exception.c: New file.

        * exception.c: New file.
        * Makefile.in (exception.lo): New.
        (OBJS): Add it.

From-SVN: r83331

libobjc/ChangeLog

+2004-06-17  Richard Henderson  <rth@redhat.com>
+
+	* exception.c: New file.
+	* Makefile.in (exception.lo): New.
+	(OBJS): Add it.
+
 2004-06-14  Andrew Pinski  <pinskia@physics.uc.edu>
 
 	* linking.m (_objcInit): New empty function

libobjc/Makefile.in

@@ -145,7 +145,7 @@ OBJC_H = hash.h objc-list.h sarray.h objc.h objc-api.h \
 OBJS =    archive.lo class.lo encoding.lo gc.lo hash.lo init.lo linking.lo \
 	  misc.lo nil_method.lo NXConstStr.lo Object.lo objects.lo \
 	  Protocol.lo sarray.lo selector.lo sendmsg.lo thr.lo \
-	  $(OBJC_THREAD_FILE).lo
+	  $(OBJC_THREAD_FILE).lo exception.lo
 
 OBJS_GC = archive_gc.lo class_gc.lo encoding_gc.lo gc_gc.lo hash_gc.lo \
 	  init_gc.lo linking_gc.lo misc_gc.lo nil_method_gc.lo \
@@ -253,6 +253,10 @@ $(OBJC_THREAD_FILE)_gc.lo: $(OBJC_THREAD_FILE).c
 	$(LIBTOOL_COMPILE) $(CC) -c -o $@ $(ALL_CFLAGS) $(OBJC_GCFLAGS) \
 		$(INCLUDES) $<
 
+exception.lo: exception.c
+	$(LIBTOOL_COMPILE) $(CC) -c -o $@ $(ALL_CFLAGS) $(OBJC_GCFLAGS) \
+		-fexceptions $(INCLUDES) $<
+
 doc: info dvi html
 
 libobjc$(libext).la: $(OBJS)

libobjc/exception.c

+/* 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"
+
+
+/* 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;
+};
+
+
+
+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 ();
+}