/* * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_UTILITIES_EXCEPTIONS_HPP #define SHARE_VM_UTILITIES_EXCEPTIONS_HPP #include "memory/allocation.hpp" #include "oops/oopsHierarchy.hpp" #include "utilities/sizes.hpp" // This file provides the basic support for exception handling in the VM. // Note: We do not use C++ exceptions to avoid compiler dependencies and // unpredictable performance. // // Scheme: Exceptions are stored with the thread. There is never more // than one pending exception per thread. All functions that can throw // an exception carry a THREAD argument (usually the last argument and // declared with the TRAPS macro). Throwing an exception means setting // a pending exception in the thread. Upon return from a function that // can throw an exception, we must check if an exception is pending. // The CHECK macros do this in a convenient way. Carrying around the // thread provides also convenient access to it (e.g. for Handle // creation, w/o the need for recomputation). // Forward declarations to be independent of the include structure. // This allows us to have exceptions.hpp included in top.hpp. class Thread; class Handle; class Symbol; class JavaCallArguments; // The ThreadShadow class is a helper class to access the _pending_exception // field of the Thread class w/o having access to the Thread's interface (for // include hierachy reasons). class ThreadShadow: public CHeapObj { friend class VMStructs; protected: oop _pending_exception; // Thread has gc actions. const char* _exception_file; // file information for exception (debugging only) int _exception_line; // line information for exception (debugging only) friend void check_ThreadShadow(); // checks _pending_exception offset // The following virtual exists only to force creation of a vtable. // We need ThreadShadow to have a vtable, even in product builds, // so that its layout will start at an offset of zero relative to Thread. // Some C++ compilers are so "clever" that they put the ThreadShadow // base class at offset 4 in Thread (after Thread's vtable), if they // notice that Thread has a vtable but ThreadShadow does not. virtual void unused_initial_virtual() { } public: oop pending_exception() const { return _pending_exception; } bool has_pending_exception() const { return _pending_exception != NULL; } const char* exception_file() const { return _exception_file; } int exception_line() const { return _exception_line; } // Code generation support static ByteSize pending_exception_offset() { return byte_offset_of(ThreadShadow, _pending_exception); } // use THROW whenever possible! void set_pending_exception(oop exception, const char* file, int line); // use CLEAR_PENDING_EXCEPTION whenever possible! void clear_pending_exception(); ThreadShadow() : _pending_exception(NULL), _exception_file(NULL), _exception_line(0) {} }; // Exceptions is a helper class that encapsulates all operations // that require access to the thread interface and which are // relatively rare. The Exceptions operations should only be // used directly if the macros below are insufficient. class Exceptions { static bool special_exception(Thread *thread, const char* file, int line, Handle exception); static bool special_exception(Thread* thread, const char* file, int line, Symbol* name, const char* message); public: // this enum is defined to indicate whether it is safe to // ignore the encoding scheme of the original message string. typedef enum { safe_to_utf8 = 0, unsafe_to_utf8 = 1 } ExceptionMsgToUtf8Mode; // Throw exceptions: w/o message, w/ message & with formatted message. static void _throw_oop(Thread* thread, const char* file, int line, oop exception); static void _throw(Thread* thread, const char* file, int line, Handle exception, const char* msg = NULL); static void _throw_msg(Thread* thread, const char* file, int line, Symbol* name, const char* message); static void _throw_msg(Thread* thread, const char* file, int line, Symbol* name, const char* message, Handle loader, Handle protection_domain); static void _throw_msg_cause(Thread* thread, const char* file, int line, Symbol* name, const char* message, Handle h_cause); static void _throw_msg_cause(Thread* thread, const char* file, int line, Symbol* name, const char* message, Handle h_cause, Handle h_loader, Handle h_protection_domain); static void _throw_cause(Thread* thread, const char* file, int line, Symbol* name, Handle h_cause); static void _throw_cause(Thread* thread, const char* file, int line, Symbol* name, Handle h_cause, Handle h_loader, Handle h_protection_domain); static void _throw_args(Thread* thread, const char* file, int line, Symbol* name, Symbol* signature, JavaCallArguments* args); // There is no THROW... macro for this method. Caller should remember // to do a return after calling it. static void fthrow(Thread* thread, const char* file, int line, Symbol* name, const char* format, ...); // Create and initialize a new exception static Handle new_exception(Thread* thread, Symbol* name, Symbol* signature, JavaCallArguments* args, Handle loader, Handle protection_domain); static Handle new_exception(Thread* thread, Symbol* name, Symbol* signature, JavaCallArguments* args, Handle cause, Handle loader, Handle protection_domain); static Handle new_exception(Thread* thread, Symbol* name, Handle cause, Handle loader, Handle protection_domain, ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8); static Handle new_exception(Thread* thread, Symbol* name, const char* message, Handle cause, Handle loader, Handle protection_domain, ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8); static Handle new_exception(Thread* thread, Symbol* name, const char* message, ExceptionMsgToUtf8Mode to_utf8_safe = safe_to_utf8); static void throw_stack_overflow_exception(Thread* thread, const char* file, int line, methodHandle method); // for AbortVMOnException flag NOT_PRODUCT(static void debug_check_abort(Handle exception, const char* message = NULL);) NOT_PRODUCT(static void debug_check_abort(const char *value_string, const char* message = NULL);) }; // The THREAD & TRAPS macros facilitate the declaration of functions that throw exceptions. // Convention: Use the TRAPS macro as the last argument of such a function; e.g.: // // int this_function_may_trap(int x, float y, TRAPS) #define THREAD __the_thread__ #define TRAPS Thread* THREAD // The CHECK... macros should be used to pass along a THREAD reference and to check for pending // exceptions. In special situations it is necessary to handle pending exceptions explicitly, // in these cases the PENDING_EXCEPTION helper macros should be used. // // Macro naming conventions: Macros that end with _ require a result value to be returned. They // are for functions with non-void result type. The result value is usually ignored because of // the exception and is only needed for syntactic correctness. The _0 ending is a shortcut for // _(0) since this is a frequent case. Example: // // int result = this_function_may_trap(x_arg, y_arg, CHECK_0); // // CAUTION: make sure that the function call using a CHECK macro is not the only statement of a // conditional branch w/o enclosing {} braces, since the CHECK macros expand into several state- // ments! #define PENDING_EXCEPTION (((ThreadShadow*)THREAD)->pending_exception()) #define HAS_PENDING_EXCEPTION (((ThreadShadow*)THREAD)->has_pending_exception()) #define CLEAR_PENDING_EXCEPTION (((ThreadShadow*)THREAD)->clear_pending_exception()) #define CHECK THREAD); if (HAS_PENDING_EXCEPTION) return ; (0 #define CHECK_(result) THREAD); if (HAS_PENDING_EXCEPTION) return result; (0 #define CHECK_0 CHECK_(0) #define CHECK_NH CHECK_(Handle()) #define CHECK_NULL CHECK_(NULL) #define CHECK_false CHECK_(false) #define CHECK_AND_CLEAR THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; return; } (0 #define CHECK_AND_CLEAR_(result) THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; return result; } (0 #define CHECK_AND_CLEAR_0 CHECK_AND_CLEAR_(0) #define CHECK_AND_CLEAR_NH CHECK_AND_CLEAR_(Handle()) #define CHECK_AND_CLEAR_NULL CHECK_AND_CLEAR_(NULL) #define CHECK_AND_CLEAR_false CHECK_AND_CLEAR_(false) // The THROW... macros should be used to throw an exception. They require a THREAD variable to be // visible within the scope containing the THROW. Usually this is achieved by declaring the function // with a TRAPS argument. #define THREAD_AND_LOCATION THREAD, __FILE__, __LINE__ #define THROW_OOP(e) \ { Exceptions::_throw_oop(THREAD_AND_LOCATION, e); return; } #define THROW_HANDLE(e) \ { Exceptions::_throw(THREAD_AND_LOCATION, e); return; } #define THROW(name) \ { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return; } #define THROW_MSG(name, message) \ { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return; } #define THROW_CAUSE(name, cause) \ { Exceptions::_throw_cause(THREAD_AND_LOCATION, name, cause); return; } #define THROW_MSG_LOADER(name, message, loader, protection_domain) \ { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return; } #define THROW_ARG(name, signature, args) \ { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return; } #define THROW_OOP_(e, result) \ { Exceptions::_throw_oop(THREAD_AND_LOCATION, e); return result; } #define THROW_HANDLE_(e, result) \ { Exceptions::_throw(THREAD_AND_LOCATION, e); return result; } #define THROW_(name, result) \ { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, NULL); return result; } #define THROW_MSG_(name, message, result) \ { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message); return result; } #define THROW_MSG_LOADER_(name, message, loader, protection_domain, result) \ { Exceptions::_throw_msg(THREAD_AND_LOCATION, name, message, loader, protection_domain); return result; } #define THROW_ARG_(name, signature, args, result) \ { Exceptions::_throw_args(THREAD_AND_LOCATION, name, signature, args); return result; } #define THROW_MSG_CAUSE(name, message, cause) \ { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return; } #define THROW_MSG_CAUSE_(name, message, cause, result) \ { Exceptions::_throw_msg_cause(THREAD_AND_LOCATION, name, message, cause); return result; } #define THROW_OOP_0(e) THROW_OOP_(e, 0) #define THROW_HANDLE_0(e) THROW_HANDLE_(e, 0) #define THROW_0(name) THROW_(name, 0) #define THROW_MSG_0(name, message) THROW_MSG_(name, message, 0) #define THROW_WRAPPED_0(name, oop_to_wrap) THROW_WRAPPED_(name, oop_to_wrap, 0) #define THROW_ARG_0(name, signature, arg) THROW_ARG_(name, signature, arg, 0) #define THROW_MSG_CAUSE_0(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, 0) #define THROW_MSG_CAUSE_NULL(name, message, cause) THROW_MSG_CAUSE_(name, message, cause, NULL) #define THROW_NULL(name) THROW_(name, NULL) #define THROW_MSG_NULL(name, message) THROW_MSG_(name, message, NULL) // The CATCH macro checks that no exception has been thrown by a function; it is used at // call sites about which is statically known that the callee cannot throw an exception // even though it is declared with TRAPS. #define CATCH \ THREAD); if (HAS_PENDING_EXCEPTION) { \ oop ex = PENDING_EXCEPTION; \ CLEAR_PENDING_EXCEPTION; \ ex->print(); \ ShouldNotReachHere(); \ } (0 // ExceptionMark is a stack-allocated helper class for local exception handling. // It is used with the EXCEPTION_MARK macro. class ExceptionMark { private: Thread* _thread; public: ExceptionMark(Thread*& thread); ~ExceptionMark(); }; // Use an EXCEPTION_MARK for 'local' exceptions. EXCEPTION_MARK makes sure that no // pending exception exists upon entering its scope and tests that no pending exception // exists when leaving the scope. // See also preserveException.hpp for PRESERVE_EXCEPTION_MARK macro, // which preserves pre-existing exceptions and does not allow new // exceptions. #define EXCEPTION_MARK Thread* THREAD; ExceptionMark __em(THREAD); #endif // SHARE_VM_UTILITIES_EXCEPTIONS_HPP