1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
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   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).
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_UTILITIES_EXCEPTIONS_HPP
  26 #define SHARE_UTILITIES_EXCEPTIONS_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "oops/oopsHierarchy.hpp"
  30 #include "utilities/ostream.hpp"
  31 #include "utilities/sizes.hpp"
  32 
  33 // This file provides the basic support for exception handling in the VM.
  34 // Note: We do not use C++ exceptions to avoid compiler dependencies and
  35 // unpredictable performance.
  36 //
  37 // Scheme: Exceptions are stored with the thread. There is never more
  38 // than one pending exception per thread. All functions that can throw
  39 // an exception carry a THREAD argument (usually the last argument and
  40 // declared with the TRAPS macro). Throwing an exception means setting
  41 // a pending exception in the thread. Upon return from a function that
  42 // can throw an exception, we must check if an exception is pending.
  43 // The CHECK macros do this in a convenient way. Carrying around the
  44 // thread provides also convenient access to it (e.g. for Handle
  45 // creation, w/o the need for recomputation).
  46 
  47 
  48 
  49 // Forward declarations to be independent of the include structure.
  50 
  51 class Thread;
  52 class Handle;
  53 class Symbol;
  54 class JavaCallArguments;
  55 class methodHandle;
  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<mtThread> {
  62   friend class VMStructs;
  63   friend class JVMCIVMStructs;
  64 
  65  protected:
  66   oop  _pending_exception;                       // Thread has gc actions.
  67   const char* _exception_file;                   // file information for exception (debugging only)
  68   int         _exception_line;                   // line information for exception (debugging only)
  69   friend void check_ThreadShadow();              // checks _pending_exception offset
  70 
  71   // The following virtual exists only to force creation of a vtable.
  72   // We need ThreadShadow to have a vtable, even in product builds,
  73   // so that its layout will start at an offset of zero relative to Thread.
  74   // Some C++ compilers are so "clever" that they put the ThreadShadow
  75   // base class at offset 4 in Thread (after Thread's vtable), if they
  76   // notice that Thread has a vtable but ThreadShadow does not.
  77   virtual void unused_initial_virtual() { }
  78 
  79  public:
  80   oop  pending_exception() const                 { return _pending_exception; }
  81   bool has_pending_exception() const             { return _pending_exception != NULL; }
  82   const char* exception_file() const             { return _exception_file; }
  83   int  exception_line() const                    { return _exception_line; }
  84 
  85   // Code generation support
  86   static ByteSize pending_exception_offset()     { return byte_offset_of(ThreadShadow, _pending_exception); }
  87 
  88   // use THROW whenever possible!
  89   void set_pending_exception(oop exception, const char* file, int line);
  90 
  91   // use CLEAR_PENDING_EXCEPTION whenever possible!
  92   void clear_pending_exception();
  93 
  94   ThreadShadow() : _pending_exception(NULL),
  95                    _exception_file(NULL), _exception_line(0) {}
  96 };
  97 
  98 
  99 // Exceptions is a helper class that encapsulates all operations
 100 // that require access to the thread interface and which are
 101 // relatively rare. The Exceptions operations should only be
 102 // used directly if the macros below are insufficient.
 103 
 104 class Exceptions {
 105   static bool special_exception(Thread *thread, const char* file, int line, Handle exception);
 106   static bool special_exception(Thread* thread, const char* file, int line, Symbol* name, const char* message);
 107 
 108   // Count out of memory errors that are interesting in error diagnosis
 109   static volatile int _out_of_memory_error_java_heap_errors;
 110   static volatile int _out_of_memory_error_metaspace_errors;
 111   static volatile int _out_of_memory_error_class_metaspace_errors;
 112 
 113   // Count linkage errors
 114   static volatile int _linkage_errors;
 115  public:
 116   // this enum is defined to indicate whether it is safe to
 117   // ignore the encoding scheme of the original message string.
 118   typedef enum {
 119     safe_to_utf8 = 0,
 120     unsafe_to_utf8 = 1
 121   } ExceptionMsgToUtf8Mode;
 122   // Throw exceptions: w/o message, w/ message & with formatted message.
 123   static void _throw_oop(Thread* thread, const char* file, int line, oop exception);
 124   static void _throw(Thread* thread, const char* file, int line, Handle exception, const char* msg = NULL);
 125 
 126   static void _throw_msg(Thread* thread, const char* file, int line, Symbol* name, const char* message);
 127   static void _throw_msg(Thread* thread, const char* file, int line, Symbol* name, const char* message,
 128                          Handle loader, Handle protection_domain);
 129 
 130   static void _throw_msg_cause(Thread* thread, const char* file, int line, Symbol* name, const char* message, Handle h_cause);
 131   static void _throw_msg_cause(Thread* thread, const char* file, int line, Symbol* name, const char* message, Handle h_cause,
 132                                Handle h_loader, Handle h_protection_domain);
 133 
 134   static void _throw_cause(Thread* thread, const char* file, int line, Symbol* name, Handle h_cause);
 135   static void _throw_cause(Thread* thread, const char* file, int line, Symbol* name, Handle h_cause,
 136                            Handle h_loader, Handle h_protection_domain);
 137 
 138   static void _throw_args(Thread* thread, const char* file, int line,
 139                           Symbol* name, Symbol* signature,
 140                           JavaCallArguments* args);
 141 
 142   // There is no THROW... macro for this method. Caller should remember
 143   // to do a return after calling it.
 144   static void fthrow(Thread* thread, const char* file, int line, Symbol* name,
 145                      const char* format, ...) ATTRIBUTE_PRINTF(5, 6);
 146 
 147   // Create and initialize a new exception
 148   static Handle new_exception(Thread* thread, Symbol* name,
 149                               Symbol* signature, JavaCallArguments* args,
 150                               Handle loader, Handle protection_domain);
 151 
 152   static Handle new_exception(Thread* thread, Symbol* name,
 153                               Symbol* signature, JavaCallArguments* args,
 154                               Handle cause,
 155                               Handle loader, Handle protection_domain);
 156 
 157   static Handle new_exception(Thread* thread, Symbol* name,
 158                               Handle cause,
 159                               Handle loader, Handle protection_domain,
 160                               ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);
 161 
 162   static Handle new_exception(Thread* thread, Symbol* name,
 163                               const char* message, Handle cause,
 164                               Handle loader, Handle protection_domain,
 165                               ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);
 166 
 167   static Handle new_exception(Thread* thread, Symbol* name,
 168                               const char* message,
 169                               ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);
 170 
 171   static void throw_stack_overflow_exception(Thread* thread, const char* file, int line, const methodHandle& method);
 172 
 173   static void wrap_dynamic_exception(Thread* thread);
 174 
 175   // Exception counting for error files of interesting exceptions that may have
 176   // caused a problem for the jvm
 177   static volatile int _stack_overflow_errors;
 178 
 179   static bool has_exception_counts();
 180   static void count_out_of_memory_exceptions(Handle exception);
 181   static void print_exception_counts_on_error(outputStream* st);
 182 
 183   // for AbortVMOnException flag
 184   static void debug_check_abort(Handle exception, const char* message = NULL);
 185   static void debug_check_abort_helper(Handle exception, const char* message = NULL);
 186   static void debug_check_abort(const char *value_string, const char* message = NULL);
 187 
 188   // for logging exceptions
 189   static void log_exception(Handle exception, stringStream tempst);
 190 };
 191 
 192 
 193 // The THREAD & TRAPS macros facilitate the declaration of functions that throw exceptions.
 194 // Convention: Use the TRAPS macro as the last argument of such a function; e.g.:
 195 //
 196 // int this_function_may_trap(int x, float y, TRAPS)
 197 
 198 #define THREAD __the_thread__
 199 #define TRAPS  Thread* THREAD
 200 
 201 
 202 // The CHECK... macros should be used to pass along a THREAD reference and to check for pending
 203 // exceptions. In special situations it is necessary to handle pending exceptions explicitly,
 204 // in these cases the PENDING_EXCEPTION helper macros should be used.
 205 //
 206 // Macro naming conventions: Macros that end with _ require a result value to be returned. They
 207 // are for functions with non-void result type. The result value is usually ignored because of
 208 // the exception and is only needed for syntactic correctness. The _0 ending is a shortcut for
 209 // _(0) since this is a frequent case. Example:
 210 //
 211 // int result = this_function_may_trap(x_arg, y_arg, CHECK_0);
 212 //
 213 // CAUTION: make sure that the function call using a CHECK macro is not the only statement of a
 214 // conditional branch w/o enclosing {} braces, since the CHECK macros expand into several state-
 215 // ments! Also make sure it is not used on a function call that is part of a return statement!
 216 
 217 #define PENDING_EXCEPTION                        (((ThreadShadow*)THREAD)->pending_exception())
 218 #define HAS_PENDING_EXCEPTION                    (((ThreadShadow*)THREAD)->has_pending_exception())
 219 #define CLEAR_PENDING_EXCEPTION                  (((ThreadShadow*)THREAD)->clear_pending_exception())
 220 
 221 #define CHECK                                    THREAD); if (HAS_PENDING_EXCEPTION) return       ; (void)(0
 222 #define CHECK_(result)                           THREAD); if (HAS_PENDING_EXCEPTION) return result; (void)(0
 223 #define CHECK_0                                  CHECK_(0)
 224 #define CHECK_NH                                 CHECK_(Handle())
 225 #define CHECK_NULL                               CHECK_(NULL)
 226 #define CHECK_false                              CHECK_(false)
 227 #define CHECK_JNI_ERR                            CHECK_(JNI_ERR)
 228 
 229 #define CHECK_AND_CLEAR                         THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; return;        } (void)(0
 230 #define CHECK_AND_CLEAR_(result)                THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; return result; } (void)(0
 231 #define CHECK_AND_CLEAR_0                       CHECK_AND_CLEAR_(0)
 232 #define CHECK_AND_CLEAR_NH                      CHECK_AND_CLEAR_(Handle())
 233 #define CHECK_AND_CLEAR_NULL                    CHECK_AND_CLEAR_(NULL)
 234 #define CHECK_AND_CLEAR_false                   CHECK_AND_CLEAR_(false)
 235 
 236 // The THROW... macros should be used to throw an exception. They require a THREAD variable to be
 237 // visible within the scope containing the THROW. Usually this is achieved by declaring the function
 238 // with a TRAPS argument.
 239 
 240 #define THREAD_AND_LOCATION                      THREAD, __FILE__, __LINE__
 241 
 242 #define THROW_OOP(e)                                \
 243   { Exceptions::_throw_oop(THREAD_AND_LOCATION, e);                             return;  }
 244 
 245 #define THROW_HANDLE(e)                                \
 246   { Exceptions::_throw(THREAD_AND_LOCATION, e);                             return;  }
 247 
 248 #define THROW(name)                                 \
 249   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return;  }
 250 
 251 #define THROW_MSG(name, message)                    \
 252   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return;  }
 253 
 254 #define THROW_CAUSE(name, cause)   \
 255   { Exceptions::_throw_cause(THREAD_AND_LOCATION, name, cause); return; }
 256 
 257 #define THROW_MSG_LOADER(name, message, loader, protection_domain) \
 258   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return;  }
 259 
 260 #define THROW_ARG(name, signature, args) \
 261   { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args);   return; }
 262 
 263 #define THROW_OOP_(e, result)                       \
 264   { Exceptions::_throw_oop(THREAD_AND_LOCATION, e);                           return result; }
 265 
 266 #define THROW_HANDLE_(e, result)                       \
 267   { Exceptions::_throw(THREAD_AND_LOCATION, e);                           return result; }
 268 
 269 #define THROW_(name, result)                        \
 270   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return result; }
 271 
 272 #define THROW_MSG_(name, message, result)           \
 273   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return result; }
 274 
 275 #define THROW_MSG_LOADER_(name, message, loader, protection_domain, result) \
 276   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return result; }
 277 
 278 #define THROW_ARG_(name, signature, args, result) \
 279   { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return result; }
 280 
 281 #define THROW_MSG_CAUSE(name, message, cause)   \
 282   { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return; }
 283 
 284 #define THROW_MSG_CAUSE_(name, message, cause, result)   \
 285   { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return result; }
 286 
 287 
 288 #define THROW_OOP_0(e)                      THROW_OOP_(e, 0)
 289 #define THROW_HANDLE_0(e)                   THROW_HANDLE_(e, 0)
 290 #define THROW_0(name)                       THROW_(name, 0)
 291 #define THROW_MSG_0(name, message)          THROW_MSG_(name, message, 0)
 292 #define THROW_WRAPPED_0(name, oop_to_wrap)  THROW_WRAPPED_(name, oop_to_wrap, 0)
 293 #define THROW_ARG_0(name, signature, arg)   THROW_ARG_(name, signature, arg, 0)
 294 #define THROW_MSG_CAUSE_0(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, 0)
 295 #define THROW_MSG_CAUSE_NULL(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, NULL)
 296 
 297 #define THROW_NULL(name)                    THROW_(name, NULL)
 298 #define THROW_MSG_NULL(name, message)       THROW_MSG_(name, message, NULL)
 299 
 300 // The CATCH macro checks that no exception has been thrown by a function; it is used at
 301 // call sites about which is statically known that the callee cannot throw an exception
 302 // even though it is declared with TRAPS.
 303 
 304 #define CATCH                              \
 305   THREAD); if (HAS_PENDING_EXCEPTION) {    \
 306     oop ex = PENDING_EXCEPTION;            \
 307     CLEAR_PENDING_EXCEPTION;               \
 308     ex->print();                           \
 309     ShouldNotReachHere();                  \
 310   } (void)(0
 311 
 312 // ExceptionMark is a stack-allocated helper class for local exception handling.
 313 // It is used with the EXCEPTION_MARK macro.
 314 
 315 class ExceptionMark {
 316  private:
 317   Thread* _thread;
 318 
 319  public:
 320   ExceptionMark(Thread*& thread);
 321   ~ExceptionMark();
 322 };
 323 
 324 
 325 
 326 // Use an EXCEPTION_MARK for 'local' exceptions. EXCEPTION_MARK makes sure that no
 327 // pending exception exists upon entering its scope and tests that no pending exception
 328 // exists when leaving the scope.
 329 
 330 // See also preserveException.hpp for PRESERVE_EXCEPTION_MARK macro,
 331 // which preserves pre-existing exceptions and does not allow new
 332 // exceptions.
 333 
 334 #define EXCEPTION_MARK                           Thread* THREAD = NULL; ExceptionMark __em(THREAD);
 335 
 336 #endif // SHARE_UTILITIES_EXCEPTIONS_HPP