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[SFN] debug markers before labels no more 

Make sure that gimple and RTL IRs don't have debug markers before
labels.  When we build the CFG, we move labels before any markers
appearing before them.  Then, make sure we don't mistakenly
reintroduce them.

This reverts some of the complexity that had been brought about by the
initial SFN patches.

for  gcc/ChangeLog

	PR bootstrap/83396
	* cfgexpand.c (label_rtx_for_bb): Revert SFN changes that
	allowed debug stmts before labels.
	(expand_gimple_basic_block): Likewise.
	* gimple-iterator.c (gimple_find_edge_insert_loc): Likewise.
	* gimple-iterator.h (gsi_after_labels): Likewise.
	* tree-cfgcleanup (remove_forwarder_block): Likewise, but
	rename reused variable, and simplify using gsi_move_before.
	* tree-ssa-tail-merge.c (find_duplicate): Likewise.
	* tree-cfg.c (make_edges, cleanup_dead_labels): Likewise.
	(gimple_can_merge_blocks_p, verify_gimple_in_cfg): Likewise.
	(gimple_verify_flow_info, gimple_block_label): Likewise.
	(make_blocks): Move debug markers after adjacent labels.
	* cfgrtl.c (skip_insns_after_block): Revert SFN changes that
	allowed debug insns outside blocks.
	* df-scan.c (df_insn_delete): Likewise.
	* lra-constraints.c (update_ebb_live_info): Likewise.
	* var-tracking.c (get_first_insn, vt_emit_notes): Likewise.
	(vt_initialize, delete_vta_debug_insns): Likewise.
	(reemit_marker_as_note): Drop BB parm.  Adjust callers.

From-SVN: r255895
This commit is contained in:
Alexandre Oliva 2017-12-20 14:48:34 +00:00 committed by Alexandre Oliva
parent 8a91d54553
commit 67a8d7199f
11 changed files with 124 additions and 166 deletions
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23
gcc/ChangeLog
View File

@ -1,3 +1,26 @@
2017-12-20 Alexandre Oliva <aoliva@redhat.com>
PR bootstrap/83396
* cfgexpand.c (label_rtx_for_bb): Revert SFN changes that
allowed debug stmts before labels.
(expand_gimple_basic_block): Likewise.
* gimple-iterator.c (gimple_find_edge_insert_loc): Likewise.
* gimple-iterator.h (gsi_after_labels): Likewise.
* tree-cfgcleanup (remove_forwarder_block): Likewise, but
rename reused variable, and simplify using gsi_move_before.
* tree-ssa-tail-merge.c (find_duplicate): Likewise.
* tree-cfg.c (make_edges, cleanup_dead_labels): Likewise.
(gimple_can_merge_blocks_p, verify_gimple_in_cfg): Likewise.
(gimple_verify_flow_info, gimple_block_label): Likewise.
(make_blocks): Move debug markers after adjacent labels.
* cfgrtl.c (skip_insns_after_block): Revert SFN changes that
allowed debug insns outside blocks.
* df-scan.c (df_insn_delete): Likewise.
* lra-constraints.c (update_ebb_live_info): Likewise.
* var-tracking.c (get_first_insn, vt_emit_notes): Likewise.
(vt_initialize, delete_vta_debug_insns): Likewise.
(reemit_marker_as_note): Drop BB parm. Adjust callers.
2017-12-20 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>

13
gcc/cfgexpand.c
View File

@ -2327,9 +2327,6 @@ label_rtx_for_bb (basic_block bb ATTRIBUTE_UNUSED)
{
glabel *lab_stmt;
if (is_gimple_debug (gsi_stmt (gsi)))
continue;
lab_stmt = dyn_cast <glabel *> (gsi_stmt (gsi));
if (!lab_stmt)
break;
@ -5502,16 +5499,14 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
}
}
gsi = gsi_start_nondebug (stmts);
gsi = gsi_start (stmts);
if (!gsi_end_p (gsi))
{
stmt = gsi_stmt (gsi);
if (gimple_code (stmt) != GIMPLE_LABEL)
stmt = NULL;
}
gsi = gsi_start (stmts);
gimple *label_stmt = stmt;
rtx_code_label **elt = lab_rtx_for_bb->get (bb);
if (stmt || elt)
@ -5522,8 +5517,7 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
if (stmt)
{
expand_gimple_stmt (stmt);
if (gsi_stmt (gsi) == stmt)
gsi_next (&gsi);
gsi_next (&gsi);
}
if (elt)
@ -5549,9 +5543,6 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
stmt = gsi_stmt (gsi);
if (stmt == label_stmt)
continue;
/* If this statement is a non-debug one, and we generate debug
insns, then this one might be the last real use of a TERed
SSA_NAME, but where there are still some debug uses further

3
gcc/cfgrtl.c
View File

@ -3390,9 +3390,6 @@ skip_insns_after_block (basic_block bb)
last_insn = insn;
continue;
case DEBUG_INSN:
continue;
case NOTE:
switch (NOTE_KIND (insn))
{

2
gcc/df-scan.c
View File

@ -946,7 +946,7 @@ df_insn_delete (rtx_insn *insn)
In any case, we expect BB to be non-NULL at least up to register
allocation, so disallow a non-NULL BB up to there. Not perfect
but better than nothing... */
gcc_checking_assert (bb != NULL || DEBUG_INSN_P (insn) || reload_completed);
gcc_checking_assert (bb != NULL || reload_completed);
df_grow_bb_info (df_scan);
df_grow_reg_info ();

8
gcc/gimple-iterator.c
View File

@ -743,13 +743,9 @@ gimple_find_edge_insert_loc (edge e, gimple_stmt_iterator *gsi,
if (gsi_end_p (*gsi))
return true;
/* Make sure we insert after any leading labels. We have to
skip debug stmts before or among them, though. We didn't
have to skip debug stmts after the last label, but it
shouldn't hurt if we do. */
/* Make sure we insert after any leading labels. */
tmp = gsi_stmt (*gsi);
while (gimple_code (tmp) == GIMPLE_LABEL
|| is_gimple_debug (tmp))
while (gimple_code (tmp) == GIMPLE_LABEL)
{
gsi_next (gsi);
if (gsi_end_p (*gsi))

15
gcc/gimple-iterator.h
View File

@ -213,24 +213,17 @@ gsi_stmt (gimple_stmt_iterator i)
}
/* Return a block statement iterator that points to the first
non-label statement in block BB. Skip debug stmts only if they
precede labels. */
non-label statement in block BB. */
static inline gimple_stmt_iterator
gsi_after_labels (basic_block bb)
{
gimple_stmt_iterator gsi = gsi_start_bb (bb);
for (gimple_stmt_iterator gskip = gsi;
!gsi_end_p (gskip); )
for (; !gsi_end_p (gsi); )
{
if (is_gimple_debug (gsi_stmt (gskip)))
gsi_next (&gskip);
else if (gimple_code (gsi_stmt (gskip)) == GIMPLE_LABEL)
{
gsi_next (&gskip);
gsi = gskip;
}
if (gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL)
gsi_next (&gsi);
else
break;
}

7
gcc/lra-constraints.c
View File

@ -5820,13 +5820,6 @@ update_ebb_live_info (rtx_insn *head, rtx_insn *tail)
if (NOTE_P (curr_insn) && NOTE_KIND (curr_insn) != NOTE_INSN_BASIC_BLOCK)
continue;
curr_bb = BLOCK_FOR_INSN (curr_insn);
if (!curr_bb)
{
gcc_assert (DEBUG_INSN_P (curr_insn));
if (DEBUG_MARKER_INSN_P (curr_insn))
continue;
curr_bb = prev_bb;
}
if (curr_bb != prev_bb)
{
if (prev_bb != NULL)

101
gcc/tree-cfg.c
View File

@ -636,6 +636,67 @@ make_blocks_1 (gimple_seq seq, basic_block bb)
static void
make_blocks (gimple_seq seq)
{
/* Look for debug markers right before labels, and move the debug
stmts after the labels. Accepting labels among debug markers
adds no value, just complexity; if we wanted to annotate labels
with view numbers (so sequencing among markers would matter) or
somesuch, we're probably better off still moving the labels, but
adding other debug annotations in their original positions or
emitting nonbind or bind markers associated with the labels in
the original position of the labels.
Moving labels would probably be simpler, but we can't do that:
moving labels assigns label ids to them, and doing so because of
debug markers makes for -fcompare-debug and possibly even codegen
differences. So, we have to move the debug stmts instead. To
that end, we scan SEQ backwards, marking the position of the
latest (earliest we find) label, and moving debug stmts that are
not separated from it by nondebug nonlabel stmts after the
label. */
if (MAY_HAVE_DEBUG_MARKER_STMTS)
{
gimple_stmt_iterator label = gsi_none ();
for (gimple_stmt_iterator i = gsi_last (seq); !gsi_end_p (i); gsi_prev (&i))
{
gimple *stmt = gsi_stmt (i);
/* If this is the first label we encounter (latest in SEQ)
before nondebug stmts, record its position. */
if (is_a <glabel *> (stmt))
{
if (gsi_end_p (label))
label = i;
continue;
}
/* Without a recorded label position to move debug stmts to,
there's nothing to do. */
if (gsi_end_p (label))
continue;
/* Move the debug stmt at I after LABEL. */
if (is_gimple_debug (stmt))
{
gcc_assert (gimple_debug_nonbind_marker_p (stmt));
/* As STMT is removed, I advances to the stmt after
STMT, so the gsi_prev in the for "increment"
expression gets us to the stmt we're to visit after
STMT. LABEL, however, would advance to the moved
stmt if we passed it to gsi_move_after, so pass it a
copy instead, so as to keep LABEL pointing to the
LABEL. */
gimple_stmt_iterator copy = label;
gsi_move_after (&i, &copy);
continue;
}
/* There aren't any (more?) debug stmts before label, so
there isn't anything else to move after it. */
label = gsi_none ();
}
}
make_blocks_1 (seq, ENTRY_BLOCK_PTR_FOR_FN (cfun));
}
@ -1005,11 +1066,7 @@ make_edges (void)
tree target;
if (!label_stmt)
{
if (is_gimple_debug (gsi_stmt (gsi)))
continue;
break;
}
break;
target = gimple_label_label (label_stmt);
@ -1519,9 +1576,6 @@ cleanup_dead_labels (void)
for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
{
if (is_gimple_debug (gsi_stmt (i)))
continue;
tree label;
glabel *label_stmt = dyn_cast <glabel *> (gsi_stmt (i));
@ -1682,12 +1736,6 @@ cleanup_dead_labels (void)
for (i = gsi_start_bb (bb); !gsi_end_p (i); )
{
if (is_gimple_debug (gsi_stmt (i)))
{
gsi_next (&i);
continue;
}
tree label;
glabel *label_stmt = dyn_cast <glabel *> (gsi_stmt (i));
@ -1863,8 +1911,6 @@ gimple_can_merge_blocks_p (basic_block a, basic_block b)
gsi_next (&gsi))
{
tree lab;
if (is_gimple_debug (gsi_stmt (gsi)))
continue;
glabel *label_stmt = dyn_cast <glabel *> (gsi_stmt (gsi));
if (!label_stmt)
break;
@ -5431,7 +5477,6 @@ verify_gimple_in_cfg (struct function *fn, bool verify_nothrow)
err |= err2;
}
bool label_allowed = true;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
@ -5448,19 +5493,6 @@ verify_gimple_in_cfg (struct function *fn, bool verify_nothrow)
err2 = true;
}
/* Labels may be preceded only by debug markers, not debug bind
or source bind or any other statements. */
if (gimple_code (stmt) == GIMPLE_LABEL)
{
if (!label_allowed)
{
error ("gimple label in the middle of a basic block");
err2 = true;
}
}
else if (!gimple_debug_begin_stmt_p (stmt))
label_allowed = false;
err2 |= verify_gimple_stmt (stmt);
err2 |= verify_location (&blocks, gimple_location (stmt));
@ -5584,10 +5616,6 @@ gimple_verify_flow_info (void)
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
tree label;
if (is_gimple_debug (gsi_stmt (gsi)))
continue;
gimple *prev_stmt = stmt;
stmt = gsi_stmt (gsi);
@ -5912,10 +5940,8 @@ gimple_block_label (basic_block bb)
tree label;
glabel *stmt;
for (i = s; !gsi_end_p (i); gsi_next (&i))
for (i = s; !gsi_end_p (i); first = false, gsi_next (&i))
{
if (is_gimple_debug (gsi_stmt (i)))
continue;
stmt = dyn_cast <glabel *> (gsi_stmt (i));
if (!stmt)
break;
@ -5926,7 +5952,6 @@ gimple_block_label (basic_block bb)
gsi_move_before (&i, &s);
return label;
}
first = false;
}
label = create_artificial_label (UNKNOWN_LOCATION);

49
gcc/tree-cfgcleanup.c
View File

@ -444,7 +444,7 @@ remove_forwarder_block (basic_block bb)
{
edge succ = single_succ_edge (bb), e, s;
basic_block dest = succ->dest;
gimple *label;
gimple *stmt;
edge_iterator ei;
gimple_stmt_iterator gsi, gsi_to;
bool can_move_debug_stmts;
@ -457,9 +457,9 @@ remove_forwarder_block (basic_block bb)
/* If the destination block consists of a nonlocal label or is a
EH landing pad, do not merge it. */
label = first_stmt (dest);
if (label)
if (glabel *label_stmt = dyn_cast <glabel *> (label))
stmt = first_stmt (dest);
if (stmt)
if (glabel *label_stmt = dyn_cast <glabel *> (stmt))
if (DECL_NONLOCAL (gimple_label_label (label_stmt))
|| EH_LANDING_PAD_NR (gimple_label_label (label_stmt)) != 0)
return false;
@ -536,28 +536,23 @@ remove_forwarder_block (basic_block bb)
defined labels and labels with an EH landing pad number to the
new block, so that the redirection of the abnormal edges works,
jump targets end up in a sane place and debug information for
labels is retained.
While at that, move any debug stmts that appear before or in between
labels, but not those that can only appear after labels. */
labels is retained. */
gsi_to = gsi_start_bb (dest);
gsi = gsi_start_bb (bb);
gimple_stmt_iterator gsie = gsi_after_labels (bb);
while (gsi_stmt (gsi) != gsi_stmt (gsie))
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
{
tree decl;
label = gsi_stmt (gsi);
if (is_gimple_debug (label)
? can_move_debug_stmts
: ((decl = gimple_label_label (as_a <glabel *> (label))),
EH_LANDING_PAD_NR (decl) != 0
|| DECL_NONLOCAL (decl)
|| FORCED_LABEL (decl)
|| !DECL_ARTIFICIAL (decl)))
{
gsi_remove (&gsi, false);
gsi_insert_before (&gsi_to, label, GSI_SAME_STMT);
}
stmt = gsi_stmt (gsi);
if (is_gimple_debug (stmt))
break;
/* Forwarder blocks can only contain labels and debug stmts, and
labels must come first, so if we get to this point, we know
we're looking at a label. */
tree decl = gimple_label_label (as_a <glabel *> (stmt));
if (EH_LANDING_PAD_NR (decl) != 0
|| DECL_NONLOCAL (decl)
|| FORCED_LABEL (decl)
|| !DECL_ARTIFICIAL (decl))
gsi_move_before (&gsi, &gsi_to);
else
gsi_next (&gsi);
}
@ -565,14 +560,12 @@ remove_forwarder_block (basic_block bb)
/* Move debug statements if the destination has a single predecessor. */
if (can_move_debug_stmts && !gsi_end_p (gsi))
{
gcc_assert (gsi_stmt (gsi) == gsi_stmt (gsie));
gimple_stmt_iterator gsie_to = gsi_after_labels (dest);
gsi_to = gsi_after_labels (dest);
do
{
gimple *debug = gsi_stmt (gsi);
gcc_assert (is_gimple_debug (debug));
gsi_remove (&gsi, false);
gsi_insert_before (&gsie_to, debug, GSI_SAME_STMT);
gsi_move_before (&gsi, &gsi_to);
}
while (!gsi_end_p (gsi));
}

4
gcc/tree-ssa-tail-merge.c
View File

@ -1295,14 +1295,14 @@ find_duplicate (same_succ *same_succ, basic_block bb1, basic_block bb2)
tree label = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi1)));
if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
return;
gsi_prev_nondebug (&gsi1);
gsi_prev (&gsi1);
}
while (!gsi_end_p (gsi2) && gimple_code (gsi_stmt (gsi2)) == GIMPLE_LABEL)
{
tree label = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi2)));
if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
return;
gsi_prev_nondebug (&gsi2);
gsi_prev (&gsi2);
}
if (!(gsi_end_p (gsi1) && gsi_end_p (gsi2)))
return;

65
gcc/var-tracking.c
View File

@ -9511,24 +9511,6 @@ emit_notes_in_bb (basic_block bb, dataflow_set *set)
}
}
/* Return BB's head, unless BB is the block that succeeds ENTRY_BLOCK,
in which case it searches back from BB's head for the very first
insn. Use [get_first_insn (bb), BB_HEAD (bb->next_bb)[ as a range
to iterate over all insns of a function while iterating over its
BBs. */
static rtx_insn *
get_first_insn (basic_block bb)
{
rtx_insn *insn = BB_HEAD (bb);
if (bb->prev_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun))
while (rtx_insn *prev = PREV_INSN (insn))
insn = prev;
return insn;
}
/* Emit notes for the whole function. */
static void
@ -9557,8 +9539,7 @@ vt_emit_notes (void)
{
/* Emit the notes for changes of variable locations between two
subsequent basic blocks. */
emit_notes_for_differences (get_first_insn (bb),
&cur, &VTI (bb)->in);
emit_notes_for_differences (BB_HEAD (bb), &cur, &VTI (bb)->in);
if (MAY_HAVE_DEBUG_BIND_INSNS)
local_get_addr_cache = new hash_map<rtx, rtx>;
@ -9966,7 +9947,7 @@ vt_init_cfa_base (void)
/* Reemit INSN, a MARKER_DEBUG_INSN, as a note. */
static rtx_insn *
reemit_marker_as_note (rtx_insn *insn, basic_block *bb)
reemit_marker_as_note (rtx_insn *insn)
{
gcc_checking_assert (DEBUG_MARKER_INSN_P (insn));
@ -9981,8 +9962,6 @@ reemit_marker_as_note (rtx_insn *insn, basic_block *bb)
{
note = emit_note_before (kind, insn);
NOTE_MARKER_LOCATION (note) = INSN_LOCATION (insn);
if (bb)
BLOCK_FOR_INSN (note) = *bb;
}
delete_insn (insn);
return note;
@ -10190,39 +10169,11 @@ vt_initialize (void)
HOST_WIDE_INT offset = VTI (bb)->out.stack_adjust;
VTI (bb)->out.stack_adjust = VTI (bb)->in.stack_adjust;
/* If we are walking the first basic block, walk any HEADER
insns that might be before it too. Unfortunately,
BB_HEADER and BB_FOOTER are not set while we run this
pass. */
rtx_insn *next;
bool outside_bb = true;
for (insn = get_first_insn (bb); insn != BB_HEAD (bb->next_bb);
insn = next)
FOR_BB_INSNS_SAFE (bb, insn, next)
{
if (insn == BB_HEAD (bb))
outside_bb = false;
else if (insn == NEXT_INSN (BB_END (bb)))
outside_bb = true;
next = NEXT_INSN (insn);
if (INSN_P (insn))
{
if (outside_bb)
{
/* Ignore non-debug insns outside of basic blocks. */
if (!DEBUG_INSN_P (insn))
continue;
/* Debug binds shouldn't appear outside of bbs. */
gcc_assert (!DEBUG_BIND_INSN_P (insn));
}
basic_block save_bb = BLOCK_FOR_INSN (insn);
if (!BLOCK_FOR_INSN (insn))
{
gcc_assert (outside_bb);
BLOCK_FOR_INSN (insn) = bb;
}
else
gcc_assert (BLOCK_FOR_INSN (insn) == bb);
if (!frame_pointer_needed)
{
insn_stack_adjust_offset_pre_post (insn, &pre, &post);
@ -10244,7 +10195,7 @@ vt_initialize (void)
adjust_insn (bb, insn);
if (DEBUG_MARKER_INSN_P (insn))
{
insn = reemit_marker_as_note (insn, &save_bb);
reemit_marker_as_note (insn);
continue;
}
@ -10296,7 +10247,6 @@ vt_initialize (void)
}
}
}
BLOCK_FOR_INSN (insn) = save_bb;
}
}
gcc_assert (offset == VTI (bb)->out.stack_adjust);
@ -10338,15 +10288,12 @@ delete_vta_debug_insns (void)
FOR_EACH_BB_FN (bb, cfun)
{
for (insn = get_first_insn (bb);
insn != BB_HEAD (bb->next_bb)
? next = NEXT_INSN (insn), true : false;
insn = next)
FOR_BB_INSNS_SAFE (bb, insn, next)
if (DEBUG_INSN_P (insn))
{
if (DEBUG_MARKER_INSN_P (insn))
{
insn = reemit_marker_as_note (insn, NULL);
reemit_marker_as_note (insn);
continue;
}