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cfghooks.c
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/* Hooks for cfg representation specific functions.
Copyright (C) 2003-2013 Free Software Foundation, Inc.
Contributed by Sebastian Pop <[email protected]>
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "dumpfile.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "basic-block.h"
#include "tree-flow.h"
#include "timevar.h"
#include "diagnostic-core.h"
#include "cfgloop.h"
/* A pointer to one of the hooks containers. */
static struct cfg_hooks *cfg_hooks;
/* Initialization of functions specific to the rtl IR. */
void
rtl_register_cfg_hooks (void)
{
cfg_hooks = &rtl_cfg_hooks;
}
/* Initialization of functions specific to the rtl IR. */
void
cfg_layout_rtl_register_cfg_hooks (void)
{
cfg_hooks = &cfg_layout_rtl_cfg_hooks;
}
/* Initialization of functions specific to the tree IR. */
void
gimple_register_cfg_hooks (void)
{
cfg_hooks = &gimple_cfg_hooks;
}
struct cfg_hooks
get_cfg_hooks (void)
{
return *cfg_hooks;
}
void
set_cfg_hooks (struct cfg_hooks new_cfg_hooks)
{
*cfg_hooks = new_cfg_hooks;
}
/* Returns current ir type. */
enum ir_type
current_ir_type (void)
{
if (cfg_hooks == &gimple_cfg_hooks)
return IR_GIMPLE;
else if (cfg_hooks == &rtl_cfg_hooks)
return IR_RTL_CFGRTL;
else if (cfg_hooks == &cfg_layout_rtl_cfg_hooks)
return IR_RTL_CFGLAYOUT;
else
gcc_unreachable ();
}
/* Verify the CFG consistency.
Currently it does following: checks edge and basic block list correctness
and calls into IL dependent checking then. */
DEBUG_FUNCTION void
verify_flow_info (void)
{
size_t *edge_checksum;
int err = 0;
basic_block bb, last_bb_seen;
basic_block *last_visited;
timevar_push (TV_CFG_VERIFY);
last_visited = XCNEWVEC (basic_block, last_basic_block);
edge_checksum = XCNEWVEC (size_t, last_basic_block);
/* Check bb chain & numbers. */
last_bb_seen = ENTRY_BLOCK_PTR;
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb, NULL, next_bb)
{
if (bb != EXIT_BLOCK_PTR
&& bb != BASIC_BLOCK (bb->index))
{
error ("bb %d on wrong place", bb->index);
err = 1;
}
if (bb->prev_bb != last_bb_seen)
{
error ("prev_bb of %d should be %d, not %d",
bb->index, last_bb_seen->index, bb->prev_bb->index);
err = 1;
}
last_bb_seen = bb;
}
/* Now check the basic blocks (boundaries etc.) */
FOR_EACH_BB_REVERSE (bb)
{
int n_fallthru = 0;
edge e;
edge_iterator ei;
if (bb->loop_father != NULL && current_loops == NULL)
{
error ("verify_flow_info: Block %i has loop_father, but there are no loops",
bb->index);
err = 1;
}
if (bb->loop_father == NULL && current_loops != NULL)
{
error ("verify_flow_info: Block %i lacks loop_father", bb->index);
err = 1;
}
if (bb->count < 0)
{
error ("verify_flow_info: Wrong count of block %i %i",
bb->index, (int)bb->count);
err = 1;
}
if (bb->frequency < 0)
{
error ("verify_flow_info: Wrong frequency of block %i %i",
bb->index, bb->frequency);
err = 1;
}
FOR_EACH_EDGE (e, ei, bb->succs)
{
if (last_visited [e->dest->index] == bb)
{
error ("verify_flow_info: Duplicate edge %i->%i",
e->src->index, e->dest->index);
err = 1;
}
if (e->probability < 0 || e->probability > REG_BR_PROB_BASE)
{
error ("verify_flow_info: Wrong probability of edge %i->%i %i",
e->src->index, e->dest->index, e->probability);
err = 1;
}
if (e->count < 0)
{
error ("verify_flow_info: Wrong count of edge %i->%i %i",
e->src->index, e->dest->index, (int)e->count);
err = 1;
}
last_visited [e->dest->index] = bb;
if (e->flags & EDGE_FALLTHRU)
n_fallthru++;
if (e->src != bb)
{
error ("verify_flow_info: Basic block %d succ edge is corrupted",
bb->index);
fprintf (stderr, "Predecessor: ");
dump_edge_info (stderr, e, TDF_DETAILS, 0);
fprintf (stderr, "\nSuccessor: ");
dump_edge_info (stderr, e, TDF_DETAILS, 1);
fprintf (stderr, "\n");
err = 1;
}
edge_checksum[e->dest->index] += (size_t) e;
}
if (n_fallthru > 1)
{
error ("wrong amount of branch edges after unconditional jump %i", bb->index);
err = 1;
}
FOR_EACH_EDGE (e, ei, bb->preds)
{
if (e->dest != bb)
{
error ("basic block %d pred edge is corrupted", bb->index);
fputs ("Predecessor: ", stderr);
dump_edge_info (stderr, e, TDF_DETAILS, 0);
fputs ("\nSuccessor: ", stderr);
dump_edge_info (stderr, e, TDF_DETAILS, 1);
fputc ('\n', stderr);
err = 1;
}
if (ei.index != e->dest_idx)
{
error ("basic block %d pred edge is corrupted", bb->index);
error ("its dest_idx should be %d, not %d",
ei.index, e->dest_idx);
fputs ("Predecessor: ", stderr);
dump_edge_info (stderr, e, TDF_DETAILS, 0);
fputs ("\nSuccessor: ", stderr);
dump_edge_info (stderr, e, TDF_DETAILS, 1);
fputc ('\n', stderr);
err = 1;
}
edge_checksum[e->dest->index] -= (size_t) e;
}
}
/* Complete edge checksumming for ENTRY and EXIT. */
{
edge e;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
edge_checksum[e->dest->index] += (size_t) e;
FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
edge_checksum[e->dest->index] -= (size_t) e;
}
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
if (edge_checksum[bb->index])
{
error ("basic block %i edge lists are corrupted", bb->index);
err = 1;
}
last_bb_seen = ENTRY_BLOCK_PTR;
/* Clean up. */
free (last_visited);
free (edge_checksum);
if (cfg_hooks->verify_flow_info)
err |= cfg_hooks->verify_flow_info ();
if (err)
internal_error ("verify_flow_info failed");
timevar_pop (TV_CFG_VERIFY);
}
/* Print out one basic block BB to file OUTF. INDENT is printed at the
start of each new line. FLAGS are the TDF_* flags in dumpfile.h.
This function takes care of the purely graph related information.
The cfg hook for the active representation should dump
representation-specific information. */
void
dump_bb (FILE *outf, basic_block bb, int indent, int flags)
{
if (flags & TDF_BLOCKS)
dump_bb_info (outf, bb, indent, flags, true, false);
if (cfg_hooks->dump_bb)
cfg_hooks->dump_bb (outf, bb, indent, flags);
if (flags & TDF_BLOCKS)
dump_bb_info (outf, bb, indent, flags, false, true);
fputc ('\n', outf);
}
/* Dumps basic block BB to pretty-printer PP, for use as a label of
a DOT graph record-node. The implementation of this hook is
expected to write the label to the stream that is attached to PP.
Field separators between instructions are pipe characters printed
verbatim. Instructions should be written with some characters
escaped, using pp_write_text_as_dot_label_to_stream(). */
void
dump_bb_for_graph (pretty_printer *pp, basic_block bb)
{
if (!cfg_hooks->dump_bb_for_graph)
internal_error ("%s does not support dump_bb_for_graph",
cfg_hooks->name);
cfg_hooks->dump_bb_for_graph (pp, bb);
}
/* Dump the complete CFG to FILE. FLAGS are the TDF_* flags in dumpfile.h. */
void
dump_flow_info (FILE *file, int flags)
{
basic_block bb;
fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
FOR_ALL_BB (bb)
dump_bb (file, bb, 0, flags);
putc ('\n', file);
}
/* Like above, but dump to stderr. To be called from debuggers. */
void debug_flow_info (void);
DEBUG_FUNCTION void
debug_flow_info (void)
{
dump_flow_info (stderr, TDF_DETAILS);
}
/* Redirect edge E to the given basic block DEST and update underlying program
representation. Returns edge representing redirected branch (that may not
be equivalent to E in the case of duplicate edges being removed) or NULL
if edge is not easily redirectable for whatever reason. */
edge
redirect_edge_and_branch (edge e, basic_block dest)
{
edge ret;
if (!cfg_hooks->redirect_edge_and_branch)
internal_error ("%s does not support redirect_edge_and_branch",
cfg_hooks->name);
ret = cfg_hooks->redirect_edge_and_branch (e, dest);
/* If RET != E, then either the redirection failed, or the edge E
was removed since RET already lead to the same destination. */
if (current_loops != NULL && ret == e)
rescan_loop_exit (e, false, false);
return ret;
}
/* Returns true if it is possible to remove the edge E by redirecting it
to the destination of the other edge going from its source. */
bool
can_remove_branch_p (const_edge e)
{
if (!cfg_hooks->can_remove_branch_p)
internal_error ("%s does not support can_remove_branch_p",
cfg_hooks->name);
if (EDGE_COUNT (e->src->succs) != 2)
return false;
return cfg_hooks->can_remove_branch_p (e);
}
/* Removes E, by redirecting it to the destination of the other edge going
from its source. Can_remove_branch_p must be true for E, hence this
operation cannot fail. */
void
remove_branch (edge e)
{
edge other;
basic_block src = e->src;
int irr;
gcc_assert (EDGE_COUNT (e->src->succs) == 2);
other = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
irr = other->flags & EDGE_IRREDUCIBLE_LOOP;
e = redirect_edge_and_branch (e, other->dest);
gcc_assert (e != NULL);
e->flags &= ~EDGE_IRREDUCIBLE_LOOP;
e->flags |= irr;
}
/* Removes edge E from cfg. Unlike remove_branch, it does not update IL. */
void
remove_edge (edge e)
{
if (current_loops != NULL)
rescan_loop_exit (e, false, true);
/* This is probably not needed, but it doesn't hurt. */
/* FIXME: This should be called via a remove_edge hook. */
if (current_ir_type () == IR_GIMPLE)
redirect_edge_var_map_clear (e);
remove_edge_raw (e);
}
/* Like redirect_edge_succ but avoid possible duplicate edge. */
edge
redirect_edge_succ_nodup (edge e, basic_block new_succ)
{
edge s;
s = find_edge (e->src, new_succ);
if (s && s != e)
{
s->flags |= e->flags;
s->probability += e->probability;
if (s->probability > REG_BR_PROB_BASE)
s->probability = REG_BR_PROB_BASE;
s->count += e->count;
/* FIXME: This should be called via a hook and only for IR_GIMPLE. */
redirect_edge_var_map_dup (s, e);
remove_edge (e);
e = s;
}
else
redirect_edge_succ (e, new_succ);
return e;
}
/* Redirect the edge E to basic block DEST even if it requires creating
of a new basic block; then it returns the newly created basic block.
Aborts when redirection is impossible. */
basic_block
redirect_edge_and_branch_force (edge e, basic_block dest)
{
basic_block ret, src = e->src;
if (!cfg_hooks->redirect_edge_and_branch_force)
internal_error ("%s does not support redirect_edge_and_branch_force",
cfg_hooks->name);
if (current_loops != NULL)
rescan_loop_exit (e, false, true);
ret = cfg_hooks->redirect_edge_and_branch_force (e, dest);
if (ret != NULL && dom_info_available_p (CDI_DOMINATORS))
set_immediate_dominator (CDI_DOMINATORS, ret, src);
if (current_loops != NULL)
{
if (ret != NULL)
{
struct loop *loop
= find_common_loop (single_pred (ret)->loop_father,
single_succ (ret)->loop_father);
add_bb_to_loop (ret, loop);
}
else if (find_edge (src, dest) == e)
rescan_loop_exit (e, true, false);
}
return ret;
}
/* Splits basic block BB after the specified instruction I (but at least after
the labels). If I is NULL, splits just after labels. The newly created edge
is returned. The new basic block is created just after the old one. */
edge
split_block (basic_block bb, void *i)
{
basic_block new_bb;
edge res;
if (!cfg_hooks->split_block)
internal_error ("%s does not support split_block", cfg_hooks->name);
new_bb = cfg_hooks->split_block (bb, i);
if (!new_bb)
return NULL;
new_bb->count = bb->count;
new_bb->frequency = bb->frequency;
new_bb->discriminator = bb->discriminator;
if (dom_info_available_p (CDI_DOMINATORS))
{
redirect_immediate_dominators (CDI_DOMINATORS, bb, new_bb);
set_immediate_dominator (CDI_DOMINATORS, new_bb, bb);
}
if (current_loops != NULL)
{
add_bb_to_loop (new_bb, bb->loop_father);
if (bb->loop_father->latch == bb)
bb->loop_father->latch = new_bb;
}
res = make_single_succ_edge (bb, new_bb, EDGE_FALLTHRU);
if (bb->flags & BB_IRREDUCIBLE_LOOP)
{
new_bb->flags |= BB_IRREDUCIBLE_LOOP;
res->flags |= EDGE_IRREDUCIBLE_LOOP;
}
return res;
}
/* Splits block BB just after labels. The newly created edge is returned. */
edge
split_block_after_labels (basic_block bb)
{
return split_block (bb, NULL);
}
/* Moves block BB immediately after block AFTER. Returns false if the
movement was impossible. */
bool
move_block_after (basic_block bb, basic_block after)
{
bool ret;
if (!cfg_hooks->move_block_after)
internal_error ("%s does not support move_block_after", cfg_hooks->name);
ret = cfg_hooks->move_block_after (bb, after);
return ret;
}
/* Deletes the basic block BB. */
void
delete_basic_block (basic_block bb)
{
if (!cfg_hooks->delete_basic_block)
internal_error ("%s does not support delete_basic_block", cfg_hooks->name);
cfg_hooks->delete_basic_block (bb);
if (current_loops != NULL)
{
struct loop *loop = bb->loop_father;
/* If we remove the header or the latch of a loop, mark the loop for
removal by setting its header and latch to NULL. */
if (loop->latch == bb
|| loop->header == bb)
{
loop->header = NULL;
loop->latch = NULL;
loops_state_set (LOOPS_NEED_FIXUP);
}
remove_bb_from_loops (bb);
}
/* Remove the edges into and out of this block. Note that there may
indeed be edges in, if we are removing an unreachable loop. */
while (EDGE_COUNT (bb->preds) != 0)
remove_edge (EDGE_PRED (bb, 0));
while (EDGE_COUNT (bb->succs) != 0)
remove_edge (EDGE_SUCC (bb, 0));
if (dom_info_available_p (CDI_DOMINATORS))
delete_from_dominance_info (CDI_DOMINATORS, bb);
if (dom_info_available_p (CDI_POST_DOMINATORS))
delete_from_dominance_info (CDI_POST_DOMINATORS, bb);
/* Remove the basic block from the array. */
expunge_block (bb);
}
/* Splits edge E and returns the newly created basic block. */
basic_block
split_edge (edge e)
{
basic_block ret;
gcov_type count = e->count;
int freq = EDGE_FREQUENCY (e);
edge f;
bool irr = (e->flags & EDGE_IRREDUCIBLE_LOOP) != 0;
struct loop *loop;
basic_block src = e->src, dest = e->dest;
if (!cfg_hooks->split_edge)
internal_error ("%s does not support split_edge", cfg_hooks->name);
if (current_loops != NULL)
rescan_loop_exit (e, false, true);
ret = cfg_hooks->split_edge (e);
ret->count = count;
ret->frequency = freq;
single_succ_edge (ret)->probability = REG_BR_PROB_BASE;
single_succ_edge (ret)->count = count;
if (irr)
{
ret->flags |= BB_IRREDUCIBLE_LOOP;
single_pred_edge (ret)->flags |= EDGE_IRREDUCIBLE_LOOP;
single_succ_edge (ret)->flags |= EDGE_IRREDUCIBLE_LOOP;
}
if (dom_info_available_p (CDI_DOMINATORS))
set_immediate_dominator (CDI_DOMINATORS, ret, single_pred (ret));
if (dom_info_state (CDI_DOMINATORS) >= DOM_NO_FAST_QUERY)
{
/* There are two cases:
If the immediate dominator of e->dest is not e->src, it
remains unchanged.
If immediate dominator of e->dest is e->src, it may become
ret, provided that all other predecessors of e->dest are
dominated by e->dest. */
if (get_immediate_dominator (CDI_DOMINATORS, single_succ (ret))
== single_pred (ret))
{
edge_iterator ei;
FOR_EACH_EDGE (f, ei, single_succ (ret)->preds)
{
if (f == single_succ_edge (ret))
continue;
if (!dominated_by_p (CDI_DOMINATORS, f->src,
single_succ (ret)))
break;
}
if (!f)
set_immediate_dominator (CDI_DOMINATORS, single_succ (ret), ret);
}
}
if (current_loops != NULL)
{
loop = find_common_loop (src->loop_father, dest->loop_father);
add_bb_to_loop (ret, loop);
if (loop->latch == src)
loop->latch = ret;
}
return ret;
}
/* Creates a new basic block just after the basic block AFTER.
HEAD and END are the first and the last statement belonging
to the block. If both are NULL, an empty block is created. */
basic_block
create_basic_block (void *head, void *end, basic_block after)
{
basic_block ret;
if (!cfg_hooks->create_basic_block)
internal_error ("%s does not support create_basic_block", cfg_hooks->name);
ret = cfg_hooks->create_basic_block (head, end, after);
if (dom_info_available_p (CDI_DOMINATORS))
add_to_dominance_info (CDI_DOMINATORS, ret);
if (dom_info_available_p (CDI_POST_DOMINATORS))
add_to_dominance_info (CDI_POST_DOMINATORS, ret);
return ret;
}
/* Creates an empty basic block just after basic block AFTER. */
basic_block
create_empty_bb (basic_block after)
{
return create_basic_block (NULL, NULL, after);
}
/* Checks whether we may merge blocks BB1 and BB2. */
bool
can_merge_blocks_p (basic_block bb1, basic_block bb2)
{
bool ret;
if (!cfg_hooks->can_merge_blocks_p)
internal_error ("%s does not support can_merge_blocks_p", cfg_hooks->name);
ret = cfg_hooks->can_merge_blocks_p (bb1, bb2);
return ret;
}
void
predict_edge (edge e, enum br_predictor predictor, int probability)
{
if (!cfg_hooks->predict_edge)
internal_error ("%s does not support predict_edge", cfg_hooks->name);
cfg_hooks->predict_edge (e, predictor, probability);
}
bool
predicted_by_p (const_basic_block bb, enum br_predictor predictor)
{
if (!cfg_hooks->predict_edge)
internal_error ("%s does not support predicted_by_p", cfg_hooks->name);
return cfg_hooks->predicted_by_p (bb, predictor);
}
/* Merges basic block B into basic block A. */
void
merge_blocks (basic_block a, basic_block b)
{
edge e;
edge_iterator ei;
if (!cfg_hooks->merge_blocks)
internal_error ("%s does not support merge_blocks", cfg_hooks->name);
cfg_hooks->merge_blocks (a, b);
if (current_loops != NULL)
{
/* If the block we merge into is a loop header do nothing unless ... */
if (a->loop_father->header == a)
{
/* ... we merge two loop headers, in which case we kill
the inner loop. */
if (b->loop_father->header == b)
{
b->loop_father->header = NULL;
b->loop_father->latch = NULL;
loops_state_set (LOOPS_NEED_FIXUP);
}
}
/* If we merge a loop header into its predecessor, update the loop
structure. */
else if (b->loop_father->header == b)
{
remove_bb_from_loops (a);
add_bb_to_loop (a, b->loop_father);
a->loop_father->header = a;
}
remove_bb_from_loops (b);
}
/* Normally there should only be one successor of A and that is B, but
partway though the merge of blocks for conditional_execution we'll
be merging a TEST block with THEN and ELSE successors. Free the
whole lot of them and hope the caller knows what they're doing. */
while (EDGE_COUNT (a->succs) != 0)
remove_edge (EDGE_SUCC (a, 0));
/* Adjust the edges out of B for the new owner. */
FOR_EACH_EDGE (e, ei, b->succs)
{
e->src = a;
if (current_loops != NULL)
rescan_loop_exit (e, true, false);
}
a->succs = b->succs;
a->flags |= b->flags;
/* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
b->preds = b->succs = NULL;
if (dom_info_available_p (CDI_DOMINATORS))
redirect_immediate_dominators (CDI_DOMINATORS, b, a);
if (dom_info_available_p (CDI_DOMINATORS))
delete_from_dominance_info (CDI_DOMINATORS, b);
if (dom_info_available_p (CDI_POST_DOMINATORS))
delete_from_dominance_info (CDI_POST_DOMINATORS, b);
expunge_block (b);
}
/* Split BB into entry part and the rest (the rest is the newly created block).
Redirect those edges for that REDIRECT_EDGE_P returns true to the entry
part. Returns the edge connecting the entry part to the rest. */
edge
make_forwarder_block (basic_block bb, bool (*redirect_edge_p) (edge),
void (*new_bb_cbk) (basic_block))
{
edge e, fallthru;
edge_iterator ei;
basic_block dummy, jump;
struct loop *loop, *ploop, *cloop;
if (!cfg_hooks->make_forwarder_block)
internal_error ("%s does not support make_forwarder_block",
cfg_hooks->name);
fallthru = split_block_after_labels (bb);
dummy = fallthru->src;
bb = fallthru->dest;
/* Redirect back edges we want to keep. */
for (ei = ei_start (dummy->preds); (e = ei_safe_edge (ei)); )
{
basic_block e_src;
if (redirect_edge_p (e))
{
ei_next (&ei);
continue;
}
dummy->frequency -= EDGE_FREQUENCY (e);
dummy->count -= e->count;
if (dummy->frequency < 0)
dummy->frequency = 0;
if (dummy->count < 0)
dummy->count = 0;
fallthru->count -= e->count;
if (fallthru->count < 0)
fallthru->count = 0;
e_src = e->src;
jump = redirect_edge_and_branch_force (e, bb);
if (jump != NULL)
{
/* If we redirected the loop latch edge, the JUMP block now acts like
the new latch of the loop. */
if (current_loops != NULL
&& dummy->loop_father != NULL
&& dummy->loop_father->header == dummy
&& dummy->loop_father->latch == e_src)
dummy->loop_father->latch = jump;
if (new_bb_cbk != NULL)
new_bb_cbk (jump);
}
}
if (dom_info_available_p (CDI_DOMINATORS))
{
vec<basic_block> doms_to_fix;
doms_to_fix.create (2);
doms_to_fix.quick_push (dummy);
doms_to_fix.quick_push (bb);
iterate_fix_dominators (CDI_DOMINATORS, doms_to_fix, false);
doms_to_fix.release ();
}
if (current_loops != NULL)
{
/* If we do not split a loop header, then both blocks belong to the
same loop. In case we split loop header and do not redirect the
latch edge to DUMMY, then DUMMY belongs to the outer loop, and
BB becomes the new header. If latch is not recorded for the loop,
we leave this updating on the caller (this may only happen during
loop analysis). */
loop = dummy->loop_father;
if (loop->header == dummy
&& loop->latch != NULL
&& find_edge (loop->latch, dummy) == NULL)
{
remove_bb_from_loops (dummy);
loop->header = bb;
cloop = loop;
FOR_EACH_EDGE (e, ei, dummy->preds)
{
cloop = find_common_loop (cloop, e->src->loop_father);
}
add_bb_to_loop (dummy, cloop);
}
/* In case we split loop latch, update it. */
for (ploop = loop; ploop; ploop = loop_outer (ploop))
if (ploop->latch == dummy)
ploop->latch = bb;
}
cfg_hooks->make_forwarder_block (fallthru);
return fallthru;
}
/* Try to make the edge fallthru. */
void
tidy_fallthru_edge (edge e)
{
if (cfg_hooks->tidy_fallthru_edge)
cfg_hooks->tidy_fallthru_edge (e);
}
/* Fix up edges that now fall through, or rather should now fall through
but previously required a jump around now deleted blocks. Simplify
the search by only examining blocks numerically adjacent, since this
is how they were created.
??? This routine is currently RTL specific. */
void
tidy_fallthru_edges (void)
{
basic_block b, c;
if (!cfg_hooks->tidy_fallthru_edge)
return;
if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
return;
FOR_BB_BETWEEN (b, ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR->prev_bb, next_bb)
{
edge s;
c = b->next_bb;
/* We care about simple conditional or unconditional jumps with
a single successor.
If we had a conditional branch to the next instruction when
CFG was built, then there will only be one out edge for the
block which ended with the conditional branch (since we do
not create duplicate edges).
Furthermore, the edge will be marked as a fallthru because we
merge the flags for the duplicate edges. So we do not want to
check that the edge is not a FALLTHRU edge. */
if (single_succ_p (b))
{
s = single_succ_edge (b);
if (! (s->flags & EDGE_COMPLEX)
&& s->dest == c
&& !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX))
tidy_fallthru_edge (s);
}
}
}
/* Edge E is assumed to be fallthru edge. Emit needed jump instruction
(and possibly create new basic block) to make edge non-fallthru.
Return newly created BB or NULL if none. */
basic_block
force_nonfallthru (edge e)
{
basic_block ret, src = e->src;
if (!cfg_hooks->force_nonfallthru)
internal_error ("%s does not support force_nonfallthru",
cfg_hooks->name);
ret = cfg_hooks->force_nonfallthru (e);
if (ret != NULL)
{
if (dom_info_available_p (CDI_DOMINATORS))
set_immediate_dominator (CDI_DOMINATORS, ret, src);
if (current_loops != NULL)
{
struct loop *loop
= find_common_loop (single_pred (ret)->loop_father,
single_succ (ret)->loop_father);
rescan_loop_exit (e, false, true);
add_bb_to_loop (ret, loop);
}
}
return ret;
}
/* Returns true if we can duplicate basic block BB. */
bool
can_duplicate_block_p (const_basic_block bb)
{
if (!cfg_hooks->can_duplicate_block_p)
internal_error ("%s does not support can_duplicate_block_p",
cfg_hooks->name);
if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR)
return false;
return cfg_hooks->can_duplicate_block_p (bb);
}
/* Duplicates basic block BB and redirects edge E to it. Returns the
new basic block. The new basic block is placed after the basic block
AFTER. */
basic_block
duplicate_block (basic_block bb, edge e, basic_block after)
{
edge s, n;
basic_block new_bb;
gcov_type new_count = e ? e->count : 0;
edge_iterator ei;