1 /*

     2  * Copyright (c) 1998, 2016, 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.

    22  *

    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/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 

    56 // The ThreadShadow class is a helper class to access the _pending_exception

    57 // field of the Thread class w/o having access to the Thread's interface (for

    58 // include hierachy reasons).

    59 

    60 class ThreadShadow: public CHeapObj<mtThread> {

    61   friend class VMStructs;

    62   friend class JVMCIVMStructs;

    63 

    64  protected:

    65   oop  _pending_exception;                       // Thread has gc actions.

    66   const char* _exception_file;                   // file information for exception (debugging only)

    67   int         _exception_line;                   // line information for exception (debugging only)

    68   friend void check_ThreadShadow();              // checks _pending_exception offset

    69 

    70   // The following virtual exists only to force creation of a vtable.

    71   // We need ThreadShadow to have a vtable, even in product builds,

    72   // so that its layout will start at an offset of zero relative to Thread.

    73   // Some C++ compilers are so "clever" that they put the ThreadShadow

    74   // base class at offset 4 in Thread (after Thread's vtable), if they

    75   // notice that Thread has a vtable but ThreadShadow does not.

    76   virtual void unused_initial_virtual() { }

    77 

    78  public:

    79   oop  pending_exception() const                 { return _pending_exception; }

    80   bool has_pending_exception() const             { return _pending_exception != NULL; }

    81   const char* exception_file() const             { return _exception_file; }

    82   int  exception_line() const                    { return _exception_line; }

    83 

    84   // Code generation support

    85   static ByteSize pending_exception_offset()     { return byte_offset_of(ThreadShadow, _pending_exception); }

    86 

    87   // use THROW whenever possible!

    88   void set_pending_exception(oop exception, const char* file, int line);

    89 

    90   // use CLEAR_PENDING_EXCEPTION whenever possible!

    91   void clear_pending_exception();

    92 

    93   ThreadShadow() : _pending_exception(NULL),

    94                    _exception_file(NULL), _exception_line(0) {}

    95 };

    96 

    97 

    98 // Exceptions is a helper class that encapsulates all operations

    99 // that require access to the thread interface and which are

   100 // relatively rare. The Exceptions operations should only be

   101 // used directly if the macros below are insufficient.

   102 

   103 class Exceptions {

   104   static bool special_exception(Thread *thread, const char* file, int line, Handle exception);

   105   static bool special_exception(Thread* thread, const char* file, int line, Symbol* name, const char* message);

   106 

   107   // Count out of memory errors that are interesting in error diagnosis

   108   static volatile int _out_of_memory_error_java_heap_errors;

   109   static volatile int _out_of_memory_error_metaspace_errors;

   110   static volatile int _out_of_memory_error_class_metaspace_errors;

   111  public:

   112   // this enum is defined to indicate whether it is safe to

   113   // ignore the encoding scheme of the original message string.

   114   typedef enum {

   115     safe_to_utf8 = 0,

   116     unsafe_to_utf8 = 1

   117   } ExceptionMsgToUtf8Mode;

   118   // Throw exceptions: w/o message, w/ message & with formatted message.

   119   static void _throw_oop(Thread* thread, const char* file, int line, oop exception);

   120   static void _throw(Thread* thread, const char* file, int line, Handle exception, const char* msg = NULL);

   121 

   122   static void _throw_msg(Thread* thread, const char* file, int line, Symbol* name, const char* message);

   123   static void _throw_msg(Thread* thread, const char* file, int line, Symbol* name, const char* message,

   124                          Handle loader, Handle protection_domain);

   125 

   126   static void _throw_msg_cause(Thread* thread, const char* file, int line, Symbol* name, const char* message, Handle h_cause);

   127   static void _throw_msg_cause(Thread* thread, const char* file, int line, Symbol* name, const char* message, Handle h_cause,

   128                                Handle h_loader, Handle h_protection_domain);

   129 

   130   static void _throw_cause(Thread* thread, const char* file, int line, Symbol* name, Handle h_cause);

   131   static void _throw_cause(Thread* thread, const char* file, int line, Symbol* name, Handle h_cause,

   132                            Handle h_loader, Handle h_protection_domain);

   133 

   134   static void _throw_args(Thread* thread, const char* file, int line,

   135                           Symbol* name, Symbol* signature,

   136                           JavaCallArguments* args);

   137 

   138   // There is no THROW... macro for this method. Caller should remember

   139   // to do a return after calling it.

   140   static void fthrow(Thread* thread, const char* file, int line, Symbol* name,

   141                      const char* format, ...) ATTRIBUTE_PRINTF(5, 6);

   142 

   143   // Create and initialize a new exception

   144   static Handle new_exception(Thread* thread, Symbol* name,

   145                               Symbol* signature, JavaCallArguments* args,

   146                               Handle loader, Handle protection_domain);

   147 

   148   static Handle new_exception(Thread* thread, Symbol* name,

   149                               Symbol* signature, JavaCallArguments* args,

   150                               Handle cause,

   151                               Handle loader, Handle protection_domain);

   152 

   153   static Handle new_exception(Thread* thread, Symbol* name,

   154                               Handle cause,

   155                               Handle loader, Handle protection_domain,

   156                               ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);

   157 

   158   static Handle new_exception(Thread* thread, Symbol* name,

   159                               const char* message, Handle cause,

   160                               Handle loader, Handle protection_domain,

   161                               ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);

   162 

   163   static Handle new_exception(Thread* thread, Symbol* name,

   164                               const char* message,

   165                               ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8);

   166 

   167   static void throw_stack_overflow_exception(Thread* thread, const char* file, int line, const methodHandle& method);

   168 

   169   // Exception counting for error files of interesting exceptions that may have

   170   // caused a problem for the jvm

   171   static volatile int _stack_overflow_errors;

   172 

   173   static bool has_exception_counts();

   174   static void count_out_of_memory_exceptions(Handle exception);

   175   static void print_exception_counts_on_error(outputStream* st);

   176 

   177   // for AbortVMOnException flag

   178   static void debug_check_abort(Handle exception, const char* message = NULL);

   179   static void debug_check_abort_helper(Handle exception, const char* message = NULL);

   180   static void debug_check_abort(const char *value_string, const char* message = NULL);

   181 

   182   // for logging exceptions

   183   static void log_exception(Handle exception, stringStream tempst);

   184 };

   185 

   186 

   187 // The THREAD & TRAPS macros facilitate the declaration of functions that throw exceptions.

   188 // Convention: Use the TRAPS macro as the last argument of such a function; e.g.:

   189 //

   190 // int this_function_may_trap(int x, float y, TRAPS)

   191 

   192 #define THREAD __the_thread__

   193 #define TRAPS  Thread* THREAD

   194 

   195 

   196 // The CHECK... macros should be used to pass along a THREAD reference and to check for pending

   197 // exceptions. In special situations it is necessary to handle pending exceptions explicitly,

   198 // in these cases the PENDING_EXCEPTION helper macros should be used.

   199 //

   200 // Macro naming conventions: Macros that end with _ require a result value to be returned. They

   201 // are for functions with non-void result type. The result value is usually ignored because of

   202 // the exception and is only needed for syntactic correctness. The _0 ending is a shortcut for

   203 // _(0) since this is a frequent case. Example:

   204 //

   205 // int result = this_function_may_trap(x_arg, y_arg, CHECK_0);

   206 //

   207 // CAUTION: make sure that the function call using a CHECK macro is not the only statement of a

   208 // conditional branch w/o enclosing {} braces, since the CHECK macros expand into several state-

   209 // ments!

   210 

   211 #define PENDING_EXCEPTION                        (((ThreadShadow*)THREAD)->pending_exception())

   212 #define HAS_PENDING_EXCEPTION                    (((ThreadShadow*)THREAD)->has_pending_exception())

   213 #define CLEAR_PENDING_EXCEPTION                  (((ThreadShadow*)THREAD)->clear_pending_exception())

   214 

   215 #define CHECK                                    THREAD); if (HAS_PENDING_EXCEPTION) return       ; (void)(0

   216 #define CHECK_(result)                           THREAD); if (HAS_PENDING_EXCEPTION) return result; (void)(0

   217 #define CHECK_0                                  CHECK_(0)

   218 #define CHECK_NH                                 CHECK_(Handle())

   219 #define CHECK_NULL                               CHECK_(NULL)

   220 #define CHECK_false                              CHECK_(false)

   221 #define CHECK_JNI_ERR                            CHECK_(JNI_ERR)

   222 

   223 #define CHECK_AND_CLEAR                         THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; return;        } (void)(0

   224 #define CHECK_AND_CLEAR_(result)                THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; return result; } (void)(0

   225 #define CHECK_AND_CLEAR_0                       CHECK_AND_CLEAR_(0)

   226 #define CHECK_AND_CLEAR_NH                      CHECK_AND_CLEAR_(Handle())

   227 #define CHECK_AND_CLEAR_NULL                    CHECK_AND_CLEAR_(NULL)

   228 #define CHECK_AND_CLEAR_false                   CHECK_AND_CLEAR_(false)

   229 

   230 // The THROW... macros should be used to throw an exception. They require a THREAD variable to be

   231 // visible within the scope containing the THROW. Usually this is achieved by declaring the function

   232 // with a TRAPS argument.

   233 

   234 #define THREAD_AND_LOCATION                      THREAD, __FILE__, __LINE__

   235 

   236 #define THROW_OOP(e)                                \

   237   { Exceptions::_throw_oop(THREAD_AND_LOCATION, e);                             return;  }

   238 

   239 #define THROW_HANDLE(e)                                \

   240   { Exceptions::_throw(THREAD_AND_LOCATION, e);                             return;  }

   241 

   242 #define THROW(name)                                 \

   243   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return;  }

   244 

   245 #define THROW_MSG(name, message)                    \

   246   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return;  }

   247 

   248 #define THROW_CAUSE(name, cause)   \

   249   { Exceptions::_throw_cause(THREAD_AND_LOCATION, name, cause); return; }

   250 

   251 #define THROW_MSG_LOADER(name, message, loader, protection_domain) \

   252   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return;  }

   253 

   254 #define THROW_ARG(name, signature, args) \

   255   { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args);   return; }

   256 

   257 #define THROW_OOP_(e, result)                       \

   258   { Exceptions::_throw_oop(THREAD_AND_LOCATION, e);                           return result; }

   259 

   260 #define THROW_HANDLE_(e, result)                       \

   261   { Exceptions::_throw(THREAD_AND_LOCATION, e);                           return result; }

   262 

   263 #define THROW_(name, result)                        \

   264   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return result; }

   265 

   266 #define THROW_MSG_(name, message, result)           \

   267   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return result; }

   268 

   269 #define THROW_MSG_LOADER_(name, message, loader, protection_domain, result) \

   270   { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return result; }

   271 

   272 #define THROW_ARG_(name, signature, args, result) \

   273   { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return result; }

   274 

   275 #define THROW_MSG_CAUSE(name, message, cause)   \

   276   { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return; }

   277 

   278 #define THROW_MSG_CAUSE_(name, message, cause, result)   \

   279   { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return result; }

   280 

   281 

   282 #define THROW_OOP_0(e)                      THROW_OOP_(e, 0)

   283 #define THROW_HANDLE_0(e)                   THROW_HANDLE_(e, 0)

   284 #define THROW_0(name)                       THROW_(name, 0)

   285 #define THROW_MSG_0(name, message)          THROW_MSG_(name, message, 0)

   286 #define THROW_WRAPPED_0(name, oop_to_wrap)  THROW_WRAPPED_(name, oop_to_wrap, 0)

   287 #define THROW_ARG_0(name, signature, arg)   THROW_ARG_(name, signature, arg, 0)

   288 #define THROW_MSG_CAUSE_0(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, 0)

   289 #define THROW_MSG_CAUSE_NULL(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, NULL)

   290 

   291 #define THROW_NULL(name)                    THROW_(name, NULL)

   292 #define THROW_MSG_NULL(name, message)       THROW_MSG_(name, message, NULL)

   293 

   294 // The CATCH macro checks that no exception has been thrown by a function; it is used at

   295 // call sites about which is statically known that the callee cannot throw an exception

   296 // even though it is declared with TRAPS.

   297 

   298 #define CATCH                              \

   299   THREAD); if (HAS_PENDING_EXCEPTION) {    \

   300     oop ex = PENDING_EXCEPTION;            \

   301     CLEAR_PENDING_EXCEPTION;               \

   302     ex->print();                           \

   303     ShouldNotReachHere();                  \

   304   } (void)(0

   305 

   306 // ExceptionMark is a stack-allocated helper class for local exception handling.

   307 // It is used with the EXCEPTION_MARK macro.

   308 

   309 class ExceptionMark {

   310  private:

   311   Thread* _thread;

   312 

   313  public:

   314   ExceptionMark(Thread*& thread);

   315   ~ExceptionMark();

   316 };

   317 

   318 

   319 

   320 // Use an EXCEPTION_MARK for 'local' exceptions. EXCEPTION_MARK makes sure that no

   321 // pending exception exists upon entering its scope and tests that no pending exception

   322 // exists when leaving the scope.

   323 

   324 // See also preserveException.hpp for PRESERVE_EXCEPTION_MARK macro,

   325 // which preserves pre-existing exceptions and does not allow new

   326 // exceptions.

   327 

   328 #define EXCEPTION_MARK                           Thread* THREAD = NULL; ExceptionMark __em(THREAD);

   329 

   330 #endif // SHARE_VM_UTILITIES_EXCEPTIONS_HPP