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 51class Thread; 52class Handle; 53class Symbol; 54class 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 60class 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 103class 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 309class 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 331