91 void verify() { ShouldNotCallThis(); } // verifies the Stub
92 void print() { ShouldNotCallThis(); } // prints some information about the stub
93 };
94
95
96 // A stub interface defines the interface between a stub queue
97 // and the stubs it queues. In order to avoid a vtable and
98 // (and thus the extra word) in each stub, a concrete stub
99 // interface object is created and associated with a stub
100 // buffer which in turn uses the stub interface to interact
101 // with its stubs.
102 //
103 // StubInterface serves as an abstract base class. A concrete
104 // stub interface implementation is a subclass of StubInterface,
105 // forwarding its virtual function calls to non-virtual calls
106 // of the concrete stub (see also macro below). There's exactly
107 // one stub interface instance required per stub queue.
108
109 class StubInterface: public CHeapObj<mtCode> {
110 public:
111 // Initialization/finalization
112 virtual void initialize(Stub* self, int size,
113 CodeStrings& strings) = 0; // called after creation (called twice if allocated via (request, commit))
114 virtual void finalize(Stub* self) = 0; // called before deallocation
115
116 // General info/converters
117 virtual int size(Stub* self) const = 0; // the total size of the stub in bytes (must be a multiple of CodeEntryAlignment)
118 virtual int code_size_to_size(int code_size) const = 0; // computes the total stub size in bytes given the code size in bytes
119
120 // Code info
121 virtual address code_begin(Stub* self) const = 0; // points to the first code byte
122 virtual address code_end(Stub* self) const = 0; // points to the first byte after the code
123
124 // Debugging
125 virtual void verify(Stub* self) = 0; // verifies the stub
126 virtual void print(Stub* self) = 0; // prints information about the stub
127 };
128
129
130 // DEF_STUB_INTERFACE is used to create a concrete stub interface
131 // class, forwarding stub interface calls to the corresponding
132 // stub calls.
133
134 #define DEF_STUB_INTERFACE(stub) \
135 class stub##Interface: public StubInterface { \
136 private: \
137 static stub* cast(Stub* self) { return (stub*)self; } \
138 \
139 public: \
140 /* Initialization/finalization */ \
141 virtual void initialize(Stub* self, int size, \
142 CodeStrings& strings) { cast(self)->initialize(size, strings); } \
143 virtual void finalize(Stub* self) { cast(self)->finalize(); } \
144 \
145 /* General info */ \
146 virtual int size(Stub* self) const { return cast(self)->size(); } \
147 virtual int code_size_to_size(int code_size) const { return stub::code_size_to_size(code_size); } \
148 \
149 /* Code info */ \
150 virtual address code_begin(Stub* self) const { return cast(self)->code_begin(); } \
151 virtual address code_end(Stub* self) const { return cast(self)->code_end(); } \
152 \
153 /* Debugging */ \
154 virtual void verify(Stub* self) { cast(self)->verify(); } \
155 virtual void print(Stub* self) { cast(self)->print(); } \
156 };
157
158
159 // A StubQueue maintains a queue of stubs.
160 // Note: All sizes (spaces) are given in bytes.
161
162 class StubQueue: public CHeapObj<mtCode> {
163 friend class VMStructs;
164 private:
165 StubInterface* _stub_interface; // the interface prototype
166 address _stub_buffer; // where all stubs are stored
167 int _buffer_size; // the buffer size in bytes
168 int _buffer_limit; // the (byte) index of the actual buffer limit (_buffer_limit <= _buffer_size)
169 int _queue_begin; // the (byte) index of the first queue entry (word-aligned)
170 int _queue_end; // the (byte) index of the first entry after the queue (word-aligned)
171 int _number_of_stubs; // the number of buffered stubs
172 Mutex* const _mutex; // the lock used for a (request, commit) transaction
173
174 void check_index(int i) const { assert(0 <= i && i < _buffer_limit && i % CodeEntryAlignment == 0, "illegal index"); }
175 bool is_contiguous() const { return _queue_begin <= _queue_end; }
176 int index_of(Stub* s) const { int i = (address)s - _stub_buffer; check_index(i); return i; }
177 Stub* stub_at(int i) const { check_index(i); return (Stub*)(_stub_buffer + i); }
178 Stub* current_stub() const { return stub_at(_queue_end); }
179
180 // Stub functionality accessed via interface
181 void stub_initialize(Stub* s, int size,
182 CodeStrings& strings) { assert(size % CodeEntryAlignment == 0, "size not aligned"); _stub_interface->initialize(s, size, strings); }
183 void stub_finalize(Stub* s) { _stub_interface->finalize(s); }
184 int stub_size(Stub* s) const { return _stub_interface->size(s); }
185 bool stub_contains(Stub* s, address pc) const { return _stub_interface->code_begin(s) <= pc && pc < _stub_interface->code_end(s); }
186 int stub_code_size_to_size(int code_size) const { return _stub_interface->code_size_to_size(code_size); }
187 void stub_verify(Stub* s) { _stub_interface->verify(s); }
188 void stub_print(Stub* s) { _stub_interface->print(s); }
189
190 static void register_queue(StubQueue*);
191
192 public:
193 StubQueue(StubInterface* stub_interface, int buffer_size, Mutex* lock,
194 const char* name);
195 ~StubQueue();
196
197 // General queue info
198 bool is_empty() const { return _queue_begin == _queue_end; }
199 int total_space() const { return _buffer_size - 1; }
200 int available_space() const { int d = _queue_begin - _queue_end - 1; return d < 0 ? d + _buffer_size : d; }
201 int used_space() const { return total_space() - available_space(); }
202 int number_of_stubs() const { return _number_of_stubs; }
203 bool contains(address pc) const { return _stub_buffer <= pc && pc < _stub_buffer + _buffer_limit; }
204 Stub* stub_containing(address pc) const;
205 address code_start() const { return _stub_buffer; }
206 address code_end() const { return _stub_buffer + _buffer_limit; }
207
208 // Stub allocation (atomic transactions)
209 Stub* request_committed(int code_size); // request a stub that provides exactly code_size space for code
210 Stub* request(int requested_code_size); // request a stub with a (maximum) code space - locks the queue
211 void commit (int committed_code_size,
212 CodeStrings& strings); // commit the previously requested stub - unlocks the queue
213
214 // Stub deallocation
215 void remove_first(); // remove the first stub in the queue
216 void remove_first(int n); // remove the first n stubs in the queue
217 void remove_all(); // remove all stubs in the queue
218
219 // Iteration
220 static void queues_do(void f(StubQueue* s)); // call f with each StubQueue
221 void stubs_do(void f(Stub* s)); // call f with all stubs
222 Stub* first() const { return number_of_stubs() > 0 ? stub_at(_queue_begin) : NULL; }
223 Stub* next(Stub* s) const { int i = index_of(s) + stub_size(s);
224 if (i == _buffer_limit) i = 0;
225 return (i == _queue_end) ? NULL : stub_at(i);
226 }
227
228 address stub_code_begin(Stub* s) const { return _stub_interface->code_begin(s); }
229 address stub_code_end(Stub* s) const { return _stub_interface->code_end(s); }
230
231 // Debugging/printing
232 void verify(); // verifies the stub queue
233 void print(); // prints information about the stub queue
234 };
235
236 #endif // SHARE_VM_CODE_STUBS_HPP