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gnu / gcc / 2c564e813c0626802e5bfb066c094933d5e6a774 / . / gcc / cfgrtl.c
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/* Control flow graph manipulation code for GNU compiler.
Copyright (C) 1987-2021 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 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/>. */
/* This file contains low level functions to manipulate the CFG and analyze it
that are aware of the RTL intermediate language.
Available functionality:
- Basic CFG/RTL manipulation API documented in cfghooks.h
- CFG-aware instruction chain manipulation
delete_insn, delete_insn_chain
- Edge splitting and committing to edges
insert_insn_on_edge, commit_edge_insertions
- CFG updating after insn simplification
purge_dead_edges, purge_all_dead_edges
- CFG fixing after coarse manipulation
fixup_abnormal_edges
Functions not supposed for generic use:
- Infrastructure to determine quickly basic block for insn
compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
- Edge redirection with updating and optimizing of insn chain
block_label, tidy_fallthru_edge, force_nonfallthru */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "target.h"
#include "rtl.h"
#include "tree.h"
#include "cfghooks.h"
#include "df.h"
#include "insn-config.h"
#include "memmodel.h"
#include "emit-rtl.h"
#include "cfgrtl.h"
#include "cfganal.h"
#include "cfgbuild.h"
#include "cfgcleanup.h"
#include "bb-reorder.h"
#include "rtl-error.h"
#include "insn-attr.h"
#include "dojump.h"
#include "expr.h"
#include "cfgloop.h"
#include "tree-pass.h"
#include "print-rtl.h"
#include "rtl-iter.h"
#include "gimplify.h"
/* Disable warnings about missing quoting in GCC diagnostics. */
#if __GNUC__ >= 10
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wformat-diag"
#endif
/* Holds the interesting leading and trailing notes for the function.
Only applicable if the CFG is in cfglayout mode. */
static GTY(()) rtx_insn *cfg_layout_function_footer;
static GTY(()) rtx_insn *cfg_layout_function_header;
static rtx_insn *skip_insns_after_block (basic_block);
static void record_effective_endpoints (void);
static void fixup_reorder_chain (void);
void verify_insn_chain (void);
static void fixup_fallthru_exit_predecessor (void);
static int can_delete_note_p (const rtx_note *);
static int can_delete_label_p (const rtx_code_label *);
static basic_block rtl_split_edge (edge);
static bool rtl_move_block_after (basic_block, basic_block);
static int rtl_verify_flow_info (void);
static basic_block cfg_layout_split_block (basic_block, void *);
static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
static void cfg_layout_delete_block (basic_block);
static void rtl_delete_block (basic_block);
static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
static edge rtl_redirect_edge_and_branch (edge, basic_block);
static basic_block rtl_split_block (basic_block, void *);
static void rtl_dump_bb (FILE *, basic_block, int, dump_flags_t);
static int rtl_verify_flow_info_1 (void);
static void rtl_make_forwarder_block (edge);
static bool rtl_bb_info_initialized_p (basic_block bb);
/* Return true if NOTE is not one of the ones that must be kept paired,
so that we may simply delete it. */
static int
can_delete_note_p (const rtx_note *note)
{
switch (NOTE_KIND (note))
{
case NOTE_INSN_DELETED:
case NOTE_INSN_BASIC_BLOCK:
case NOTE_INSN_EPILOGUE_BEG:
return true;
default:
return false;
}
}
/* True if a given label can be deleted. */
static int
can_delete_label_p (const rtx_code_label *label)
{
return (!LABEL_PRESERVE_P (label)
/* User declared labels must be preserved. */
&& LABEL_NAME (label) == 0
&& !vec_safe_contains<rtx_insn *> (forced_labels,
const_cast<rtx_code_label *> (label)));
}
/* Delete INSN by patching it out. */
void
delete_insn (rtx_insn *insn)
{
rtx note;
bool really_delete = true;
if (LABEL_P (insn))
{
/* Some labels can't be directly removed from the INSN chain, as they
might be references via variables, constant pool etc.
Convert them to the special NOTE_INSN_DELETED_LABEL note. */
if (! can_delete_label_p (as_a <rtx_code_label *> (insn)))
{
const char *name = LABEL_NAME (insn);
basic_block bb = BLOCK_FOR_INSN (insn);
rtx_insn *bb_note = NEXT_INSN (insn);
really_delete = false;
PUT_CODE (insn, NOTE);
NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL;
NOTE_DELETED_LABEL_NAME (insn) = name;
/* If the note following the label starts a basic block, and the
label is a member of the same basic block, interchange the two. */
if (bb_note != NULL_RTX
&& NOTE_INSN_BASIC_BLOCK_P (bb_note)
&& bb != NULL
&& bb == BLOCK_FOR_INSN (bb_note))
{
reorder_insns_nobb (insn, insn, bb_note);
BB_HEAD (bb) = bb_note;
if (BB_END (bb) == bb_note)
BB_END (bb) = insn;
}
}
remove_node_from_insn_list (insn, &nonlocal_goto_handler_labels);
}
if (really_delete)
{
/* If this insn has already been deleted, something is very wrong. */
gcc_assert (!insn->deleted ());
if (INSN_P (insn))
df_insn_delete (insn);
remove_insn (insn);
insn->set_deleted ();
}
/* If deleting a jump, decrement the use count of the label. Deleting
the label itself should happen in the normal course of block merging. */
if (JUMP_P (insn))
{
if (JUMP_LABEL (insn)
&& LABEL_P (JUMP_LABEL (insn)))
LABEL_NUSES (JUMP_LABEL (insn))--;
/* If there are more targets, remove them too. */
while ((note
= find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
&& LABEL_P (XEXP (note, 0)))
{
LABEL_NUSES (XEXP (note, 0))--;
remove_note (insn, note);
}
}
/* Also if deleting any insn that references a label as an operand. */
while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
&& LABEL_P (XEXP (note, 0)))
{
LABEL_NUSES (XEXP (note, 0))--;
remove_note (insn, note);
}
if (rtx_jump_table_data *table = dyn_cast <rtx_jump_table_data *> (insn))
{
rtvec vec = table->get_labels ();
int len = GET_NUM_ELEM (vec);
int i;
for (i = 0; i < len; i++)
{
rtx label = XEXP (RTVEC_ELT (vec, i), 0);
/* When deleting code in bulk (e.g. removing many unreachable
blocks) we can delete a label that's a target of the vector
before deleting the vector itself. */
if (!NOTE_P (label))
LABEL_NUSES (label)--;
}
}
}
/* Like delete_insn but also purge dead edges from BB.
Return true if any edges are eliminated. */
bool
delete_insn_and_edges (rtx_insn *insn)
{
bool purge = false;
if (INSN_P (insn) && BLOCK_FOR_INSN (insn))
{
basic_block bb = BLOCK_FOR_INSN (insn);
if (BB_END (bb) == insn)
purge = true;
else if (DEBUG_INSN_P (BB_END (bb)))
for (rtx_insn *dinsn = NEXT_INSN (insn);
DEBUG_INSN_P (dinsn); dinsn = NEXT_INSN (dinsn))
if (BB_END (bb) == dinsn)
{
purge = true;
break;
}
}
delete_insn (insn);
if (purge)
return purge_dead_edges (BLOCK_FOR_INSN (insn));
return false;
}
/* Unlink a chain of insns between START and FINISH, leaving notes
that must be paired. If CLEAR_BB is true, we set bb field for
insns that cannot be removed to NULL. */
void
delete_insn_chain (rtx start, rtx_insn *finish, bool clear_bb)
{
/* Unchain the insns one by one. It would be quicker to delete all of these
with a single unchaining, rather than one at a time, but we need to keep
the NOTE's. */
rtx_insn *current = finish;
while (1)
{
rtx_insn *prev = PREV_INSN (current);
if (NOTE_P (current) && !can_delete_note_p (as_a <rtx_note *> (current)))
;
else
delete_insn (current);
if (clear_bb && !current->deleted ())
set_block_for_insn (current, NULL);
if (current == start)
break;
current = prev;
}
}
/* Create a new basic block consisting of the instructions between HEAD and END
inclusive. This function is designed to allow fast BB construction - reuses
the note and basic block struct in BB_NOTE, if any and do not grow
BASIC_BLOCK chain and should be used directly only by CFG construction code.
END can be NULL in to create new empty basic block before HEAD. Both END
and HEAD can be NULL to create basic block at the end of INSN chain.
AFTER is the basic block we should be put after. */
basic_block
create_basic_block_structure (rtx_insn *head, rtx_insn *end, rtx_note *bb_note,
basic_block after)
{
basic_block bb;
if (bb_note
&& (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
&& bb->aux == NULL)
{
/* If we found an existing note, thread it back onto the chain. */
rtx_insn *after;
if (LABEL_P (head))
after = head;
else
{
after = PREV_INSN (head);
head = bb_note;
}
if (after != bb_note && NEXT_INSN (after) != bb_note)
reorder_insns_nobb (bb_note, bb_note, after);
}
else
{
/* Otherwise we must create a note and a basic block structure. */
bb = alloc_block ();
init_rtl_bb_info (bb);
if (!head && !end)
head = end = bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
else if (LABEL_P (head) && end)
{
bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
if (head == end)
end = bb_note;
}
else
{
bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
head = bb_note;
if (!end)
end = head;
}
NOTE_BASIC_BLOCK (bb_note) = bb;
}
/* Always include the bb note in the block. */
if (NEXT_INSN (end) == bb_note)
end = bb_note;
BB_HEAD (bb) = head;
BB_END (bb) = end;
bb->index = last_basic_block_for_fn (cfun)++;
bb->flags = BB_NEW | BB_RTL;
link_block (bb, after);
SET_BASIC_BLOCK_FOR_FN (cfun, bb->index, bb);
df_bb_refs_record (bb->index, false);
update_bb_for_insn (bb);
BB_SET_PARTITION (bb, BB_UNPARTITIONED);
/* Tag the block so that we know it has been used when considering
other basic block notes. */
bb->aux = bb;
return bb;
}
/* Create new basic block consisting of instructions in between HEAD and END
and place it to the BB chain after block AFTER. END can be NULL to
create a new empty basic block before HEAD. Both END and HEAD can be
NULL to create basic block at the end of INSN chain. */
static basic_block
rtl_create_basic_block (void *headp, void *endp, basic_block after)
{
rtx_insn *head = (rtx_insn *) headp;
rtx_insn *end = (rtx_insn *) endp;
basic_block bb;
/* Grow the basic block array if needed. */
if ((size_t) last_basic_block_for_fn (cfun)
>= basic_block_info_for_fn (cfun)->length ())
vec_safe_grow_cleared (basic_block_info_for_fn (cfun),
last_basic_block_for_fn (cfun) + 1);
n_basic_blocks_for_fn (cfun)++;
bb = create_basic_block_structure (head, end, NULL, after);
bb->aux = NULL;
return bb;
}
static basic_block
cfg_layout_create_basic_block (void *head, void *end, basic_block after)
{
basic_block newbb = rtl_create_basic_block (head, end, after);
return newbb;
}
/* Delete the insns in a (non-live) block. We physically delete every
non-deleted-note insn, and update the flow graph appropriately.
Return nonzero if we deleted an exception handler. */
/* ??? Preserving all such notes strikes me as wrong. It would be nice
to post-process the stream to remove empty blocks, loops, ranges, etc. */
static void
rtl_delete_block (basic_block b)
{
rtx_insn *insn, *end;
/* If the head of this block is a CODE_LABEL, then it might be the
label for an exception handler which can't be reached. We need
to remove the label from the exception_handler_label list. */
insn = BB_HEAD (b);
end = get_last_bb_insn (b);
/* Selectively delete the entire chain. */
BB_HEAD (b) = NULL;
delete_insn_chain (insn, end, true);
if (dump_file)
fprintf (dump_file, "deleting block %d\n", b->index);
df_bb_delete (b->index);
}
/* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
void
compute_bb_for_insn (void)
{
basic_block bb;
FOR_EACH_BB_FN (bb, cfun)
{
rtx_insn *end = BB_END (bb);
rtx_insn *insn;
for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
{
BLOCK_FOR_INSN (insn) = bb;
if (insn == end)
break;
}
}
}
/* Release the basic_block_for_insn array. */
unsigned int
free_bb_for_insn (void)
{
rtx_insn *insn;
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
if (!BARRIER_P (insn))
BLOCK_FOR_INSN (insn) = NULL;
return 0;
}
namespace {
const pass_data pass_data_free_cfg =
{
RTL_PASS, /* type */
"*free_cfg", /* name */
OPTGROUP_NONE, /* optinfo_flags */
TV_NONE, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
PROP_cfg, /* properties_destroyed */
0, /* todo_flags_start */
0, /* todo_flags_finish */
};
class pass_free_cfg : public rtl_opt_pass
{
public:
pass_free_cfg (gcc::context *ctxt)
: rtl_opt_pass (pass_data_free_cfg, ctxt)
{}
/* opt_pass methods: */
virtual unsigned int execute (function *);
}; // class pass_free_cfg
unsigned int
pass_free_cfg::execute (function *)
{
/* The resource.c machinery uses DF but the CFG isn't guaranteed to be
valid at that point so it would be too late to call df_analyze. */
if (DELAY_SLOTS && optimize > 0 && flag_delayed_branch)
{
df_note_add_problem ();
df_analyze ();
}
if (crtl->has_bb_partition)
insert_section_boundary_note ();
free_bb_for_insn ();
return 0;
}
} // anon namespace
rtl_opt_pass *
make_pass_free_cfg (gcc::context *ctxt)
{
return new pass_free_cfg (ctxt);
}
/* Return RTX to emit after when we want to emit code on the entry of function. */
rtx_insn *
entry_of_function (void)
{
return (n_basic_blocks_for_fn (cfun) > NUM_FIXED_BLOCKS ?
BB_HEAD (ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb) : get_insns ());
}
/* Emit INSN at the entry point of the function, ensuring that it is only
executed once per function. */
void
emit_insn_at_entry (rtx insn)
{
edge_iterator ei = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs);
edge e = ei_safe_edge (ei);
gcc_assert (e->flags & EDGE_FALLTHRU);
insert_insn_on_edge (insn, e);
commit_edge_insertions ();
}
/* Update BLOCK_FOR_INSN of insns between BEGIN and END
(or BARRIER if found) and notify df of the bb change.
The insn chain range is inclusive
(i.e. both BEGIN and END will be updated. */
static void
update_bb_for_insn_chain (rtx_insn *begin, rtx_insn *end, basic_block bb)
{
rtx_insn *insn;
end = NEXT_INSN (end);
for (insn = begin; insn != end; insn = NEXT_INSN (insn))
if (!BARRIER_P (insn))
df_insn_change_bb (insn, bb);
}
/* Update BLOCK_FOR_INSN of insns in BB to BB,
and notify df of the change. */
void
update_bb_for_insn (basic_block bb)
{
update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
}
/* Like active_insn_p, except keep the return value use or clobber around
even after reload. */
static bool
flow_active_insn_p (const rtx_insn *insn)
{
if (active_insn_p (insn))
return true;
/* A clobber of the function return value exists for buggy
programs that fail to return a value. Its effect is to
keep the return value from being live across the entire
function. If we allow it to be skipped, we introduce the
possibility for register lifetime confusion.
Similarly, keep a USE of the function return value, otherwise
the USE is dropped and we could fail to thread jump if USE
appears on some paths and not on others, see PR90257. */
if ((GET_CODE (PATTERN (insn)) == CLOBBER
|| GET_CODE (PATTERN (insn)) == USE)
&& REG_P (XEXP (PATTERN (insn), 0))
&& REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0)))
return true;
return false;
}
/* Return true if the block has no effect and only forwards control flow to
its single destination. */
bool
contains_no_active_insn_p (const_basic_block bb)
{
rtx_insn *insn;
if (bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
|| bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)
|| !single_succ_p (bb)
|| (single_succ_edge (bb)->flags & EDGE_FAKE) != 0)
return false;
for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn))
if (INSN_P (insn) && flow_active_insn_p (insn))
return false;
return (!INSN_P (insn)
|| (JUMP_P (insn) && simplejump_p (insn))
|| !flow_active_insn_p (insn));
}
/* Likewise, but protect loop latches, headers and preheaders. */
/* FIXME: Make this a cfg hook. */
bool
forwarder_block_p (const_basic_block bb)
{
if (!contains_no_active_insn_p (bb))
return false;
/* Protect loop latches, headers and preheaders. */
if (current_loops)
{
basic_block dest;
if (bb->loop_father->header == bb)
return false;
dest = EDGE_SUCC (bb, 0)->dest;
if (dest->loop_father->header == dest)
return false;
}
return true;
}
/* Return nonzero if we can reach target from src by falling through. */
/* FIXME: Make this a cfg hook, the result is only valid in cfgrtl mode. */
bool
can_fallthru (basic_block src, basic_block target)
{
rtx_insn *insn = BB_END (src);
rtx_insn *insn2;
edge e;
edge_iterator ei;
if (target == EXIT_BLOCK_PTR_FOR_FN (cfun))
return true;
if (src->next_bb != target)
return false;
/* ??? Later we may add code to move jump tables offline. */
if (tablejump_p (insn, NULL, NULL))
return false;
FOR_EACH_EDGE (e, ei, src->succs)
if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)
&& e->flags & EDGE_FALLTHRU)
return false;
insn2 = BB_HEAD (target);
if (!active_insn_p (insn2))
insn2 = next_active_insn (insn2);
return next_active_insn (insn) == insn2;
}
/* Return nonzero if we could reach target from src by falling through,
if the target was made adjacent. If we already have a fall-through
edge to the exit block, we can't do that. */
static bool
could_fall_through (basic_block src, basic_block target)
{
edge e;
edge_iterator ei;
if (target == EXIT_BLOCK_PTR_FOR_FN (cfun))
return true;
FOR_EACH_EDGE (e, ei, src->succs)
if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)
&& e->flags & EDGE_FALLTHRU)
return 0;
return true;
}
/* Return the NOTE_INSN_BASIC_BLOCK of BB. */
rtx_note *
bb_note (basic_block bb)
{
rtx_insn *note;
note = BB_HEAD (bb);
if (LABEL_P (note))
note = NEXT_INSN (note);
gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note));
return as_a <rtx_note *> (note);
}
/* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
note associated with the BLOCK. */
static rtx_insn *
first_insn_after_basic_block_note (basic_block block)
{
rtx_insn *insn;
/* Get the first instruction in the block. */
insn = BB_HEAD (block);
if (insn == NULL_RTX)
return NULL;
if (LABEL_P (insn))
insn = NEXT_INSN (insn);
gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
return NEXT_INSN (insn);
}
/* Creates a new basic block just after basic block BB by splitting
everything after specified instruction INSNP. */
static basic_block
rtl_split_block (basic_block bb, void *insnp)
{
basic_block new_bb;
rtx_insn *insn = (rtx_insn *) insnp;
edge e;
edge_iterator ei;
if (!insn)
{
insn = first_insn_after_basic_block_note (bb);
if (insn)
{
rtx_insn *next = insn;
insn = PREV_INSN (insn);
/* If the block contains only debug insns, insn would have
been NULL in a non-debug compilation, and then we'd end
up emitting a DELETED note. For -fcompare-debug
stability, emit the note too. */
if (insn != BB_END (bb)
&& DEBUG_INSN_P (next)
&& DEBUG_INSN_P (BB_END (bb)))
{
while (next != BB_END (bb) && DEBUG_INSN_P (next))
next = NEXT_INSN (next);
if (next == BB_END (bb))
emit_note_after (NOTE_INSN_DELETED, next);
}
}
else
insn = get_last_insn ();
}
/* We probably should check type of the insn so that we do not create
inconsistent cfg. It is checked in verify_flow_info anyway, so do not
bother. */
if (insn == BB_END (bb))
emit_note_after (NOTE_INSN_DELETED, insn);
/* Create the new basic block. */
new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
BB_COPY_PARTITION (new_bb, bb);
BB_END (bb) = insn;
/* Redirect the outgoing edges. */
new_bb->succs = bb->succs;
bb->succs = NULL;
FOR_EACH_EDGE (e, ei, new_bb->succs)
e->src = new_bb;
/* The new block starts off being dirty. */
df_set_bb_dirty (bb);
return new_bb;
}
/* Return true if the single edge between blocks A and B is the only place
in RTL which holds some unique locus. */
static bool
unique_locus_on_edge_between_p (basic_block a, basic_block b)
{
const location_t goto_locus = EDGE_SUCC (a, 0)->goto_locus;
rtx_insn *insn, *end;
if (LOCATION_LOCUS (goto_locus) == UNKNOWN_LOCATION)
return false;
/* First scan block A backward. */
insn = BB_END (a);
end = PREV_INSN (BB_HEAD (a));
while (insn != end && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn)))
insn = PREV_INSN (insn);
if (insn != end && INSN_LOCATION (insn) == goto_locus)
return false;
/* Then scan block B forward. */
insn = BB_HEAD (b);
if (insn)
{
end = NEXT_INSN (BB_END (b));
while (insn != end && !NONDEBUG_INSN_P (insn))
insn = NEXT_INSN (insn);
if (insn != end && INSN_HAS_LOCATION (insn)
&& INSN_LOCATION (insn) == goto_locus)
return false;
}
return true;
}
/* If the single edge between blocks A and B is the only place in RTL which
holds some unique locus, emit a nop with that locus between the blocks. */
static void
emit_nop_for_unique_locus_between (basic_block a, basic_block b)
{
if (!unique_locus_on_edge_between_p (a, b))
return;
BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
INSN_LOCATION (BB_END (a)) = EDGE_SUCC (a, 0)->goto_locus;
}
/* Blocks A and B are to be merged into a single block A. The insns
are already contiguous. */
static void
rtl_merge_blocks (basic_block a, basic_block b)
{
/* If B is a forwarder block whose outgoing edge has no location, we'll
propagate the locus of the edge between A and B onto it. */
const bool forward_edge_locus
= (b->flags & BB_FORWARDER_BLOCK) != 0
&& LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) == UNKNOWN_LOCATION;
rtx_insn *b_head = BB_HEAD (b), *b_end = BB_END (b), *a_end = BB_END (a);
rtx_insn *del_first = NULL, *del_last = NULL;
rtx_insn *b_debug_start = b_end, *b_debug_end = b_end;
int b_empty = 0;
if (dump_file)
fprintf (dump_file, "Merging block %d into block %d...\n", b->index,
a->index);
while (DEBUG_INSN_P (b_end))
b_end = PREV_INSN (b_debug_start = b_end);
/* If there was a CODE_LABEL beginning B, delete it. */
if (LABEL_P (b_head))
{
/* Detect basic blocks with nothing but a label. This can happen
in particular at the end of a function. */
if (b_head == b_end)
b_empty = 1;
del_first = del_last = b_head;
b_head = NEXT_INSN (b_head);
}
/* Delete the basic block note and handle blocks containing just that
note. */
if (NOTE_INSN_BASIC_BLOCK_P (b_head))
{
if (b_head == b_end)
b_empty = 1;
if (! del_last)
del_first = b_head;
del_last = b_head;
b_head = NEXT_INSN (b_head);
}
/* If there was a jump out of A, delete it. */
if (JUMP_P (a_end))
{
rtx_insn *prev;
for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
if (!NOTE_P (prev)
|| NOTE_INSN_BASIC_BLOCK_P (prev)
|| prev == BB_HEAD (a))
break;
del_first = a_end;
a_end = PREV_INSN (del_first);
}
else if (BARRIER_P (NEXT_INSN (a_end)))
del_first = NEXT_INSN (a_end);
/* Delete everything marked above as well as crap that might be
hanging out between the two blocks. */
BB_END (a) = a_end;
BB_HEAD (b) = b_empty ? NULL : b_head;
delete_insn_chain (del_first, del_last, true);
/* If not optimizing, preserve the locus of the single edge between
blocks A and B if necessary by emitting a nop. */
if (!optimize
&& !forward_edge_locus
&& !DECL_IGNORED_P (current_function_decl))
{
emit_nop_for_unique_locus_between (a, b);
a_end = BB_END (a);
}
/* Reassociate the insns of B with A. */
if (!b_empty)
{
update_bb_for_insn_chain (a_end, b_debug_end, a);
BB_END (a) = b_debug_end;
BB_HEAD (b) = NULL;
}
else if (b_end != b_debug_end)
{
/* Move any deleted labels and other notes between the end of A
and the debug insns that make up B after the debug insns,
bringing the debug insns into A while keeping the notes after
the end of A. */
if (NEXT_INSN (a_end) != b_debug_start)
reorder_insns_nobb (NEXT_INSN (a_end), PREV_INSN (b_debug_start),
b_debug_end);
update_bb_for_insn_chain (b_debug_start, b_debug_end, a);
BB_END (a) = b_debug_end;
}
df_bb_delete (b->index);
if (forward_edge_locus)
EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
if (dump_file)
fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index);
}
/* Return true when block A and B can be merged. */
static bool
rtl_can_merge_blocks (basic_block a, basic_block b)
{
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
and cold sections.
Basic block partitioning may result in some jumps that appear to
be optimizable (or blocks that appear to be mergeable), but which really
must be left untouched (they are required to make it safely across
partition boundaries). See the comments at the top of
bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
if (BB_PARTITION (a) != BB_PARTITION (b))
return false;
/* Protect the loop latches. */
if (current_loops && b->loop_father->latch == b)
return false;
/* There must be exactly one edge in between the blocks. */
return (single_succ_p (a)
&& single_succ (a) == b
&& single_pred_p (b)
&& a != b
/* Must be simple edge. */
&& !(single_succ_edge (a)->flags & EDGE_COMPLEX)
&& a->next_bb == b
&& a != ENTRY_BLOCK_PTR_FOR_FN (cfun)
&& b != EXIT_BLOCK_PTR_FOR_FN (cfun)
/* If the jump insn has side effects,
we can't kill the edge. */
&& (!JUMP_P (BB_END (a))
|| (reload_completed
? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
}
/* Return the label in the head of basic block BLOCK. Create one if it doesn't
exist. */
rtx_code_label *
block_label (basic_block block)
{
if (block == EXIT_BLOCK_PTR_FOR_FN (cfun))
return NULL;
if (!LABEL_P (BB_HEAD (block)))
{
BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
}
return as_a <rtx_code_label *> (BB_HEAD (block));
}
/* Remove all barriers from BB_FOOTER of a BB. */
static void
remove_barriers_from_footer (basic_block bb)
{
rtx_insn *insn = BB_FOOTER (bb);
/* Remove barriers but keep jumptables. */
while (insn)
{
if (BARRIER_P (insn))
{
if (PREV_INSN (insn))
SET_NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
else
BB_FOOTER (bb) = NEXT_INSN (insn);
if (NEXT_INSN (insn))
SET_PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
}
if (LABEL_P (insn))
return;
insn = NEXT_INSN (insn);
}
}
/* Attempt to perform edge redirection by replacing possibly complex jump
instruction by unconditional jump or removing jump completely. This can
apply only if all edges now point to the same block. The parameters and
return values are equivalent to redirect_edge_and_branch. */
edge
try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
{
basic_block src = e->src;
rtx_insn *insn = BB_END (src);
rtx set;
int fallthru = 0;
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
and cold sections.
Basic block partitioning may result in some jumps that appear to
be optimizable (or blocks that appear to be mergeable), but which really
must be left untouched (they are required to make it safely across
partition boundaries). See the comments at the top of
bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
if (BB_PARTITION (src) != BB_PARTITION (target))
return NULL;
/* We can replace or remove a complex jump only when we have exactly
two edges. Also, if we have exactly one outgoing edge, we can
redirect that. */
if (EDGE_COUNT (src->succs) >= 3
/* Verify that all targets will be TARGET. Specifically, the
edge that is not E must also go to TARGET. */
|| (EDGE_COUNT (src->succs) == 2
&& EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
return NULL;
if (!onlyjump_p (insn))
return NULL;
if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
return NULL;
/* Avoid removing branch with side effects. */
set = single_set (insn);
if (!set || side_effects_p (set))
return NULL;
/* See if we can create the fallthru edge. */
if (in_cfglayout || can_fallthru (src, target))
{
if (dump_file)
fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
fallthru = 1;
/* Selectively unlink whole insn chain. */
if (in_cfglayout)
{
delete_insn_chain (insn, BB_END (src), false);
remove_barriers_from_footer (src);
}
else
delete_insn_chain (insn, PREV_INSN (BB_HEAD (target)), false);
}
/* If this already is simplejump, redirect it. */
else if (simplejump_p (insn))
{
if (e->dest == target)
return NULL;
if (dump_file)
fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
INSN_UID (insn), e->dest->index, target->index);
if (!redirect_jump (as_a <rtx_jump_insn *> (insn),
block_label (target), 0))
{
gcc_assert (target == EXIT_BLOCK_PTR_FOR_FN (cfun));
return NULL;
}
}
/* Cannot do anything for target exit block. */
else if (target == EXIT_BLOCK_PTR_FOR_FN (cfun))
return NULL;
/* Or replace possibly complicated jump insn by simple jump insn. */
else
{
rtx_code_label *target_label = block_label (target);
rtx_insn *barrier;
rtx_insn *label;
rtx_jump_table_data *table;
emit_jump_insn_after_noloc (targetm.gen_jump (target_label), insn);
JUMP_LABEL (BB_END (src)) = target_label;
LABEL_NUSES (target_label)++;
if (dump_file)
fprintf (dump_file, "Replacing insn %i by jump %i\n",
INSN_UID (insn), INSN_UID (BB_END (src)));
delete_insn_chain (insn, insn, false);
/* Recognize a tablejump that we are converting to a
simple jump and remove its associated CODE_LABEL
and ADDR_VEC or ADDR_DIFF_VEC. */
if (tablejump_p (insn, &label, &table))
delete_insn_chain (label, table, false);
barrier = next_nonnote_nondebug_insn (BB_END (src));
if (!barrier || !BARRIER_P (barrier))
emit_barrier_after (BB_END (src));
else
{
if (barrier != NEXT_INSN (BB_END (src)))
{
/* Move the jump before barrier so that the notes
which originally were or were created before jump table are
inside the basic block. */
rtx_insn *new_insn = BB_END (src);
update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
PREV_INSN (barrier), src);
SET_NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
SET_PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
SET_NEXT_INSN (new_insn) = barrier;
SET_NEXT_INSN (PREV_INSN (barrier)) = new_insn;
SET_PREV_INSN (new_insn) = PREV_INSN (barrier);
SET_PREV_INSN (barrier) = new_insn;
}
}
}
/* Keep only one edge out and set proper flags. */
if (!single_succ_p (src))
remove_edge (e);
gcc_assert (single_succ_p (src));
e = single_succ_edge (src);
if (fallthru)
e->flags = EDGE_FALLTHRU;
else
e->flags = 0;
e->probability = profile_probability::always ();
if (e->dest != target)
redirect_edge_succ (e, target);
return e;
}
/* Subroutine of redirect_branch_edge that tries to patch the jump
instruction INSN so that it reaches block NEW. Do this
only when it originally reached block OLD. Return true if this
worked or the original target wasn't OLD, return false if redirection
doesn't work. */
static bool
patch_jump_insn (rtx_insn *insn, rtx_insn *old_label, basic_block new_bb)
{
rtx_jump_table_data *table;
rtx tmp;
/* Recognize a tablejump and adjust all matching cases. */
if (tablejump_p (insn, NULL, &table))
{
rtvec vec;
int j;
rtx_code_label *new_label = block_label (new_bb);
if (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
return false;
vec = table->get_labels ();
for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
{
RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
--LABEL_NUSES (old_label);
++LABEL_NUSES (new_label);
}
/* Handle casesi dispatch insns. */
if ((tmp = tablejump_casesi_pattern (insn)) != NULL_RTX
&& label_ref_label (XEXP (SET_SRC (tmp), 2)) == old_label)
{
XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
new_label);
--LABEL_NUSES (old_label);
++LABEL_NUSES (new_label);
}
}
else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL)
{
int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp);
rtx note;
if (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
return false;
rtx_code_label *new_label = block_label (new_bb);
for (i = 0; i < n; ++i)
{
rtx old_ref = ASM_OPERANDS_LABEL (tmp, i);
gcc_assert (GET_CODE (old_ref) == LABEL_REF);
if (XEXP (old_ref, 0) == old_label)
{
ASM_OPERANDS_LABEL (tmp, i)
= gen_rtx_LABEL_REF (Pmode, new_label);
--LABEL_NUSES (old_label);
++LABEL_NUSES (new_label);
}
}
if (JUMP_LABEL (insn) == old_label)
{
JUMP_LABEL (insn) = new_label;
note = find_reg_note (insn, REG_LABEL_TARGET, new_label);
if (note)
remove_note (insn, note);
}
else
{
note = find_reg_note (insn, REG_LABEL_TARGET, old_label);
if (note)
remove_note (insn, note);
if (JUMP_LABEL (insn) != new_label
&& !find_reg_note (insn, REG_LABEL_TARGET, new_label))
add_reg_note (insn, REG_LABEL_TARGET, new_label);
}
while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label))
!= NULL_RTX)
XEXP (note, 0) = new_label;
}
else
{
/* ?? We may play the games with moving the named labels from
one basic block to the other in case only one computed_jump is
available. */
if (computed_jump_p (insn)
/* A return instruction can't be redirected. */
|| returnjump_p (insn))
return false;
if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label)
{
/* If the insn doesn't go where we think, we're confused. */
gcc_assert (JUMP_LABEL (insn) == old_label);
/* If the substitution doesn't succeed, die. This can happen
if the back end emitted unrecognizable instructions or if
target is exit block on some arches. Or for crossing
jumps. */
if (!redirect_jump (as_a <rtx_jump_insn *> (insn),
block_label (new_bb), 0))
{
gcc_assert (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
|| CROSSING_JUMP_P (insn));
return false;
}
}
}
return true;
}
/* Redirect edge representing branch of (un)conditional jump or tablejump,
NULL on failure */
static edge
redirect_branch_edge (edge e, basic_block target)
{
rtx_insn *old_label = BB_HEAD (e->dest);
basic_block src = e->src;
rtx_insn *insn = BB_END (src);
/* We can only redirect non-fallthru edges of jump insn. */
if (e->flags & EDGE_FALLTHRU)
return NULL;
else if (!JUMP_P (insn) && !currently_expanding_to_rtl)
return NULL;
if (!currently_expanding_to_rtl)
{
if (!patch_jump_insn (as_a <rtx_jump_insn *> (insn), old_label, target))
return NULL;
}
else
/* When expanding this BB might actually contain multiple
jumps (i.e. not yet split by find_many_sub_basic_blocks).
Redirect all of those that match our label. */
FOR_BB_INSNS (src, insn)
if (JUMP_P (insn) && !patch_jump_insn (as_a <rtx_jump_insn *> (insn),
old_label, target))
return NULL;
if (dump_file)
fprintf (dump_file, "Edge %i->%i redirected to %i\n",
e->src->index, e->dest->index, target->index);
if (e->dest != target)
e = redirect_edge_succ_nodup (e, target);
return e;
}
/* Called when edge E has been redirected to a new destination,
in order to update the region crossing flag on the edge and
jump. */
static void
fixup_partition_crossing (edge e)
{
if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) || e->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun))
return;
/* If we redirected an existing edge, it may already be marked
crossing, even though the new src is missing a reg crossing note.
But make sure reg crossing note doesn't already exist before
inserting. */
if (BB_PARTITION (e->src) != BB_PARTITION (e->dest))
{
e->flags |= EDGE_CROSSING;
if (JUMP_P (BB_END (e->src)))
CROSSING_JUMP_P (BB_END (e->src)) = 1;
}
else if (BB_PARTITION (e->src) == BB_PARTITION (e->dest))
{
e->flags &= ~EDGE_CROSSING;
/* Remove the section crossing note from jump at end of
src if it exists, and if no other successors are
still crossing. */
if (JUMP_P (BB_END (e->src)) && CROSSING_JUMP_P (BB_END (e->src)))
{
bool has_crossing_succ = false;
edge e2;
edge_iterator ei;
FOR_EACH_EDGE (e2, ei, e->src->succs)
{
has_crossing_succ |= (e2->flags & EDGE_CROSSING);
if (has_crossing_succ)
break;
}
if (!has_crossing_succ)
CROSSING_JUMP_P (BB_END (e->src)) = 0;
}
}
}
/* Called when block BB has been reassigned to the cold partition,
because it is now dominated by another cold block,
to ensure that the region crossing attributes are updated. */
static void
fixup_new_cold_bb (basic_block bb)
{
edge e;
edge_iterator ei;
/* This is called when a hot bb is found to now be dominated
by a cold bb and therefore needs to become cold. Therefore,
its preds will no longer be region crossing. Any non-dominating
preds that were previously hot would also have become cold
in the caller for the same region. Any preds that were previously
region-crossing will be adjusted in fixup_partition_crossing. */
FOR_EACH_EDGE (e, ei, bb->preds)
{
fixup_partition_crossing (e);
}
/* Possibly need to make bb's successor edges region crossing,
or remove stale region crossing. */
FOR_EACH_EDGE (e, ei, bb->succs)
{
/* We can't have fall-through edges across partition boundaries.
Note that force_nonfallthru will do any necessary partition
boundary fixup by calling fixup_partition_crossing itself. */
if ((e->flags & EDGE_FALLTHRU)
&& BB_PARTITION (bb) != BB_PARTITION (e->dest)
&& e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
force_nonfallthru (e);
else
fixup_partition_crossing (e);
}
}
/* Attempt to change code to redirect edge E to TARGET. Don't do that on
expense of adding new instructions or reordering basic blocks.
Function can be also called with edge destination equivalent to the TARGET.
Then it should try the simplifications and do nothing if none is possible.
Return edge representing the branch if transformation succeeded. Return NULL
on failure.
We still return NULL in case E already destinated TARGET and we didn't
managed to simplify instruction stream. */
static edge
rtl_redirect_edge_and_branch (edge e, basic_block target)
{
edge ret;
basic_block src = e->src;
basic_block dest = e->dest;
if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
return NULL;
if (dest == target)
return e;
if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
{
df_set_bb_dirty (src);
fixup_partition_crossing (ret);
return ret;
}
ret = redirect_branch_edge (e, target);
if (!ret)
return NULL;
df_set_bb_dirty (src);
fixup_partition_crossing (ret);
return ret;
}
/* Emit a barrier after BB, into the footer if we are in CFGLAYOUT mode. */
void
emit_barrier_after_bb (basic_block bb)
{
rtx_barrier *barrier = emit_barrier_after (BB_END (bb));
gcc_assert (current_ir_type () == IR_RTL_CFGRTL
|| current_ir_type () == IR_RTL_CFGLAYOUT);
if (current_ir_type () == IR_RTL_CFGLAYOUT)
{
rtx_insn *insn = unlink_insn_chain (barrier, barrier);
if (BB_FOOTER (bb))
{
rtx_insn *footer_tail = BB_FOOTER (bb);
while (NEXT_INSN (footer_tail))
footer_tail = NEXT_INSN (footer_tail);
if (!BARRIER_P (footer_tail))
{
SET_NEXT_INSN (footer_tail) = insn;
SET_PREV_INSN (insn) = footer_tail;
}
}
else
BB_FOOTER (bb) = insn;
}
}
/* Like force_nonfallthru below, but additionally performs redirection
Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
when redirecting to the EXIT_BLOCK, it is either ret_rtx or
simple_return_rtx, indicating which kind of returnjump to create.
It should be NULL otherwise. */
basic_block
force_nonfallthru_and_redirect (edge e, basic_block target, rtx jump_label)
{
basic_block jump_block, new_bb = NULL, src = e->src;
rtx note;
edge new_edge;
int abnormal_edge_flags = 0;
bool asm_goto_edge = false;
int loc;
/* In the case the last instruction is conditional jump to the next
instruction, first redirect the jump itself and then continue
by creating a basic block afterwards to redirect fallthru edge. */
if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
&& e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
&& any_condjump_p (BB_END (e->src))
&& JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
{
rtx note;
edge b = unchecked_make_edge (e->src, target, 0);
bool redirected;
redirected = redirect_jump (as_a <rtx_jump_insn *> (BB_END (e->src)),
block_label (target), 0);
gcc_assert (redirected);
note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
if (note)
{
int prob = XINT (note, 0);
b->probability = profile_probability::from_reg_br_prob_note (prob);
e->probability -= e->probability;
}
}
if (e->flags & EDGE_ABNORMAL)
{
/* Irritating special case - fallthru edge to the same block as abnormal
edge.
We can't redirect abnormal edge, but we still can split the fallthru
one and create separate abnormal edge to original destination.
This allows bb-reorder to make such edge non-fallthru. */
gcc_assert (e->dest == target);
abnormal_edge_flags = e->flags & ~EDGE_FALLTHRU;
e->flags &= EDGE_FALLTHRU;
}
else
{
gcc_assert (e->flags & EDGE_FALLTHRU);
if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun))
{
/* We can't redirect the entry block. Create an empty block
at the start of the function which we use to add the new
jump. */
edge tmp;
edge_iterator ei;
bool found = false;
basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL,
ENTRY_BLOCK_PTR_FOR_FN (cfun));
bb->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
/* Make sure new block ends up in correct hot/cold section. */
BB_COPY_PARTITION (bb, e->dest);
/* Change the existing edge's source to be the new block, and add
a new edge from the entry block to the new block. */
e->src = bb;
for (ei = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs);
(tmp = ei_safe_edge (ei)); )
{
if (tmp == e)
{
ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs->unordered_remove (ei.index);
found = true;
break;
}
else
ei_next (&ei);
}
gcc_assert (found);
vec_safe_push (bb->succs, e);
make_single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb,
EDGE_FALLTHRU);
}
}
/* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
don't point to the target or fallthru label. */
if (JUMP_P (BB_END (e->src))
&& target != EXIT_BLOCK_PTR_FOR_FN (cfun)
&& (e->flags & EDGE_FALLTHRU)
&& (note = extract_asm_operands (PATTERN (BB_END (e->src)))))
{
int i, n = ASM_OPERANDS_LABEL_LENGTH (note);
bool adjust_jump_target = false;
for (i = 0; i < n; ++i)
{
if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (e->dest))
{
LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note, i), 0))--;
XEXP (ASM_OPERANDS_LABEL (note, i), 0) = block_label (target);
LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note, i), 0))++;
adjust_jump_target = true;
}
if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (target))
asm_goto_edge = true;
}
if (adjust_jump_target)
{
rtx_insn *insn = BB_END (e->src);
rtx note;
rtx_insn *old_label = BB_HEAD (e->dest);
rtx_insn *new_label = BB_HEAD (target);
if (JUMP_LABEL (insn) == old_label)
{
JUMP_LABEL (insn) = new_label;
note = find_reg_note (insn, REG_LABEL_TARGET, new_label);
if (note)
remove_note (insn, note);
}
else
{
note = find_reg_note (insn, REG_LABEL_TARGET, old_label);
if (note)
remove_note (insn, note);
if (JUMP_LABEL (insn) != new_label
&& !find_reg_note (insn, REG_LABEL_TARGET, new_label))
add_reg_note (insn, REG_LABEL_TARGET, new_label);
}
while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label))
!= NULL_RTX)
XEXP (note, 0) = new_label;
}
}
if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags || asm_goto_edge)
{
rtx_insn *new_head;
profile_count count = e->count ();
profile_probability probability = e->probability;
/* Create the new structures. */
/* If the old block ended with a tablejump, skip its table
by searching forward from there. Otherwise start searching
forward from the last instruction of the old block. */
rtx_jump_table_data *table;
if (tablejump_p (BB_END (e->src), NULL, &table))
new_head = table;
else
new_head = BB_END (e->src);
new_head = NEXT_INSN (new_head);
jump_block = create_basic_block (new_head, NULL, e->src);
jump_block->count = count;
/* Make sure new block ends up in correct hot/cold section. */
BB_COPY_PARTITION (jump_block, e->src);
/* Wire edge in. */
new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
new_edge->probability = probability;
/* Redirect old edge. */
redirect_edge_pred (e, jump_block);
e->probability = profile_probability::always ();
/* If e->src was previously region crossing, it no longer is
and the reg crossing note should be removed. */
fixup_partition_crossing (new_edge);
/* If asm goto has any label refs to target's label,
add also edge from asm goto bb to target. */
if (asm_goto_edge)
{
new_edge->probability = new_edge->probability.apply_scale (1, 2);
jump_block->count = jump_block->count.apply_scale (1, 2);
edge new_edge2 = make_edge (new_edge->src, target,
e->flags & ~EDGE_FALLTHRU);
new_edge2->probability = probability - new_edge->probability;
}
new_bb = jump_block;
}
else
jump_block = e->src;
loc = e->goto_locus;
e->flags &= ~EDGE_FALLTHRU;
if (target == EXIT_BLOCK_PTR_FOR_FN (cfun))
{
if (jump_label == ret_rtx)
emit_jump_insn_after_setloc (targetm.gen_return (),
BB_END (jump_block), loc);
else
{
gcc_assert (jump_label == simple_return_rtx);
emit_jump_insn_after_setloc (targetm.gen_simple_return (),
BB_END (jump_block), loc);
}
set_return_jump_label (BB_END (jump_block));
}
else
{
rtx_code_label *label = block_label (target);
emit_jump_insn_after_setloc (targetm.gen_jump (label),
BB_END (jump_block), loc);
JUMP_LABEL (BB_END (jump_block)) = label;
LABEL_NUSES (label)++;
}
/* We might be in cfg layout mode, and if so, the following routine will
insert the barrier correctly. */
emit_barrier_after_bb (jump_block);
redirect_edge_succ_nodup (e, target);
if (abnormal_edge_flags)
make_edge (src, target, abnormal_edge_flags);
df_mark_solutions_dirty ();
fixup_partition_crossing (e);
return new_bb;
}
/* 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. */
static basic_block
rtl_force_nonfallthru (edge e)
{
return force_nonfallthru_and_redirect (e, e->dest, NULL_RTX);
}
/* Redirect edge even at the expense of creating new jump insn or
basic block. Return new basic block if created, NULL otherwise.
Conversion must be possible. */
static basic_block
rtl_redirect_edge_and_branch_force (edge e, basic_block target)
{
if (redirect_edge_and_branch (e, target)
|| e->dest == target)
return NULL;
/* In case the edge redirection failed, try to force it to be non-fallthru
and redirect newly created simplejump. */
df_set_bb_dirty (e->src);
return force_nonfallthru_and_redirect (e, target, NULL_RTX);
}
/* The given edge should potentially be a fallthru edge. If that is in
fact true, delete the jump and barriers that are in the way. */
static void
rtl_tidy_fallthru_edge (edge e)
{
rtx_insn *q;
basic_block b = e->src, c = b->next_bb;
/* ??? In a late-running flow pass, other folks may have deleted basic
blocks by nopping out blocks, leaving multiple BARRIERs between here
and the target label. They ought to be chastised and fixed.
We can also wind up with a sequence of undeletable labels between
one block and the next.
So search through a sequence of barriers, labels, and notes for
the head of block C and assert that we really do fall through. */
for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
if (NONDEBUG_INSN_P (q))
return;
/* Remove what will soon cease being the jump insn from the source block.
If block B consisted only of this single jump, turn it into a deleted
note. */
q = BB_END (b);
if (JUMP_P (q)
&& onlyjump_p (q)
&& (any_uncondjump_p (q)
|| single_succ_p (b)))
{
rtx_insn *label;
rtx_jump_table_data *table;
if (tablejump_p (q, &label, &table))
{
/* The label is likely mentioned in some instruction before
the tablejump and might not be DCEd, so turn it into
a note instead and move before the tablejump that is going to
be deleted. */
const char *name = LABEL_NAME (label);
PUT_CODE (label, NOTE);
NOTE_KIND (label) = NOTE_INSN_DELETED_LABEL;
NOTE_DELETED_LABEL_NAME (label) = name;
reorder_insns (label, label, PREV_INSN (q));
delete_insn (table);
}
q = PREV_INSN (q);
}
/* Unconditional jumps with side-effects (i.e. which we can't just delete
together with the barrier) should never have a fallthru edge. */
else if (JUMP_P (q) && any_uncondjump_p (q))
return;
/* Selectively unlink the sequence. */
if (q != PREV_INSN (BB_HEAD (c)))
delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
e->flags |= EDGE_FALLTHRU;
}
/* Should move basic block BB after basic block AFTER. NIY. */
static bool
rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
basic_block after ATTRIBUTE_UNUSED)
{
return false;
}
/* Locate the last bb in the same partition as START_BB. */
static basic_block
last_bb_in_partition (basic_block start_bb)
{
basic_block bb;
FOR_BB_BETWEEN (bb, start_bb, EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
{
if (BB_PARTITION (start_bb) != BB_PARTITION (bb->next_bb))
return bb;
}
/* Return bb before the exit block. */
return bb->prev_bb;
}
/* Split a (typically critical) edge. Return the new block.
The edge must not be abnormal.
??? The code generally expects to be called on critical edges.
The case of a block ending in an unconditional jump to a
block with multiple predecessors is not handled optimally. */
static basic_block
rtl_split_edge (edge edge_in)
{
basic_block bb, new_bb;
rtx_insn *before;
/* Abnormal edges cannot be split. */
gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
/* We are going to place the new block in front of edge destination.
Avoid existence of fallthru predecessors. */
if ((edge_in->flags & EDGE_FALLTHRU) == 0)
{
edge e = find_fallthru_edge (edge_in->dest->preds);
if (e)
force_nonfallthru (e);
}
/* Create the basic block note. */
if (edge_in->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
before = BB_HEAD (edge_in->dest);
else
before = NULL;
/* If this is a fall through edge to the exit block, the blocks might be
not adjacent, and the right place is after the source. */
if ((edge_in->flags & EDGE_FALLTHRU)
&& edge_in->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
{
before = NEXT_INSN (BB_END (edge_in->src));
bb = create_basic_block (before, NULL, edge_in->src);
BB_COPY_PARTITION (bb, edge_in->src);
}
else
{
if (edge_in->src == ENTRY_BLOCK_PTR_FOR_FN (cfun))
{
bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
BB_COPY_PARTITION (bb, edge_in->dest);
}
else
{
basic_block after = edge_in->dest->prev_bb;
/* If this is post-bb reordering, and the edge crosses a partition
boundary, the new block needs to be inserted in the bb chain
at the end of the src partition (since we put the new bb into
that partition, see below). Otherwise we may end up creating
an extra partition crossing in the chain, which is illegal.
It can't go after the src, because src may have a fall-through
to a different block. */
if (crtl->bb_reorder_complete
&& (edge_in->flags & EDGE_CROSSING))
{
after = last_bb_in_partition (edge_in->src);
before = get_last_bb_insn (after);
/* The instruction following the last bb in partition should
be a barrier, since it cannot end in a fall-through. */
gcc_checking_assert (BARRIER_P (before));
before = NEXT_INSN (before);
}
bb = create_basic_block (before, NULL, after);
/* Put the split bb into the src partition, to avoid creating
a situation where a cold bb dominates a hot bb, in the case
where src is cold and dest is hot. The src will dominate
the new bb (whereas it might not have dominated dest). */
BB_COPY_PARTITION (bb, edge_in->src);
}
}
make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
/* Can't allow a region crossing edge to be fallthrough. */
if (BB_PARTITION (bb) != BB_PARTITION (edge_in->dest)
&& edge_in->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
{
new_bb = force_nonfallthru (single_succ_edge (bb));
gcc_assert (!new_bb);
}
/* For non-fallthru edges, we must adjust the predecessor's
jump instruction to target our new block. */
if ((edge_in->flags & EDGE_FALLTHRU) == 0)
{
edge redirected = redirect_edge_and_branch (edge_in, bb);
gcc_assert (redirected);
}
else
{
if (edge_in->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
{
/* For asm goto even splitting of fallthru edge might
need insn patching, as other labels might point to the
old label. */
rtx_insn *last = BB_END (edge_in->src);
if (last
&& JUMP_P (last)
&& edge_in->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
&& (extract_asm_operands (PATTERN (last))
|| JUMP_LABEL (last) == before)
&& patch_jump_insn (last, before, bb))
df_set_bb_dirty (edge_in->src);
}
redirect_edge_succ (edge_in, bb);
}
return bb;
}
/* Queue instructions for insertion on an edge between two basic blocks.
The new instructions and basic blocks (if any) will not appear in the
CFG until commit_edge_insertions is called. */
void
insert_insn_on_edge (rtx pattern, edge e)
{
/* We cannot insert instructions on an abnormal critical edge.
It will be easier to find the culprit if we die now. */
gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
if (e->insns.r == NULL_RTX)
start_sequence ();
else
push_to_sequence (e->insns.r);
emit_insn (pattern);
e->insns.r = get_insns ();
end_sequence ();
}
/* Update the CFG for the instructions queued on edge E. */
void
commit_one_edge_insertion (edge e)
{
rtx_insn *before = NULL, *after = NULL, *insns, *tmp, *last;
basic_block bb;
/* Pull the insns off the edge now since the edge might go away. */
insns = e->insns.r;
e->insns.r = NULL;
/* Figure out where to put these insns. If the destination has
one predecessor, insert there. Except for the exit block. */
if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
{
bb = e->dest;
/* Get the location correct wrt a code label, and "nice" wrt
a basic block note, and before everything else. */
tmp = BB_HEAD (bb);
if (LABEL_P (tmp))
tmp = NEXT_INSN (tmp);
if (NOTE_INSN_BASIC_BLOCK_P (tmp))
tmp = NEXT_INSN (tmp);
if (tmp == BB_HEAD (bb))
before = tmp;
else if (tmp)
after = PREV_INSN (tmp);
else
after = get_last_insn ();
}
/* If the source has one successor and the edge is not abnormal,
insert there. Except for the entry block.
Don't do this if the predecessor ends in a jump other than
unconditional simple jump. E.g. for asm goto that points all
its labels at the fallthru basic block, we can't insert instructions
before the asm goto, as the asm goto can have various of side effects,
and can't emit instructions after the asm goto, as it must end
the basic block. */
else if ((e->flags & EDGE_ABNORMAL) == 0
&& single_succ_p (e->src)
&& e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
&& (!JUMP_P (BB_END (e->src))
|| simplejump_p (BB_END (e->src))))
{
bb = e->src;
/* It is possible to have a non-simple jump here. Consider a target
where some forms of unconditional jumps clobber a register. This
happens on the fr30 for example.
We know this block has a single successor, so we can just emit
the queued insns before the jump. */
if (JUMP_P (BB_END (bb)))
before = BB_END (bb);
else
{
/* We'd better be fallthru, or we've lost track of what's what. */
gcc_assert (e->flags & EDGE_FALLTHRU);
after = BB_END (bb);
}
}
/* Otherwise we must split the edge. */
else
{
bb = split_edge (e);
/* If E crossed a partition boundary, we needed to make bb end in
a region-crossing jump, even though it was originally fallthru. */
if (JUMP_P (BB_END (bb)))
before = BB_END (bb);
else
after = BB_END (bb);
}
/* Now that we've found the spot, do the insertion. */
if (before)
{
emit_insn_before_noloc (insns, before, bb);
last = prev_nonnote_insn (before);
}
else
last = emit_insn_after_noloc (insns, after, bb);
if (returnjump_p (last))
{
/* ??? Remove all outgoing edges from BB and add one for EXIT.
This is not currently a problem because this only happens
for the (single) epilogue, which already has a fallthru edge
to EXIT. */
e = single_succ_edge (bb);
gcc_assert (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)
&& single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
e->flags &= ~EDGE_FALLTHRU;
emit_barrier_after (last);
if (before)
delete_insn (before);
}
else
gcc_assert (!JUMP_P (last));
}
/* Update the CFG for all queued instructions. */
void
commit_edge_insertions (void)
{
basic_block bb;
/* Optimization passes that invoke this routine can cause hot blocks
previously reached by both hot and cold blocks to become dominated only
by cold blocks. This will cause the verification below to fail,
and lead to now cold code in the hot section. In some cases this
may only be visible after newly unreachable blocks are deleted,
which will be done by fixup_partitions. */
fixup_partitions ();
if (!currently_expanding_to_rtl)
checking_verify_flow_info ();
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun),
EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
{
edge e;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, bb->succs)
if (e->insns.r)
{
if (currently_expanding_to_rtl)
rebuild_jump_labels_chain (e->insns.r);
commit_one_edge_insertion (e);
}
}
}
/* Print out RTL-specific basic block information (live information
at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
documented in dumpfile.h. */
static void
rtl_dump_bb (FILE *outf, basic_block bb, int indent, dump_flags_t flags)
{
char *s_indent;
s_indent = (char *) alloca ((size_t) indent + 1);
memset (s_indent, ' ', (size_t) indent);
s_indent[indent] = '\0';
if (df && (flags & TDF_DETAILS))
{
df_dump_top (bb, outf);
putc ('\n', outf);
}
if (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK
&& rtl_bb_info_initialized_p (bb))
{
rtx_insn *last = BB_END (bb);
if (last)
last = NEXT_INSN (last);
for (rtx_insn *insn = BB_HEAD (bb); insn != last; insn = NEXT_INSN (insn))
{
if (flags & TDF_DETAILS)
df_dump_insn_top (insn, outf);
if (! (flags & TDF_SLIM))
print_rtl_single (outf, insn);
else
dump_insn_slim (outf, insn);
if (flags & TDF_DETAILS)
df_dump_insn_bottom (insn, outf);
}
}
if (df && (flags & TDF_DETAILS))
{
df_dump_bottom (bb, outf);
putc ('\n', outf);
}
}
/* Like dump_function_to_file, but for RTL. Print out dataflow information
for the start of each basic block. FLAGS are the TDF_* masks documented
in dumpfile.h. */
void
print_rtl_with_bb (FILE *outf, const rtx_insn *rtx_first, dump_flags_t flags)
{
const rtx_insn *tmp_rtx;
if (rtx_first == 0)
fprintf (outf, "(nil)\n");
else
{
enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
int max_uid = get_max_uid ();
basic_block *start = XCNEWVEC (basic_block, max_uid);
basic_block *end = XCNEWVEC (basic_block, max_uid);
enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
basic_block bb;
/* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
insns, but the CFG is not maintained so the basic block info
is not reliable. Therefore it's omitted from the dumps. */
if (! (cfun->curr_properties & PROP_cfg))
flags &= ~TDF_BLOCKS;
if (df)
df_dump_start (outf);
if (cfun->curr_properties & PROP_cfg)
{
FOR_EACH_BB_REVERSE_FN (bb, cfun)
{
rtx_insn *x;
start[INSN_UID (BB_HEAD (bb))] = bb;
end[INSN_UID (BB_END (bb))] = bb;
if (flags & TDF_BLOCKS)
{
for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
{
enum bb_state state = IN_MULTIPLE_BB;
if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
state = IN_ONE_BB;
in_bb_p[INSN_UID (x)] = state;
if (x == BB_END (bb))
break;
}
}
}
}
for (tmp_rtx = rtx_first; tmp_rtx != NULL; tmp_rtx = NEXT_INSN (tmp_rtx))
{
if (flags & TDF_BLOCKS)
{
bb = start[INSN_UID (tmp_rtx)];
if (bb != NULL)
{
dump_bb_info (outf, bb, 0, dump_flags, true, false);
if (df && (flags & TDF_DETAILS))
df_dump_top (bb, outf);
}
if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
&& !NOTE_P (tmp_rtx)
&& !BARRIER_P (tmp_rtx))
fprintf (outf, ";; Insn is not within a basic block\n");
else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
fprintf (outf, ";; Insn is in multiple basic blocks\n");
}
if (flags & TDF_DETAILS)
df_dump_insn_top (tmp_rtx, outf);
if (! (flags & TDF_SLIM))
print_rtl_single (outf, tmp_rtx);
else
dump_insn_slim (outf, tmp_rtx);
if (flags & TDF_DETAILS)
df_dump_insn_bottom (tmp_rtx, outf);
bb = end[INSN_UID (tmp_rtx)];
if (bb != NULL)
{
if (flags & TDF_BLOCKS)
{
dump_bb_info (outf, bb, 0, dump_flags, false, true);
if (df && (flags & TDF_DETAILS))
df_dump_bottom (bb, outf);
putc ('\n', outf);
}
/* Emit a hint if the fallthrough target of current basic block
isn't the one placed right next. */
else if (EDGE_COUNT (bb->succs) > 0)
{
gcc_assert (BB_END (bb) == tmp_rtx);
const rtx_insn *ninsn = NEXT_INSN (tmp_rtx);
/* Bypass intervening deleted-insn notes and debug insns. */
while (ninsn
&& !NONDEBUG_INSN_P (ninsn)
&& !start[INSN_UID (ninsn)])
ninsn = NEXT_INSN (ninsn);
edge e = find_fallthru_edge (bb->succs);
if (e && ninsn)
{
basic_block dest = e->dest;
if (start[INSN_UID (ninsn)] != dest)
fprintf (outf, "%s ; pc falls through to BB %d\n",
print_rtx_head, dest->index);
}
}
}
}
free (start);
free (end);
free (in_bb_p);
}
}
/* Update the branch probability of BB if a REG_BR_PROB is present. */
void
update_br_prob_note (basic_block bb)
{
rtx note;
note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
if (!JUMP_P (BB_END (bb)) || !BRANCH_EDGE (bb)->probability.initialized_p ())
{
if (note)
{
rtx *note_link, this_rtx;
note_link = &REG_NOTES (BB_END (bb));
for (this_rtx = *note_link; this_rtx; this_rtx = XEXP (this_rtx, 1))
if (this_rtx == note)
{
*note_link = XEXP (this_rtx, 1);
break;
}
}
return;
}
if (!note
|| XINT (note, 0) == BRANCH_EDGE (bb)->probability.to_reg_br_prob_note ())
return;
XINT (note, 0) = BRANCH_EDGE (bb)->probability.to_reg_br_prob_note ();
}
/* Get the last insn associated with block BB (that includes barriers and
tablejumps after BB). */
rtx_insn *
get_last_bb_insn (basic_block bb)
{
rtx_jump_table_data *table;
rtx_insn *tmp;
rtx_insn *end = BB_END (bb);
/* Include any jump table following the basic block. */
if (tablejump_p (end, NULL, &table))
end = table;
/* Include any barriers that may follow the basic block. */
tmp = next_nonnote_nondebug_insn_bb (end);
while (tmp && BARRIER_P (tmp))
{
end = tmp;
tmp = next_nonnote_nondebug_insn_bb (end);
}
return end;
}
/* Add all BBs reachable from entry via hot paths into the SET. */
void
find_bbs_reachable_by_hot_paths (hash_set<basic_block> *set)
{
auto_vec<basic_block, 64> worklist;
set->add (ENTRY_BLOCK_PTR_FOR_FN (cfun));
worklist.safe_push (ENTRY_BLOCK_PTR_FOR_FN (cfun));
while (worklist.length () > 0)
{
basic_block bb = worklist.pop ();
edge_iterator ei;
edge e;
FOR_EACH_EDGE (e, ei, bb->succs)
if (BB_PARTITION (e->dest) != BB_COLD_PARTITION
&& !set->add (e->dest))
worklist.safe_push (e->dest);
}
}
/* Sanity check partition hotness to ensure that basic blocks in
  the cold partition don't dominate basic blocks in the hot partition.
If FLAG_ONLY is true, report violations as errors. Otherwise
re-mark the dominated blocks as cold, since this is run after
cfg optimizations that may make hot blocks previously reached
by both hot and cold blocks now only reachable along cold paths. */
static auto_vec<basic_block>
find_partition_fixes (bool flag_only)
{
basic_block bb;
auto_vec<basic_block> bbs_to_fix;
hash_set<basic_block> set;
/* Callers check this. */
gcc_checking_assert (crtl->has_bb_partition);
find_bbs_reachable_by_hot_paths (&set);
FOR_EACH_BB_FN (bb, cfun)
if (!set.contains (bb)
&& BB_PARTITION (bb) != BB_COLD_PARTITION)
{
if (flag_only)
error ("non-cold basic block %d reachable only "
"by paths crossing the cold partition", bb->index);
else
BB_SET_PARTITION (bb, BB_COLD_PARTITION);
bbs_to_fix.safe_push (bb);
}
return bbs_to_fix;
}
/* Perform cleanup on the hot/cold bb partitioning after optimization
passes that modify the cfg. */
void
fixup_partitions (void)
{
if (!crtl->has_bb_partition)
return;
/* Delete any blocks that became unreachable and weren't
already cleaned up, for example during edge forwarding
and convert_jumps_to_returns. This will expose more
opportunities for fixing the partition boundaries here.
Also, the calculation of the dominance graph during verification
will assert if there are unreachable nodes. */
delete_unreachable_blocks ();
/* If there are partitions, do a sanity check on them: A basic block in
  a cold partition cannot dominate a basic block in a hot partition.
Fixup any that now violate this requirement, as a result of edge
forwarding and unreachable block deletion.  */
auto_vec<basic_block> bbs_to_fix = find_partition_fixes (false);
/* Do the partition fixup after all necessary blocks have been converted to
cold, so that we only update the region crossings the minimum number of
places, which can require forcing edges to be non fallthru. */
if (! bbs_to_fix.is_empty ())
{
do
{
basic_block bb = bbs_to_fix.pop ();
fixup_new_cold_bb (bb);
}
while (! bbs_to_fix.is_empty ());
/* Fix up hot cold block grouping if needed. */
if (crtl->bb_reorder_complete && current_ir_type () == IR_RTL_CFGRTL)
{
basic_block bb, first = NULL, second = NULL;
int current_partition = BB_UNPARTITIONED;
FOR_EACH_BB_FN (bb, cfun)
{
if (current_partition != BB_UNPARTITIONED
&& BB_PARTITION (bb) != current_partition)
{
if (first == NULL)
first = bb;
else if (second == NULL)
second = bb;
else
{
/* If we switch partitions for the 3rd, 5th etc. time,
move bbs first (inclusive) .. second (exclusive) right
before bb. */
basic_block prev_first = first->prev_bb;
basic_block prev_second = second->prev_bb;
basic_block prev_bb = bb->prev_bb;
prev_first->next_bb = second;
second->prev_bb = prev_first;
prev_second->next_bb = bb;
bb->prev_bb = prev_second;
prev_bb->next_bb = first;
first->prev_bb = prev_bb;
rtx_insn *prev_first_insn = PREV_INSN (BB_HEAD (first));
rtx_insn *prev_second_insn
= PREV_INSN (BB_HEAD (second));
rtx_insn *prev_bb_insn = PREV_INSN (BB_HEAD (bb));
SET_NEXT_INSN (prev_first_insn) = BB_HEAD (second);
SET_PREV_INSN (BB_HEAD (second)) = prev_first_insn;
SET_NEXT_INSN (prev_second_insn) = BB_HEAD (bb);
SET_PREV_INSN (BB_HEAD (bb)) = prev_second_insn;
SET_NEXT_INSN (prev_bb_insn) = BB_HEAD (first);
SET_PREV_INSN (BB_HEAD (first)) = prev_bb_insn;
second = NULL;
}
}
current_partition = BB_PARTITION (bb);
}
gcc_assert (!second);
}
}
}
/* Verify, in the basic block chain, that there is at most one switch
between hot/cold partitions. This condition will not be true until
after reorder_basic_blocks is called. */
static int
verify_hot_cold_block_grouping (void)
{
basic_block bb;
int err = 0;
bool switched_sections = false;
int current_partition = BB_UNPARTITIONED;
/* Even after bb reordering is complete, we go into cfglayout mode
again (in compgoto). Ensure we don't call this before going back
into linearized RTL when any layout fixes would have been committed. */
if (!crtl->bb_reorder_complete
|| current_ir_type () != IR_RTL_CFGRTL)
return err;
FOR_EACH_BB_FN (bb, cfun)
{
if (current_partition != BB_UNPARTITIONED
&& BB_PARTITION (bb) != current_partition)
{
if (switched_sections)
{
error ("multiple hot/cold transitions found (bb %i)",
bb->index);
err = 1;
}
else
switched_sections = true;
if (!crtl->has_bb_partition)
error ("partition found but function partition flag not set");
}
current_partition = BB_PARTITION (bb);
}
return err;
}
/* Perform several checks on the edges out of each block, such as
the consistency of the branch probabilities, the correctness
of hot/cold partition crossing edges, and the number of expected
successor edges. Also verify that the dominance relationship
between hot/cold blocks is sane. */
static int
rtl_verify_edges (void)
{
int err = 0;
basic_block bb;
FOR_EACH_BB_REVERSE_FN (bb, cfun)
{
int n_fallthru = 0, n_branch = 0, n_abnormal_call = 0, n_sibcall = 0;
int n_eh = 0, n_abnormal = 0;
edge e, fallthru = NULL;
edge_iterator ei;
rtx note;
bool has_crossing_edge = false;
if (JUMP_P (BB_END (bb))
&& (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
&& EDGE_COUNT (bb->succs) >= 2
&& any_condjump_p (BB_END (bb)))
{
if (!BRANCH_EDGE (bb)->probability.initialized_p ())
{
if (profile_status_for_fn (cfun) != PROFILE_ABSENT)
{
error ("verify_flow_info: "
"REG_BR_PROB is set but cfg probability is not");
err = 1;
}
}
else if (XINT (note, 0)
!= BRANCH_EDGE (bb)->probability.to_reg_br_prob_note ()
&& profile_status_for_fn (cfun) != PROFILE_ABSENT)
{
error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i",
XINT (note, 0),
BRANCH_EDGE (bb)->probability.to_reg_br_prob_note ());
err = 1;
}
}
FOR_EACH_EDGE (e, ei, bb->succs)
{
bool is_crossing;
if (e->flags & EDGE_FALLTHRU)
n_fallthru++, fallthru = e;
is_crossing = (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
&& e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
&& e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun));
has_crossing_edge |= is_crossing;
if (e->flags & EDGE_CROSSING)
{
if (!is_crossing)
{
error ("EDGE_CROSSING incorrectly set across same section");
err = 1;
}
if (e->flags & EDGE_FALLTHRU)
{
error ("fallthru edge crosses section boundary in bb %i",
e->src->index);
err = 1;
}
if (e->flags & EDGE_EH)
{
error ("EH edge crosses section boundary in bb %i",
e->src->index);
err = 1;
}
if (JUMP_P (BB_END (bb)) && !CROSSING_JUMP_P (BB_END (bb)))
{
error ("No region crossing jump at section boundary in bb %i",
bb->index);
err = 1;
}
}
else if (is_crossing)
{
error ("EDGE_CROSSING missing across section boundary");
err = 1;
}
if ((e->flags & ~(EDGE_DFS_BACK
| EDGE_CAN_FALLTHRU
| EDGE_IRREDUCIBLE_LOOP
| EDGE_LOOP_EXIT
| EDGE_CROSSING
| EDGE_PRESERVE)) == 0)
n_branch++;
if (e->flags & EDGE_ABNORMAL_CALL)
n_abnormal_call++;
if (e->flags & EDGE_SIBCALL)
n_sibcall++;
if (e->flags & EDGE_EH)
n_eh++;
if (e->flags & EDGE_ABNORMAL)
n_abnormal++;
}
if (!has_crossing_edge
&& JUMP_P (BB_END (bb))
&& CROSSING_JUMP_P (BB_END (bb)))
{
print_rtl_with_bb (stderr, get_insns (), TDF_BLOCKS | TDF_DETAILS);
error ("Region crossing jump across same section in bb %i",
bb->index);
err = 1;
}
if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
{
error ("missing REG_EH_REGION note at the end of bb %i", bb->index);
err = 1;
}
if (n_eh > 1)
{
error ("too many exception handling edges in bb %i", bb->index);
err = 1;
}
if (n_branch
&& (!JUMP_P (BB_END (bb))
|| (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
|| any_condjump_p (BB_END (bb))))))
{
error ("too many outgoing branch edges from bb %i", bb->index);
err = 1;
}
if (n_fallthru && any_uncondjump_p (BB_END (bb)))
{
error ("fallthru edge after unconditional jump in bb %i", bb->index);
err = 1;
}
if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
{
error ("wrong number of branch edges after unconditional jump"
" in bb %i", bb->index);
err = 1;
}
if (n_branch != 1 && any_condjump_p (BB_END (bb))
&& JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
{
error ("wrong amount of branch edges after conditional jump"
" in bb %i", bb->index);
err = 1;
}
if (n_abnormal_call && !CALL_P (BB_END (bb)))
{
error ("abnormal call edges for non-call insn in bb %i", bb->index);
err = 1;
}
if (n_sibcall && !CALL_P (BB_END (bb)))
{
error ("sibcall edges for non-call insn in bb %i", bb->index);
err = 1;
}
if (n_abnormal > n_eh
&& !(CALL_P (BB_END (bb))
&& n_abnormal == n_abnormal_call + n_sibcall)
&& (!JUMP_P (BB_END (bb))
|| any_condjump_p (BB_END (bb))
|| any_uncondjump_p (BB_END (bb))))
{
error ("abnormal edges for no purpose in bb %i", bb->index);
err = 1;
}
int has_eh = -1;
FOR_EACH_EDGE (e, ei, bb->preds)
{
if (has_eh == -1)
has_eh = (e->flags & EDGE_EH);
if ((e->flags & EDGE_EH) == has_eh)
continue;
error ("EH incoming edge mixed with non-EH incoming edges "
"in bb %i", bb->index);
err = 1;
break;
}
}
/* If there are partitions, do a sanity check on them: A basic block in
  a cold partition cannot dominate a basic block in a hot partition.  */
if (crtl->has_bb_partition && !err
&& current_ir_type () == IR_RTL_CFGLAYOUT)
{
auto_vec<basic_block> bbs_to_fix = find_partition_fixes (true);
err = !bbs_to_fix.is_empty ();
}
/* Clean up. */
return err;
}
/* Checks on the instructions within blocks. Currently checks that each
block starts with a basic block note, and that basic block notes and
control flow jumps are not found in the middle of the block. */
static int
rtl_verify_bb_insns (void)
{
rtx_insn *x;
int err = 0;
basic_block bb;
FOR_EACH_BB_REVERSE_FN (bb, cfun)
{
/* Now check the header of basic
block. It ought to contain optional CODE_LABEL followed
by NOTE_BASIC_BLOCK. */
x = BB_HEAD (bb);
if (LABEL_P (x))
{
if (BB_END (bb) == x)
{
error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
bb->index);
err = 1;
}
x = NEXT_INSN (x);
}
if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
{
error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
bb->index);
err = 1;
}
if (BB_END (bb) == x)
/* Do checks for empty blocks here. */
;
else
for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
{
if (NOTE_INSN_BASIC_BLOCK_P (x))
{
error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
INSN_UID (x), bb->index);
err = 1;
}
if (x == BB_END (bb))
break;
if (control_flow_insn_p (x))
{
error ("in basic block %d:", bb->index);
fatal_insn ("flow control insn inside a basic block", x);
}
}
}
/* Clean up. */
return err;
}
/* Verify that block pointers for instructions in basic blocks, headers and
footers are set appropriately. */
static int
rtl_verify_bb_pointers (void)
{
int err = 0;
basic_block bb;
/* Check the general integrity of the basic blocks. */
FOR_EACH_BB_REVERSE_FN (bb, cfun)
{
rtx_insn *insn;
if (!(bb->flags & BB_RTL))
{
error ("BB_RTL flag not set for block %d", bb->index);
err = 1;
}
FOR_BB_INSNS (bb, insn)
if (BLOCK_FOR_INSN (insn) != bb)
{
error ("insn %d basic block pointer is %d, should be %d",
INSN_UID (insn),
BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
bb->index);
err = 1;
}
for (insn = BB_HEADER (bb); insn; insn = NEXT_INSN (insn))
if (!BARRIER_P (insn)
&& BLOCK_FOR_INSN (insn) != NULL)
{
error ("insn %d in header of bb %d has non-NULL basic block",
INSN_UID (insn), bb->index);
err = 1;
}
for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn))
if (!BARRIER_P (insn)
&& BLOCK_FOR_INSN (insn) != NULL)
{
error ("insn %d in footer of bb %d has non-NULL basic block",
INSN_UID (insn), bb->index);
err = 1;
}
}
/* Clean up. */
return err;
}
/* Verify the CFG and RTL consistency common for both underlying RTL and
cfglayout RTL.
Currently it does following checks:
- overlapping of basic blocks
- insns with wrong BLOCK_FOR_INSN pointers
- headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
- tails of basic blocks (ensure that boundary is necessary)
- scans body of the basic block for JUMP_INSN, CODE_LABEL
and NOTE_INSN_BASIC_BLOCK
- verify that no fall_thru edge crosses hot/cold partition boundaries
- verify that there are no pending RTL branch predictions
- verify that hot blocks are not dominated by cold blocks
In future it can be extended check a lot of other stuff as well
(reachability of basic blocks, life information, etc. etc.). */
static int
rtl_verify_flow_info_1 (void)
{
int err = 0;
err |= rtl_verify_bb_pointers ();
err |= rtl_verify_bb_insns ();
err |= rtl_verify_edges ();
return err;
}
/* Walk the instruction chain and verify that bb head/end pointers
are correct, and that instructions are in exactly one bb and have
correct block pointers. */
static int
rtl_verify_bb_insn_chain (void)
{
basic_block bb;
int err = 0;
rtx_insn *x;
rtx_insn *last_head = get_last_insn ();
basic_block *bb_info;
const int max_uid = get_max_uid ();
bb_info = XCNEWVEC (basic_block, max_uid);
FOR_EACH_BB_REVERSE_FN (bb, cfun)
{
rtx_insn *head = BB_HEAD (bb);
rtx_insn *end = BB_END (bb);
for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
{
/* Verify the end of the basic block is in the INSN chain. */
if (x == end)
break;
/* And that the code outside of basic blocks has NULL bb field. */
if (!BARRIER_P (x)
&& BLOCK_FOR_INSN (x) != NULL)
{
error ("insn %d outside of basic blocks has non-NULL bb field",
INSN_UID (x));
err = 1;
}
}
if (!x)
{
error ("end insn %d for block %d not found in the insn stream",
INSN_UID (end), bb->index);
err = 1;
}
/* Work backwards from the end to the head of the basic block
to verify the head is in the RTL chain. */
for (; x != NULL_RTX; x = PREV_INSN (x))
{
/* While walking over the insn chain, verify insns appear
in only one basic block. */
if (bb_info[INSN_UID (x)] != NULL)
{
error ("insn %d is in multiple basic blocks (%d and %d)",
INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
err = 1;
}
bb_info[INSN_UID (x)] = bb;
if (x == head)
break;
}
if (!x)
{
error ("head insn %d for block %d not found in the insn stream",
INSN_UID (head), bb->index);
err = 1;
}
last_head = PREV_INSN (x);
}
for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
{
/* Check that the code before the first basic block has NULL
bb field. */
if (!BARRIER_P (x)
&& BLOCK_FOR_INSN (x) != NULL)
{
error ("insn %d outside of basic blocks has non-NULL bb field",
INSN_UID (x));
err = 1;
}
}
free (bb_info);
return err;
}
/* Verify that fallthru edges point to adjacent blocks in layout order and
that barriers exist after non-fallthru blocks. */
static int
rtl_verify_fallthru (void)
{
basic_block bb;
int err = 0;
FOR_EACH_BB_REVERSE_FN (bb, cfun)
{
edge e;
e = find_fallthru_edge (bb->succs);
if (!e)
{
rtx_insn *insn;
/* Ensure existence of barrier in BB with no fallthru edges. */
for (insn = NEXT_INSN (BB_END (bb)); ; insn = NEXT_INSN (insn))
{
if (!insn || NOTE_INSN_BASIC_BLOCK_P (insn))
{
error ("missing barrier after block %i", bb->index);
err = 1;
break;
}
if (BARRIER_P (insn))
break;
}
}
else if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
&& e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
{
rtx_insn *insn;
if (e->src->next_bb != e->dest)
{
error
("verify_flow_info: Incorrect blocks for fallthru %i->%i",
e->src->index, e->dest->index);
err = 1;
}
else
for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
insn = NEXT_INSN (insn))
if (BARRIER_P (insn) || NONDEBUG_INSN_P (insn))
{
error ("verify_flow_info: Incorrect fallthru %i->%i",
e->src->index, e->dest->index);
fatal_insn ("wrong insn in the fallthru edge", insn);
err = 1;
}
}
}
return err;
}
/* Verify that blocks are laid out in consecutive order. While walking the
instructions, verify that all expected instructions are inside the basic
blocks, and that all returns are followed by barriers. */
static int
rtl_verify_bb_layout (void)
{
basic_block bb;
int err = 0;
rtx_insn *x, *y;
int num_bb_notes;
rtx_insn * const rtx_first = get_insns ();
basic_block last_bb_seen = ENTRY_BLOCK_PTR_FOR_FN (cfun), curr_bb = NULL;
num_bb_notes = 0;
for (x = rtx_first; x; x = NEXT_INSN (x))
{
if (NOTE_INSN_BASIC_BLOCK_P (x))
{
bb = NOTE_BASIC_BLOCK (x);
num_bb_notes++;
if (bb != last_bb_seen->next_bb)
internal_error ("basic blocks not laid down consecutively");
curr_bb = last_bb_seen = bb;
}
if (!curr_bb)
{
switch (GET_CODE (x))
{
case BARRIER:
case NOTE:
break;
case CODE_LABEL:
/* An ADDR_VEC is placed outside any basic block. */
if (NEXT_INSN (x)
&& JUMP_TABLE_DATA_P (NEXT_INSN (x)))
x = NEXT_INSN (x);
/* But in any case, non-deletable labels can appear anywhere. */
break;
default:
fatal_insn ("insn outside basic block", x);
}
}
if (JUMP_P (x)
&& returnjump_p (x) && ! condjump_p (x)
&& ! ((y = next_nonnote_nondebug_insn (x))
&& BARRIER_P (y)))
fatal_insn ("return not followed by barrier", x);
if (curr_bb && x == BB_END (curr_bb))
curr_bb = NULL;
}
if (num_bb_notes != n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS)
internal_error
("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
num_bb_notes, n_basic_blocks_for_fn (cfun));
return err;
}
/* Verify the CFG and RTL consistency common for both underlying RTL and
cfglayout RTL, plus consistency checks specific to linearized RTL mode.
Currently it does following checks:
- all checks of rtl_verify_flow_info_1
- test head/end pointers
- check that blocks are laid out in consecutive order
- check that all insns are in the basic blocks
(except the switch handling code, barriers and notes)
- check that all returns are followed by barriers
- check that all fallthru edge points to the adjacent blocks
- verify that there is a single hot/cold partition boundary after bbro */
static int
rtl_verify_flow_info (void)
{
int err = 0;
err |= rtl_verify_flow_info_1 ();
err |= rtl_verify_bb_insn_chain ();
err |= rtl_verify_fallthru ();
err |= rtl_verify_bb_layout ();
err |= verify_hot_cold_block_grouping ();
return err;
}
/* Assume that the preceding pass has possibly eliminated jump instructions
or converted the unconditional jumps. Eliminate the edges from CFG.
Return true if any edges are eliminated. */
bool
purge_dead_edges (basic_block bb)
{
edge e;
rtx_insn *insn = BB_END (bb);
rtx note;
bool purged = false;
bool found;
edge_iterator ei;
if ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb))
do
insn = PREV_INSN (insn);
while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb));
/* If this instruction cannot trap, remove REG_EH_REGION notes. */
if (NONJUMP_INSN_P (insn)
&& (note = find_reg_note (insn, REG_EH_REGION, NULL)))
{
rtx eqnote;
if (! may_trap_p (PATTERN (insn))
|| ((eqnote = find_reg_equal_equiv_note (insn))
&& ! may_trap_p (XEXP (eqnote, 0))))
remove_note (insn, note);
}
/* Cleanup abnormal edges caused by exceptions or non-local gotos. */
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
bool remove = false;
/* There are three types of edges we need to handle correctly here: EH
edges, abnormal call EH edges, and abnormal call non-EH edges. The
latter can appear when nonlocal gotos are used. */
if (e->flags & EDGE_ABNORMAL_CALL)
{
if (!CALL_P (insn))
remove = true;
else if (can_nonlocal_goto (insn))
;
else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
;
else if (flag_tm && find_reg_note (insn, REG_TM, NULL))
;
else
remove = true;
}
else if (e->flags & EDGE_EH)
remove = !can_throw_internal (insn);
if (remove)
{
remove_edge (e);
df_set_bb_dirty (bb);
purged = true;
}
else
ei_next (&ei);
}
if (JUMP_P (insn))
{
rtx note;
edge b,f;
edge_iterator ei;
/* We do care only about conditional jumps and simplejumps. */
if (!any_condjump_p (insn)
&& !returnjump_p (insn)
&& !simplejump_p (insn))
return purged;
/* Branch probability/prediction notes are defined only for
condjumps. We've possibly turned condjump into simplejump. */
if (simplejump_p (insn))
{
note = find_reg_note (insn, REG_BR_PROB, NULL);
if (note)
remove_note (insn, note);
while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
remove_note (insn, note);
}
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
/* Avoid abnormal flags to leak from computed jumps turned
into simplejumps. */
e->flags &= ~EDGE_ABNORMAL;
/* See if this edge is one we should keep. */
if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
/* A conditional jump can fall through into the next
block, so we should keep the edge. */
{
ei_next (&ei);
continue;
}
else if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
&& BB_HEAD (e->dest) == JUMP_LABEL (insn))
/* If the destination block is the target of the jump,
keep the edge. */
{
ei_next (&ei);
continue;
}
else if (e->dest == EXIT_BLOCK_PTR_FOR_FN (