--- /dev/null
+/* The implementation of exception handling primitives for Objective-C.
+ Copyright (C) 2004 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 2, 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.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING. If not, write to
+the Free Software Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
+
+/* As a special exception, if you link this library with files compiled
+ with GCC to produce an executable, this does not cause the resulting
+ executable to be covered by the GNU General Public License. This
+ exception does not however invalidate any other reasons why the
+ executable file might be covered by the GNU General Public License. */
+
+#include <stdlib.h>
+#include "objc/objc-api.h"
+#include "unwind.h"
+#include "unwind-pe.h"
+
+\f
+/* This is the exception class we report -- "GNUCOBJC". */
+#define __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')
+
+/* 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. */
+ id value;
+
+ /* Cache some internal unwind data between phase 1 and phase 2. */
+ _Unwind_Ptr landingPad;
+ int handlerSwitchValue;
+};
+
+\f
+
+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)
+{
+ _Unwind_Word 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;
+}
+
+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. */
+ if (ptr)
+ return objc_get_class ((const char *) ptr);
+ else
+ return 0;
+}
+
+/* Like unto the method of the same name on Object, but takes an id. */
+/* ??? Does this bork the meta-type system? Can/should we look up an
+ isKindOf method on the id? */
+
+static int
+isKindOf (id value, Class target)
+{
+ Class c;
+
+ /* NULL target is catch-all. */
+ if (target == 0)
+ return 1;
+
+ for (c = value->class_pointer; c; c = class_get_super_class (c))
+ if (c == target)
+ return 1;
+ return 0;
+}
+
+/* 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
+
+_Unwind_Reason_Code
+PERSONALITY_FUNCTION (int version,
+ _Unwind_Action actions,
+ _Unwind_Exception_Class exception_class,
+ struct _Unwind_Exception *ue_header,
+ struct _Unwind_Context *context)
+{
+ 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, saw_handler;
+
+ /* Interface version check. */
+ if (version != 1)
+ return _URC_FATAL_PHASE1_ERROR;
+
+ /* Shortcut for phase 2 found handler for domestic exception. */
+ if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)
+ && exception_class == __objc_exception_class)
+ {
+ handler_switch_value = xh->handlerSwitchValue;
+ landing_pad = xh->landingPad;
+ 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)
+ return _URC_CONTINUE_UNWIND;
+
+ /* Parse the LSDA header. */
+ p = parse_lsda_header (context, language_specific_data, &info);
+ info.ttype_base = base_of_encoded_value (info.ttype_encoding, context);
+ ip = _Unwind_GetIP (context) - 1;
+ 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
+ {
+ _Unwind_Word 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;
+ _Unwind_Word 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. */
+ return _URC_CONTINUE_UNWIND;
+
+ 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. */
+ _Unwind_Sword 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)
+ || exception_class != __objc_exception_class)
+ ;
+
+ else if (ar_filter > 0)
+ {
+ /* Positive filter values are handlers. */
+
+ Class catch_type = get_ttype_entry (&info, ar_filter);
+
+ if (isKindOf (xh->value, catch_type))
+ {
+ 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)
+ return _URC_CONTINUE_UNWIND;
+
+ if (actions & _UA_SEARCH_PHASE)
+ {
+ if (!saw_handler)
+ return _URC_CONTINUE_UNWIND;
+
+ /* For domestic exceptions, we cache data from phase 1 for phase 2. */
+ if (exception_class == __objc_exception_class)
+ {
+ xh->handlerSwitchValue = handler_switch_value;
+ xh->landingPad = landing_pad;
+ }
+ return _URC_HANDLER_FOUND;
+ }
+
+ install_context:
+ _Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
+ __builtin_extend_pointer (xh->value));
+ _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 value)
+{
+ struct ObjcException *header = calloc (1, sizeof (*header));
+ header->base.exception_class = __objc_exception_class;
+ header->base.exception_cleanup = __objc_exception_cleanup;
+ header->value = value;
+
+#ifdef _GLIBCXX_SJLJ_EXCEPTIONS
+ _Unwind_SjLj_RaiseException (&header->base);
+#else
+ _Unwind_RaiseException (&header->base);
+#endif
+
+ /* Some sort of unwinding error. */
+ abort ();
+}
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