#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
-#include "basic-block.h"
+#include "regs.h"
#include "flags.h"
#include "timevar.h"
#include "output.h"
#include "tm_p.h"
#include "obstack.h"
#include "expr.h"
-#include "regs.h"
/* The number of rounds. In most cases there will only be 4 rounds, but
when partitioning hot and cold basic blocks into separate sections of
#define GET_ARRAY_SIZE(X) ((((X) / 4) + 1) * 5)
/* Free the memory and set the pointer to NULL. */
-#define FREE(P) \
- do { if (P) { free (P); P = 0; } else { abort (); } } while (0)
+#define FREE(P) (gcc_assert (P), free (P), P = 0)
/* Structure for holding information about a trace. */
struct trace
int i;
int number_of_rounds;
edge e;
+ edge_iterator ei;
fibheap_t heap;
/* Add one extra round of trace collection when partitioning hot/cold
heap = fibheap_new ();
max_entry_frequency = 0;
max_entry_count = 0;
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
{
bbd[e->dest->index].heap = heap;
bbd[e->dest->index].node = fibheap_insert (heap, bb_to_key (e->dest),
do
{
edge e;
- for (e = bb->succ; e; e = e->succ_next)
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e->dest != EXIT_BLOCK_PTR
&& e->dest->rbi->visited != trace_n
&& (e->flags & EDGE_CAN_FALLTHRU)
prev_bb->rbi->next = best_bb->rbi->next;
/* Try to get rid of uncond jump to cond jump. */
- if (prev_bb->succ && !prev_bb->succ->succ_next)
+ if (EDGE_COUNT (prev_bb->succs) == 1)
{
- basic_block header = prev_bb->succ->dest;
+ basic_block header = EDGE_SUCC (prev_bb, 0)->dest;
/* Duplicate HEADER if it is a small block containing cond jump
in the end. */
&& !find_reg_note (BB_END (header), REG_CROSSING_JUMP,
NULL_RTX))
{
- copy_bb (header, prev_bb->succ, prev_bb, trace_n);
+ copy_bb (header, EDGE_SUCC (prev_bb, 0), prev_bb, trace_n);
}
}
}
struct trace *trace;
edge best_edge, e;
fibheapkey_t key;
+ edge_iterator ei;
bb = fibheap_extract_min (*heap);
bbd[bb->index].heap = NULL;
bb->index, *n_traces - 1);
/* Select the successor that will be placed after BB. */
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
-#ifdef ENABLE_CHECKING
- if (e->flags & EDGE_FAKE)
- abort ();
-#endif
+ gcc_assert (!(e->flags & EDGE_FAKE));
if (e->dest == EXIT_BLOCK_PTR)
continue;
freq = EDGE_FREQUENCY (e);
/* Edge that cannot be fallthru or improbable or infrequent
- successor (ie. it is unsuitable successor). */
+ successor (i.e. it is unsuitable successor). */
if (!(e->flags & EDGE_CAN_FALLTHRU) || (e->flags & EDGE_COMPLEX)
|| prob < branch_th || freq < exec_th || e->count < count_th)
continue;
/* If the best destination has multiple predecessors, and can be
duplicated cheaper than a jump, don't allow it to be added
to a trace. We'll duplicate it when connecting traces. */
- if (best_edge && best_edge->dest->pred->pred_next
+ if (best_edge && EDGE_COUNT (best_edge->dest->preds) >= 2
&& copy_bb_p (best_edge->dest, 0))
best_edge = NULL;
/* Add all non-selected successors to the heaps. */
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
if (e == best_edge
|| e->dest == EXIT_BLOCK_PTR
{
/* The loop has less than 4 iterations. */
- /* Check whether there is another edge from BB. */
- edge another_edge;
- for (another_edge = bb->succ;
- another_edge;
- another_edge = another_edge->succ_next)
- if (another_edge != best_edge)
- break;
-
- if (!another_edge && copy_bb_p (best_edge->dest,
- !optimize_size))
+ if (EDGE_COUNT (bb->succs) == 1
+ && copy_bb_p (best_edge->dest, !optimize_size))
{
bb = copy_bb (best_edge->dest, best_edge, bb,
*n_traces);
*/
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e != best_edge
&& (e->flags & EDGE_CAN_FALLTHRU)
&& !(e->flags & EDGE_COMPLEX)
&& !e->dest->rbi->visited
- && !e->dest->pred->pred_next
+ && EDGE_COUNT (e->dest->preds) == 1
&& !(e->flags & EDGE_CROSSING)
- && e->dest->succ
- && (e->dest->succ->flags & EDGE_CAN_FALLTHRU)
- && !(e->dest->succ->flags & EDGE_COMPLEX)
- && !e->dest->succ->succ_next
- && e->dest->succ->dest == best_edge->dest
+ && EDGE_COUNT (e->dest->succs) == 1
+ && (EDGE_SUCC (e->dest, 0)->flags & EDGE_CAN_FALLTHRU)
+ && !(EDGE_SUCC (e->dest, 0)->flags & EDGE_COMPLEX)
+ && EDGE_SUCC (e->dest, 0)->dest == best_edge->dest
&& 2 * e->dest->frequency >= EDGE_FREQUENCY (best_edge))
{
best_edge = e;
/* The trace is terminated so we have to recount the keys in heap
(some block can have a lower key because now one of its predecessors
is an end of the trace). */
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
if (e->dest == EXIT_BLOCK_PTR
|| e->dest->rbi->visited)
new_bb = duplicate_block (old_bb, e);
BB_COPY_PARTITION (new_bb, old_bb);
- if (e->dest != new_bb)
- abort ();
- if (e->dest->rbi->visited)
- abort ();
+ gcc_assert (e->dest == new_bb);
+ gcc_assert (!e->dest->rbi->visited);
+
if (dump_file)
fprintf (dump_file,
"Duplicated bb %d (created bb %d)\n",
bb_to_key (basic_block bb)
{
edge e;
-
+ edge_iterator ei;
int priority = 0;
/* Do not start in probably never executed blocks. */
/* Prefer blocks whose predecessor is an end of some trace
or whose predecessor edge is EDGE_DFS_BACK. */
- for (e = bb->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, bb->preds)
{
if ((e->src != ENTRY_BLOCK_PTR && bbd[e->src->index].end_of_trace >= 0)
|| (e->flags & EDGE_DFS_BACK))
/* Find the predecessor traces. */
for (t2 = t; t2 > 0;)
{
+ edge_iterator ei;
best = NULL;
best_len = 0;
- for (e = traces[t2].first->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, traces[t2].first->preds)
{
int si = e->src->index;
while (1)
{
/* Find the continuation of the chain. */
+ edge_iterator ei;
best = NULL;
best_len = 0;
- for (e = traces[t].last->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, traces[t].last->succs)
{
int di = e->dest->index;
basic_block next_bb = NULL;
bool try_copy = false;
- for (e = traces[t].last->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, traces[t].last->succs)
if (e->dest != EXIT_BLOCK_PTR
&& (e->flags & EDGE_CAN_FALLTHRU)
&& !(e->flags & EDGE_COMPLEX)
&& (!best || e->probability > best->probability))
{
+ edge_iterator ei;
edge best2 = NULL;
int best2_len = 0;
continue;
}
- for (e2 = e->dest->succ; e2; e2 = e2->succ_next)
+ FOR_EACH_EDGE (e2, ei, e->dest->succs)
{
int di = e2->dest->index;
int size = 0;
int max_size = uncond_jump_length;
rtx insn;
- int n_succ;
- edge e;
if (!bb->frequency)
return false;
- if (!bb->pred || !bb->pred->pred_next)
+ if (EDGE_COUNT (bb->preds) < 2)
return false;
if (!can_duplicate_block_p (bb))
return false;
/* Avoid duplicating blocks which have many successors (PR/13430). */
- n_succ = 0;
- for (e = bb->succ; e; e = e->succ_next)
- {
- n_succ++;
- if (n_succ > 8)
- return false;
- }
+ if (EDGE_COUNT (bb->succs) > 8)
+ return false;
if (code_may_grow && maybe_hot_bb_p (bb))
max_size *= 8;
bool has_hot_blocks = false;
edge e;
int i;
+ edge_iterator ei;
/* Mark which partition (hot/cold) each basic block belongs in. */
the hot partition (if there is one). */
if (has_hot_blocks)
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
if (e->dest->index >= 0)
{
BB_SET_PARTITION (e->dest, BB_HOT_PARTITION);
if (targetm.have_named_sections)
{
FOR_EACH_BB (bb)
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
if (e->src != ENTRY_BLOCK_PTR
&& e->dest != EXIT_BLOCK_PTR
/* If basic block does not contain a NOTE_INSN_BASIC_BLOCK, there is
a major problem. */
-
- if (!insert_insn)
- abort ();
+ gcc_assert (insert_insn);
/* Insert note and assign basic block number to it. */
/* bb just falls through. */
{
/* make sure there's only one successor */
- if (src->succ && (src->succ->succ_next == NULL))
- {
- /* Find label in dest block. */
- label = block_label (dest);
-
- new_jump = emit_jump_insn_after (gen_jump (label),
- BB_END (src));
- barrier = emit_barrier_after (new_jump);
- JUMP_LABEL (new_jump) = label;
- LABEL_NUSES (label) += 1;
- src->rbi->footer = unlink_insn_chain (barrier,
- barrier);
- /* Mark edge as non-fallthru. */
- crossing_edges[i]->flags &= ~EDGE_FALLTHRU;
- }
- else
- {
- /* Basic block has two successors, but
- doesn't end in a jump; something is wrong
- here! */
- abort();
- }
+ gcc_assert (EDGE_COUNT (src->succs) == 1);
+
+ /* Find label in dest block. */
+ label = block_label (dest);
+
+ new_jump = emit_jump_insn_after (gen_jump (label),
+ BB_END (src));
+ barrier = emit_barrier_after (new_jump);
+ JUMP_LABEL (new_jump) = label;
+ LABEL_NUSES (label) += 1;
+ src->rbi->footer = unlink_insn_chain (barrier, barrier);
+ /* Mark edge as non-fallthru. */
+ crossing_edges[i]->flags &= ~EDGE_FALLTHRU;
} /* end: 'if (GET_CODE ... ' */
} /* end: 'if (src && src->index...' */
} /* end: 'if (dest && dest->index...' */
FOR_EACH_BB (cur_bb)
{
fall_thru = NULL;
- succ1 = cur_bb->succ;
- if (succ1)
- succ2 = succ1->succ_next;
+ if (EDGE_COUNT (cur_bb->succs) > 0)
+ succ1 = EDGE_SUCC (cur_bb, 0);
+ else
+ succ1 = NULL;
+
+ if (EDGE_COUNT (cur_bb->succs) > 1)
+ succ2 = EDGE_SUCC (cur_bb, 1);
else
succ2 = NULL;
partition as bb it's falling through from. */
BB_COPY_PARTITION (new_bb, cur_bb);
- new_bb->succ->flags |= EDGE_CROSSING;
+ EDGE_SUCC (new_bb, 0)->flags |= EDGE_CROSSING;
}
/* Add barrier after new jump */
basic_block source_bb = NULL;
edge e;
rtx insn;
+ edge_iterator ei;
- for (e = jump_dest->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, jump_dest->preds)
if (e->flags & EDGE_CROSSING)
{
basic_block src = e->src;
FOR_EACH_BB (cur_bb)
{
crossing_edge = NULL;
- succ1 = cur_bb->succ;
- if (succ1)
- succ2 = succ1->succ_next;
+ if (EDGE_COUNT (cur_bb->succs) > 0)
+ succ1 = EDGE_SUCC (cur_bb, 0);
+ else
+ succ1 = NULL;
+
+ if (EDGE_COUNT (cur_bb->succs) > 1)
+ succ2 = EDGE_SUCC (cur_bb, 1);
else
- succ2 = NULL;
+ succ2 = NULL;
/* We already took care of fall-through edges, so only one successor
can be a crossing edge. */
/* Update register liveness information. */
- new_bb->global_live_at_start =
- OBSTACK_ALLOC_REG_SET (&flow_obstack);
- new_bb->global_live_at_end =
- OBSTACK_ALLOC_REG_SET (&flow_obstack);
+ new_bb->global_live_at_start = ALLOC_REG_SET (®_obstack);
+ new_bb->global_live_at_end = ALLOC_REG_SET (®_obstack);
COPY_REG_SET (new_bb->global_live_at_end,
prev_bb->global_live_at_end);
COPY_REG_SET (new_bb->global_live_at_start,
(old_label),
BB_END (new_bb));
}
- else if (HAVE_return
- && GET_CODE (old_label) == RETURN)
- new_jump = emit_jump_insn_after (gen_return (),
- BB_END (new_bb));
else
- abort ();
+ {
+ gcc_assert (HAVE_return
+ && GET_CODE (old_label) == RETURN);
+ new_jump = emit_jump_insn_after (gen_return (),
+ BB_END (new_bb));
+ }
barrier = emit_barrier_after (new_jump);
JUMP_LABEL (new_jump) = old_label;
will be a successor for new_bb and a predecessor
for 'dest'. */
- if (!new_bb->succ)
+ if (EDGE_COUNT (new_bb->succs) == 0)
new_edge = make_edge (new_bb, dest, 0);
else
- new_edge = new_bb->succ;
+ new_edge = EDGE_SUCC (new_bb, 0);
crossing_edge->flags &= ~EDGE_CROSSING;
new_edge->flags |= EDGE_CROSSING;
FOR_EACH_BB (cur_bb)
{
last_insn = BB_END (cur_bb);
- succ = cur_bb->succ;
+ succ = EDGE_SUCC (cur_bb, 0);
/* Check to see if bb ends in a crossing (unconditional) jump. At
this point, no crossing jumps should be conditional. */
{
rtx label2, table;
- if (any_condjump_p (last_insn))
- abort ();
+ gcc_assert (!any_condjump_p (last_insn));
/* Make sure the jump is not already an indirect or table jump. */
- else if (!computed_jump_p (last_insn)
- && !tablejump_p (last_insn, &label2, &table))
+ if (!computed_jump_p (last_insn)
+ && !tablejump_p (last_insn, &label2, &table))
{
/* We have found a "crossing" unconditional branch. Now
we must convert it to an indirect jump. First create
{
basic_block bb;
edge e;
+ edge_iterator ei;
FOR_EACH_BB (bb)
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if ((e->flags & EDGE_CROSSING)
&& JUMP_P (BB_END (e->src)))
REG_NOTES (BB_END (e->src)) = gen_rtx_EXPR_LIST (REG_CROSSING_JUMP,
been called. However part of this optimization may introduce new
register usage, so it must be called before register allocation has
occurred. This means that this optimization is actually called
- well before the optimization that reorders basic blocks (see function
- above).
+ well before the optimization that reorders basic blocks (see
+ function above).
This optimization checks the feedback information to determine
- which basic blocks are hot/cold and adds
- NOTE_INSN_UNLIKELY_EXECUTED_CODE to non-hot basic blocks. The
+ which basic blocks are hot/cold and causes reorder_basic_blocks to
+ add NOTE_INSN_UNLIKELY_EXECUTED_CODE to non-hot basic blocks. The
presence or absence of this note is later used for writing out
- sections in the .o file. This optimization must also modify the
- CFG to make sure there are no fallthru edges between hot & cold
- blocks, as those blocks will not necessarily be contiguous in the
- .o (or assembly) file; and in those cases where the architecture
- requires it, conditional and unconditional branches that cross
- between sections are converted into unconditional or indirect
- jumps, depending on what is appropriate. */
+ sections in the .o file. Because hot and cold sections can be
+ arbitrarily large (within the bounds of memory), far beyond the
+ size of a single function, it is necessary to fix up all edges that
+ cross section boundaries, to make sure the instructions used can
+ actually span the required distance. The fixes are described
+ below.
+
+ Fall-through edges must be changed into jumps; it is not safe or
+ legal to fall through across a section boundary. Whenever a
+ fall-through edge crossing a section boundary is encountered, a new
+ basic block is inserted (in the same section as the fall-through
+ source), and the fall through edge is redirected to the new basic
+ block. The new basic block contains an unconditional jump to the
+ original fall-through target. (If the unconditional jump is
+ insufficient to cross section boundaries, that is dealt with a
+ little later, see below).
+
+ In order to deal with architectures that have short conditional
+ branches (which cannot span all of memory) we take any conditional
+ jump that attempts to cross a section boundary and add a level of
+ indirection: it becomes a conditional jump to a new basic block, in
+ the same section. The new basic block contains an unconditional
+ jump to the original target, in the other section.
+
+ For those architectures whose unconditional branch is also
+ incapable of reaching all of memory, those unconditional jumps are
+ converted into indirect jumps, through a register.
+
+ IMPORTANT NOTE: This optimization causes some messy interactions
+ with the cfg cleanup optimizations; those optimizations want to
+ merge blocks wherever possible, and to collapse indirect jump
+ sequences (change "A jumps to B jumps to C" directly into "A jumps
+ to C"). Those optimizations can undo the jump fixes that
+ partitioning is required to make (see above), in order to ensure
+ that jumps attempting to cross section boundaries are really able
+ to cover whatever distance the jump requires (on many architectures
+ conditional or unconditional jumps are not able to reach all of
+ memory). Therefore tests have to be inserted into each such
+ optimization to make sure that it does not undo stuff necessary to
+ cross partition boundaries. This would be much less of a problem
+ if we could perform this optimization later in the compilation, but
+ unfortunately the fact that we may need to create indirect jumps
+ (through registers) requires that this optimization be performed
+ before register allocation. */
void
partition_hot_cold_basic_blocks (void)
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