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except.h (current_function_eh_stub_label): Declare. 

* except.h (current_function_eh_stub_label): Declare.
        (current_function_eh_old_stub_label): Declare.
        * function.h (struct function): New members eh_stub_label and
        eh_old_stub_label.
        * except.c (current_function_eh_stub_label): New variable.
        (current_function_eh_old_stub_label): New variable.
        (init_eh_for_function): Clear them.
        (save_eh_status): Save them.
        (restore_eh_status): Restore them.
        (expand_builtin_eh_stub): Set current_function_eh_stub_label.
        (expand_builtin_eh_stub_old): Set current_function_eh_old_stub_label.
        * flow.c (find_basic_blocks_1): When handling a REG_LABEL note, don't
        make an edge from the block that contains it to the block starting
        with the label if this label is one of the eh stub labels.
        If eh stub labels exist, show they are reachable from the last block
        in the function.

From-SVN: r22369
This commit is contained in:
Bernd Schmidt 1998-09-09 21:48:42 +00:00 committed by Jeff Law
parent e1e837810e
commit c708eef986
5 changed files with 67 additions and 5 deletions
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17
gcc/ChangeLog
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@ -1,5 +1,22 @@
Wed Sep 9 21:58:41 1998 Bernd Schmidt <crux@pool.informatik.rwth-aachen.de>
* except.h (current_function_eh_stub_label): Declare.
(current_function_eh_old_stub_label): Declare.
* function.h (struct function): New members eh_stub_label and
eh_old_stub_label.
* except.c (current_function_eh_stub_label): New variable.
(current_function_eh_old_stub_label): New variable.
(init_eh_for_function): Clear them.
(save_eh_status): Save them.
(restore_eh_status): Restore them.
(expand_builtin_eh_stub): Set current_function_eh_stub_label.
(expand_builtin_eh_stub_old): Set current_function_eh_old_stub_label.
* flow.c (find_basic_blocks_1): When handling a REG_LABEL note, don't
make an edge from the block that contains it to the block starting
with the label if this label is one of the eh stub labels.
If eh stub labels exist, show they are reachable from the last block
in the function.
* reload1.c (reload): Break out several subroutines and make some
variables global.
(calculate_needs_all_insns): New function, broken out of reload.

16
gcc/except.c
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@ -431,6 +431,12 @@ rtx exception_handler_labels;
rtx current_function_ehc;
/* The labels generated by expand_builtin_eh_stub and
expand_builtin_eh_stub_old. */
rtx current_function_eh_stub_label;
rtx current_function_eh_old_stub_label;
/* A stack used for keeping track of the currently active exception
handling region. As each exception region is started, an entry
describing the region is pushed onto this stack. The current
@ -2148,6 +2154,8 @@ init_eh_for_function ()
caught_return_label_stack = 0;
protect_list = NULL_TREE;
current_function_ehc = NULL_RTX;
current_function_eh_stub_label = NULL_RTX;
current_function_eh_old_stub_label = NULL_RTX;
}
/* Save some of the per-function EH info into the save area denoted by
@ -2170,6 +2178,8 @@ save_eh_status (p)
p->caught_return_label_stack = caught_return_label_stack;
p->protect_list = protect_list;
p->ehc = current_function_ehc;
p->eh_stub_label = current_function_eh_stub_label;
p->eh_old_stub_label = current_function_eh_old_stub_label;
init_eh_for_function ();
}
@ -2193,6 +2203,8 @@ restore_eh_status (p)
ehstack = p->ehstack;
catchstack = p->catchstack;
current_function_ehc = p->ehc;
current_function_eh_stub_label = p->eh_stub_label;
current_function_eh_old_stub_label = p->eh_old_stub_label;
}
/* This section is for the exception handling specific optimization
@ -2502,6 +2514,8 @@ expand_builtin_eh_stub_old ()
rtx after_stub = gen_label_rtx ();
rtx handler, offset;
current_function_eh_old_stub_label = stub_start;
emit_jump (after_stub);
emit_label (stub_start);
@ -2521,6 +2535,8 @@ expand_builtin_eh_stub ()
rtx handler, offset;
rtx temp;
current_function_eh_stub_label = stub_start;
emit_jump (after_stub);
emit_label (stub_start);

7
gcc/except.h
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@ -24,6 +24,12 @@ typedef struct rtx_def *_except_rtx;
#define rtx _except_rtx
#endif
/* The labels generated by expand_builtin_eh_stub and
expand_builtin_eh_stub_old. */
extern rtx current_function_eh_stub_label;
extern rtx current_function_eh_old_stub_label;
#ifdef TREE_CODE
/* A stack of labels. CHAIN points to the next entry in the stack. */
@ -82,7 +88,6 @@ struct eh_queue {
struct eh_node *tail;
};
/* Start an exception handling region. All instructions emitted after
this point are considered to be part of the region until
expand_eh_region_end () is invoked. */

30
gcc/flow.c
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@ -484,7 +484,9 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
{
/* Make a list of all labels referred to other than by jumps. */
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
if (REG_NOTE_KIND (note) == REG_LABEL)
if (REG_NOTE_KIND (note) == REG_LABEL
&& XEXP (note, 0) != current_function_eh_stub_label
&& XEXP (note, 0) != current_function_eh_old_stub_label)
label_value_list = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0),
label_value_list);
}
@ -589,7 +591,6 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
{
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
/* References to labels in non-jumping insns have
REG_LABEL notes attached to them.
@ -609,12 +610,17 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
associated insns aren't marked dead, so we make
the block in question live and create an edge from
this insn to the label. This is not strictly
correct, but it is close enough for now. */
correct, but it is close enough for now.
See below for code that handles the eh_stub labels
specially. */
for (note = REG_NOTES (insn);
note;
note = XEXP (note, 1))
{
if (REG_NOTE_KIND (note) == REG_LABEL)
if (REG_NOTE_KIND (note) == REG_LABEL
&& XEXP (note, 0) != current_function_eh_stub_label
&& XEXP (note, 0) != current_function_eh_old_stub_label)
{
x = XEXP (note, 0);
block_live[BLOCK_NUM (x)] = 1;
@ -695,6 +701,22 @@ find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p)
}
}
}
/* We know something about the structure of the function
__throw in libgcc2.c. It is the only function that ever
contains eh_stub labels. It modifies its return address
so that the last block returns to one of the eh_stub labels
within it. So we have to make additional edges in the
flow graph. */
if (i + 1 == n_basic_blocks
&& current_function_eh_stub_label != 0)
{
mark_label_ref (gen_rtx_LABEL_REF (VOIDmode,
current_function_eh_stub_label),
basic_block_end[i], 0);
mark_label_ref (gen_rtx_LABEL_REF (VOIDmode,
current_function_eh_old_stub_label),
basic_block_end[i], 0);
}
}
}

2
gcc/function.h
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@ -142,6 +142,8 @@ struct function
rtx catch_clauses;
struct label_node *false_label_stack;
struct label_node *caught_return_label_stack;
rtx eh_stub_label;
rtx eh_old_stub_label;
tree protect_list;
rtx ehc;