This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
eh patch
- To: egcs-patches at cygnus dot com
- Subject: eh patch
- From: Andrew Macleod <amacleod at cygnus dot com>
- Date: Tue, 15 Sep 1998 11:29:56 -0700
The following patch has been applied to egcs as part of the effort to
unify the exception handling interface (new/old/sjlj). No one should notice
any difference (hopefully!), except the front end no longer needs to understand
the flag flag_new_exceptions as it use to.
The front end mechanism for exception regions now looks something like:
start_try_block ()
start_catch_block ()
for each handler in try block
{
start_catch_handler (type_match)
end_catch_handler ();
}
end_catch_block ()
And its transparent whether a handler has its own entry in the exception
table (-fnew-exceptions), one handler contains compares and branch around code
for each run-time possibility (-fexceptions) or one handler and
runtime compares using setjmp/longjmp (-fsjlj-exceptions).
If anyone experiences problems, let me know ASAP.
Thanks
Andrew
Index: ChangeLog
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/ChangeLog,v
retrieving revision 1.2077
diff -c -p -r1.2077 ChangeLog
*** ChangeLog 1998/09/15 11:02:57 1.2077
--- ChangeLog 1998/09/15 18:14:54
***************
*** 1,3 ****
--- 1,18 ----
+ Tue Sep 15 14:10:54 EDT 1998 Andrew MacLeod <amacleod@cygnus.com>
+
+ * except.h (struct eh_entry): Add false_label field.
+ (end_catch_handler): Add prototype.
+ * except.c (push_eh_entry): Set false_label field to NULL_RTX.
+ (start_catch_handler): When using old style exceptions, issue
+ runtime typematch code before continuing with the handler.
+ (end_catch_handler): New function, generates label after handler
+ if needed by older style exceptions.
+ (expand_start_all_catch): No need to check for new style exceptions.
+ (output_exception_table_entry): Only output the first handler label
+ for old style exceptions.
+ * libgcc2.c (__eh_rtime_match): New routine to lump runtime matching
+ mechanism into one function, if a runtime matcher is provided.
+
Tue Sep 15 13:53:59 EDT 1998 Andrew MacLeod <amacleod@cygnus.com>
* config/i960/i960.h (SLOW_BYTE_ACCESS): Change definition to 1.
Index: except.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/except.c,v
retrieving revision 1.63
diff -c -p -r1.63 except.c
*** except.c 1998/09/09 21:48:40 1.63
--- except.c 1998/09/15 18:14:57
*************** push_eh_entry (stack)
*** 597,602 ****
--- 597,603 ----
entry->finalization = NULL_TREE;
entry->label_used = 0;
entry->exception_handler_label = gen_exception_label ();
+ entry->false_label = NULL_RTX;
node->entry = entry;
node->chain = stack->top;
*************** start_catch_handler (rtime)
*** 1600,1605 ****
--- 1601,1654 ----
receive_exception_label (handler_label);
add_new_handler (eh_region_entry, get_new_handler (handler_label, rtime));
+
+ if (flag_new_exceptions && ! exceptions_via_longjmp)
+ return;
+
+ /* Under the old mechanism, as well as setjmp/longjmp, we need to
+ issue code to compare 'rtime' to the value in eh_info, via the
+ matching function in eh_info. If its is false, we branch around
+ the handler we are about to issue. */
+
+ if (rtime != NULL_TREE && rtime != CATCH_ALL_TYPE)
+ {
+ rtx call_rtx, rtime_address;
+
+ if (catchstack.top->entry->false_label != NULL_RTX)
+ error ("never issued previous false_label");
+ catchstack.top->entry->false_label = gen_exception_label ();
+
+ rtime_address = expand_expr (rtime, NULL_RTX, Pmode, EXPAND_INITIALIZER);
+ rtime_address = force_reg (Pmode, rtime_address);
+
+ /* Now issue the call, and branch around handler if needed */
+ call_rtx = emit_library_call_value (
+ gen_rtx_SYMBOL_REF (Pmode, "__eh_rtime_match"), NULL_RTX,
+ 0, SImode, 1, rtime_address, Pmode);
+
+ /* Did the function return true? */
+ emit_cmp_insn (call_rtx, const0_rtx, EQ, NULL_RTX,
+ GET_MODE (call_rtx), 0 ,0);
+ emit_jump_insn (gen_beq (catchstack.top->entry->false_label));
+ }
+ }
+
+ /* Called to end a catch clause. If we aren't using the new exception
+ model tabel mechanism, we need to issue the branch-around label
+ for the end of the catch block. */
+
+ void
+ end_catch_handler ()
+ {
+ if (! doing_eh (1) || (flag_new_exceptions && ! exceptions_via_longjmp))
+ return;
+
+ /* A NULL label implies the catch clause was a catch all or cleanup */
+ if (catchstack.top->entry->false_label == NULL_RTX)
+ return;
+
+ emit_label (catchstack.top->entry->false_label);
+ catchstack.top->entry->false_label = NULL_RTX;
}
/* Generate RTL for the start of a group of catch clauses.
*************** expand_start_all_catch ()
*** 1693,1701 ****
ehstack.top->entry->outer_context = outer_context;
}
- /* We also have to start the handler if we aren't using the new model. */
- if (! flag_new_exceptions)
- start_catch_handler (NULL);
}
/* Finish up the catch block. At this point all the insns for the
--- 1742,1747 ----
*************** output_exception_table_entry (file, n)
*** 1927,1932 ****
--- 1973,1981 ----
POINTER_SIZE / BITS_PER_UNIT);
}
putc ('\n', file); /* blank line */
+ /* We only output the first label under the old scheme */
+ if (! flag_new_exceptions)
+ break;
}
}
Index: except.h
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/except.h,v
retrieving revision 1.22
diff -c -p -r1.22 except.h
*** except.h 1998/09/09 21:48:39 1.22
--- except.h 1998/09/15 18:14:58
*************** struct label_node {
*** 53,58 ****
--- 53,62 ----
label or not. New ones are needed for additional catch blocks if
it has.
+ FALSE_LABEL is used when either setjmp/longjmp exceptions are in
+ use, or old style table exceptions. It contains the label for
+ branching to the next runtime type check as handlers are processed.
+
FINALIZATION is the tree codes for the handler, or is NULL_TREE if
one hasn't been generated yet, or is integer_zero_node to mark the
end of a group of try blocks. */
*************** struct eh_entry {
*** 62,67 ****
--- 66,72 ----
rtx exception_handler_label;
tree finalization;
int label_used;
+ rtx false_label;
};
/* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next
*************** extern void add_eh_table_entry PROTO((
*** 236,241 ****
--- 241,250 ----
#ifdef TREE_CODE
extern void start_catch_handler PROTO((tree));
#endif
+
+ /* End an individual catch clause. */
+
+ extern void end_catch_handler PROTO((void));
/* Returns a non-zero value if we need to output an exception table. */
Index: libgcc2.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/libgcc2.c,v
retrieving revision 1.46
diff -c -p -r1.46 libgcc2.c
*** libgcc2.c 1998/07/06 23:52:21 1.46
--- libgcc2.c 1998/09/15 18:15:00
*************** __sjpopnthrow ()
*** 3355,3360 ****
--- 3355,3375 ----
/* Support code for all exception region-based exception handling. */
+ int
+ __eh_rtime_match (void *rtime)
+ {
+ void *info;
+ __eh_matcher matcher;
+ void *ret;
+
+ info = *(__get_eh_info ());
+ matcher = ((__eh_info *)info)->match_function;
+ if (!matcher)
+ perror ("No runtime type matcher available");
+ ret = (*matcher) (info, rtime, (void *)0);
+ return ((int)ret);
+ }
+
/* This value identifies the place from which an exception is being
thrown. */
Index: cp/ChangeLog
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/cp/ChangeLog,v
retrieving revision 1.678
diff -c -p -r1.678 ChangeLog
*** ChangeLog 1998/09/15 11:03:01 1.678
--- ChangeLog 1998/09/15 18:15:16
***************
*** 1,5 ****
--- 1,15 ----
1998-09-15 Andrew MacLeod <amacleod@cygnus.com>
+ * except.c (expand_start_catch_block): No need to check for new
+ exception model.
+ (process_start_catch_block_old): Deleted.
+ (process_start_catch_block): Add call to start_decl_1().
+ (expand_end_catch_block): Add call to end_catch_handler().
+ * exception.cc (__cplus_type_matcher): Only check the exception
+ language if there is an exception table.
+
+ 1998-09-15 Andrew MacLeod <amacleod@cygnus.com>
+
* search.c (expand_indirect_vtbls_init): Mark temporary stack slots
as used to prevent conflicts with virtual function tables.
Index: cp/except.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/cp/except.c,v
retrieving revision 1.51
diff -c -p -r1.51 except.c
*** except.c 1998/09/07 14:25:06 1.51
--- except.c 1998/09/15 18:15:18
*************** expand_start_catch_block (declspecs, dec
*** 597,731 ****
if (! doing_eh (1))
return;
! if (flag_new_exceptions)
! process_start_catch_block (declspecs, declarator);
! else
! process_start_catch_block_old (declspecs, declarator);
}
/* This function performs the expand_start_catch_block functionality for
- exceptions implemented in the old style, where catch blocks were all
- called, and had to check the runtime information themselves. */
-
- static void
- process_start_catch_block_old (declspecs, declarator)
- tree declspecs, declarator;
- {
- rtx false_label_rtx;
- tree decl = NULL_TREE;
- tree init;
-
- /* Create a binding level for the eh_info and the exception object
- cleanup. */
- pushlevel (0);
- expand_start_bindings (0);
-
- false_label_rtx = gen_label_rtx ();
- push_label_entry (&false_label_stack, false_label_rtx, NULL_TREE);
-
- emit_line_note (input_filename, lineno);
-
- push_eh_info ();
-
- if (declspecs)
- {
- decl = grokdeclarator (declarator, declspecs, CATCHPARM, 1, NULL_TREE);
-
- if (decl == NULL_TREE)
- error ("invalid catch parameter");
- }
-
- if (decl)
- {
- tree exp;
- rtx call_rtx, return_value_rtx;
- tree init_type;
-
- /* Make sure we mark the catch param as used, otherwise we'll get
- a warning about an unused ((anonymous)). */
- TREE_USED (decl) = 1;
-
- /* Figure out the type that the initializer is. */
- init_type = TREE_TYPE (decl);
- if (TREE_CODE (init_type) != REFERENCE_TYPE
- && TREE_CODE (init_type) != POINTER_TYPE)
- init_type = build_reference_type (init_type);
-
- exp = get_eh_value ();
-
- /* Since pointers are passed by value, initialize a reference to
- pointer catch parm with the address of the value slot. */
- if (TREE_CODE (init_type) == REFERENCE_TYPE
- && TREE_CODE (TREE_TYPE (init_type)) == POINTER_TYPE)
- exp = build_unary_op (ADDR_EXPR, exp, 1);
-
- exp = expr_tree_cons (NULL_TREE,
- build_eh_type_type (TREE_TYPE (decl)),
- expr_tree_cons (NULL_TREE,
- get_eh_type (),
- expr_tree_cons (NULL_TREE, exp, NULL_TREE)));
- exp = build_function_call (CatchMatch, exp);
- call_rtx = expand_call (exp, NULL_RTX, 0);
-
- return_value_rtx = hard_function_value (ptr_type_node, exp);
-
- /* did the throw type match function return TRUE? */
- emit_cmp_insn (return_value_rtx, const0_rtx, EQ, NULL_RTX,
- GET_MODE (return_value_rtx), 0, 0);
-
- /* if it returned FALSE, jump over the catch block, else fall into it */
- emit_jump_insn (gen_beq (false_label_rtx));
-
- push_eh_cleanup ();
-
- /* Create a binding level for the parm. */
- pushlevel (0);
- expand_start_bindings (0);
-
- init = convert_from_reference (make_tree (init_type, call_rtx));
-
- /* If the constructor for the catch parm exits via an exception, we
- must call terminate. See eh23.C. */
- if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
- {
- /* Generate the copy constructor call directly so we can wrap it.
- See also expand_default_init. */
- init = ocp_convert (TREE_TYPE (decl), init,
- CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
- init = build (TRY_CATCH_EXPR, TREE_TYPE (init), init,
- build_terminate_handler ());
- }
-
- /* Let `cp_finish_decl' know that this initializer is ok. */
- DECL_INITIAL (decl) = init;
- decl = pushdecl (decl);
-
- start_decl_1 (decl);
- cp_finish_decl (decl, DECL_INITIAL (decl),
- NULL_TREE, 0, LOOKUP_ONLYCONVERTING);
- }
- else
- {
- push_eh_cleanup ();
-
- /* Create a binding level for the parm. */
- pushlevel (0);
- expand_start_bindings (0);
-
- /* Fall into the catch all section. */
- }
-
- init = build_modify_expr (get_eh_caught (), NOP_EXPR, integer_one_node);
- expand_expr (init, const0_rtx, VOIDmode, EXPAND_NORMAL);
-
- emit_line_note (input_filename, lineno);
- }
-
- /* This function performs the expand_start_catch_block functionality for
exceptions implemented in the new style. __throw determines whether
a handler needs to be called or not, so the handler itself has to do
! nothing additionaal. */
static void
process_start_catch_block (declspecs, declarator)
--- 597,610 ----
if (! doing_eh (1))
return;
! process_start_catch_block (declspecs, declarator);
}
/* This function performs the expand_start_catch_block functionality for
exceptions implemented in the new style. __throw determines whether
a handler needs to be called or not, so the handler itself has to do
! nothing additional. */
static void
process_start_catch_block (declspecs, declarator)
*************** process_start_catch_block (declspecs, de
*** 806,811 ****
--- 685,691 ----
DECL_INITIAL (decl) = init;
decl = pushdecl (decl);
+ start_decl_1 (decl);
cp_finish_decl (decl, init, NULL_TREE, 0, LOOKUP_ONLYCONVERTING);
}
else
*************** expand_end_catch_block ()
*** 849,858 ****
documentation. */
expand_goto (top_label_entry (&caught_return_label_stack));
! /* label we emit to jump to if this catch block didn't match. */
! /* This the closing } in the `if (eq) {' of the documentation. */
! if (! flag_new_exceptions)
! emit_label (pop_label_entry (&false_label_stack));
}
/* An exception spec is implemented more or less like:
--- 729,735 ----
documentation. */
expand_goto (top_label_entry (&caught_return_label_stack));
! end_catch_handler ();
}
/* An exception spec is implemented more or less like:
Index: cp/exception.cc
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/cp/exception.cc,v
retrieving revision 1.16
diff -c -p -r1.16 exception.cc
*** exception.cc 1998/06/25 14:11:53 1.16
--- exception.cc 1998/09/15 18:15:18
*************** __cplus_type_matcher (cp_eh_info *info,
*** 157,163 ****
{
void *ret;
! if (exception_table->lang.language != EH_LANG_C_plus_plus)
return NULL;
if (match_info == CATCH_ALL_TYPE)
--- 157,165 ----
{
void *ret;
! /* No exception table implies the old style mechanism, so don't check. */
! if (exception_table != NULL &&
! exception_table->lang.language != EH_LANG_C_plus_plus)
return NULL;
if (match_info == CATCH_ALL_TYPE)