libcxxrt

cxxabi.h (8810B)

---

 /* 
  * Copyright 2012 David Chisnall. All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to
  * deal in the Software without restriction, including without limitation the
  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  * sell copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  * 
  * The above copyright notice and this permission notice shall be
  * included in all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */ 
 
 #ifndef __CXXABI_H_
 #define __CXXABI_H_
 #include <stddef.h>
 #include <stdint.h>
 #include "unwind.h"
 namespace std 
 {
 	class type_info;
 }
 /*
  * The cxxabi.h header provides a set of public definitions for types and
  * functions defined by the Itanium C++ ABI specification.  For reference, see
  * the ABI specification here:
  *
  * http://sourcery.mentor.com/public/cxx-abi/abi.html
  *
  * All deviations from this specification, unless otherwise noted, are
  * accidental.
  */
 
 #ifdef __cplusplus
 namespace __cxxabiv1 {
 extern "C" {
 #endif
 /**
  * Function type to call when an unexpected exception is encountered.
  */
 typedef void (*unexpected_handler)();
 /**
  * Function type to call when an unrecoverable condition is encountered.
  */
 typedef void (*terminate_handler)();
 
 
 /**
  * Structure used as a header on thrown exceptions.  This is the same layout as
  * defined by the Itanium ABI spec, so should be interoperable with any other
  * implementation of this spec, such as GNU libsupc++.
  *
  * This structure is allocated when an exception is thrown.  Unwinding happens
  * in two phases, the first looks for a handler and the second installs the
  * context.  This structure stores a cache of the handler location between
  * phase 1 and phase 2.  Unfortunately, cleanup information is not cached, so
  * must be looked up in both phases.  This happens for two reasons.  The first
  * is that we don't know how many frames containing cleanups there will be, and
  * we should avoid dynamic allocation during unwinding (the exception may be
  * reporting that we've run out of memory).  The second is that finding
  * cleanups is much cheaper than finding handlers, because we don't have to
  * look at the type table at all.
  *
  * Note: Several fields of this structure have not-very-informative names.
  * These are taken from the ABI spec and have not been changed to make it
  * easier for people referring to to the spec while reading this code.
  */
 struct __cxa_exception
 {
 #if __LP64__
 	/**
 	 * Reference count.  Used to support the C++11 exception_ptr class.  This
 	 * is prepended to the structure in 64-bit mode and squeezed in to the
 	 * padding left before the 64-bit aligned _Unwind_Exception at the end in
 	 * 32-bit mode.
 	 *
 	 * Note that it is safe to extend this structure at the beginning, rather
 	 * than the end, because the public API for creating it returns the address
 	 * of the end (where the exception object can be stored).
 	 */
 	uintptr_t referenceCount;
 #endif
 	/** Type info for the thrown object. */
 	std::type_info *exceptionType;
 	/** Destructor for the object, if one exists. */
 	void (*exceptionDestructor) (void *); 
 	/** Handler called when an exception specification is violated. */
 	unexpected_handler unexpectedHandler;
 	/** Hander called to terminate. */
 	terminate_handler terminateHandler;
 	/**
 	 * Next exception in the list.  If an exception is thrown inside a catch
 	 * block and caught in a nested catch, this points to the exception that
 	 * will be handled after the inner catch block completes.
 	 */
 	__cxa_exception *nextException;
 	/**
 	 * The number of handlers that currently have references to this
 	 * exception.  The top (non-sign) bit of this is used as a flag to indicate
 	 * that the exception is being rethrown, so should not be deleted when its
 	 * handler count reaches 0 (which it doesn't with the top bit set).
 	 */
 	int handlerCount;
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 	/**
 	 * The ARM EH ABI requires the unwind library to keep track of exceptions
 	 * during cleanups.  These support nesting, so we need to keep a list of
 	 * them.
 	 */
 	_Unwind_Exception *nextCleanup;
 	/**
 	 * The number of cleanups that are currently being run on this exception. 
 	 */
 	int cleanupCount;
 #endif
 	/**
 	 * The selector value to be returned when installing the catch handler.
 	 * Used at the call site to determine which catch() block should execute.
 	 * This is found in phase 1 of unwinding then installed in phase 2.
 	 */
 	int handlerSwitchValue;
 	/**
 	 * The action record for the catch.  This is cached during phase 1
 	 * unwinding.
 	 */
 	const char *actionRecord;
 	/**
 	 * Pointer to the language-specific data area (LSDA) for the handler
 	 * frame.  This is unused in this implementation, but set for ABI
 	 * compatibility in case we want to mix code in very weird ways.
 	 */
 	const char *languageSpecificData;
 	/** The cached landing pad for the catch handler.*/
 	void *catchTemp;
 	/**
 	 * The pointer that will be returned as the pointer to the object.  When
 	 * throwing a class and catching a virtual superclass (for example), we
 	 * need to adjust the thrown pointer to make it all work correctly.
 	 */
 	void *adjustedPtr;
 #if !__LP64__
 	/**
 	 * Reference count.  Used to support the C++11 exception_ptr class.  This
 	 * is prepended to the structure in 64-bit mode and squeezed in to the
 	 * padding left before the 64-bit aligned _Unwind_Exception at the end in
 	 * 32-bit mode.
 	 *
 	 * Note that it is safe to extend this structure at the beginning, rather
 	 * than the end, because the public API for creating it returns the address
 	 * of the end (where the exception object can be stored) 
 	 */
 	uintptr_t referenceCount;
 #endif
 	/** The language-agnostic part of the exception header. */
 	_Unwind_Exception unwindHeader;
 };
 
 /**
  * ABI-specified globals structure.  Returned by the __cxa_get_globals()
  * function and its fast variant.  This is a per-thread structure - every
  * thread will have one lazily allocated.
  *
  * This structure is defined by the ABI, so may be used outside of this
  * library.
  */
 struct __cxa_eh_globals
 {
 	/**
 	 * A linked list of exceptions that are currently caught.  There may be
 	 * several of these in nested catch() blocks.
 	 */
 	__cxa_exception *caughtExceptions;
 	/**
 	 * The number of uncaught exceptions.
 	 */
 	unsigned int uncaughtExceptions;
 };
 /**
  * ABI function returning the __cxa_eh_globals structure.
  */
 __cxa_eh_globals *__cxa_get_globals(void);
 /**
  * Version of __cxa_get_globals() assuming that __cxa_get_globals() has already
  * been called at least once by this thread.
  */
 __cxa_eh_globals *__cxa_get_globals_fast(void);
 
 std::type_info * __cxa_current_exception_type();
 
 /**
  * Throws an exception returned by __cxa_current_primary_exception().  This
  * exception may have been caught in another thread.
  */
 void __cxa_rethrow_primary_exception(void* thrown_exception);
 /**
  * Returns the current exception in a form that can be stored in an
  * exception_ptr object and then rethrown by a call to
  * __cxa_rethrow_primary_exception().
  */
 void *__cxa_current_primary_exception(void);
 /**
  * Increments the reference count of an exception.  Called when an
  * exception_ptr is copied.
  */
 void __cxa_increment_exception_refcount(void* thrown_exception);
 /**
  * Decrements the reference count of an exception.  Called when an
  * exception_ptr is deleted.
  */
 void __cxa_decrement_exception_refcount(void* thrown_exception);
 /**
  * Demangles a C++ symbol or type name.  The buffer, if non-NULL, must be
  * allocated with malloc() and must be *n bytes or more long.  This function
  * may call realloc() on the value pointed to by buf, and will return the
  * length of the string via *n.
  *
  * The value pointed to by status is set to one of the following:
  *
  * 0: success
  * -1: memory allocation failure
  * -2: invalid mangled name
  * -3: invalid arguments
  */
 char* __cxa_demangle(const char* mangled_name,
                      char* buf,
                      size_t* n,
                      int* status);
 #ifdef __cplusplus
 } // extern "C"
 } // namespace
 
 namespace abi = __cxxabiv1;
 
 #endif /* __cplusplus */
 #endif /* __CXXABI_H_ */