1 /*
2 * Copyright (c) 1998, 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_UTILITIES_EXCEPTIONS_HPP
26 #define SHARE_VM_UTILITIES_EXCEPTIONS_HPP
27
28 #include "memory/allocation.hpp"
29 #include "oops/oopsHierarchy.hpp"
30 #include "utilities/sizes.hpp"
31
32 // This file provides the basic support for exception handling in the VM.
33 // Note: We do not use C++ exceptions to avoid compiler dependencies and
34 // unpredictable performance.
35 //
36 // Scheme: Exceptions are stored with the thread. There is never more
37 // than one pending exception per thread. All functions that can throw
38 // an exception carry a THREAD argument (usually the last argument and
39 // declared with the TRAPS macro). Throwing an exception means setting
40 // a pending exception in the thread. Upon return from a function that
41 // can throw an exception, we must check if an exception is pending.
42 // The CHECK macros do this in a convenient way. Carrying around the
43 // thread provides also convenient access to it (e.g. for Handle
44 // creation, w/o the need for recomputation).
45
46
47
48 // Forward declarations to be independent of the include structure.
49 // This allows us to have exceptions.hpp included in top.hpp.
50
51 class Thread;
52 class Handle;
53 class symbolHandle;
54 class symbolOopDesc;
55 class JavaCallArguments;
56
57 // The ThreadShadow class is a helper class to access the _pending_exception
58 // field of the Thread class w/o having access to the Thread's interface (for
59 // include hierachy reasons).
60
61 class ThreadShadow: public CHeapObj {
62 protected:
63 oop _pending_exception; // Thread has gc actions.
64 const char* _exception_file; // file information for exception (debugging only)
65 int _exception_line; // line information for exception (debugging only)
66 friend void check_ThreadShadow(); // checks _pending_exception offset
67
68 // The following virtual exists only to force creation of a vtable.
69 // We need ThreadShadow to have a vtable, even in product builds,
70 // so that its layout will start at an offset of zero relative to Thread.
71 // Some C++ compilers are so "clever" that they put the ThreadShadow
72 // base class at offset 4 in Thread (after Thread's vtable), if they
73 // notice that Thread has a vtable but ThreadShadow does not.
74 virtual void unused_initial_virtual() { }
75
76 public:
77 oop pending_exception() const { return _pending_exception; }
78 bool has_pending_exception() const { return _pending_exception != NULL; }
79 const char* exception_file() const { return _exception_file; }
80 int exception_line() const { return _exception_line; }
81
82 // Code generation support
83 static ByteSize pending_exception_offset() { return byte_offset_of(ThreadShadow, _pending_exception); }
84
85 // use THROW whenever possible!
86 void set_pending_exception(oop exception, const char* file, int line);
87
88 // use CLEAR_PENDING_EXCEPTION whenever possible!
89 void clear_pending_exception();
90
91 ThreadShadow() : _pending_exception(NULL),
92 _exception_file(NULL), _exception_line(0) {}
93 };
94
95
96 // Exceptions is a helper class that encapsulates all operations
97 // that require access to the thread interface and which are
98 // relatively rare. The Exceptions operations should only be
99 // used directly if the macros below are insufficient.
100
101 class Exceptions {
102 static bool special_exception(Thread *thread, const char* file, int line, Handle exception);
103 static bool special_exception(Thread* thread, const char* file, int line, symbolHandle name, const char* message);
104 public:
105 // this enum is defined to indicate whether it is safe to
106 // ignore the encoding scheme of the original message string.
107 typedef enum {
108 safe_to_utf8 = 0,
109 unsafe_to_utf8 = 1
110 } ExceptionMsgToUtf8Mode;
111 // Throw exceptions: w/o message, w/ message & with formatted message.
112 static void _throw_oop(Thread* thread, const char* file, int line, oop exception);
113 static void _throw(Thread* thread, const char* file, int line, Handle exception, const char* msg = NULL);
114 static void _throw_msg(Thread* thread, const char* file, int line,
115 symbolHandle name, const char* message, Handle loader,
116 Handle protection_domain);
117 static void _throw_msg(Thread* thread, const char* file, int line,
118 symbolOop name, const char* message);
119 static void _throw_msg(Thread* thread, const char* file, int line,
120 symbolHandle name, const char* message);
121 static void _throw_args(Thread* thread, const char* file, int line,
122 symbolHandle name, symbolHandle signature,
123 JavaCallArguments* args);
124 static void _throw_msg_cause(Thread* thread, const char* file,
125 int line, symbolHandle h_name, const char* message,
126 Handle h_cause, Handle h_loader, Handle h_protection_domain);
127 static void _throw_msg_cause(Thread* thread, const char* file, int line,
128 symbolHandle name, const char* message, Handle cause);
129
130 // There is no THROW... macro for this method. Caller should remember
131 // to do a return after calling it.
132 static void fthrow(Thread* thread, const char* file, int line, symbolHandle name,
133 const char* format, ...);
134
135 // Create and initialize a new exception
136 static Handle new_exception(Thread* thread, symbolHandle name,
137 symbolHandle signature, JavaCallArguments* args,
138 Handle cause, Handle loader,
139 Handle protection_domain);
140
141 static Handle new_exception(Thread* thread, symbolHandle name,
142 const char* message, Handle cause, Handle loader,
143 Handle protection_domain,
144 ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);
145
146 static Handle new_exception(Thread* thread, symbolOop name,
147 const char* message,
148 ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);
149
150 static void throw_stack_overflow_exception(Thread* thread, const char* file, int line);
151
152 // for AbortVMOnException flag
153 NOT_PRODUCT(static void debug_check_abort(Handle exception, const char* message = NULL);)
154 NOT_PRODUCT(static void debug_check_abort(const char *value_string, const char* message = NULL);)
155 };
156
157
158 // The THREAD & TRAPS macros facilitate the declaration of functions that throw exceptions.
159 // Convention: Use the TRAPS macro as the last argument of such a function; e.g.:
160 //
161 // int this_function_may_trap(int x, float y, TRAPS)
162
163 #define THREAD __the_thread__
164 #define TRAPS Thread* THREAD
165
166
167 // The CHECK... macros should be used to pass along a THREAD reference and to check for pending
168 // exceptions. In special situations it is necessary to handle pending exceptions explicitly,
169 // in these cases the PENDING_EXCEPTION helper macros should be used.
170 //
171 // Macro naming conventions: Macros that end with _ require a result value to be returned. They
172 // are for functions with non-void result type. The result value is usually ignored because of
173 // the exception and is only needed for syntactic correctness. The _0 ending is a shortcut for
174 // _(0) since this is a frequent case. Example:
175 //
176 // int result = this_function_may_trap(x_arg, y_arg, CHECK_0);
177 //
178 // CAUTION: make sure that the function call using a CHECK macro is not the only statement of a
179 // conditional branch w/o enclosing {} braces, since the CHECK macros expand into several state-
180 // ments!
181
182 #define PENDING_EXCEPTION (((ThreadShadow*)THREAD)->pending_exception())
183 #define HAS_PENDING_EXCEPTION (((ThreadShadow*)THREAD)->has_pending_exception())
184 #define CLEAR_PENDING_EXCEPTION (((ThreadShadow*)THREAD)->clear_pending_exception())
185
186 #define CHECK THREAD); if (HAS_PENDING_EXCEPTION) return ; (0
187 #define CHECK_(result) THREAD); if (HAS_PENDING_EXCEPTION) return result; (0
188 #define CHECK_0 CHECK_(0)
189 #define CHECK_NH CHECK_(Handle())
190 #define CHECK_NULL CHECK_(NULL)
191 #define CHECK_false CHECK_(false)
192
193 // The THROW... macros should be used to throw an exception. They require a THREAD variable to be
194 // visible within the scope containing the THROW. Usually this is achieved by declaring the function
195 // with a TRAPS argument.
196
197 #define THREAD_AND_LOCATION THREAD, __FILE__, __LINE__
198
199 #define THROW_OOP(e) \
200 { Exceptions::_throw_oop(THREAD_AND_LOCATION, e); return; }
201
202 #define THROW_HANDLE(e) \
203 { Exceptions::_throw(THREAD_AND_LOCATION, e); return; }
204
205 #define THROW(name) \
206 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return; }
207
208 #define THROW_MSG(name, message) \
209 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return; }
210
211 #define THROW_MSG_LOADER(name, message, loader, protection_domain) \
212 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return; }
213
214 #define THROW_ARG(name, signature, args) \
215 { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return; }
216
217 #define THROW_OOP_(e, result) \
218 { Exceptions::_throw_oop(THREAD_AND_LOCATION, e); return result; }
219
220 #define THROW_HANDLE_(e, result) \
221 { Exceptions::_throw(THREAD_AND_LOCATION, e); return result; }
222
223 #define THROW_(name, result) \
224 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return result; }
225
226 #define THROW_MSG_(name, message, result) \
227 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return result; }
228
229 #define THROW_MSG_LOADER_(name, message, loader, protection_domain, result) \
230 { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return result; }
231
232 #define THROW_ARG_(name, signature, args, result) \
233 { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return result; }
234
235 #define THROW_MSG_CAUSE_(name, message, cause, result) \
236 { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return result; }
237
238
239 #define THROW_OOP_0(e) THROW_OOP_(e, 0)
240 #define THROW_HANDLE_0(e) THROW_HANDLE_(e, 0)
241 #define THROW_0(name) THROW_(name, 0)
242 #define THROW_MSG_0(name, message) THROW_MSG_(name, message, 0)
243 #define THROW_WRAPPED_0(name, oop_to_wrap) THROW_WRAPPED_(name, oop_to_wrap, 0)
244 #define THROW_ARG_0(name, signature, arg) THROW_ARG_(name, signature, arg, 0)
245 #define THROW_MSG_CAUSE_0(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, 0)
246
247 #define THROW_NULL(name) THROW_(name, NULL)
248 #define THROW_MSG_NULL(name, message) THROW_MSG_(name, message, NULL)
249
250 // The CATCH macro checks that no exception has been thrown by a function; it is used at
251 // call sites about which is statically known that the callee cannot throw an exception
252 // even though it is declared with TRAPS.
253
254 #define CATCH \
255 THREAD); if (HAS_PENDING_EXCEPTION) { \
256 oop ex = PENDING_EXCEPTION; \
257 CLEAR_PENDING_EXCEPTION; \
258 ex->print(); \
259 ShouldNotReachHere(); \
260 } (0
261
262
263 // ExceptionMark is a stack-allocated helper class for local exception handling.
264 // It is used with the EXCEPTION_MARK macro.
265
266 class ExceptionMark {
267 private:
268 Thread* _thread;
269
270 public:
271 ExceptionMark(Thread*& thread);
272 ~ExceptionMark();
273 };
274
275
276
277 // Use an EXCEPTION_MARK for 'local' exceptions. EXCEPTION_MARK makes sure that no
278 // pending exception exists upon entering its scope and tests that no pending exception
279 // exists when leaving the scope.
280
281 // See also preserveException.hpp for PRESERVE_EXCEPTION_MARK macro,
282 // which preserves pre-existing exceptions and does not allow new
283 // exceptions.
284
285 #define EXCEPTION_MARK Thread* THREAD; ExceptionMark __em(THREAD);
286
287 #endif // SHARE_VM_UTILITIES_EXCEPTIONS_HPP