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comparison src/share/vm/utilities/exceptions.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | e5b0439ef4ae |
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1 /* | |
2 * Copyright 1998-2007 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 // This file provides the basic support for exception handling in the VM. | |
26 // Note: We do not use C++ exceptions to avoid compiler dependencies and | |
27 // unpredictable performance. | |
28 // | |
29 // Scheme: Exceptions are stored with the thread. There is never more | |
30 // than one pending exception per thread. All functions that can throw | |
31 // an exception carry a THREAD argument (usually the last argument and | |
32 // declared with the TRAPS macro). Throwing an exception means setting | |
33 // a pending exception in the thread. Upon return from a function that | |
34 // can throw an exception, we must check if an exception is pending. | |
35 // The CHECK macros do this in a convenient way. Carrying around the | |
36 // thread provides also convenient access to it (e.g. for Handle | |
37 // creation, w/o the need for recomputation). | |
38 | |
39 | |
40 | |
41 // Forward declarations to be independent of the include structure. | |
42 // This allows us to have exceptions.hpp included in top.hpp. | |
43 | |
44 class Thread; | |
45 class Handle; | |
46 class symbolHandle; | |
47 class symbolOopDesc; | |
48 class JavaCallArguments; | |
49 | |
50 // The ThreadShadow class is a helper class to access the _pending_exception | |
51 // field of the Thread class w/o having access to the Thread's interface (for | |
52 // include hierachy reasons). | |
53 | |
54 class ThreadShadow: public CHeapObj { | |
55 protected: | |
56 oop _pending_exception; // Thread has gc actions. | |
57 const char* _exception_file; // file information for exception (debugging only) | |
58 int _exception_line; // line information for exception (debugging only) | |
59 friend void check_ThreadShadow(); // checks _pending_exception offset | |
60 | |
61 // The following virtual exists only to force creation of a vtable. | |
62 // We need ThreadShadow to have a vtable, even in product builds, | |
63 // so that its layout will start at an offset of zero relative to Thread. | |
64 // Some C++ compilers are so "clever" that they put the ThreadShadow | |
65 // base class at offset 4 in Thread (after Thread's vtable), if they | |
66 // notice that Thread has a vtable but ThreadShadow does not. | |
67 virtual void unused_initial_virtual() { } | |
68 | |
69 public: | |
70 oop pending_exception() const { return _pending_exception; } | |
71 bool has_pending_exception() const { return _pending_exception != NULL; } | |
72 const char* exception_file() const { return _exception_file; } | |
73 int exception_line() const { return _exception_line; } | |
74 | |
75 // Code generation support | |
76 static ByteSize pending_exception_offset() { return byte_offset_of(ThreadShadow, _pending_exception); } | |
77 | |
78 // use THROW whenever possible! | |
79 void set_pending_exception(oop exception, const char* file, int line); | |
80 | |
81 // use CLEAR_PENDING_EXCEPTION whenever possible! | |
82 void clear_pending_exception(); | |
83 | |
84 ThreadShadow() : _pending_exception(NULL), | |
85 _exception_file(NULL), _exception_line(0) {} | |
86 }; | |
87 | |
88 | |
89 // Exceptions is a helper class that encapsulates all operations | |
90 // that require access to the thread interface and which are | |
91 // relatively rare. The Exceptions operations should only be | |
92 // used directly if the macros below are insufficient. | |
93 | |
94 class Exceptions { | |
95 static bool special_exception(Thread *thread, const char* file, int line, Handle exception); | |
96 static bool special_exception(Thread* thread, const char* file, int line, symbolHandle name, const char* message); | |
97 public: | |
98 // this enum is defined to indicate whether it is safe to | |
99 // ignore the encoding scheme of the original message string. | |
100 typedef enum { | |
101 safe_to_utf8 = 0, | |
102 unsafe_to_utf8 = 1 | |
103 } ExceptionMsgToUtf8Mode; | |
104 // Throw exceptions: w/o message, w/ message & with formatted message. | |
105 static void _throw_oop(Thread* thread, const char* file, int line, oop exception); | |
106 static void _throw(Thread* thread, const char* file, int line, Handle exception); | |
107 static void _throw_msg(Thread* thread, const char* file, int line, | |
108 symbolHandle name, const char* message, Handle loader, | |
109 Handle protection_domain); | |
110 static void _throw_msg(Thread* thread, const char* file, int line, | |
111 symbolOop name, const char* message); | |
112 static void _throw_msg(Thread* thread, const char* file, int line, | |
113 symbolHandle name, const char* message); | |
114 static void _throw_args(Thread* thread, const char* file, int line, | |
115 symbolHandle name, symbolHandle signature, | |
116 JavaCallArguments* args); | |
117 static void _throw_msg_cause(Thread* thread, const char* file, | |
118 int line, symbolHandle h_name, const char* message, | |
119 Handle h_cause, Handle h_loader, Handle h_protection_domain); | |
120 static void _throw_msg_cause(Thread* thread, const char* file, int line, | |
121 symbolHandle name, const char* message, Handle cause); | |
122 | |
123 // There is no THROW... macro for this method. Caller should remember | |
124 // to do a return after calling it. | |
125 static void fthrow(Thread* thread, const char* file, int line, symbolHandle name, | |
126 const char* format, ...); | |
127 | |
128 // Create and initialize a new exception | |
129 static Handle new_exception(Thread* thread, symbolHandle name, | |
130 symbolHandle signature, JavaCallArguments* args, | |
131 Handle cause, Handle loader, | |
132 Handle protection_domain); | |
133 | |
134 static Handle new_exception(Thread* thread, symbolHandle name, | |
135 const char* message, Handle cause, Handle loader, | |
136 Handle protection_domain, | |
137 ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8); | |
138 | |
139 static Handle new_exception(Thread* thread, symbolOop name, | |
140 const char* message, | |
141 ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8); | |
142 | |
143 static void throw_stack_overflow_exception(Thread* thread, const char* file, int line); | |
144 | |
145 // for AbortVMOnException flag | |
146 NOT_PRODUCT(static void debug_check_abort(Handle exception);) | |
147 NOT_PRODUCT(static void debug_check_abort(const char *value_string);) | |
148 }; | |
149 | |
150 | |
151 // The THREAD & TRAPS macros facilitate the declaration of functions that throw exceptions. | |
152 // Convention: Use the TRAPS macro as the last argument of such a function; e.g.: | |
153 // | |
154 // int this_function_may_trap(int x, float y, TRAPS) | |
155 | |
156 #define THREAD __the_thread__ | |
157 #define TRAPS Thread* THREAD | |
158 | |
159 | |
160 // The CHECK... macros should be used to pass along a THREAD reference and to check for pending | |
161 // exceptions. In special situations it is necessary to handle pending exceptions explicitly, | |
162 // in these cases the PENDING_EXCEPTION helper macros should be used. | |
163 // | |
164 // Macro naming conventions: Macros that end with _ require a result value to be returned. They | |
165 // are for functions with non-void result type. The result value is usually ignored because of | |
166 // the exception and is only needed for syntactic correctness. The _0 ending is a shortcut for | |
167 // _(0) since this is a frequent case. Example: | |
168 // | |
169 // int result = this_function_may_trap(x_arg, y_arg, CHECK_0); | |
170 // | |
171 // CAUTION: make sure that the function call using a CHECK macro is not the only statement of a | |
172 // conditional branch w/o enclosing {} braces, since the CHECK macros expand into several state- | |
173 // ments! | |
174 | |
175 #define PENDING_EXCEPTION (((ThreadShadow*)THREAD)->pending_exception()) | |
176 #define HAS_PENDING_EXCEPTION (((ThreadShadow*)THREAD)->has_pending_exception()) | |
177 #define CLEAR_PENDING_EXCEPTION (((ThreadShadow*)THREAD)->clear_pending_exception()) | |
178 | |
179 #define CHECK THREAD); if (HAS_PENDING_EXCEPTION) return ; (0 | |
180 #define CHECK_(result) THREAD); if (HAS_PENDING_EXCEPTION) return result; (0 | |
181 #define CHECK_0 CHECK_(0) | |
182 #define CHECK_NH CHECK_(Handle()) | |
183 #define CHECK_NULL CHECK_(NULL) | |
184 #define CHECK_false CHECK_(false) | |
185 | |
186 // The THROW... macros should be used to throw an exception. They require a THREAD variable to be | |
187 // visible within the scope containing the THROW. Usually this is achieved by declaring the function | |
188 // with a TRAPS argument. | |
189 | |
190 #define THREAD_AND_LOCATION THREAD, __FILE__, __LINE__ | |
191 | |
192 #define THROW_OOP(e) \ | |
193 { Exceptions::_throw_oop(THREAD_AND_LOCATION, e); return; } | |
194 | |
195 #define THROW_HANDLE(e) \ | |
196 { Exceptions::_throw(THREAD_AND_LOCATION, e); return; } | |
197 | |
198 #define THROW(name) \ | |
199 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return; } | |
200 | |
201 #define THROW_MSG(name, message) \ | |
202 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return; } | |
203 | |
204 #define THROW_MSG_LOADER(name, message, loader, protection_domain) \ | |
205 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return; } | |
206 | |
207 #define THROW_ARG(name, signature, args) \ | |
208 { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return; } | |
209 | |
210 #define THROW_OOP_(e, result) \ | |
211 { Exceptions::_throw_oop(THREAD_AND_LOCATION, e); return result; } | |
212 | |
213 #define THROW_HANDLE_(e, result) \ | |
214 { Exceptions::_throw(THREAD_AND_LOCATION, e); return result; } | |
215 | |
216 #define THROW_(name, result) \ | |
217 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return result; } | |
218 | |
219 #define THROW_MSG_(name, message, result) \ | |
220 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return result; } | |
221 | |
222 #define THROW_MSG_LOADER_(name, message, loader, protection_domain, result) \ | |
223 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return result; } | |
224 | |
225 #define THROW_ARG_(name, signature, args, result) \ | |
226 { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return result; } | |
227 | |
228 #define THROW_MSG_CAUSE_(name, message, cause, result) \ | |
229 { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return result; } | |
230 | |
231 | |
232 #define THROW_OOP_0(e) THROW_OOP_(e, 0) | |
233 #define THROW_HANDLE_0(e) THROW_HANDLE_(e, 0) | |
234 #define THROW_0(name) THROW_(name, 0) | |
235 #define THROW_MSG_0(name, message) THROW_MSG_(name, message, 0) | |
236 #define THROW_WRAPPED_0(name, oop_to_wrap) THROW_WRAPPED_(name, oop_to_wrap, 0) | |
237 #define THROW_ARG_0(name, signature, arg) THROW_ARG_(name, signature, arg, 0) | |
238 #define THROW_MSG_CAUSE_0(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, 0) | |
239 | |
240 // The CATCH macro checks that no exception has been thrown by a function; it is used at | |
241 // call sites about which is statically known that the callee cannot throw an exception | |
242 // even though it is declared with TRAPS. | |
243 | |
244 #define CATCH \ | |
245 THREAD); if (HAS_PENDING_EXCEPTION) { \ | |
246 oop ex = PENDING_EXCEPTION; \ | |
247 CLEAR_PENDING_EXCEPTION; \ | |
248 ex->print(); \ | |
249 ShouldNotReachHere(); \ | |
250 } (0 | |
251 | |
252 | |
253 // ExceptionMark is a stack-allocated helper class for local exception handling. | |
254 // It is used with the EXCEPTION_MARK macro. | |
255 | |
256 class ExceptionMark { | |
257 private: | |
258 Thread* _thread; | |
259 | |
260 public: | |
261 ExceptionMark(Thread*& thread); | |
262 ~ExceptionMark(); | |
263 }; | |
264 | |
265 | |
266 | |
267 // Use an EXCEPTION_MARK for 'local' exceptions. EXCEPTION_MARK makes sure that no | |
268 // pending exception exists upon entering its scope and tests that no pending exception | |
269 // exists when leaving the scope. | |
270 | |
271 // See also preserveException.hpp for PRESERVE_EXCEPTION_MARK macro, | |
272 // which preserves pre-existing exceptions and does not allow new | |
273 // exceptions. | |
274 | |
275 #define EXCEPTION_MARK Thread* THREAD; ExceptionMark __em(THREAD); |