/* Exception handling semantics and decomposition for trees.
- Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
This file is part of GCC.
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
-#include "rtl.h"
-#include "tm_p.h"
#include "flags.h"
#include "function.h"
#include "except.h"
+#include "pointer-set.h"
#include "tree-flow.h"
#include "tree-dump.h"
#include "tree-inline.h"
#include "ggc.h"
#include "toplev.h"
#include "gimple.h"
+#include "target.h"
/* In some instances a tree and a gimple need to be stored in a same table,
i.e. in hash tables. This is a structure to do this. */
}
-/* Remember and lookup EH region data for arbitrary statements.
+/* Remember and lookup EH landing pad data for arbitrary statements.
Really this means any statement that could_throw_p. We could
stuff this information into the stmt_ann data structure, but:
compared to those that can. We should be saving some amount
of space by only allocating memory for those that can throw. */
-static void
-record_stmt_eh_region (struct eh_region *region, gimple t)
-{
- if (!region)
- return;
-
- add_stmt_to_eh_region (t, get_eh_region_number (region));
-}
-
-
-/* Add statement T in function IFUN to EH region NUM. */
+/* Add statement T in function IFUN to landing pad NUM. */
void
-add_stmt_to_eh_region_fn (struct function *ifun, gimple t, int num)
+add_stmt_to_eh_lp_fn (struct function *ifun, gimple t, int num)
{
struct throw_stmt_node *n;
void **slot;
- gcc_assert (num >= 0);
- gcc_assert (gimple_code (t) != GIMPLE_RESX);
+ gcc_assert (num != 0);
n = GGC_NEW (struct throw_stmt_node);
n->stmt = t;
- n->region_nr = num;
+ n->lp_nr = num;
if (!get_eh_throw_stmt_table (ifun))
set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash,
*slot = n;
}
-
-/* Add statement T in the current function (cfun) to EH region number
- NUM. */
+/* Add statement T in the current function (cfun) to EH landing pad NUM. */
void
-add_stmt_to_eh_region (gimple t, int num)
+add_stmt_to_eh_lp (gimple t, int num)
{
- add_stmt_to_eh_region_fn (cfun, t, num);
+ add_stmt_to_eh_lp_fn (cfun, t, num);
+}
+
+/* Add statement T to the single EH landing pad in REGION. */
+
+static void
+record_stmt_eh_region (eh_region region, gimple t)
+{
+ if (region == NULL)
+ return;
+ if (region->type == ERT_MUST_NOT_THROW)
+ add_stmt_to_eh_lp_fn (cfun, t, -region->index);
+ else
+ {
+ eh_landing_pad lp = region->landing_pads;
+ if (lp == NULL)
+ lp = gen_eh_landing_pad (region);
+ else
+ gcc_assert (lp->next_lp == NULL);
+ add_stmt_to_eh_lp_fn (cfun, t, lp->index);
+ }
}
-/* Remove statement T in function IFUN from the EH region holding it. */
+/* Remove statement T in function IFUN from its EH landing pad. */
bool
-remove_stmt_from_eh_region_fn (struct function *ifun, gimple t)
+remove_stmt_from_eh_lp_fn (struct function *ifun, gimple t)
{
struct throw_stmt_node dummy;
void **slot;
}
-/* Remove statement T in the current function (cfun) from the EH
- region holding it. */
+/* Remove statement T in the current function (cfun) from its
+ EH landing pad. */
bool
-remove_stmt_from_eh_region (gimple t)
+remove_stmt_from_eh_lp (gimple t)
{
- return remove_stmt_from_eh_region_fn (cfun, t);
+ return remove_stmt_from_eh_lp_fn (cfun, t);
}
/* Determine if statement T is inside an EH region in function IFUN.
- Return the EH region number if found, return -2 if IFUN does not
- have an EH table and -1 if T could not be found in IFUN's EH region
- table. */
+ Positive numbers indicate a landing pad index; negative numbers
+ indicate a MUST_NOT_THROW region index; zero indicates that the
+ statement is not recorded in the region table. */
int
-lookup_stmt_eh_region_fn (struct function *ifun, gimple t)
+lookup_stmt_eh_lp_fn (struct function *ifun, gimple t)
{
struct throw_stmt_node *p, n;
- if (!get_eh_throw_stmt_table (ifun))
- return -2;
+ if (ifun->eh->throw_stmt_table == NULL)
+ return 0;
n.stmt = t;
- p = (struct throw_stmt_node *) htab_find (get_eh_throw_stmt_table (ifun), &n);
- return (p ? p->region_nr : -1);
-}
-
-
-/* Determine if statement T is inside an EH region in the current
- function (cfun). Return the EH region number if found, return -2
- if cfun does not have an EH table and -1 if T could not be found in
- cfun's EH region table. */
-
-int
-lookup_stmt_eh_region (gimple t)
-{
- /* We can get called from initialized data when -fnon-call-exceptions
- is on; prevent crash. */
- if (!cfun)
- return -1;
-
- return lookup_stmt_eh_region_fn (cfun, t);
+ p = (struct throw_stmt_node *) htab_find (ifun->eh->throw_stmt_table, &n);
+ return p ? p->lp_nr : 0;
}
-
-/* Determine if expression T is inside an EH region in the current
- function (cfun). Return the EH region number if found, return -2
- if IFUN does not have an EH table and -1 if T could not be found in
- IFUN's EH region table. */
+/* Likewise, but always use the current function. */
int
-lookup_expr_eh_region (tree t)
+lookup_stmt_eh_lp (gimple t)
{
/* We can get called from initialized data when -fnon-call-exceptions
is on; prevent crash. */
if (!cfun)
- return -1;
-
- if (!get_eh_throw_stmt_table (cfun))
- return -2;
-
- if (t && EXPR_P (t))
- {
- tree_ann_common_t ann = tree_common_ann (t);
- if (ann)
- return (int) ann->rn;
- }
-
- return -1;
+ return 0;
+ return lookup_stmt_eh_lp_fn (cfun, t);
}
-
/* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
nodes and LABEL_DECL nodes. We will use this during the second phase to
determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
when deciding whether a GOTO to a certain LABEL_DECL (which is a
tree) leaves the TRY block, its necessary to record a tree in
this field. Thus a treemple is used. */
- treemple child;
+ treemple child;
gimple parent;
};
static void
collect_finally_tree (gimple stmt, gimple region);
-/* Go through the gimple sequence. Works with collect_finally_tree to
+/* Go through the gimple sequence. Works with collect_finally_tree to
record all GIMPLE_LABEL and GIMPLE_TRY statements. */
static void
The eh region creation is straight-forward, but frobbing all the gotos
and such into shape isn't. */
+/* The sequence into which we record all EH stuff. This will be
+ placed at the end of the function when we're all done. */
+static gimple_seq eh_seq;
+
+/* Record whether an EH region contains something that can throw,
+ indexed by EH region number. */
+static bitmap eh_region_may_contain_throw_map;
+
+/* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
+ statements that are seen to escape this GIMPLE_TRY_FINALLY node.
+ The idea is to record a gimple statement for everything except for
+ the conditionals, which get their labels recorded. Since labels are
+ of type 'tree', we need this node to store both gimple and tree
+ objects. REPL_STMT is the sequence used to replace the goto/return
+ statement. CONT_STMT is used to store the statement that allows
+ the return/goto to jump to the original destination. */
+
+struct goto_queue_node
+{
+ treemple stmt;
+ gimple_seq repl_stmt;
+ gimple cont_stmt;
+ int index;
+ /* This is used when index >= 0 to indicate that stmt is a label (as
+ opposed to a goto stmt). */
+ int is_label;
+};
+
/* State of the world while lowering. */
struct leh_state
/* What's "current" while constructing the eh region tree. These
correspond to variables of the same name in cfun->eh, which we
don't have easy access to. */
- struct eh_region *cur_region;
- struct eh_region *prev_try;
+ eh_region cur_region;
+
+ /* What's "current" for the purposes of __builtin_eh_pointer. For
+ a CATCH, this is the associated TRY. For an EH_FILTER, this is
+ the associated ALLOWED_EXCEPTIONS, etc. */
+ eh_region ehp_region;
/* Processing of TRY_FINALLY requires a bit more state. This is
split out into a separate structure so that we don't have to
in the collect_finally_tree data structures. */
gimple try_finally_expr;
gimple top_p;
+
/* While lowering a top_p usually it is expanded into multiple statements,
thus we need the following field to store them. */
gimple_seq top_p_seq;
struct leh_state *outer;
/* The exception region created for it. */
- struct eh_region *region;
-
- /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN statements
- that are seen to escape this GIMPLE_TRY_FINALLY node.
- The idea is to record a gimple statement for everything except for
- the conditionals, which get their labels recorded. Since labels are of
- type 'tree', we need this node to store both gimple and tree objects.
- REPL_STMT is the sequence used to replace the goto/return statement.
- CONT_STMT is used to store the statement that allows the return/goto to
- jump to the original destination. */
- struct goto_queue_node {
- treemple stmt;
- gimple_seq repl_stmt;
- gimple cont_stmt;
- int index;
- /* this is used when index >= 0 to indicate that stmt is a label(as
- opposed to a goto stmt) */
- int is_label;
- } *goto_queue;
+ eh_region region;
+
+ /* The goto queue. */
+ struct goto_queue_node *goto_queue;
size_t goto_queue_size;
size_t goto_queue_active;
though subsequent transformations may have cleared that flag. */
tree fallthru_label;
- /* A label that has been registered with except.c to be the
- landing pad for this try block. */
- tree eh_label;
-
/* True if it is possible to fall out the bottom of the try block.
Cleared if the fallthru is converted to a goto. */
bool may_fallthru;
bool may_throw;
};
-static gimple_seq lower_eh_filter (struct leh_state *, gimple);
+static gimple_seq lower_eh_must_not_throw (struct leh_state *, gimple);
/* Search for STMT in the goto queue. Return the replacement,
or null if the statement isn't in the queue. */
tree label;
gimple_seq new_seq;
treemple temp;
+ location_t loc = gimple_location (gsi_stmt (*gsi));
temp.tp = tp;
new_seq = find_goto_replacement (tf, temp);
return;
}
- label = create_artificial_label ();
+ label = create_artificial_label (loc);
/* Set the new label for the GIMPLE_COND */
*tp = label;
if (tf->goto_queue_active == 0)
return;
replace_goto_queue_stmt_list (tf->top_p_seq, tf);
+ replace_goto_queue_stmt_list (eh_seq, tf);
}
/* Add a new record to the goto queue contained in TF. NEW_STMT is the
labels. */
new_stmt = stmt;
record_in_goto_queue (tf, new_stmt, index, true);
-
}
/* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
if (!q->repl_stmt)
q->repl_stmt = gimple_seq_alloc ();
- q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array,q->index));
+ q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array, q->index));
if (mod)
gimple_seq_add_seq (&q->repl_stmt, mod);
gimple_seq_add_stmt (&q->repl_stmt, x);
}
+/* Emit a standard landing pad sequence into SEQ for REGION. */
+
+static void
+emit_post_landing_pad (gimple_seq *seq, eh_region region)
+{
+ eh_landing_pad lp = region->landing_pads;
+ gimple x;
+
+ if (lp == NULL)
+ lp = gen_eh_landing_pad (region);
+
+ lp->post_landing_pad = create_artificial_label (UNKNOWN_LOCATION);
+ EH_LANDING_PAD_NR (lp->post_landing_pad) = lp->index;
+
+ x = gimple_build_label (lp->post_landing_pad);
+ gimple_seq_add_stmt (seq, x);
+}
+
+/* Emit a RESX statement into SEQ for REGION. */
+
+static void
+emit_resx (gimple_seq *seq, eh_region region)
+{
+ gimple x = gimple_build_resx (region->index);
+ gimple_seq_add_stmt (seq, x);
+ if (region->outer)
+ record_stmt_eh_region (region->outer, x);
+}
+
+/* Emit an EH_DISPATCH statement into SEQ for REGION. */
+
+static void
+emit_eh_dispatch (gimple_seq *seq, eh_region region)
+{
+ gimple x = gimple_build_eh_dispatch (region->index);
+ gimple_seq_add_stmt (seq, x);
+}
+
+/* Note that the current EH region may contain a throw, or a
+ call to a function which itself may contain a throw. */
+
+static void
+note_eh_region_may_contain_throw (eh_region region)
+{
+ while (!bitmap_bit_p (eh_region_may_contain_throw_map, region->index))
+ {
+ bitmap_set_bit (eh_region_may_contain_throw_map, region->index);
+ region = region->outer;
+ if (region == NULL)
+ break;
+ }
+}
+
+/* Check if REGION has been marked as containing a throw. If REGION is
+ NULL, this predicate is false. */
+
+static inline bool
+eh_region_may_contain_throw (eh_region r)
+{
+ return r && bitmap_bit_p (eh_region_may_contain_throw_map, r->index);
+}
+
/* We want to transform
try { body; } catch { stuff; }
to
- body; goto over; lab: stuff; over:
-
- TP is a GIMPLE_TRY node. LAB is the label that
+ normal_seqence:
+ body;
+ over:
+ eh_seqence:
+ landing_pad:
+ stuff;
+ goto over;
+
+ TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
should be placed before the second operand, or NULL. OVER is
an existing label that should be put at the exit, or NULL. */
static gimple_seq
-frob_into_branch_around (gimple tp, tree lab, tree over)
+frob_into_branch_around (gimple tp, eh_region region, tree over)
{
gimple x;
gimple_seq cleanup, result;
+ location_t loc = gimple_location (tp);
cleanup = gimple_try_cleanup (tp);
result = gimple_try_eval (tp);
- if (gimple_seq_may_fallthru (result))
+ if (region)
+ emit_post_landing_pad (&eh_seq, region);
+
+ if (gimple_seq_may_fallthru (cleanup))
{
if (!over)
- over = create_artificial_label ();
+ over = create_artificial_label (loc);
x = gimple_build_goto (over);
- gimple_seq_add_stmt (&result, x);
- }
-
- if (lab)
- {
- x = gimple_build_label (lab);
- gimple_seq_add_stmt (&result, x);
+ gimple_seq_add_stmt (&cleanup, x);
}
-
- gimple_seq_add_seq (&result, cleanup);
+ gimple_seq_add_seq (&eh_seq, cleanup);
if (over)
{
if (!label)
{
- label = create_artificial_label ();
+ label = create_artificial_label (gimple_location (tf->try_finally_expr));
tf->fallthru_label = label;
if (tf->outer->tf)
{
struct leh_state *this_state,
struct leh_tf_state *tf)
{
- gimple protect_cleanup_actions;
+ tree protect_cleanup_actions;
gimple_stmt_iterator gsi;
bool finally_may_fallthru;
gimple_seq finally;
gimple x;
/* First check for nothing to do. */
- if (lang_protect_cleanup_actions)
- protect_cleanup_actions = lang_protect_cleanup_actions ();
- else
- protect_cleanup_actions = NULL;
+ if (lang_protect_cleanup_actions == NULL)
+ return;
+ protect_cleanup_actions = lang_protect_cleanup_actions ();
+ if (protect_cleanup_actions == NULL)
+ return;
finally = gimple_try_cleanup (tf->top_p);
-
- /* If the EH case of the finally block can fall through, this may be a
- structure of the form
- try {
- try {
- throw ...;
- } cleanup {
- try {
- throw ...;
- } catch (...) {
- }
- }
- } catch (...) {
- yyy;
- }
- E.g. with an inline destructor with an embedded try block. In this
- case we must save the runtime EH data around the nested exception.
-
- This complication means that any time the previous runtime data might
- be used (via fallthru from the finally) we handle the eh case here,
- whether or not protect_cleanup_actions is active. */
-
finally_may_fallthru = gimple_seq_may_fallthru (finally);
- if (!finally_may_fallthru && !protect_cleanup_actions)
- return;
/* Duplicate the FINALLY block. Only need to do this for try-finally,
and not for cleanups. */
MUST_NOT_THROW filter. */
gsi = gsi_start (finally);
x = gsi_stmt (gsi);
- if (protect_cleanup_actions
- && gimple_code (x) == GIMPLE_TRY
+ if (gimple_code (x) == GIMPLE_TRY
&& gimple_try_kind (x) == GIMPLE_TRY_CATCH
&& gimple_try_catch_is_cleanup (x))
{
gsi_remove (&gsi, false);
}
- /* Resume execution after the exception. Adding this now lets
- lower_eh_filter not add unnecessary gotos, as it is clear that
- we never fallthru from this copy of the finally block. */
- if (finally_may_fallthru)
- {
- tree save_eptr, save_filt;
- tree tmp;
-
- save_eptr = create_tmp_var (ptr_type_node, "save_eptr");
- save_filt = create_tmp_var (integer_type_node, "save_filt");
-
- gsi = gsi_start (finally);
- tmp = build0 (EXC_PTR_EXPR, ptr_type_node);
- x = gimple_build_assign (save_eptr, tmp);
- gsi_insert_before (&gsi, x, GSI_CONTINUE_LINKING);
-
- tmp = build0 (FILTER_EXPR, integer_type_node);
- x = gimple_build_assign (save_filt, tmp);
- gsi_insert_before (&gsi, x, GSI_CONTINUE_LINKING);
-
- gsi = gsi_last (finally);
- tmp = build0 (EXC_PTR_EXPR, ptr_type_node);
- x = gimple_build_assign (tmp, save_eptr);
- gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING);
-
- tmp = build0 (FILTER_EXPR, integer_type_node);
- x = gimple_build_assign (tmp, save_filt);
- gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING);
-
- x = gimple_build_resx (get_eh_region_number (tf->region));
- gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING);
- }
-
/* Wrap the block with protect_cleanup_actions as the action. */
- if (protect_cleanup_actions)
- {
- gimple_seq seq = NULL, failure = NULL;
-
- gimple_seq_add_stmt (&failure, protect_cleanup_actions);
- x = gimple_build_eh_filter (NULL, failure);
- gimple_eh_filter_set_must_not_throw (x, 1);
-
- gimple_seq_add_stmt (&seq, x);
- x = gimple_build_try (finally, seq, GIMPLE_TRY_CATCH);
- finally = lower_eh_filter (outer_state, x);
- }
- else
- lower_eh_constructs_1 (outer_state, finally);
-
- /* Hook this up to the end of the existing try block. If we
- previously fell through the end, we'll have to branch around.
- This means adding a new goto, and adding it to the queue. */
-
- gsi = gsi_last (gimple_try_eval (tf->top_p));
-
- if (tf->may_fallthru)
- {
- tree tmp;
- tmp = lower_try_finally_fallthru_label (tf);
- x = gimple_build_goto (tmp);
- gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING);
-
- if (this_state)
- maybe_record_in_goto_queue (this_state, x);
-
- tf->may_fallthru = false;
- }
-
- x = gimple_build_label (tf->eh_label);
- gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING);
- gsi_insert_seq_after (&gsi, finally, GSI_CONTINUE_LINKING);
+ x = gimple_build_eh_must_not_throw (protect_cleanup_actions);
+ x = gimple_build_try (finally, gimple_seq_alloc_with_stmt (x),
+ GIMPLE_TRY_CATCH);
+ finally = lower_eh_must_not_throw (outer_state, x);
+
+ /* Drop all of this into the exception sequence. */
+ emit_post_landing_pad (&eh_seq, tf->region);
+ gimple_seq_add_seq (&eh_seq, finally);
+ if (finally_may_fallthru)
+ emit_resx (&eh_seq, tf->region);
/* Having now been handled, EH isn't to be considered with
the rest of the outgoing edges. */
gimple_seq finally;
struct goto_queue_node *q, *qe;
- if (tf->may_throw)
- lab = tf->eh_label;
- else
- lab = create_artificial_label ();
+ lab = create_artificial_label (gimple_location (tf->try_finally_expr));
/* We expect that tf->top_p is a GIMPLE_TRY. */
finally = gimple_try_cleanup (tf->top_p);
lower_eh_constructs_1 (state, finally);
gimple_seq_add_seq (&tf->top_p_seq, finally);
+
+ if (tf->may_throw)
+ {
+ emit_post_landing_pad (&eh_seq, tf->region);
+
+ x = gimple_build_goto (lab);
+ gimple_seq_add_stmt (&eh_seq, x);
+ }
}
/* A subroutine of lower_try_finally. We have determined that there is
gimple x;
gimple_seq finally;
tree finally_label;
+ location_t loc = gimple_location (tf->try_finally_expr);
finally = gimple_try_cleanup (tf->top_p);
tf->top_p_seq = gimple_try_eval (tf->top_p);
{
/* Only reachable via the exception edge. Add the given label to
the head of the FINALLY block. Append a RESX at the end. */
-
- x = gimple_build_label (tf->eh_label);
- gimple_seq_add_stmt (&tf->top_p_seq, x);
-
- gimple_seq_add_seq (&tf->top_p_seq, finally);
-
- x = gimple_build_resx (get_eh_region_number (tf->region));
-
- gimple_seq_add_stmt (&tf->top_p_seq, x);
-
+ emit_post_landing_pad (&eh_seq, tf->region);
+ gimple_seq_add_seq (&eh_seq, finally);
+ emit_resx (&eh_seq, tf->region);
return;
}
return;
}
- finally_label = create_artificial_label ();
+ finally_label = create_artificial_label (loc);
x = gimple_build_label (finally_label);
gimple_seq_add_stmt (&tf->top_p_seq, x);
gimple_seq seq;
gimple x;
tree tmp;
+ location_t tf_loc = gimple_location (tf->try_finally_expr);
finally = gimple_try_cleanup (tf->top_p);
tf->top_p_seq = gimple_try_eval (tf->top_p);
if (tf->may_throw)
{
- x = gimple_build_label (tf->eh_label);
- gimple_seq_add_stmt (&new_stmt, x);
-
seq = lower_try_finally_dup_block (finally, state);
lower_eh_constructs_1 (state, seq);
- gimple_seq_add_seq (&new_stmt, seq);
- x = gimple_build_resx (get_eh_region_number (tf->region));
- gimple_seq_add_stmt (&new_stmt, x);
+ emit_post_landing_pad (&eh_seq, tf->region);
+ gimple_seq_add_seq (&eh_seq, seq);
+ emit_resx (&eh_seq, tf->region);
}
if (tf->goto_queue)
if (! q)
continue;
- lab = labels[index].label = create_artificial_label ();
+ lab = labels[index].label
+ = create_artificial_label (tf_loc);
if (index == return_index)
do_return_redirection (q, lab, NULL, &return_val);
else
do_goto_redirection (q, lab, NULL, tf);
}
-
+
replace_goto_queue (tf);
free (labels);
}
gimple switch_stmt;
gimple_seq finally;
struct pointer_map_t *cont_map = NULL;
+ /* The location of the TRY_FINALLY stmt. */
+ location_t tf_loc = gimple_location (tf->try_finally_expr);
+ /* The location of the finally block. */
+ location_t finally_loc;
switch_body = gimple_seq_alloc ();
finally = gimple_try_cleanup (tf->top_p);
tf->top_p_seq = gimple_try_eval (tf->top_p);
+ /* The location of the finally is either the last stmt in the finally
+ block or the location of the TRY_FINALLY itself. */
+ finally_loc = gimple_seq_last_stmt (tf->top_p_seq) != NULL ?
+ gimple_location (gimple_seq_last_stmt (tf->top_p_seq))
+ : tf_loc;
+
/* Lower the finally block itself. */
lower_eh_constructs_1 (state, finally);
ndests = fallthru_index + tf->may_fallthru;
finally_tmp = create_tmp_var (integer_type_node, "finally_tmp");
- finally_label = create_artificial_label ();
+ finally_label = create_artificial_label (finally_loc);
/* We use VEC_quick_push on case_label_vec throughout this function,
since we know the size in advance and allocate precisely as muce
if (tf->may_fallthru)
{
- x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node,
- fallthru_index));
+ x = gimple_build_assign (finally_tmp,
+ build_int_cst (NULL, fallthru_index));
gimple_seq_add_stmt (&tf->top_p_seq, x);
- if (tf->may_throw)
- {
- x = gimple_build_goto (finally_label);
- gimple_seq_add_stmt (&tf->top_p_seq, x);
- }
-
-
last_case = build3 (CASE_LABEL_EXPR, void_type_node,
- build_int_cst (NULL_TREE, fallthru_index), NULL,
- create_artificial_label ());
+ build_int_cst (NULL, fallthru_index),
+ NULL, create_artificial_label (tf_loc));
VEC_quick_push (tree, case_label_vec, last_case);
last_case_index++;
if (tf->may_throw)
{
- x = gimple_build_label (tf->eh_label);
- gimple_seq_add_stmt (&tf->top_p_seq, x);
+ emit_post_landing_pad (&eh_seq, tf->region);
- x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node,
- eh_index));
- gimple_seq_add_stmt (&tf->top_p_seq, x);
+ x = gimple_build_assign (finally_tmp,
+ build_int_cst (NULL, eh_index));
+ gimple_seq_add_stmt (&eh_seq, x);
+
+ x = gimple_build_goto (finally_label);
+ gimple_seq_add_stmt (&eh_seq, x);
last_case = build3 (CASE_LABEL_EXPR, void_type_node,
- build_int_cst (NULL_TREE, eh_index), NULL,
- create_artificial_label ());
+ build_int_cst (NULL, eh_index),
+ NULL, create_artificial_label (tf_loc));
VEC_quick_push (tree, case_label_vec, last_case);
last_case_index++;
x = gimple_build_label (CASE_LABEL (last_case));
- gimple_seq_add_stmt (&switch_body, x);
- x = gimple_build_resx (get_eh_region_number (tf->region));
- gimple_seq_add_stmt (&switch_body, x);
+ gimple_seq_add_stmt (&eh_seq, x);
+ emit_resx (&eh_seq, tf->region);
}
x = gimple_build_label (finally_label);
if (q->index < 0)
{
x = gimple_build_assign (finally_tmp,
- build_int_cst (integer_type_node,
- return_index));
+ build_int_cst (NULL, return_index));
gimple_seq_add_stmt (&mod, x);
do_return_redirection (q, finally_label, mod, &return_val);
switch_id = return_index;
else
{
x = gimple_build_assign (finally_tmp,
- build_int_cst (integer_type_node, q->index));
+ build_int_cst (NULL, q->index));
gimple_seq_add_stmt (&mod, x);
do_goto_redirection (q, finally_label, mod, tf);
switch_id = q->index;
tree case_lab;
void **slot;
case_lab = build3 (CASE_LABEL_EXPR, void_type_node,
- build_int_cst (NULL_TREE, switch_id), NULL,
- NULL);
+ build_int_cst (NULL, switch_id),
+ NULL, NULL);
/* We store the cont_stmt in the pointer map, so that we can recover
it in the loop below. We don't create the new label while
- walking the goto_queue because pointers don't offer a stable
+ walking the goto_queue because pointers don't offer a stable
order. */
if (!cont_map)
cont_map = pointer_map_create ();
gcc_assert (slot);
cont_stmt = *(gimple *) slot;
- label = create_artificial_label ();
+ label = create_artificial_label (tf_loc);
CASE_LABEL (last_case) = label;
x = gimple_build_label (label);
label. */
switch_stmt = gimple_build_switch_vec (finally_tmp, last_case,
case_label_vec);
+ gimple_set_location (switch_stmt, finally_loc);
/* Need to link SWITCH_STMT after running replace_goto_queue
due to not wanting to process the same goto stmts twice. */
return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3;
}
+/* REG is the enclosing region for a possible cleanup region, or the region
+ itself. Returns TRUE if such a region would be unreachable.
+
+ Cleanup regions within a must-not-throw region aren't actually reachable
+ even if there are throwing stmts within them, because the personality
+ routine will call terminate before unwinding. */
+
+static bool
+cleanup_is_dead_in (eh_region reg)
+{
+ while (reg && reg->type == ERT_CLEANUP)
+ reg = reg->outer;
+ return (reg && reg->type == ERT_MUST_NOT_THROW);
+}
/* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
to a sequence of labels and blocks, plus the exception region trees
struct leh_tf_state this_tf;
struct leh_state this_state;
int ndests;
+ gimple_seq old_eh_seq;
/* Process the try block. */
this_tf.try_finally_expr = tp;
this_tf.top_p = tp;
this_tf.outer = state;
- if (using_eh_for_cleanups_p)
- this_tf.region
- = gen_eh_region_cleanup (state->cur_region, state->prev_try);
+ if (using_eh_for_cleanups_p && !cleanup_is_dead_in (state->cur_region))
+ {
+ this_tf.region = gen_eh_region_cleanup (state->cur_region);
+ this_state.cur_region = this_tf.region;
+ }
else
- this_tf.region = NULL;
+ {
+ this_tf.region = NULL;
+ this_state.cur_region = state->cur_region;
+ }
- this_state.cur_region = this_tf.region;
- this_state.prev_try = state->prev_try;
+ this_state.ehp_region = state->ehp_region;
this_state.tf = &this_tf;
+ old_eh_seq = eh_seq;
+ eh_seq = NULL;
+
lower_eh_constructs_1 (&this_state, gimple_try_eval(tp));
/* Determine if the try block is escaped through the bottom. */
this_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
/* Determine if any exceptions are possible within the try block. */
- if (using_eh_for_cleanups_p)
- this_tf.may_throw = get_eh_region_may_contain_throw (this_tf.region);
+ if (this_tf.region)
+ this_tf.may_throw = eh_region_may_contain_throw (this_tf.region);
if (this_tf.may_throw)
- {
- this_tf.eh_label = create_artificial_label ();
- set_eh_region_tree_label (this_tf.region, this_tf.eh_label);
- honor_protect_cleanup_actions (state, &this_state, &this_tf);
- }
+ honor_protect_cleanup_actions (state, &this_state, &this_tf);
/* Determine how many edges (still) reach the finally block. Or rather,
how many destinations are reached by the finally block. Use this to
if (this_tf.goto_queue_map)
pointer_map_destroy (this_tf.goto_queue_map);
+ /* If there was an old (aka outer) eh_seq, append the current eh_seq.
+ If there was no old eh_seq, then the append is trivially already done. */
+ if (old_eh_seq)
+ {
+ if (eh_seq == NULL)
+ eh_seq = old_eh_seq;
+ else
+ {
+ gimple_seq new_eh_seq = eh_seq;
+ eh_seq = old_eh_seq;
+ gimple_seq_add_seq(&eh_seq, new_eh_seq);
+ }
+ }
+
return this_tf.top_p_seq;
}
static gimple_seq
lower_catch (struct leh_state *state, gimple tp)
{
- struct eh_region *try_region;
- struct leh_state this_state;
+ eh_region try_region = NULL;
+ struct leh_state this_state = *state;
gimple_stmt_iterator gsi;
tree out_label;
+ gimple_seq new_seq;
+ gimple x;
+ location_t try_catch_loc = gimple_location (tp);
- try_region = gen_eh_region_try (state->cur_region);
- this_state.cur_region = try_region;
- this_state.prev_try = try_region;
- this_state.tf = state->tf;
+ if (flag_exceptions)
+ {
+ try_region = gen_eh_region_try (state->cur_region);
+ this_state.cur_region = try_region;
+ }
lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
- if (!get_eh_region_may_contain_throw (try_region))
- {
- return gimple_try_eval (tp);
- }
+ if (!eh_region_may_contain_throw (try_region))
+ return gimple_try_eval (tp);
+
+ new_seq = NULL;
+ emit_eh_dispatch (&new_seq, try_region);
+ emit_resx (&new_seq, try_region);
+
+ this_state.cur_region = state->cur_region;
+ this_state.ehp_region = try_region;
out_label = NULL;
- for (gsi = gsi_start (gimple_try_cleanup (tp)); !gsi_end_p (gsi); )
+ for (gsi = gsi_start (gimple_try_cleanup (tp));
+ !gsi_end_p (gsi);
+ gsi_next (&gsi))
{
- struct eh_region *catch_region;
- tree eh_label;
- gimple x, gcatch;
+ eh_catch c;
+ gimple gcatch;
+ gimple_seq handler;
gcatch = gsi_stmt (gsi);
- catch_region = gen_eh_region_catch (try_region,
- gimple_catch_types (gcatch));
+ c = gen_eh_region_catch (try_region, gimple_catch_types (gcatch));
- this_state.cur_region = catch_region;
- this_state.prev_try = state->prev_try;
- lower_eh_constructs_1 (&this_state, gimple_catch_handler (gcatch));
+ handler = gimple_catch_handler (gcatch);
+ lower_eh_constructs_1 (&this_state, handler);
- eh_label = create_artificial_label ();
- set_eh_region_tree_label (catch_region, eh_label);
+ c->label = create_artificial_label (UNKNOWN_LOCATION);
+ x = gimple_build_label (c->label);
+ gimple_seq_add_stmt (&new_seq, x);
- x = gimple_build_label (eh_label);
- gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+ gimple_seq_add_seq (&new_seq, handler);
- if (gimple_seq_may_fallthru (gimple_catch_handler (gcatch)))
+ if (gimple_seq_may_fallthru (new_seq))
{
if (!out_label)
- out_label = create_artificial_label ();
+ out_label = create_artificial_label (try_catch_loc);
x = gimple_build_goto (out_label);
- gimple_seq_add_stmt (gimple_catch_handler_ptr (gcatch), x);
+ gimple_seq_add_stmt (&new_seq, x);
}
-
- gsi_insert_seq_before (&gsi, gimple_catch_handler (gcatch),
- GSI_SAME_STMT);
- gsi_remove (&gsi, false);
+ if (!c->type_list)
+ break;
}
- return frob_into_branch_around (tp, NULL, out_label);
+ gimple_try_set_cleanup (tp, new_seq);
+
+ return frob_into_branch_around (tp, try_region, out_label);
}
/* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
static gimple_seq
lower_eh_filter (struct leh_state *state, gimple tp)
{
- struct leh_state this_state;
- struct eh_region *this_region;
- gimple inner;
- tree eh_label;
+ struct leh_state this_state = *state;
+ eh_region this_region = NULL;
+ gimple inner, x;
+ gimple_seq new_seq;
inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
- if (gimple_eh_filter_must_not_throw (inner))
- this_region = gen_eh_region_must_not_throw (state->cur_region);
- else
- this_region = gen_eh_region_allowed (state->cur_region,
- gimple_eh_filter_types (inner));
- this_state = *state;
- this_state.cur_region = this_region;
- /* For must not throw regions any cleanup regions inside it
- can't reach outer catch regions. */
- if (gimple_eh_filter_must_not_throw (inner))
- this_state.prev_try = NULL;
+ if (flag_exceptions)
+ {
+ this_region = gen_eh_region_allowed (state->cur_region,
+ gimple_eh_filter_types (inner));
+ this_state.cur_region = this_region;
+ }
lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
- if (!get_eh_region_may_contain_throw (this_region))
+ if (!eh_region_may_contain_throw (this_region))
+ return gimple_try_eval (tp);
+
+ new_seq = NULL;
+ this_state.cur_region = state->cur_region;
+ this_state.ehp_region = this_region;
+
+ emit_eh_dispatch (&new_seq, this_region);
+ emit_resx (&new_seq, this_region);
+
+ this_region->u.allowed.label = create_artificial_label (UNKNOWN_LOCATION);
+ x = gimple_build_label (this_region->u.allowed.label);
+ gimple_seq_add_stmt (&new_seq, x);
+
+ lower_eh_constructs_1 (&this_state, gimple_eh_filter_failure (inner));
+ gimple_seq_add_seq (&new_seq, gimple_eh_filter_failure (inner));
+
+ gimple_try_set_cleanup (tp, new_seq);
+
+ return frob_into_branch_around (tp, this_region, NULL);
+}
+
+/* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
+ an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
+ plus the exception region trees that record all the magic. */
+
+static gimple_seq
+lower_eh_must_not_throw (struct leh_state *state, gimple tp)
+{
+ struct leh_state this_state = *state;
+
+ if (flag_exceptions)
{
- return gimple_try_eval (tp);
- }
+ gimple inner = gimple_seq_first_stmt (gimple_try_cleanup (tp));
+ eh_region this_region;
+
+ this_region = gen_eh_region_must_not_throw (state->cur_region);
+ this_region->u.must_not_throw.failure_decl
+ = gimple_eh_must_not_throw_fndecl (inner);
+ this_region->u.must_not_throw.failure_loc = gimple_location (tp);
- lower_eh_constructs_1 (state, gimple_eh_filter_failure (inner));
- gimple_try_set_cleanup (tp, gimple_eh_filter_failure (inner));
+ /* In order to get mangling applied to this decl, we must mark it
+ used now. Otherwise, pass_ipa_free_lang_data won't think it
+ needs to happen. */
+ TREE_USED (this_region->u.must_not_throw.failure_decl) = 1;
- eh_label = create_artificial_label ();
- set_eh_region_tree_label (this_region, eh_label);
+ this_state.cur_region = this_region;
+ }
+
+ lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
- return frob_into_branch_around (tp, eh_label, NULL);
+ return gimple_try_eval (tp);
}
/* Implement a cleanup expression. This is similar to try-finally,
static gimple_seq
lower_cleanup (struct leh_state *state, gimple tp)
{
- struct leh_state this_state;
- struct eh_region *this_region;
+ struct leh_state this_state = *state;
+ eh_region this_region = NULL;
struct leh_tf_state fake_tf;
gimple_seq result;
+ bool cleanup_dead = cleanup_is_dead_in (state->cur_region);
- /* If not using eh, then exception-only cleanups are no-ops. */
- if (!flag_exceptions)
+ if (flag_exceptions && !cleanup_dead)
{
- result = gimple_try_eval (tp);
- lower_eh_constructs_1 (state, result);
- return result;
+ this_region = gen_eh_region_cleanup (state->cur_region);
+ this_state.cur_region = this_region;
}
- this_region = gen_eh_region_cleanup (state->cur_region, state->prev_try);
- this_state = *state;
- this_state.cur_region = this_region;
-
lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
- if (!get_eh_region_may_contain_throw (this_region))
- {
- return gimple_try_eval (tp);
- }
+ if (cleanup_dead || !eh_region_may_contain_throw (this_region))
+ return gimple_try_eval (tp);
/* Build enough of a try-finally state so that we can reuse
honor_protect_cleanup_actions. */
memset (&fake_tf, 0, sizeof (fake_tf));
- fake_tf.top_p = tp;
+ fake_tf.top_p = fake_tf.try_finally_expr = tp;
fake_tf.outer = state;
fake_tf.region = this_region;
fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
fake_tf.may_throw = true;
- fake_tf.eh_label = create_artificial_label ();
- set_eh_region_tree_label (this_region, fake_tf.eh_label);
-
honor_protect_cleanup_actions (state, NULL, &fake_tf);
if (fake_tf.may_throw)
/* In this case honor_protect_cleanup_actions had nothing to do,
and we should process this normally. */
lower_eh_constructs_1 (state, gimple_try_cleanup (tp));
- result = frob_into_branch_around (tp, fake_tf.eh_label,
- fake_tf.fallthru_label);
+ result = frob_into_branch_around (tp, this_region,
+ fake_tf.fallthru_label);
}
else
{
return result;
}
-
-
-/* Main loop for lowering eh constructs. Also moves gsi to the next
+/* Main loop for lowering eh constructs. Also moves gsi to the next
statement. */
static void
switch (gimple_code (stmt))
{
case GIMPLE_CALL:
+ {
+ tree fndecl = gimple_call_fndecl (stmt);
+ tree rhs, lhs;
+
+ if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (fndecl))
+ {
+ case BUILT_IN_EH_POINTER:
+ /* The front end may have generated a call to
+ __builtin_eh_pointer (0) within a catch region. Replace
+ this zero argument with the current catch region number. */
+ if (state->ehp_region)
+ {
+ tree nr = build_int_cst (NULL, state->ehp_region->index);
+ gimple_call_set_arg (stmt, 0, nr);
+ }
+ else
+ {
+ /* The user has dome something silly. Remove it. */
+ rhs = build_int_cst (ptr_type_node, 0);
+ goto do_replace;
+ }
+ break;
+
+ case BUILT_IN_EH_FILTER:
+ /* ??? This should never appear, but since it's a builtin it
+ is accessible to abuse by users. Just remove it and
+ replace the use with the arbitrary value zero. */
+ rhs = build_int_cst (TREE_TYPE (TREE_TYPE (fndecl)), 0);
+ do_replace:
+ lhs = gimple_call_lhs (stmt);
+ x = gimple_build_assign (lhs, rhs);
+ gsi_insert_before (gsi, x, GSI_SAME_STMT);
+ /* FALLTHRU */
+
+ case BUILT_IN_EH_COPY_VALUES:
+ /* Likewise this should not appear. Remove it. */
+ gsi_remove (gsi, true);
+ return;
+
+ default:
+ break;
+ }
+ }
+ /* FALLTHRU */
+
case GIMPLE_ASSIGN:
/* If the stmt can throw use a new temporary for the assignment
to a LHS. This makes sure the old value of the LHS is
- available on the EH edge. */
+ available on the EH edge. Only do so for statements that
+ potentially fall thru (no noreturn calls e.g.), otherwise
+ this new assignment might create fake fallthru regions. */
if (stmt_could_throw_p (stmt)
&& gimple_has_lhs (stmt)
+ && gimple_stmt_may_fallthru (stmt)
&& !tree_could_throw_p (gimple_get_lhs (stmt))
&& is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt))))
{
else
{
x = gimple_seq_first_stmt (gimple_try_cleanup (stmt));
- switch (gimple_code (x))
+ if (!x)
{
- case GIMPLE_CATCH:
- replace = lower_catch (state, stmt);
- break;
- case GIMPLE_EH_FILTER:
- replace = lower_eh_filter (state, stmt);
- break;
- default:
- replace = lower_cleanup (state, stmt);
- break;
+ replace = gimple_try_eval (stmt);
+ lower_eh_constructs_1 (state, replace);
}
+ else
+ switch (gimple_code (x))
+ {
+ case GIMPLE_CATCH:
+ replace = lower_catch (state, stmt);
+ break;
+ case GIMPLE_EH_FILTER:
+ replace = lower_eh_filter (state, stmt);
+ break;
+ case GIMPLE_EH_MUST_NOT_THROW:
+ replace = lower_eh_must_not_throw (state, stmt);
+ break;
+ default:
+ replace = lower_cleanup (state, stmt);
+ break;
+ }
}
/* Remove the old stmt and insert the transformed sequence
lower_eh_constructs (void)
{
struct leh_state null_state;
+ gimple_seq bodyp;
- gimple_seq bodyp = gimple_body (current_function_decl);
+ bodyp = gimple_body (current_function_decl);
+ if (bodyp == NULL)
+ return 0;
finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free);
+ eh_region_may_contain_throw_map = BITMAP_ALLOC (NULL);
+ memset (&null_state, 0, sizeof (null_state));
collect_finally_tree_1 (bodyp, NULL);
-
- memset (&null_state, 0, sizeof (null_state));
lower_eh_constructs_1 (&null_state, bodyp);
+ /* We assume there's a return statement, or something, at the end of
+ the function, and thus ploping the EH sequence afterward won't
+ change anything. */
+ gcc_assert (!gimple_seq_may_fallthru (bodyp));
+ gimple_seq_add_seq (&bodyp, eh_seq);
+
+ /* We assume that since BODYP already existed, adding EH_SEQ to it
+ didn't change its value, and we don't have to re-set the function. */
+ gcc_assert (bodyp == gimple_body (current_function_decl));
+
htab_delete (finally_tree);
+ BITMAP_FREE (eh_region_may_contain_throw_map);
+ eh_seq = NULL;
+
+ /* If this function needs a language specific EH personality routine
+ and the frontend didn't already set one do so now. */
+ if (function_needs_eh_personality (cfun) == eh_personality_lang
+ && !DECL_FUNCTION_PERSONALITY (current_function_decl))
+ DECL_FUNCTION_PERSONALITY (current_function_decl)
+ = lang_hooks.eh_personality ();
- collect_eh_region_array ();
return 0;
}
TODO_dump_func /* todo_flags_finish */
}
};
-
\f
-/* Construct EH edges for STMT. */
+/* Create the multiple edges from an EH_DISPATCH statement to all of
+ the possible handlers for its EH region. Return true if there's
+ no fallthru edge; false if there is. */
-static void
-make_eh_edge (struct eh_region *region, void *data)
+bool
+make_eh_dispatch_edges (gimple stmt)
{
- gimple stmt;
- tree lab;
+ eh_region r;
+ eh_catch c;
basic_block src, dst;
- stmt = (gimple) data;
- lab = get_eh_region_tree_label (region);
-
+ r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
src = gimple_bb (stmt);
- dst = label_to_block (lab);
-
- make_edge (src, dst, EDGE_ABNORMAL | EDGE_EH);
-}
-/* See if STMT is call that might be inlined. */
+ switch (r->type)
+ {
+ case ERT_TRY:
+ for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
+ {
+ dst = label_to_block (c->label);
+ make_edge (src, dst, 0);
-static bool
-inlinable_call_p (gimple stmt)
-{
- tree decl;
- if (gimple_code (stmt) != GIMPLE_CALL)
- return false;
- if (cfun->after_inlining)
- return false;
- /* Indirect calls can be propagated to direct call
- and inlined. */
- decl = gimple_call_fndecl (stmt);
- if (!decl)
- return true;
- if (cgraph_function_flags_ready
- && cgraph_function_body_availability (cgraph_node (decl))
- < AVAIL_OVERWRITABLE)
- return false;
- return !DECL_UNINLINABLE (decl);
+ /* A catch-all handler doesn't have a fallthru. */
+ if (c->type_list == NULL)
+ return false;
+ }
+ break;
+
+ case ERT_ALLOWED_EXCEPTIONS:
+ dst = label_to_block (r->u.allowed.label);
+ make_edge (src, dst, 0);
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+
+ return true;
}
+/* Create the single EH edge from STMT to its nearest landing pad,
+ if there is such a landing pad within the current function. */
+
void
make_eh_edges (gimple stmt)
{
- int region_nr;
- bool is_resx;
- bool inlinable = false;
- basic_block bb;
+ basic_block src, dst;
+ eh_landing_pad lp;
+ int lp_nr;
- if (gimple_code (stmt) == GIMPLE_RESX)
- {
- region_nr = gimple_resx_region (stmt);
- is_resx = true;
- }
- else
- {
- region_nr = lookup_stmt_eh_region (stmt);
- if (region_nr < 0)
- return;
- is_resx = false;
- inlinable = inlinable_call_p (stmt);
- }
+ lp_nr = lookup_stmt_eh_lp (stmt);
+ if (lp_nr <= 0)
+ return;
- foreach_reachable_handler (region_nr, is_resx, inlinable, make_eh_edge, stmt);
+ lp = get_eh_landing_pad_from_number (lp_nr);
+ gcc_assert (lp != NULL);
- /* Make CFG profile more consistent assuming that exception will resume to first
- available EH handler. In practice this makes little difference, but we get
- fewer consistency errors in the dumps. */
- bb = gimple_bb (stmt);
- if (is_resx && EDGE_COUNT (bb->succs))
- EDGE_SUCC (bb, 0)->probability = REG_BR_PROB_BASE;
+ src = gimple_bb (stmt);
+ dst = label_to_block (lp->post_landing_pad);
+ make_edge (src, dst, EDGE_EH);
}
-static bool mark_eh_edge_found_error;
+/* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
+ do not actually perform the final edge redirection.
-/* Mark edge make_eh_edge would create for given region by setting it aux
- field, output error if something goes wrong. */
+ CHANGE_REGION is true when we're being called from cleanup_empty_eh and
+ we intend to change the destination EH region as well; this means
+ EH_LANDING_PAD_NR must already be set on the destination block label.
+ If false, we're being called from generic cfg manipulation code and we
+ should preserve our place within the region tree. */
static void
-mark_eh_edge (struct eh_region *region, void *data)
+redirect_eh_edge_1 (edge edge_in, basic_block new_bb, bool change_region)
{
- gimple stmt;
- tree lab;
- basic_block src, dst;
+ eh_landing_pad old_lp, new_lp;
+ basic_block old_bb;
+ gimple throw_stmt;
+ int old_lp_nr, new_lp_nr;
+ tree old_label, new_label;
+ edge_iterator ei;
edge e;
- stmt = (gimple) data;
- lab = get_eh_region_tree_label (region);
+ old_bb = edge_in->dest;
+ old_label = gimple_block_label (old_bb);
+ old_lp_nr = EH_LANDING_PAD_NR (old_label);
+ gcc_assert (old_lp_nr > 0);
+ old_lp = get_eh_landing_pad_from_number (old_lp_nr);
- src = gimple_bb (stmt);
- dst = label_to_block (lab);
+ throw_stmt = last_stmt (edge_in->src);
+ gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
- e = find_edge (src, dst);
- if (!e)
- {
- error ("EH edge %i->%i is missing", src->index, dst->index);
- mark_eh_edge_found_error = true;
- }
- else if (!(e->flags & EDGE_EH))
+ new_label = gimple_block_label (new_bb);
+
+ /* Look for an existing region that might be using NEW_BB already. */
+ new_lp_nr = EH_LANDING_PAD_NR (new_label);
+ if (new_lp_nr)
{
- error ("EH edge %i->%i miss EH flag", src->index, dst->index);
- mark_eh_edge_found_error = true;
+ new_lp = get_eh_landing_pad_from_number (new_lp_nr);
+ gcc_assert (new_lp);
+
+ /* Unless CHANGE_REGION is true, the new and old landing pad
+ had better be associated with the same EH region. */
+ gcc_assert (change_region || new_lp->region == old_lp->region);
}
- else if (e->aux)
+ else
{
- /* ??? might not be mistake. */
- error ("EH edge %i->%i has duplicated regions", src->index, dst->index);
- mark_eh_edge_found_error = true;
+ new_lp = NULL;
+ gcc_assert (!change_region);
}
- else
- e->aux = (void *)1;
-}
-/* Verify that BB containing STMT as the last statement, has precisely the
- edges that make_eh_edges would create. */
-
-bool
-verify_eh_edges (gimple stmt)
-{
- int region_nr;
- bool is_resx;
- basic_block bb = gimple_bb (stmt);
- edge_iterator ei;
- edge e;
- bool inlinable = false;
+ /* Notice when we redirect the last EH edge away from OLD_BB. */
+ FOR_EACH_EDGE (e, ei, old_bb->preds)
+ if (e != edge_in && (e->flags & EDGE_EH))
+ break;
- FOR_EACH_EDGE (e, ei, bb->succs)
- gcc_assert (!e->aux);
- mark_eh_edge_found_error = false;
- if (gimple_code (stmt) == GIMPLE_RESX)
+ if (new_lp)
{
- region_nr = gimple_resx_region (stmt);
- is_resx = true;
+ /* NEW_LP already exists. If there are still edges into OLD_LP,
+ there's nothing to do with the EH tree. If there are no more
+ edges into OLD_LP, then we want to remove OLD_LP as it is unused.
+ If CHANGE_REGION is true, then our caller is expecting to remove
+ the landing pad. */
+ if (e == NULL && !change_region)
+ remove_eh_landing_pad (old_lp);
}
else
{
- region_nr = lookup_stmt_eh_region (stmt);
- if (region_nr < 0)
- {
- FOR_EACH_EDGE (e, ei, bb->succs)
- if (e->flags & EDGE_EH)
- {
- error ("BB %i can not throw but has EH edges", bb->index);
- return true;
- }
- return false;
- }
- if (!stmt_could_throw_p (stmt))
+ /* No correct landing pad exists. If there are no more edges
+ into OLD_LP, then we can simply re-use the existing landing pad.
+ Otherwise, we have to create a new landing pad. */
+ if (e == NULL)
{
- error ("BB %i last statement has incorrectly set region", bb->index);
- return true;
+ EH_LANDING_PAD_NR (old_lp->post_landing_pad) = 0;
+ new_lp = old_lp;
}
- inlinable = inlinable_call_p (stmt);
- is_resx = false;
+ else
+ new_lp = gen_eh_landing_pad (old_lp->region);
+ new_lp->post_landing_pad = new_label;
+ EH_LANDING_PAD_NR (new_label) = new_lp->index;
}
- foreach_reachable_handler (region_nr, is_resx, inlinable, mark_eh_edge, stmt);
- FOR_EACH_EDGE (e, ei, bb->succs)
+ /* Maybe move the throwing statement to the new region. */
+ if (old_lp != new_lp)
+ {
+ remove_stmt_from_eh_lp (throw_stmt);
+ add_stmt_to_eh_lp (throw_stmt, new_lp->index);
+ }
+}
+
+/* Redirect EH edge E to NEW_BB. */
+
+edge
+redirect_eh_edge (edge edge_in, basic_block new_bb)
+{
+ redirect_eh_edge_1 (edge_in, new_bb, false);
+ return ssa_redirect_edge (edge_in, new_bb);
+}
+
+/* This is a subroutine of gimple_redirect_edge_and_branch. Update the
+ labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
+ The actual edge update will happen in the caller. */
+
+void
+redirect_eh_dispatch_edge (gimple stmt, edge e, basic_block new_bb)
+{
+ tree new_lab = gimple_block_label (new_bb);
+ bool any_changed = false;
+ basic_block old_bb;
+ eh_region r;
+ eh_catch c;
+
+ r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
+ switch (r->type)
{
- if ((e->flags & EDGE_EH) && !e->aux)
+ case ERT_TRY:
+ for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
{
- error ("unnecessary EH edge %i->%i", bb->index, e->dest->index);
- mark_eh_edge_found_error = true;
- return true;
+ old_bb = label_to_block (c->label);
+ if (old_bb == e->dest)
+ {
+ c->label = new_lab;
+ any_changed = true;
+ }
}
- e->aux = NULL;
+ break;
+
+ case ERT_ALLOWED_EXCEPTIONS:
+ old_bb = label_to_block (r->u.allowed.label);
+ gcc_assert (old_bb == e->dest);
+ r->u.allowed.label = new_lab;
+ any_changed = true;
+ break;
+
+ default:
+ gcc_unreachable ();
}
- return mark_eh_edge_found_error;
+ gcc_assert (any_changed);
}
-
\f
/* Helper function for operation_could_trap_p and stmt_could_throw_p. */
if (!expr)
return false;
-
+
code = TREE_CODE (expr);
t = TREE_TYPE (expr);
base = TREE_OPERAND (expr, 0);
if (tree_could_trap_p (base))
return true;
-
if (TREE_THIS_NOTRAP (expr))
return false;
-
return !range_in_array_bounds_p (expr);
case ARRAY_REF:
base = TREE_OPERAND (expr, 0);
if (tree_could_trap_p (base))
return true;
-
if (TREE_THIS_NOTRAP (expr))
return false;
-
return !in_array_bounds_p (expr);
case INDIRECT_REF:
case ASM_EXPR:
return TREE_THIS_VOLATILE (expr);
-
case CALL_EXPR:
t = get_callee_fndecl (expr);
/* Assume that calls to weak functions may trap. */
bool
stmt_could_throw_p (gimple stmt)
{
- enum gimple_code code;
-
if (!flag_exceptions)
return false;
/* The only statements that can throw an exception are assignments,
- conditionals, calls and asms. */
- code = gimple_code (stmt);
- if (code != GIMPLE_ASSIGN
- && code != GIMPLE_COND
- && code != GIMPLE_CALL
- && code != GIMPLE_ASM)
- return false;
+ conditionals, calls, resx, and asms. */
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_RESX:
+ return true;
- /* If exceptions can only be thrown by function calls and STMT is not a
- GIMPLE_CALL, the statement cannot throw. */
- if (!flag_non_call_exceptions && code != GIMPLE_CALL)
- return false;
+ case GIMPLE_CALL:
+ return !gimple_call_nothrow_p (stmt);
- if (code == GIMPLE_ASSIGN || code == GIMPLE_COND)
- return stmt_could_throw_1_p (stmt);
- else if (is_gimple_call (stmt))
- return (gimple_call_flags (stmt) & ECF_NOTHROW) == 0;
- else if (gimple_code (stmt) == GIMPLE_ASM)
- return (gimple_asm_volatile_p (stmt));
- else
- gcc_unreachable ();
+ case GIMPLE_ASSIGN:
+ case GIMPLE_COND:
+ if (!flag_non_call_exceptions)
+ return false;
+ return stmt_could_throw_1_p (stmt);
- return false;
+ case GIMPLE_ASM:
+ if (!flag_non_call_exceptions)
+ return false;
+ return gimple_asm_volatile_p (stmt);
+
+ default:
+ return false;
+ }
}
if (TREE_CODE (t) == MODIFY_EXPR)
{
if (flag_non_call_exceptions
- && tree_could_trap_p (TREE_OPERAND (t, 0)))
- return true;
+ && tree_could_trap_p (TREE_OPERAND (t, 0)))
+ return true;
t = TREE_OPERAND (t, 1);
}
bool
stmt_can_throw_external (gimple stmt)
{
- int region_nr;
- bool is_resx = false;
- bool inlinable_call = false;
+ int lp_nr;
if (!stmt_could_throw_p (stmt))
return false;
- if (gimple_code (stmt) == GIMPLE_RESX)
- {
- region_nr = gimple_resx_region (stmt);
- is_resx = true;
- }
- else
- region_nr = lookup_stmt_eh_region (stmt);
-
- if (region_nr < 0)
- return true;
-
- return can_throw_external_1 (region_nr, is_resx, inlinable_call);
+ lp_nr = lookup_stmt_eh_lp (stmt);
+ return lp_nr == 0;
}
/* Return true if STMT can throw an exception that is caught within
bool
stmt_can_throw_internal (gimple stmt)
{
- int region_nr;
- bool is_resx = false;
- bool inlinable_call = false;
+ int lp_nr;
- if (gimple_code (stmt) == GIMPLE_RESX)
- {
- region_nr = gimple_resx_region (stmt);
- is_resx = true;
- }
- else
- {
- region_nr = lookup_stmt_eh_region (stmt);
- inlinable_call = inlinable_call_p (stmt);
- }
-
- if (region_nr < 0)
+ if (!stmt_could_throw_p (stmt))
return false;
- return can_throw_internal_1 (region_nr, is_resx, inlinable_call);
+ lp_nr = lookup_stmt_eh_lp (stmt);
+ return lp_nr > 0;
+}
+
+/* Given a statement STMT in IFUN, if STMT can no longer throw, then
+ remove any entry it might have from the EH table. Return true if
+ any change was made. */
+
+bool
+maybe_clean_eh_stmt_fn (struct function *ifun, gimple stmt)
+{
+ if (stmt_could_throw_p (stmt))
+ return false;
+ return remove_stmt_from_eh_lp_fn (ifun, stmt);
}
+/* Likewise, but always use the current function. */
+
+bool
+maybe_clean_eh_stmt (gimple stmt)
+{
+ return maybe_clean_eh_stmt_fn (cfun, stmt);
+}
/* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
in the table if it should be in there. Return TRUE if a replacement was
done that my require an EH edge purge. */
-bool
-maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt)
+bool
+maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt)
{
- int region_nr = lookup_stmt_eh_region (old_stmt);
+ int lp_nr = lookup_stmt_eh_lp (old_stmt);
- if (region_nr >= 0)
+ if (lp_nr != 0)
{
bool new_stmt_could_throw = stmt_could_throw_p (new_stmt);
if (new_stmt == old_stmt && new_stmt_could_throw)
return false;
- remove_stmt_from_eh_region (old_stmt);
+ remove_stmt_from_eh_lp (old_stmt);
if (new_stmt_could_throw)
{
- add_stmt_to_eh_region (new_stmt, region_nr);
+ add_stmt_to_eh_lp (new_stmt, lp_nr);
return false;
}
else
return false;
}
+
+/* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
+ in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
+ operand is the return value of duplicate_eh_regions. */
+
+bool
+maybe_duplicate_eh_stmt_fn (struct function *new_fun, gimple new_stmt,
+ struct function *old_fun, gimple old_stmt,
+ struct pointer_map_t *map, int default_lp_nr)
+{
+ int old_lp_nr, new_lp_nr;
+ void **slot;
+
+ if (!stmt_could_throw_p (new_stmt))
+ return false;
+
+ old_lp_nr = lookup_stmt_eh_lp_fn (old_fun, old_stmt);
+ if (old_lp_nr == 0)
+ {
+ if (default_lp_nr == 0)
+ return false;
+ new_lp_nr = default_lp_nr;
+ }
+ else if (old_lp_nr > 0)
+ {
+ eh_landing_pad old_lp, new_lp;
+
+ old_lp = VEC_index (eh_landing_pad, old_fun->eh->lp_array, old_lp_nr);
+ slot = pointer_map_contains (map, old_lp);
+ new_lp = (eh_landing_pad) *slot;
+ new_lp_nr = new_lp->index;
+ }
+ else
+ {
+ eh_region old_r, new_r;
+
+ old_r = VEC_index (eh_region, old_fun->eh->region_array, -old_lp_nr);
+ slot = pointer_map_contains (map, old_r);
+ new_r = (eh_region) *slot;
+ new_lp_nr = -new_r->index;
+ }
+
+ add_stmt_to_eh_lp_fn (new_fun, new_stmt, new_lp_nr);
+ return true;
+}
+
+/* Similar, but both OLD_STMT and NEW_STMT are within the current function,
+ and thus no remapping is required. */
+
+bool
+maybe_duplicate_eh_stmt (gimple new_stmt, gimple old_stmt)
+{
+ int lp_nr;
+
+ if (!stmt_could_throw_p (new_stmt))
+ return false;
+
+ lp_nr = lookup_stmt_eh_lp (old_stmt);
+ if (lp_nr == 0)
+ return false;
+
+ add_stmt_to_eh_lp (new_stmt, lp_nr);
+ return true;
+}
\f
/* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
GIMPLE_TRY) that are similar enough to be considered the same. Currently
for (ai = 0; ai < gimple_call_num_args (ones); ++ai)
if (!operand_equal_p (gimple_call_arg (ones, ai),
- gimple_call_arg (twos, ai), 0))
+ gimple_call_arg (twos, ai), 0))
return false;
return true;
return 0;
}
+static bool
+gate_refactor_eh (void)
+{
+ return flag_exceptions != 0;
+}
+
struct gimple_opt_pass pass_refactor_eh =
{
{
GIMPLE_PASS,
"ehopt", /* name */
- NULL, /* gate */
+ gate_refactor_eh, /* gate */
refactor_eh, /* execute */
NULL, /* sub */
NULL, /* next */
TODO_dump_func /* todo_flags_finish */
}
};
+\f
+/* At the end of gimple optimization, we can lower RESX. */
-/* Walk statements, see what regions are really references and remove unreachable ones. */
-
-static void
-tree_remove_unreachable_handlers (void)
+static bool
+lower_resx (basic_block bb, gimple stmt, struct pointer_map_t *mnt_map)
{
- sbitmap reachable, contains_stmt;
- VEC(int,heap) * label_to_region;
- basic_block bb;
+ int lp_nr;
+ eh_region src_r, dst_r;
+ gimple_stmt_iterator gsi;
+ gimple x;
+ tree fn, src_nr;
+ bool ret = false;
- label_to_region = label_to_region_map ();
- reachable = sbitmap_alloc (num_eh_regions ());
- sbitmap_zero (reachable);
- contains_stmt = sbitmap_alloc (num_eh_regions ());
- sbitmap_zero (contains_stmt);
+ lp_nr = lookup_stmt_eh_lp (stmt);
+ if (lp_nr != 0)
+ dst_r = get_eh_region_from_lp_number (lp_nr);
+ else
+ dst_r = NULL;
- FOR_EACH_BB (bb)
- {
- gimple_stmt_iterator gsi;
- int region;
- bool has_eh_preds = bb_has_eh_pred (bb);
+ src_r = get_eh_region_from_number (gimple_resx_region (stmt));
+ gsi = gsi_last_bb (bb);
- for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gimple stmt = gsi_stmt (gsi);
+ if (src_r == NULL)
+ {
+ /* We can wind up with no source region when pass_cleanup_eh shows
+ that there are no entries into an eh region and deletes it, but
+ then the block that contains the resx isn't removed. This can
+ happen without optimization when the switch statement created by
+ lower_try_finally_switch isn't simplified to remove the eh case.
- if (gimple_code (stmt) == GIMPLE_LABEL && has_eh_preds)
- {
- int uid = LABEL_DECL_UID (gimple_label_label (stmt));
- int region = VEC_index (int, label_to_region, uid);
- SET_BIT (reachable, region);
- }
- if (gimple_code (stmt) == GIMPLE_RESX)
- SET_BIT (reachable, gimple_resx_region (stmt));
- if ((region = lookup_stmt_eh_region (stmt)) >= 0)
- SET_BIT (contains_stmt, region);
- }
- }
+ Resolve this by expanding the resx node to an abort. */
- if (dump_file)
- {
- fprintf (dump_file, "Before removal of unreachable regions:\n");
- dump_eh_tree (dump_file, cfun);
- fprintf (dump_file, "Reachable regions: ");
- dump_sbitmap_file (dump_file, reachable);
- fprintf (dump_file, "Regions containing insns: ");
- dump_sbitmap_file (dump_file, contains_stmt);
- }
+ fn = implicit_built_in_decls[BUILT_IN_TRAP];
+ x = gimple_build_call (fn, 0);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
- remove_unreachable_regions (reachable, contains_stmt);
- sbitmap_free (reachable);
- sbitmap_free (contains_stmt);
- VEC_free (int, heap, label_to_region);
- if (dump_file)
- {
- fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n");
- dump_eh_tree (dump_file, cfun);
- fprintf (dump_file, "\n\n");
+ while (EDGE_COUNT (bb->succs) > 0)
+ remove_edge (EDGE_SUCC (bb, 0));
}
-}
-
-/* Pattern match emtpy EH receiver looking like:
-
- save_filt.6352_662 = [filter_expr] <<<filter object>>>;
- save_eptr.6351_663 = [exc_ptr_expr] <<<exception object>>>;
- <<<exception object>>> = save_eptr.6351_663;
- <<<filter object>>> = save_filt.6352_662;
- resx 1
+ else if (dst_r)
+ {
+ /* When we have a destination region, we resolve this by copying
+ the excptr and filter values into place, and changing the edge
+ to immediately after the landing pad. */
+ edge e;
- And various minor variants after DCE or copy propagation.
- */
+ if (lp_nr < 0)
+ {
+ basic_block new_bb;
+ void **slot;
+ tree lab;
-static int
-tree_empty_eh_handler_p (basic_block bb)
-{
- gimple_stmt_iterator gsi;
- int region;
- use_operand_p imm_use;
- gimple use_stmt;
+ /* We are resuming into a MUST_NOT_CALL region. Expand a call to
+ the failure decl into a new block, if needed. */
+ gcc_assert (dst_r->type == ERT_MUST_NOT_THROW);
- gsi = gsi_last_bb (bb);
+ slot = pointer_map_contains (mnt_map, dst_r);
+ if (slot == NULL)
+ {
+ gimple_stmt_iterator gsi2;
- /* RESX */
- if (gsi_end_p (gsi))
- return 0;
- if (gimple_code (gsi_stmt (gsi)) != GIMPLE_RESX)
- return 0;
- region = gimple_resx_region (gsi_stmt (gsi));
+ new_bb = create_empty_bb (bb);
+ lab = gimple_block_label (new_bb);
+ gsi2 = gsi_start_bb (new_bb);
- /* filter_object set. */
- gsi_prev (&gsi);
- if (gsi_end_p (gsi))
- return 0;
- if (gimple_code (gsi_stmt (gsi)) == GIMPLE_ASSIGN)
- {
- tree filter_tmp;
- tree exc_ptr_tmp;
+ fn = dst_r->u.must_not_throw.failure_decl;
+ x = gimple_build_call (fn, 0);
+ gimple_set_location (x, dst_r->u.must_not_throw.failure_loc);
+ gsi_insert_after (&gsi2, x, GSI_CONTINUE_LINKING);
- if (TREE_CODE (gimple_assign_lhs (gsi_stmt (gsi))) != FILTER_EXPR)
- return 0;
- filter_tmp = gimple_assign_rhs1 (gsi_stmt (gsi));
+ slot = pointer_map_insert (mnt_map, dst_r);
+ *slot = lab;
+ }
+ else
+ {
+ lab = (tree) *slot;
+ new_bb = label_to_block (lab);
+ }
- /* filter_object set. */
- gsi_prev (&gsi);
- if (gsi_end_p (gsi))
- return 0;
- if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN)
- return 0;
- if (TREE_CODE (gimple_assign_lhs (gsi_stmt (gsi))) != EXC_PTR_EXPR)
- return 0;
- exc_ptr_tmp = gimple_assign_rhs1 (gsi_stmt (gsi));
-
- /* exc_ptr get. */
- if (TREE_CODE (exc_ptr_tmp) != EXC_PTR_EXPR)
- {
- gsi_prev (&gsi);
- if (gsi_end_p (gsi))
- return 0;
- if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN)
- return 0;
- if (TREE_CODE (gimple_assign_rhs1 (gsi_stmt (gsi))) != EXC_PTR_EXPR)
- return 0;
- if (exc_ptr_tmp != gimple_assign_lhs (gsi_stmt (gsi)))
- return 0;
- if (!single_imm_use (exc_ptr_tmp, &imm_use, &use_stmt))
- return 0;
+ gcc_assert (EDGE_COUNT (bb->succs) == 0);
+ e = make_edge (bb, new_bb, EDGE_FALLTHRU);
+ e->count = bb->count;
+ e->probability = REG_BR_PROB_BASE;
}
-
- /* filter_object get. */
- if (TREE_CODE (filter_tmp) != FILTER_EXPR)
+ else
{
- gsi_prev (&gsi);
- if (gsi_end_p (gsi))
- return 0;
- if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN)
- return 0;
- if (TREE_CODE (gimple_assign_rhs1 (gsi_stmt (gsi))) != FILTER_EXPR)
- return 0;
- if (filter_tmp != gimple_assign_lhs (gsi_stmt (gsi)))
- return 0;
- if (!single_imm_use (filter_tmp, &imm_use, &use_stmt))
- return 0;
+ edge_iterator ei;
+ tree dst_nr = build_int_cst (NULL, dst_r->index);
+
+ fn = implicit_built_in_decls[BUILT_IN_EH_COPY_VALUES];
+ src_nr = build_int_cst (NULL, src_r->index);
+ x = gimple_build_call (fn, 2, dst_nr, src_nr);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+
+ /* Update the flags for the outgoing edge. */
+ e = single_succ_edge (bb);
+ gcc_assert (e->flags & EDGE_EH);
+ e->flags = (e->flags & ~EDGE_EH) | EDGE_FALLTHRU;
+
+ /* If there are no more EH users of the landing pad, delete it. */
+ FOR_EACH_EDGE (e, ei, e->dest->preds)
+ if (e->flags & EDGE_EH)
+ break;
+ if (e == NULL)
+ {
+ eh_landing_pad lp = get_eh_landing_pad_from_number (lp_nr);
+ remove_eh_landing_pad (lp);
+ }
}
- /* label. */
- gsi_prev (&gsi);
- if (gsi_end_p (gsi))
- return 0;
+ ret = true;
}
- while (gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL)
+ else
{
- if (gimple_label_label (gsi_stmt (gsi))
- == get_eh_region_no_tree_label (region))
- return region;
- gsi_prev (&gsi);
- if (gsi_end_p (gsi))
- return 0;
- }
- return 0;
-}
+ tree var;
-/* Return true if it is possible to remove basic block BB and propagate
- through PHIs.
+ /* When we don't have a destination region, this exception escapes
+ up the call chain. We resolve this by generating a call to the
+ _Unwind_Resume library function. */
- This means that every PHI in BB has all uses such that they are PHIs
- of basic blocks reachable througt BB and they appears only in use
- reachable by the edge from BB to the block contianing the use.
-
- This is same as in merge-phi code, but in slightly more general setting
- because BB can have multiple successors. */
+ /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
+ with no arguments for C++ and Java. Check for that. */
+ if (src_r->use_cxa_end_cleanup)
+ {
+ fn = implicit_built_in_decls[BUILT_IN_CXA_END_CLEANUP];
+ x = gimple_build_call (fn, 0);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+ }
+ else
+ {
+ fn = implicit_built_in_decls[BUILT_IN_EH_POINTER];
+ src_nr = build_int_cst (NULL, src_r->index);
+ x = gimple_build_call (fn, 1, src_nr);
+ var = create_tmp_var (ptr_type_node, NULL);
+ var = make_ssa_name (var, x);
+ gimple_call_set_lhs (x, var);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+
+ fn = implicit_built_in_decls[BUILT_IN_UNWIND_RESUME];
+ x = gimple_build_call (fn, 1, var);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+ }
-static bool
-all_phis_safe_to_merge (basic_block bb)
-{
- gimple_stmt_iterator si;
- bool ok = true;
-
- for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
- {
- gimple phi = gsi_stmt (si);
- tree result = gimple_phi_result (phi);
- gimple stmt;
- use_operand_p imm_use;
- imm_use_iterator imm_iter;
-
- /* If the PHI's result is never used, then we can just
- ignore it. */
- if (has_zero_uses (result))
- continue;
- /* We can always rebuild virtuals if needed. */
- if (!is_gimple_reg (result))
- continue;
- FOR_EACH_IMM_USE_STMT (stmt, imm_iter, result)
- {
- if (gimple_code (stmt) != GIMPLE_PHI)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file,
- "PHI result has use in non-PHI statement.\n");
- ok = false;
- BREAK_FROM_IMM_USE_STMT (imm_iter);
- }
- else
- FOR_EACH_IMM_USE_ON_STMT (imm_use, imm_iter)
- {
- edge e;
- e = gimple_phi_arg_edge (stmt, PHI_ARG_INDEX_FROM_USE (imm_use));
- if (e->src != bb)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "PHI has use in PHI not reached from"
- "empty cleanup itself.\n");
- ok = false;
- break;
- }
- }
- if (!ok)
- BREAK_FROM_IMM_USE_STMT (imm_iter);
- }
- if (!ok)
- return false;
+ gcc_assert (EDGE_COUNT (bb->succs) == 0);
}
- return ok;
-}
-static bool dominance_info_invalidated;
+ gsi_remove (&gsi, true);
-/* Information to pass into make_eh_edge_and_update_phi. */
+ return ret;
+}
-struct update_info
+static unsigned
+execute_lower_resx (void)
{
- basic_block bb_to_remove, bb;
- edge edge_to_remove;
-};
-
-/* DATA points to update-info structure.
- Like make_eh_edge create EH edge from DATA->bb to basic block containing
- handler of REGION. In addition also update PHI operands by copying
- operands from DATA->bb_to_remove. */
+ basic_block bb;
+ struct pointer_map_t *mnt_map;
+ bool dominance_invalidated = false;
+ bool any_rewritten = false;
-static void
-make_eh_edge_and_update_phi (struct eh_region *region, void *data)
-{
- struct update_info *info = (struct update_info *) data;
- edge e, e2;
- tree lab;
- basic_block src, dst;
- gimple_stmt_iterator si;
+ mnt_map = pointer_map_create ();
- lab = get_eh_region_tree_label (region);
+ FOR_EACH_BB (bb)
+ {
+ gimple last = last_stmt (bb);
+ if (last && is_gimple_resx (last))
+ {
+ dominance_invalidated |= lower_resx (bb, last, mnt_map);
+ any_rewritten = true;
+ }
+ }
- src = info->bb;
- dst = label_to_block (lab);
+ pointer_map_destroy (mnt_map);
- e = find_edge (src, dst);
- if (e)
+ if (dominance_invalidated)
{
- gcc_assert (e->flags & EDGE_EH);
- e->aux = e;
- return;
+ free_dominance_info (CDI_DOMINATORS);
+ free_dominance_info (CDI_POST_DOMINATORS);
}
- dominance_info_invalidated = true;
- e2 = find_edge (info->bb_to_remove, dst);
- e = make_edge (src, dst, EDGE_ABNORMAL | EDGE_EH);
- e->aux = e;
- gcc_assert (e2);
- for (si = gsi_start_phis (dst); !gsi_end_p (si); gsi_next (&si))
+
+ return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
+}
+
+static bool
+gate_lower_resx (void)
+{
+ return flag_exceptions != 0;
+}
+
+struct gimple_opt_pass pass_lower_resx =
+{
+ {
+ GIMPLE_PASS,
+ "resx", /* name */
+ gate_lower_resx, /* gate */
+ execute_lower_resx, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_EH, /* tv_id */
+ PROP_gimple_lcf, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func | TODO_verify_flow /* todo_flags_finish */
+ }
+};
+
+
+/* At the end of inlining, we can lower EH_DISPATCH. Return true when
+ we have found some duplicate labels and removed some edges. */
+
+static bool
+lower_eh_dispatch (basic_block src, gimple stmt)
+{
+ gimple_stmt_iterator gsi;
+ int region_nr;
+ eh_region r;
+ tree filter, fn;
+ gimple x;
+ bool redirected = false;
+
+ region_nr = gimple_eh_dispatch_region (stmt);
+ r = get_eh_region_from_number (region_nr);
+
+ gsi = gsi_last_bb (src);
+
+ switch (r->type)
{
- gimple phi = gsi_stmt (si);
- tree use = USE_FROM_PTR (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e2));
- gimple def = (TREE_CODE (use) == SSA_NAME
- ? SSA_NAME_DEF_STMT (use) : NULL);
+ case ERT_TRY:
+ {
+ VEC (tree, heap) *labels = NULL;
+ tree default_label = NULL;
+ eh_catch c;
+ edge_iterator ei;
+ edge e;
+ struct pointer_set_t *seen_values = pointer_set_create ();
+
+ /* Collect the labels for a switch. Zero the post_landing_pad
+ field becase we'll no longer have anything keeping these labels
+ in existance and the optimizer will be free to merge these
+ blocks at will. */
+ for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
+ {
+ tree tp_node, flt_node, lab = c->label;
+ bool have_label = false;
- if (def && gimple_bb (def) == info->bb_to_remove)
- {
- use = USE_FROM_PTR (PHI_ARG_DEF_PTR_FROM_EDGE (def,
- info->edge_to_remove));
- gcc_assert (info->bb_to_remove == info->edge_to_remove->dest);
- def = TREE_CODE (use) == SSA_NAME ? SSA_NAME_DEF_STMT (use) : NULL;
- gcc_assert (!def
- || gimple_bb (def) != info->bb_to_remove
- || !is_gimple_reg (use));
- }
- SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e), use);
+ c->label = NULL;
+ tp_node = c->type_list;
+ flt_node = c->filter_list;
+
+ if (tp_node == NULL)
+ {
+ default_label = lab;
+ break;
+ }
+ do
+ {
+ /* Filter out duplicate labels that arise when this handler
+ is shadowed by an earlier one. When no labels are
+ attached to the handler anymore, we remove
+ the corresponding edge and then we delete unreachable
+ blocks at the end of this pass. */
+ if (! pointer_set_contains (seen_values, TREE_VALUE (flt_node)))
+ {
+ tree t = build3 (CASE_LABEL_EXPR, void_type_node,
+ TREE_VALUE (flt_node), NULL, lab);
+ VEC_safe_push (tree, heap, labels, t);
+ pointer_set_insert (seen_values, TREE_VALUE (flt_node));
+ have_label = true;
+ }
+
+ tp_node = TREE_CHAIN (tp_node);
+ flt_node = TREE_CHAIN (flt_node);
+ }
+ while (tp_node);
+ if (! have_label)
+ {
+ remove_edge (find_edge (src, label_to_block (lab)));
+ redirected = true;
+ }
+ }
+
+ /* Clean up the edge flags. */
+ FOR_EACH_EDGE (e, ei, src->succs)
+ {
+ if (e->flags & EDGE_FALLTHRU)
+ {
+ /* If there was no catch-all, use the fallthru edge. */
+ if (default_label == NULL)
+ default_label = gimple_block_label (e->dest);
+ e->flags &= ~EDGE_FALLTHRU;
+ }
+ }
+ gcc_assert (default_label != NULL);
+
+ /* Don't generate a switch if there's only a default case.
+ This is common in the form of try { A; } catch (...) { B; }. */
+ if (labels == NULL)
+ {
+ e = single_succ_edge (src);
+ e->flags |= EDGE_FALLTHRU;
+ }
+ else
+ {
+ fn = implicit_built_in_decls[BUILT_IN_EH_FILTER];
+ x = gimple_build_call (fn, 1, build_int_cst (NULL, region_nr));
+ filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
+ filter = make_ssa_name (filter, x);
+ gimple_call_set_lhs (x, filter);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+
+ /* Turn the default label into a default case. */
+ default_label = build3 (CASE_LABEL_EXPR, void_type_node,
+ NULL, NULL, default_label);
+ sort_case_labels (labels);
+
+ x = gimple_build_switch_vec (filter, default_label, labels);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+
+ VEC_free (tree, heap, labels);
+ }
+ pointer_set_destroy (seen_values);
+ }
+ break;
+
+ case ERT_ALLOWED_EXCEPTIONS:
+ {
+ edge b_e = BRANCH_EDGE (src);
+ edge f_e = FALLTHRU_EDGE (src);
+
+ fn = implicit_built_in_decls[BUILT_IN_EH_FILTER];
+ x = gimple_build_call (fn, 1, build_int_cst (NULL, region_nr));
+ filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL);
+ filter = make_ssa_name (filter, x);
+ gimple_call_set_lhs (x, filter);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+
+ r->u.allowed.label = NULL;
+ x = gimple_build_cond (EQ_EXPR, filter,
+ build_int_cst (TREE_TYPE (filter),
+ r->u.allowed.filter),
+ NULL_TREE, NULL_TREE);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+
+ b_e->flags = b_e->flags | EDGE_TRUE_VALUE;
+ f_e->flags = (f_e->flags & ~EDGE_FALLTHRU) | EDGE_FALSE_VALUE;
+ }
+ break;
+
+ default:
+ gcc_unreachable ();
}
+
+ /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
+ gsi_remove (&gsi, true);
+ return redirected;
}
-/* Make EH edges corresponding to STMT while updating PHI nodes after removal
- empty cleanup BB_TO_REMOVE joined to BB containing STMT
- by EDGE_TO_REMOVE. */
+static unsigned
+execute_lower_eh_dispatch (void)
+{
+ basic_block bb;
+ bool any_rewritten = false;
+ bool redirected = false;
+
+ assign_filter_values ();
+
+ FOR_EACH_BB (bb)
+ {
+ gimple last = last_stmt (bb);
+ if (last && gimple_code (last) == GIMPLE_EH_DISPATCH)
+ {
+ redirected |= lower_eh_dispatch (bb, last);
+ any_rewritten = true;
+ }
+ }
+
+ if (redirected)
+ delete_unreachable_blocks ();
+ return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
+}
+
+static bool
+gate_lower_eh_dispatch (void)
+{
+ return cfun->eh->region_tree != NULL;
+}
+
+struct gimple_opt_pass pass_lower_eh_dispatch =
+{
+ {
+ GIMPLE_PASS,
+ "ehdisp", /* name */
+ gate_lower_eh_dispatch, /* gate */
+ execute_lower_eh_dispatch, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_EH, /* tv_id */
+ PROP_gimple_lcf, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func | TODO_verify_flow /* todo_flags_finish */
+ }
+};
+\f
+/* Walk statements, see what regions are really referenced and remove
+ those that are unused. */
static void
-update_eh_edges (gimple stmt, basic_block bb_to_remove, edge edge_to_remove)
+remove_unreachable_handlers (void)
{
- int region_nr;
- bool is_resx;
- bool inlinable = false;
- struct update_info info;
- edge_iterator ei;
- edge e;
- int probability_sum = 0;
+ sbitmap r_reachable, lp_reachable;
+ eh_region region;
+ eh_landing_pad lp;
+ basic_block bb;
+ int lp_nr, r_nr;
+
+ r_reachable = sbitmap_alloc (VEC_length (eh_region, cfun->eh->region_array));
+ lp_reachable
+ = sbitmap_alloc (VEC_length (eh_landing_pad, cfun->eh->lp_array));
+ sbitmap_zero (r_reachable);
+ sbitmap_zero (lp_reachable);
+
+ FOR_EACH_BB (bb)
+ {
+ gimple_stmt_iterator gsi = gsi_start_bb (bb);
+
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+ lp_nr = lookup_stmt_eh_lp (stmt);
+
+ /* Negative LP numbers are MUST_NOT_THROW regions which
+ are not considered BB enders. */
+ if (lp_nr < 0)
+ SET_BIT (r_reachable, -lp_nr);
- info.bb_to_remove = bb_to_remove;
- info.bb = gimple_bb (stmt);
- info.edge_to_remove = edge_to_remove;
+ /* Positive LP numbers are real landing pads, are are BB enders. */
+ else if (lp_nr > 0)
+ {
+ gcc_assert (gsi_one_before_end_p (gsi));
+ region = get_eh_region_from_lp_number (lp_nr);
+ SET_BIT (r_reachable, region->index);
+ SET_BIT (lp_reachable, lp_nr);
+ }
+ }
+ }
- if (gimple_code (stmt) == GIMPLE_RESX)
+ if (dump_file)
{
- region_nr = gimple_resx_region (stmt);
- is_resx = true;
+ fprintf (dump_file, "Before removal of unreachable regions:\n");
+ dump_eh_tree (dump_file, cfun);
+ fprintf (dump_file, "Reachable regions: ");
+ dump_sbitmap_file (dump_file, r_reachable);
+ fprintf (dump_file, "Reachable landing pads: ");
+ dump_sbitmap_file (dump_file, lp_reachable);
}
- else
+
+ for (r_nr = 1;
+ VEC_iterate (eh_region, cfun->eh->region_array, r_nr, region); ++r_nr)
+ if (region && !TEST_BIT (r_reachable, r_nr))
+ {
+ if (dump_file)
+ fprintf (dump_file, "Removing unreachable region %d\n", r_nr);
+ remove_eh_handler (region);
+ }
+
+ for (lp_nr = 1;
+ VEC_iterate (eh_landing_pad, cfun->eh->lp_array, lp_nr, lp); ++lp_nr)
+ if (lp && !TEST_BIT (lp_reachable, lp_nr))
+ {
+ if (dump_file)
+ fprintf (dump_file, "Removing unreachable landing pad %d\n", lp_nr);
+ remove_eh_landing_pad (lp);
+ }
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n");
+ dump_eh_tree (dump_file, cfun);
+ fprintf (dump_file, "\n\n");
+ }
+
+ sbitmap_free (r_reachable);
+ sbitmap_free (lp_reachable);
+
+#ifdef ENABLE_CHECKING
+ verify_eh_tree (cfun);
+#endif
+}
+
+/* Remove regions that do not have landing pads. This assumes
+ that remove_unreachable_handlers has already been run, and
+ that we've just manipulated the landing pads since then. */
+
+static void
+remove_unreachable_handlers_no_lp (void)
+{
+ eh_region r;
+ int i;
+
+ for (i = 1; VEC_iterate (eh_region, cfun->eh->region_array, i, r); ++i)
+ if (r && r->landing_pads == NULL && r->type != ERT_MUST_NOT_THROW)
+ {
+ if (dump_file)
+ fprintf (dump_file, "Removing unreachable region %d\n", i);
+ remove_eh_handler (r);
+ }
+}
+
+/* Undo critical edge splitting on an EH landing pad. Earlier, we
+ optimisticaly split all sorts of edges, including EH edges. The
+ optimization passes in between may not have needed them; if not,
+ we should undo the split.
+
+ Recognize this case by having one EH edge incoming to the BB and
+ one normal edge outgoing; BB should be empty apart from the
+ post_landing_pad label.
+
+ Note that this is slightly different from the empty handler case
+ handled by cleanup_empty_eh, in that the actual handler may yet
+ have actual code but the landing pad has been separated from the
+ handler. As such, cleanup_empty_eh relies on this transformation
+ having been done first. */
+
+static bool
+unsplit_eh (eh_landing_pad lp)
+{
+ basic_block bb = label_to_block (lp->post_landing_pad);
+ gimple_stmt_iterator gsi;
+ edge e_in, e_out;
+
+ /* Quickly check the edge counts on BB for singularity. */
+ if (EDGE_COUNT (bb->preds) != 1 || EDGE_COUNT (bb->succs) != 1)
+ return false;
+ e_in = EDGE_PRED (bb, 0);
+ e_out = EDGE_SUCC (bb, 0);
+
+ /* Input edge must be EH and output edge must be normal. */
+ if ((e_in->flags & EDGE_EH) == 0 || (e_out->flags & EDGE_EH) != 0)
+ return false;
+
+ /* The block must be empty except for the labels and debug insns. */
+ gsi = gsi_after_labels (bb);
+ if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
+ gsi_next_nondebug (&gsi);
+ if (!gsi_end_p (gsi))
+ return false;
+
+ /* The destination block must not already have a landing pad
+ for a different region. */
+ for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
{
- region_nr = lookup_stmt_eh_region (stmt);
- if (region_nr < 0)
- return;
- is_resx = false;
- inlinable = inlinable_call_p (stmt);
+ gimple stmt = gsi_stmt (gsi);
+ tree lab;
+ int lp_nr;
+
+ if (gimple_code (stmt) != GIMPLE_LABEL)
+ break;
+ lab = gimple_label_label (stmt);
+ lp_nr = EH_LANDING_PAD_NR (lab);
+ if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
+ return false;
}
- /* First add new edges as neccesary. */
- foreach_reachable_handler (region_nr, is_resx, inlinable,
- make_eh_edge_and_update_phi, &info);
+ /* The new destination block must not already be a destination of
+ the source block, lest we merge fallthru and eh edges and get
+ all sorts of confused. */
+ if (find_edge (e_in->src, e_out->dest))
+ return false;
- /* And remove edges we didn't marked. */
- for (ei = ei_start (info.bb->succs); (e = ei_safe_edge (ei)); )
+ /* ??? We can get degenerate phis due to cfg cleanups. I would have
+ thought this should have been cleaned up by a phicprop pass, but
+ that doesn't appear to handle virtuals. Propagate by hand. */
+ if (!gimple_seq_empty_p (phi_nodes (bb)))
{
- if ((e->flags & EDGE_EH) && !e->aux && e != edge_to_remove)
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
{
- dominance_info_invalidated = true;
- remove_edge (e);
- }
- else
- {
- e->aux = NULL;
- probability_sum += e->probability;
- ei_next (&ei);
+ gimple use_stmt, phi = gsi_stmt (gsi);
+ tree lhs = gimple_phi_result (phi);
+ tree rhs = gimple_phi_arg_def (phi, 0);
+ use_operand_p use_p;
+ imm_use_iterator iter;
+
+ FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
+ {
+ FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+ SET_USE (use_p, rhs);
+ }
+
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
+
+ remove_phi_node (&gsi, true);
}
}
- /* Make CFG profile more consistent assuming that exception will resume to
- first available EH handler. In practice this makes little difference, but
- we get fewer consistency errors in the dumps. */
- if (is_resx && EDGE_COUNT (info.bb->succs) && !probability_sum)
- EDGE_SUCC (info.bb, 0)->probability = REG_BR_PROB_BASE;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Unsplit EH landing pad %d to block %i.\n",
+ lp->index, e_out->dest->index);
+
+ /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
+ a successor edge, humor it. But do the real CFG change with the
+ predecessor of E_OUT in order to preserve the ordering of arguments
+ to the PHI nodes in E_OUT->DEST. */
+ redirect_eh_edge_1 (e_in, e_out->dest, false);
+ redirect_edge_pred (e_out, e_in->src);
+ e_out->flags = e_in->flags;
+ e_out->probability = e_in->probability;
+ e_out->count = e_in->count;
+ remove_edge (e_in);
+
+ return true;
}
-/* Look for basic blocks containing empty exception handler and remove them.
- This is similar to jump forwarding, just across EH edges. */
+/* Examine each landing pad block and see if it matches unsplit_eh. */
static bool
-cleanup_empty_eh (basic_block bb)
+unsplit_all_eh (void)
{
- int region;
- gimple_stmt_iterator si;
+ bool changed = false;
+ eh_landing_pad lp;
+ int i;
+
+ for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
+ if (lp)
+ changed |= unsplit_eh (lp);
+
+ return changed;
+}
- /* When handler of EH region winds up to be empty, we can safely
- remove it. This leads to inner EH regions to be redirected
- to outer one, if present in function. So we need to rebuild
- EH edges in all sources. */
- if ((region = tree_empty_eh_handler_p (bb))
- && all_phis_safe_to_merge (bb))
+/* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
+ to OLD_BB to NEW_BB; return true on success, false on failure.
+
+ OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
+ PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
+ Virtual PHIs may be deleted and marked for renaming. */
+
+static bool
+cleanup_empty_eh_merge_phis (basic_block new_bb, basic_block old_bb,
+ edge old_bb_out, bool change_region)
+{
+ gimple_stmt_iterator ngsi, ogsi;
+ edge_iterator ei;
+ edge e;
+ bitmap rename_virts;
+ bitmap ophi_handled;
+
+ FOR_EACH_EDGE (e, ei, old_bb->preds)
+ redirect_edge_var_map_clear (e);
+
+ ophi_handled = BITMAP_ALLOC (NULL);
+ rename_virts = BITMAP_ALLOC (NULL);
+
+ /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
+ for the edges we're going to move. */
+ for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); gsi_next (&ngsi))
{
- edge e;
+ gimple ophi, nphi = gsi_stmt (ngsi);
+ tree nresult, nop;
- remove_eh_region (region);
+ nresult = gimple_phi_result (nphi);
+ nop = gimple_phi_arg_def (nphi, old_bb_out->dest_idx);
- while ((e = ei_safe_edge (ei_start (bb->preds))))
+ /* Find the corresponding PHI in OLD_BB so we can forward-propagate
+ the source ssa_name. */
+ ophi = NULL;
+ for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
{
- basic_block src = e->src;
- gcc_assert (e->flags & EDGE_EH);
- if (stmt_can_throw_internal (last_stmt (src)))
- update_eh_edges (last_stmt (src), bb, e);
- remove_edge (e);
+ ophi = gsi_stmt (ogsi);
+ if (gimple_phi_result (ophi) == nop)
+ break;
+ ophi = NULL;
}
- if (dump_file)
- fprintf (dump_file, "Empty EH handler %i removed\n", region);
- /* Verify that we eliminated all uses of PHI we are going to remove.
- If we didn't, rebuild SSA on affected variable (this is allowed only
- for virtuals). */
- for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
- {
- gimple phi = gsi_stmt (si);
- tree result = gimple_phi_result (phi);
- if (!has_zero_uses (result))
+ /* If we did find the corresponding PHI, copy those inputs. */
+ if (ophi)
+ {
+ bitmap_set_bit (ophi_handled, SSA_NAME_VERSION (nop));
+ FOR_EACH_EDGE (e, ei, old_bb->preds)
{
- use_operand_p use_p;
- imm_use_iterator iter;
- gimple stmt;
+ location_t oloc;
+ tree oop;
+
+ if ((e->flags & EDGE_EH) == 0)
+ continue;
+ oop = gimple_phi_arg_def (ophi, e->dest_idx);
+ oloc = gimple_phi_arg_location (ophi, e->dest_idx);
+ redirect_edge_var_map_add (e, nresult, oop, oloc);
+ }
+ }
+ /* If we didn't find the PHI, but it's a VOP, remember to rename
+ it later, assuming all other tests succeed. */
+ else if (!is_gimple_reg (nresult))
+ bitmap_set_bit (rename_virts, SSA_NAME_VERSION (nresult));
+ /* If we didn't find the PHI, and it's a real variable, we know
+ from the fact that OLD_BB is tree_empty_eh_handler_p that the
+ variable is unchanged from input to the block and we can simply
+ re-use the input to NEW_BB from the OLD_BB_OUT edge. */
+ else
+ {
+ location_t nloc
+ = gimple_phi_arg_location (nphi, old_bb_out->dest_idx);
+ FOR_EACH_EDGE (e, ei, old_bb->preds)
+ redirect_edge_var_map_add (e, nresult, nop, nloc);
+ }
+ }
- FOR_EACH_IMM_USE_STMT (stmt, iter, result)
- {
- /* We have use, see if it won't disappear after
- removing BB. */
- if (gimple_bb (stmt) == bb)
- continue;
- if (gimple_code (stmt) == GIMPLE_PHI)
- {
- bool bad = false;
-
- FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
- if (gimple_phi_arg_edge (stmt,
- PHI_ARG_INDEX_FROM_USE (use_p))->src != bb)
- {
- bad = true;
- break;
- }
-
- if (!bad)
- continue;
- }
-
- gcc_assert (!is_gimple_reg (result));
- mark_sym_for_renaming (SSA_NAME_VAR (result));
- /* As we are going to delete this block we will release all
- defs which makes the immediate uses on use stmts invalid.
- Avoid that by replacing all uses with the bare variable
- and updating the stmts. */
- FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
- SET_USE (use_p, SSA_NAME_VAR (result));
- update_stmt (stmt);
- }
+ /* Second, verify that all PHIs from OLD_BB have been handled. If not,
+ we don't know what values from the other edges into NEW_BB to use. */
+ for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi))
+ {
+ gimple ophi = gsi_stmt (ogsi);
+ tree oresult = gimple_phi_result (ophi);
+ if (!bitmap_bit_p (ophi_handled, SSA_NAME_VERSION (oresult)))
+ goto fail;
+ }
+
+ /* At this point we know that the merge will succeed. Remove the PHI
+ nodes for the virtuals that we want to rename. */
+ if (!bitmap_empty_p (rename_virts))
+ {
+ for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); )
+ {
+ gimple nphi = gsi_stmt (ngsi);
+ tree nresult = gimple_phi_result (nphi);
+ if (bitmap_bit_p (rename_virts, SSA_NAME_VERSION (nresult)))
+ {
+ mark_virtual_phi_result_for_renaming (nphi);
+ remove_phi_node (&ngsi, true);
}
+ else
+ gsi_next (&ngsi);
}
- delete_basic_block (bb);
+ }
+
+ /* Finally, move the edges and update the PHIs. */
+ for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)); )
+ if (e->flags & EDGE_EH)
+ {
+ redirect_eh_edge_1 (e, new_bb, change_region);
+ redirect_edge_succ (e, new_bb);
+ flush_pending_stmts (e);
+ }
+ else
+ ei_next (&ei);
+
+ BITMAP_FREE (ophi_handled);
+ BITMAP_FREE (rename_virts);
+ return true;
+
+ fail:
+ FOR_EACH_EDGE (e, ei, old_bb->preds)
+ redirect_edge_var_map_clear (e);
+ BITMAP_FREE (ophi_handled);
+ BITMAP_FREE (rename_virts);
+ return false;
+}
+
+/* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
+ old region to NEW_REGION at BB. */
+
+static void
+cleanup_empty_eh_move_lp (basic_block bb, edge e_out,
+ eh_landing_pad lp, eh_region new_region)
+{
+ gimple_stmt_iterator gsi;
+ eh_landing_pad *pp;
+
+ for (pp = &lp->region->landing_pads; *pp != lp; pp = &(*pp)->next_lp)
+ continue;
+ *pp = lp->next_lp;
+
+ lp->region = new_region;
+ lp->next_lp = new_region->landing_pads;
+ new_region->landing_pads = lp;
+
+ /* Delete the RESX that was matched within the empty handler block. */
+ gsi = gsi_last_bb (bb);
+ mark_virtual_ops_for_renaming (gsi_stmt (gsi));
+ gsi_remove (&gsi, true);
+
+ /* Clean up E_OUT for the fallthru. */
+ e_out->flags = (e_out->flags & ~EDGE_EH) | EDGE_FALLTHRU;
+ e_out->probability = REG_BR_PROB_BASE;
+}
+
+/* A subroutine of cleanup_empty_eh. Handle more complex cases of
+ unsplitting than unsplit_eh was prepared to handle, e.g. when
+ multiple incoming edges and phis are involved. */
+
+static bool
+cleanup_empty_eh_unsplit (basic_block bb, edge e_out, eh_landing_pad lp)
+{
+ gimple_stmt_iterator gsi;
+ tree lab;
+
+ /* We really ought not have totally lost everything following
+ a landing pad label. Given that BB is empty, there had better
+ be a successor. */
+ gcc_assert (e_out != NULL);
+
+ /* The destination block must not already have a landing pad
+ for a different region. */
+ lab = NULL;
+ for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+ int lp_nr;
+
+ if (gimple_code (stmt) != GIMPLE_LABEL)
+ break;
+ lab = gimple_label_label (stmt);
+ lp_nr = EH_LANDING_PAD_NR (lab);
+ if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region)
+ return false;
+ }
+
+ /* Attempt to move the PHIs into the successor block. */
+ if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, false))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file,
+ "Unsplit EH landing pad %d to block %i "
+ "(via cleanup_empty_eh).\n",
+ lp->index, e_out->dest->index);
+ return true;
+ }
+
+ return false;
+}
+
+/* Examine the block associated with LP to determine if it's an empty
+ handler for its EH region. If so, attempt to redirect EH edges to
+ an outer region. Return true the CFG was updated in any way. This
+ is similar to jump forwarding, just across EH edges. */
+
+static bool
+cleanup_empty_eh (eh_landing_pad lp)
+{
+ basic_block bb = label_to_block (lp->post_landing_pad);
+ gimple_stmt_iterator gsi;
+ gimple resx;
+ eh_region new_region;
+ edge_iterator ei;
+ edge e, e_out;
+ bool has_non_eh_pred;
+ int new_lp_nr;
+
+ /* There can be zero or one edges out of BB. This is the quickest test. */
+ switch (EDGE_COUNT (bb->succs))
+ {
+ case 0:
+ e_out = NULL;
+ break;
+ case 1:
+ e_out = EDGE_SUCC (bb, 0);
+ break;
+ default:
+ return false;
+ }
+ gsi = gsi_after_labels (bb);
+
+ /* Make sure to skip debug statements. */
+ if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
+ gsi_next_nondebug (&gsi);
+
+ /* If the block is totally empty, look for more unsplitting cases. */
+ if (gsi_end_p (gsi))
+ return cleanup_empty_eh_unsplit (bb, e_out, lp);
+
+ /* The block should consist only of a single RESX statement. */
+ resx = gsi_stmt (gsi);
+ if (!is_gimple_resx (resx))
+ return false;
+ gcc_assert (gsi_one_before_end_p (gsi));
+
+ /* Determine if there are non-EH edges, or resx edges into the handler. */
+ has_non_eh_pred = false;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (!(e->flags & EDGE_EH))
+ has_non_eh_pred = true;
+
+ /* Find the handler that's outer of the empty handler by looking at
+ where the RESX instruction was vectored. */
+ new_lp_nr = lookup_stmt_eh_lp (resx);
+ new_region = get_eh_region_from_lp_number (new_lp_nr);
+
+ /* If there's no destination region within the current function,
+ redirection is trivial via removing the throwing statements from
+ the EH region, removing the EH edges, and allowing the block
+ to go unreachable. */
+ if (new_region == NULL)
+ {
+ gcc_assert (e_out == NULL);
+ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
+ if (e->flags & EDGE_EH)
+ {
+ gimple stmt = last_stmt (e->src);
+ remove_stmt_from_eh_lp (stmt);
+ remove_edge (e);
+ }
+ else
+ ei_next (&ei);
+ goto succeed;
+ }
+
+ /* If the destination region is a MUST_NOT_THROW, allow the runtime
+ to handle the abort and allow the blocks to go unreachable. */
+ if (new_region->type == ERT_MUST_NOT_THROW)
+ {
+ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
+ if (e->flags & EDGE_EH)
+ {
+ gimple stmt = last_stmt (e->src);
+ remove_stmt_from_eh_lp (stmt);
+ add_stmt_to_eh_lp (stmt, new_lp_nr);
+ remove_edge (e);
+ }
+ else
+ ei_next (&ei);
+ goto succeed;
+ }
+
+ /* Try to redirect the EH edges and merge the PHIs into the destination
+ landing pad block. If the merge succeeds, we'll already have redirected
+ all the EH edges. The handler itself will go unreachable if there were
+ no normal edges. */
+ if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out, true))
+ goto succeed;
+
+ /* Finally, if all input edges are EH edges, then we can (potentially)
+ reduce the number of transfers from the runtime by moving the landing
+ pad from the original region to the new region. This is a win when
+ we remove the last CLEANUP region along a particular exception
+ propagation path. Since nothing changes except for the region with
+ which the landing pad is associated, the PHI nodes do not need to be
+ adjusted at all. */
+ if (!has_non_eh_pred)
+ {
+ cleanup_empty_eh_move_lp (bb, e_out, lp, new_region);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Empty EH handler %i moved to EH region %i.\n",
+ lp->index, new_region->index);
+
+ /* ??? The CFG didn't change, but we may have rendered the
+ old EH region unreachable. Trigger a cleanup there. */
return true;
}
+
return false;
+
+ succeed:
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Empty EH handler %i removed.\n", lp->index);
+ remove_eh_landing_pad (lp);
+ return true;
}
+/* Do a post-order traversal of the EH region tree. Examine each
+ post_landing_pad block and see if we can eliminate it as empty. */
+
+static bool
+cleanup_all_empty_eh (void)
+{
+ bool changed = false;
+ eh_landing_pad lp;
+ int i;
+
+ for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i)
+ if (lp)
+ changed |= cleanup_empty_eh (lp);
+
+ return changed;
+}
/* Perform cleanups and lowering of exception handling
1) cleanups regions with handlers doing nothing are optimized out
3) Info about regions that are containing instructions, and regions
reachable via local EH edges is collected
4) Eh tree is pruned for regions no longer neccesary.
- */
+
+ TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
+ Unify those that have the same failure decl and locus.
+*/
static unsigned int
-cleanup_eh (void)
+execute_cleanup_eh (void)
{
- bool changed = false;
- basic_block bb;
- int i;
+ /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
+ looking up unreachable landing pads. */
+ remove_unreachable_handlers ();
- if (!cfun->eh)
- return 0;
- if (dump_file)
+ /* Watch out for the region tree vanishing due to all unreachable. */
+ if (cfun->eh->region_tree && optimize)
{
- fprintf (dump_file, "Before cleanups:\n");
- dump_eh_tree (dump_file, cfun);
- }
+ bool changed = false;
- dominance_info_invalidated = false;
- /* We cannot use FOR_EACH_BB, since the basic blocks may get removed. */
- for (i = NUM_FIXED_BLOCKS; i < last_basic_block; i++)
- {
- bb = BASIC_BLOCK (i);
- if (bb)
- changed |= cleanup_empty_eh (bb);
- }
- if (dominance_info_invalidated)
- {
- free_dominance_info (CDI_DOMINATORS);
- free_dominance_info (CDI_POST_DOMINATORS);
- }
+ changed |= unsplit_all_eh ();
+ changed |= cleanup_all_empty_eh ();
- /* Removing contained cleanup can render MUST_NOT_THROW regions empty. */
- if (changed)
- delete_unreachable_blocks ();
+ if (changed)
+ {
+ free_dominance_info (CDI_DOMINATORS);
+ free_dominance_info (CDI_POST_DOMINATORS);
- tree_remove_unreachable_handlers ();
- if (dump_file)
- {
- fprintf (dump_file, "After cleanups:\n");
- dump_eh_tree (dump_file, cfun);
+ /* We delayed all basic block deletion, as we may have performed
+ cleanups on EH edges while non-EH edges were still present. */
+ delete_unreachable_blocks ();
+
+ /* We manipulated the landing pads. Remove any region that no
+ longer has a landing pad. */
+ remove_unreachable_handlers_no_lp ();
+
+ return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
+ }
}
- return (changed ? TODO_cleanup_cfg | TODO_update_ssa : 0);
+ return 0;
+}
+
+static bool
+gate_cleanup_eh (void)
+{
+ return cfun->eh != NULL && cfun->eh->region_tree != NULL;
}
struct gimple_opt_pass pass_cleanup_eh = {
{
GIMPLE_PASS,
"ehcleanup", /* name */
- NULL, /* gate */
- cleanup_eh, /* execute */
+ gate_cleanup_eh, /* gate */
+ execute_cleanup_eh, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TODO_dump_func /* todo_flags_finish */
}
};
+\f
+/* Verify that BB containing STMT as the last statement, has precisely the
+ edge that make_eh_edges would create. */
+
+bool
+verify_eh_edges (gimple stmt)
+{
+ basic_block bb = gimple_bb (stmt);
+ eh_landing_pad lp = NULL;
+ int lp_nr;
+ edge_iterator ei;
+ edge e, eh_edge;
+
+ lp_nr = lookup_stmt_eh_lp (stmt);
+ if (lp_nr > 0)
+ lp = get_eh_landing_pad_from_number (lp_nr);
+
+ eh_edge = NULL;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if (e->flags & EDGE_EH)
+ {
+ if (eh_edge)
+ {
+ error ("BB %i has multiple EH edges", bb->index);
+ return true;
+ }
+ else
+ eh_edge = e;
+ }
+ }
+
+ if (lp == NULL)
+ {
+ if (eh_edge)
+ {
+ error ("BB %i can not throw but has an EH edge", bb->index);
+ return true;
+ }
+ return false;
+ }
+
+ if (!stmt_could_throw_p (stmt))
+ {
+ error ("BB %i last statement has incorrectly set lp", bb->index);
+ return true;
+ }
+
+ if (eh_edge == NULL)
+ {
+ error ("BB %i is missing an EH edge", bb->index);
+ return true;
+ }
+
+ if (eh_edge->dest != label_to_block (lp->post_landing_pad))
+ {
+ error ("Incorrect EH edge %i->%i", bb->index, eh_edge->dest->index);
+ return true;
+ }
+
+ return false;
+}
+
+/* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
+
+bool
+verify_eh_dispatch_edge (gimple stmt)
+{
+ eh_region r;
+ eh_catch c;
+ basic_block src, dst;
+ bool want_fallthru = true;
+ edge_iterator ei;
+ edge e, fall_edge;
+
+ r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt));
+ src = gimple_bb (stmt);
+
+ FOR_EACH_EDGE (e, ei, src->succs)
+ gcc_assert (e->aux == NULL);
+
+ switch (r->type)
+ {
+ case ERT_TRY:
+ for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
+ {
+ dst = label_to_block (c->label);
+ e = find_edge (src, dst);
+ if (e == NULL)
+ {
+ error ("BB %i is missing an edge", src->index);
+ return true;
+ }
+ e->aux = (void *)e;
+
+ /* A catch-all handler doesn't have a fallthru. */
+ if (c->type_list == NULL)
+ {
+ want_fallthru = false;
+ break;
+ }
+ }
+ break;
+
+ case ERT_ALLOWED_EXCEPTIONS:
+ dst = label_to_block (r->u.allowed.label);
+ e = find_edge (src, dst);
+ if (e == NULL)
+ {
+ error ("BB %i is missing an edge", src->index);
+ return true;
+ }
+ e->aux = (void *)e;
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+
+ fall_edge = NULL;
+ FOR_EACH_EDGE (e, ei, src->succs)
+ {
+ if (e->flags & EDGE_FALLTHRU)
+ {
+ if (fall_edge != NULL)
+ {
+ error ("BB %i too many fallthru edges", src->index);
+ return true;
+ }
+ fall_edge = e;
+ }
+ else if (e->aux)
+ e->aux = NULL;
+ else
+ {
+ error ("BB %i has incorrect edge", src->index);
+ return true;
+ }
+ }
+ if ((fall_edge != NULL) ^ want_fallthru)
+ {
+ error ("BB %i has incorrect fallthru edge", src->index);
+ return true;
+ }
+
+ return false;
+}
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