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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libobjc/exception.c
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Diffstat (limited to 'libobjc/exception.c')
-rw-r--r--libobjc/exception.c551
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diff --git a/libobjc/exception.c b/libobjc/exception.c
new file mode 100644
index 000000000..1ffb80b53
--- /dev/null
+++ b/libobjc/exception.c
@@ -0,0 +1,551 @@
+/* The implementation of exception handling primitives for Objective-C.
+ Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3, or (at your option) any
+later version.
+
+GCC 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 for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+#include "objc-private/common.h"
+#include <stdlib.h>
+#include "config.h"
+#include "objc/runtime.h"
+#include "objc/objc-exception.h"
+#include "unwind.h"
+#include "unwind-pe.h"
+#include <string.h> /* For memcpy */
+
+/* This hook allows libraries to sepecify special actions when an
+ exception is thrown without a handler in place. This is deprecated
+ in favour of objc_set_uncaught_exception_handler (). */
+void (*_objc_unexpected_exception) (id exception); /* !T:SAFE */
+
+
+/* 'is_kind_of_exception_matcher' is our default exception matcher -
+ it determines if the object 'exception' is of class 'catch_class',
+ or of a subclass. */
+static int
+is_kind_of_exception_matcher (Class catch_class, id exception)
+{
+ /* NULL catch_class is catch-all (eg, @catch (id object)). */
+ if (catch_class == Nil)
+ return 1;
+
+ /* If exception is nil (eg, @throw nil;), then it can only be
+ catched by a catch-all (eg, @catch (id object)). */
+ if (exception != nil)
+ {
+ Class c;
+
+ for (c = exception->class_pointer; c != Nil;
+ c = class_getSuperclass (c))
+ if (c == catch_class)
+ return 1;
+ }
+ return 0;
+}
+
+/* The exception matcher currently in use. */
+static objc_exception_matcher
+__objc_exception_matcher = is_kind_of_exception_matcher;
+
+objc_exception_matcher
+objc_setExceptionMatcher (objc_exception_matcher new_matcher)
+{
+ objc_exception_matcher old_matcher = __objc_exception_matcher;
+ __objc_exception_matcher = new_matcher;
+ return old_matcher;
+}
+
+/* The uncaught exception handler currently in use. */
+static objc_uncaught_exception_handler
+__objc_uncaught_exception_handler = NULL;
+
+objc_uncaught_exception_handler
+objc_setUncaughtExceptionHandler (objc_uncaught_exception_handler
+ new_handler)
+{
+ objc_uncaught_exception_handler old_handler
+ = __objc_uncaught_exception_handler;
+ __objc_uncaught_exception_handler = new_handler;
+ return old_handler;
+}
+
+
+
+#ifdef __ARM_EABI_UNWINDER__
+
+const _Unwind_Exception_Class __objc_exception_class
+ = {'G', 'N', 'U', 'C', 'O', 'B', 'J', 'C'};
+
+#else
+
+/* This is the exception class we report -- "GNUCOBJC". */
+static const _Unwind_Exception_Class __objc_exception_class
+ = ((((((((_Unwind_Exception_Class) 'G'
+ << 8 | (_Unwind_Exception_Class) 'N')
+ << 8 | (_Unwind_Exception_Class) 'U')
+ << 8 | (_Unwind_Exception_Class) 'C')
+ << 8 | (_Unwind_Exception_Class) 'O')
+ << 8 | (_Unwind_Exception_Class) 'B')
+ << 8 | (_Unwind_Exception_Class) 'J')
+ << 8 | (_Unwind_Exception_Class) 'C');
+
+#endif
+
+/* This is the object that is passed around by the Objective C runtime
+ to represent the exception in flight. */
+struct ObjcException
+{
+ /* This bit is needed in order to interact with the unwind runtime. */
+ struct _Unwind_Exception base;
+
+ /* The actual object we want to throw. Note: must come immediately
+ after unwind header. */
+ id value;
+
+#ifdef __ARM_EABI_UNWINDER__
+ /* Note: we use the barrier cache defined in the unwind control
+ block for ARM EABI. */
+#else
+ /* Cache some internal unwind data between phase 1 and phase 2. */
+ _Unwind_Ptr landingPad;
+ int handlerSwitchValue;
+#endif
+};
+
+
+
+struct lsda_header_info
+{
+ _Unwind_Ptr Start;
+ _Unwind_Ptr LPStart;
+ _Unwind_Ptr ttype_base;
+ const unsigned char *TType;
+ const unsigned char *action_table;
+ unsigned char ttype_encoding;
+ unsigned char call_site_encoding;
+};
+
+static const unsigned char *
+parse_lsda_header (struct _Unwind_Context *context, const unsigned char *p,
+ struct lsda_header_info *info)
+{
+ _uleb128_t tmp;
+ unsigned char lpstart_encoding;
+
+ info->Start = (context ? _Unwind_GetRegionStart (context) : 0);
+
+ /* Find @LPStart, the base to which landing pad offsets are
+ relative. */
+ lpstart_encoding = *p++;
+ if (lpstart_encoding != DW_EH_PE_omit)
+ p = read_encoded_value (context, lpstart_encoding, p, &info->LPStart);
+ else
+ info->LPStart = info->Start;
+
+ /* Find @TType, the base of the handler and exception spec type
+ data. */
+ info->ttype_encoding = *p++;
+ if (info->ttype_encoding != DW_EH_PE_omit)
+ {
+ p = read_uleb128 (p, &tmp);
+ info->TType = p + tmp;
+ }
+ else
+ info->TType = 0;
+
+ /* The encoding and length of the call-site table; the action table
+ immediately follows. */
+ info->call_site_encoding = *p++;
+ p = read_uleb128 (p, &tmp);
+ info->action_table = p + tmp;
+
+ return p;
+}
+
+#ifdef __ARM_EABI_UNWINDER__
+
+static Class
+get_ttype_entry (struct lsda_header_info *info, _uleb128_t i)
+{
+ _Unwind_Ptr ptr;
+
+ ptr = (_Unwind_Ptr) (info->TType - (i * 4));
+ ptr = _Unwind_decode_target2 (ptr);
+
+ /* NULL ptr means catch-all. Note that if the class is not found,
+ this will abort the program. */
+ if (ptr)
+ return objc_getRequiredClass ((const char *) ptr);
+ else
+ return 0;
+}
+
+#else
+
+static Class
+get_ttype_entry (struct lsda_header_info *info, _Unwind_Word i)
+{
+ _Unwind_Ptr ptr;
+
+ i *= size_of_encoded_value (info->ttype_encoding);
+ read_encoded_value_with_base (info->ttype_encoding, info->ttype_base,
+ info->TType - i, &ptr);
+
+ /* NULL ptr means catch-all. Note that if the class is not found,
+ this will abort the program. */
+ if (ptr)
+ return objc_getRequiredClass ((const char *) ptr);
+ else
+ return 0;
+}
+
+#endif
+
+/* Using a different personality function name causes link failures
+ when trying to mix code using different exception handling
+ models. */
+#ifdef SJLJ_EXCEPTIONS
+#define PERSONALITY_FUNCTION __gnu_objc_personality_sj0
+#define __builtin_eh_return_data_regno(x) x
+#else
+#define PERSONALITY_FUNCTION __gnu_objc_personality_v0
+#endif
+
+#ifdef __ARM_EABI_UNWINDER__
+
+#define CONTINUE_UNWINDING \
+ do \
+ { \
+ if (__gnu_unwind_frame(ue_header, context) != _URC_OK) \
+ return _URC_FAILURE; \
+ return _URC_CONTINUE_UNWIND; \
+ } \
+ while (0)
+
+_Unwind_Reason_Code
+PERSONALITY_FUNCTION (_Unwind_State state,
+ struct _Unwind_Exception *ue_header,
+ struct _Unwind_Context *context)
+#else
+
+#define CONTINUE_UNWINDING return _URC_CONTINUE_UNWIND
+
+_Unwind_Reason_Code
+PERSONALITY_FUNCTION (int version,
+ _Unwind_Action actions,
+ _Unwind_Exception_Class exception_class,
+ struct _Unwind_Exception *ue_header,
+ struct _Unwind_Context *context)
+#endif
+{
+ struct ObjcException *xh = (struct ObjcException *) ue_header;
+
+ struct lsda_header_info info;
+ const unsigned char *language_specific_data;
+ const unsigned char *action_record;
+ const unsigned char *p;
+ _Unwind_Ptr landing_pad, ip;
+ int handler_switch_value;
+ int saw_cleanup = 0, saw_handler, foreign_exception;
+ void *return_object;
+ int ip_before_insn = 0;
+
+#ifdef __ARM_EABI_UNWINDER__
+ _Unwind_Action actions;
+
+ switch (state & _US_ACTION_MASK)
+ {
+ case _US_VIRTUAL_UNWIND_FRAME:
+ actions = _UA_SEARCH_PHASE;
+ break;
+
+ case _US_UNWIND_FRAME_STARTING:
+ actions = _UA_CLEANUP_PHASE;
+ if (!(state & _US_FORCE_UNWIND)
+ && ue_header->barrier_cache.sp == _Unwind_GetGR (context, 13))
+ actions |= _UA_HANDLER_FRAME;
+ break;
+
+ case _US_UNWIND_FRAME_RESUME:
+ CONTINUE_UNWINDING;
+ break;
+
+ default:
+ abort();
+ }
+ actions |= state & _US_FORCE_UNWIND;
+
+ /* TODO: Foreign exceptions need some attention (e.g. rethrowing
+ doesn't work). */
+ foreign_exception = 0;
+
+ /* The dwarf unwinder assumes the context structure holds things
+ like the function and LSDA pointers. The ARM implementation
+ caches these in the exception header (UCB). To avoid rewriting
+ everything we make the virtual IP register point at the UCB. */
+ ip = (_Unwind_Ptr) ue_header;
+ _Unwind_SetGR (context, 12, ip);
+
+#else /* !__ARM_EABI_UNWINDER. */
+ /* Interface version check. */
+ if (version != 1)
+ return _URC_FATAL_PHASE1_ERROR;
+
+ foreign_exception = (exception_class != __objc_exception_class);
+#endif
+
+ /* Shortcut for phase 2 found handler for domestic exception. */
+ if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)
+ && !foreign_exception)
+ {
+#ifdef __ARM_EABI_UNWINDER__
+ handler_switch_value = (int) ue_header->barrier_cache.bitpattern[1];
+ landing_pad = (_Unwind_Ptr) ue_header->barrier_cache.bitpattern[3];
+#else
+ handler_switch_value = xh->handlerSwitchValue;
+ landing_pad = xh->landingPad;
+#endif
+ goto install_context;
+ }
+
+ language_specific_data = (const unsigned char *)
+ _Unwind_GetLanguageSpecificData (context);
+
+ /* If no LSDA, then there are no handlers or cleanups. */
+ if (! language_specific_data)
+ CONTINUE_UNWINDING;
+
+ /* Parse the LSDA header. */
+ p = parse_lsda_header (context, language_specific_data, &info);
+ info.ttype_base = base_of_encoded_value (info.ttype_encoding, context);
+#ifdef HAVE_GETIPINFO
+ ip = _Unwind_GetIPInfo (context, &ip_before_insn);
+#else
+ ip = _Unwind_GetIP (context);
+#endif
+ if (!ip_before_insn)
+ --ip;
+ landing_pad = 0;
+ action_record = 0;
+ handler_switch_value = 0;
+
+#ifdef SJLJ_EXCEPTIONS
+ /* The given "IP" is an index into the call-site table, with two
+ exceptions -- -1 means no-action, and 0 means terminate. But
+ since we're using uleb128 values, we've not got random access to
+ the array. */
+ if ((int) ip < 0)
+ return _URC_CONTINUE_UNWIND;
+ else
+ {
+ _uleb128_t cs_lp, cs_action;
+ do
+ {
+ p = read_uleb128 (p, &cs_lp);
+ p = read_uleb128 (p, &cs_action);
+ }
+ while (--ip);
+
+ /* Can never have null landing pad for sjlj -- that would have
+ been indicated by a -1 call site index. */
+ landing_pad = cs_lp + 1;
+ if (cs_action)
+ action_record = info.action_table + cs_action - 1;
+ goto found_something;
+ }
+#else
+ /* Search the call-site table for the action associated with this
+ IP. */
+ while (p < info.action_table)
+ {
+ _Unwind_Ptr cs_start, cs_len, cs_lp;
+ _uleb128_t cs_action;
+
+ /* Note that all call-site encodings are "absolute"
+ displacements. */
+ p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);
+ p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);
+ p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);
+ p = read_uleb128 (p, &cs_action);
+
+ /* The table is sorted, so if we've passed the ip, stop. */
+ if (ip < info.Start + cs_start)
+ p = info.action_table;
+ else if (ip < info.Start + cs_start + cs_len)
+ {
+ if (cs_lp)
+ landing_pad = info.LPStart + cs_lp;
+ if (cs_action)
+ action_record = info.action_table + cs_action - 1;
+ goto found_something;
+ }
+ }
+#endif /* SJLJ_EXCEPTIONS */
+
+ /* If ip is not present in the table, C++ would call terminate. */
+ /* ??? As with Java, it's perhaps better to tweek the LSDA to that
+ no-action is mapped to no-entry. */
+ CONTINUE_UNWINDING;
+
+ found_something:
+ saw_cleanup = 0;
+ saw_handler = 0;
+
+ if (landing_pad == 0)
+ {
+ /* If ip is present, and has a null landing pad, there are no
+ cleanups or handlers to be run. */
+ }
+ else if (action_record == 0)
+ {
+ /* If ip is present, has a non-null landing pad, and a null
+ action table offset, then there are only cleanups present.
+ Cleanups use a zero switch value, as set above. */
+ saw_cleanup = 1;
+ }
+ else
+ {
+ /* Otherwise we have a catch handler. */
+ _sleb128_t ar_filter, ar_disp;
+
+ while (1)
+ {
+ p = action_record;
+ p = read_sleb128 (p, &ar_filter);
+ read_sleb128 (p, &ar_disp);
+
+ if (ar_filter == 0)
+ {
+ /* Zero filter values are cleanups. */
+ saw_cleanup = 1;
+ }
+
+ /* During forced unwinding, we only run cleanups. With a
+ foreign exception class, we have no class info to
+ match. */
+ else if ((actions & _UA_FORCE_UNWIND) || foreign_exception)
+ ;
+
+ else if (ar_filter > 0)
+ {
+ /* Positive filter values are handlers. */
+ Class catch_type = get_ttype_entry (&info, ar_filter);
+
+ if ((*__objc_exception_matcher) (catch_type, xh->value))
+ {
+ handler_switch_value = ar_filter;
+ saw_handler = 1;
+ break;
+ }
+ }
+ else
+ {
+ /* Negative filter values are exception specifications,
+ which Objective-C does not use. */
+ abort ();
+ }
+
+ if (ar_disp == 0)
+ break;
+ action_record = p + ar_disp;
+ }
+ }
+
+ if (! saw_handler && ! saw_cleanup)
+ CONTINUE_UNWINDING;
+
+ if (actions & _UA_SEARCH_PHASE)
+ {
+ if (!saw_handler)
+ CONTINUE_UNWINDING;
+
+ /* For domestic exceptions, we cache data from phase 1 for phase
+ 2. */
+ if (!foreign_exception)
+ {
+#ifdef __ARM_EABI_UNWINDER__
+ ue_header->barrier_cache.sp = _Unwind_GetGR (context, 13);
+ ue_header->barrier_cache.bitpattern[1] = (_uw) handler_switch_value;
+ ue_header->barrier_cache.bitpattern[3] = (_uw) landing_pad;
+#else
+ xh->handlerSwitchValue = handler_switch_value;
+ xh->landingPad = landing_pad;
+#endif
+ }
+ return _URC_HANDLER_FOUND;
+ }
+
+ install_context:
+ if (saw_cleanup == 0)
+ {
+ return_object = xh->value;
+ if (!(actions & _UA_SEARCH_PHASE))
+ _Unwind_DeleteException(&xh->base);
+ }
+
+ _Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
+ __builtin_extend_pointer (saw_cleanup ? xh : return_object));
+ _Unwind_SetGR (context, __builtin_eh_return_data_regno (1),
+ handler_switch_value);
+ _Unwind_SetIP (context, landing_pad);
+ return _URC_INSTALL_CONTEXT;
+}
+
+static void
+__objc_exception_cleanup (_Unwind_Reason_Code code __attribute__((unused)),
+ struct _Unwind_Exception *exc)
+{
+ free (exc);
+}
+
+void
+objc_exception_throw (id exception)
+{
+ struct ObjcException *header = calloc (1, sizeof (*header));
+
+ memcpy (&header->base.exception_class, &__objc_exception_class,
+ sizeof (__objc_exception_class));
+ header->base.exception_cleanup = __objc_exception_cleanup;
+ header->value = exception;
+
+#ifdef SJLJ_EXCEPTIONS
+ _Unwind_SjLj_RaiseException (&header->base);
+#else
+ _Unwind_RaiseException (&header->base);
+#endif
+
+ /* No exception handler was installed. Call the uncaught exception
+ handler if any is defined. */
+ if (__objc_uncaught_exception_handler != 0)
+ {
+ (*__objc_uncaught_exception_handler) (exception);
+ }
+
+ /* As a last resort support the old, deprecated way of setting an
+ uncaught exception handler. */
+ if (_objc_unexpected_exception != 0)
+ {
+ (*_objc_unexpected_exception) (exception);
+ }
+
+ abort ();
+}
+