/* Basic block reordering routines for the GNU compiler.
- Copyright (C) 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010
- Free Software Foundation, Inc.
+ Copyright (C) 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010, 2011,
+ 2012 Free Software Foundation, Inc.
This file is part of GCC.
#include "tree-pass.h"
#include "df.h"
#include "bb-reorder.h"
+#include "except.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
static bool better_edge_p (const_basic_block, const_edge, int, int, int, int, const_edge);
static void connect_traces (int, struct trace *);
static bool copy_bb_p (const_basic_block, int);
-static int get_uncond_jump_length (void);
static bool push_to_next_round_p (const_basic_block, int, int, int, gcov_type);
\f
/* Check to see if bb should be pushed into the next round of trace
/* Return the length of unconditional jump instruction. */
-static int
+int
get_uncond_jump_length (void)
{
rtx label, jump;
return length;
}
+/* Emit a barrier into the footer of BB. */
+
+static void
+emit_barrier_after_bb (basic_block bb)
+{
+ rtx barrier = emit_barrier_after (BB_END (bb));
+ bb->il.rtl->footer = unlink_insn_chain (barrier, barrier);
+}
+
+/* The landing pad OLD_LP, in block OLD_BB, has edges from both partitions.
+ Duplicate the landing pad and split the edges so that no EH edge
+ crosses partitions. */
+
+static void
+fix_up_crossing_landing_pad (eh_landing_pad old_lp, basic_block old_bb)
+{
+ eh_landing_pad new_lp;
+ basic_block new_bb, last_bb, post_bb;
+ rtx new_label, jump, post_label;
+ unsigned new_partition;
+ edge_iterator ei;
+ edge e;
+
+ /* Generate the new landing-pad structure. */
+ new_lp = gen_eh_landing_pad (old_lp->region);
+ new_lp->post_landing_pad = old_lp->post_landing_pad;
+ new_lp->landing_pad = gen_label_rtx ();
+ LABEL_PRESERVE_P (new_lp->landing_pad) = 1;
+
+ /* Put appropriate instructions in new bb. */
+ new_label = emit_label (new_lp->landing_pad);
+
+ expand_dw2_landing_pad_for_region (old_lp->region);
+
+ post_bb = BLOCK_FOR_INSN (old_lp->landing_pad);
+ post_bb = single_succ (post_bb);
+ post_label = block_label (post_bb);
+ jump = emit_jump_insn (gen_jump (post_label));
+ JUMP_LABEL (jump) = post_label;
+
+ /* Create new basic block to be dest for lp. */
+ last_bb = EXIT_BLOCK_PTR->prev_bb;
+ new_bb = create_basic_block (new_label, jump, last_bb);
+ new_bb->aux = last_bb->aux;
+ last_bb->aux = new_bb;
+
+ emit_barrier_after_bb (new_bb);
+
+ make_edge (new_bb, post_bb, 0);
+
+ /* Make sure new bb is in the other partition. */
+ new_partition = BB_PARTITION (old_bb);
+ new_partition ^= BB_HOT_PARTITION | BB_COLD_PARTITION;
+ BB_SET_PARTITION (new_bb, new_partition);
+
+ /* Fix up the edges. */
+ for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)) != NULL; )
+ if (BB_PARTITION (e->src) == new_partition)
+ {
+ rtx insn = BB_END (e->src);
+ rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
+
+ gcc_assert (note != NULL);
+ gcc_checking_assert (INTVAL (XEXP (note, 0)) == old_lp->index);
+ XEXP (note, 0) = GEN_INT (new_lp->index);
+
+ /* Adjust the edge to the new destination. */
+ redirect_edge_succ (e, new_bb);
+ }
+ else
+ ei_next (&ei);
+}
+
/* Find the basic blocks that are rarely executed and need to be moved to
a separate section of the .o file (to cut down on paging and improve
cache locality). Return a vector of all edges that cross. */
edge_iterator ei;
/* Mark which partition (hot/cold) each basic block belongs in. */
-
FOR_EACH_BB (bb)
{
if (probably_never_executed_bb_p (bb))
BB_SET_PARTITION (bb, BB_HOT_PARTITION);
}
- /* Mark every edge that crosses between sections. */
-
- FOR_EACH_BB (bb)
- FOR_EACH_EDGE (e, ei, bb->succs)
+ /* The format of .gcc_except_table does not allow landing pads to
+ be in a different partition as the throw. Fix this by either
+ moving or duplicating the landing pads. */
+ if (cfun->eh->lp_array)
{
- if (e->src != ENTRY_BLOCK_PTR
- && e->dest != EXIT_BLOCK_PTR
- && BB_PARTITION (e->src) != BB_PARTITION (e->dest))
+ unsigned i;
+ eh_landing_pad lp;
+
+ FOR_EACH_VEC_ELT (eh_landing_pad, cfun->eh->lp_array, i, lp)
{
- e->flags |= EDGE_CROSSING;
- VEC_safe_push (edge, heap, crossing_edges, e);
+ bool all_same, all_diff;
+
+ if (lp == NULL
+ || lp->landing_pad == NULL_RTX
+ || !LABEL_P (lp->landing_pad))
+ continue;
+
+ all_same = all_diff = true;
+ bb = BLOCK_FOR_INSN (lp->landing_pad);
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ gcc_assert (e->flags & EDGE_EH);
+ if (BB_PARTITION (bb) == BB_PARTITION (e->src))
+ all_diff = false;
+ else
+ all_same = false;
+ }
+
+ if (all_same)
+ ;
+ else if (all_diff)
+ {
+ int which = BB_PARTITION (bb);
+ which ^= BB_HOT_PARTITION | BB_COLD_PARTITION;
+ BB_SET_PARTITION (bb, which);
+ }
+ else
+ fix_up_crossing_landing_pad (lp, bb);
}
- else
- e->flags &= ~EDGE_CROSSING;
}
- return crossing_edges;
-}
+ /* Mark every edge that crosses between sections. */
-/* Emit a barrier into the footer of BB. */
+ FOR_EACH_BB (bb)
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ unsigned int flags = e->flags;
+
+ /* We should never have EDGE_CROSSING set yet. */
+ gcc_checking_assert ((flags & EDGE_CROSSING) == 0);
+
+ if (e->src != ENTRY_BLOCK_PTR
+ && e->dest != EXIT_BLOCK_PTR
+ && BB_PARTITION (e->src) != BB_PARTITION (e->dest))
+ {
+ VEC_safe_push (edge, heap, crossing_edges, e);
+ flags |= EDGE_CROSSING;
+ }
-static void
-emit_barrier_after_bb (basic_block bb)
-{
- rtx barrier = emit_barrier_after (BB_END (bb));
- bb->il.rtl->footer = unlink_insn_chain (barrier, barrier);
+ /* Now that we've split eh edges as appropriate, allow landing pads
+ to be merged with the post-landing pads. */
+ flags &= ~EDGE_PRESERVE;
+
+ e->flags = flags;
+ }
+
+ return crossing_edges;
}
/* If any destination of a crossing edge does not have a label, add label;
rtx new_note;
int first_partition = 0;
- if (flag_reorder_blocks_and_partition)
- FOR_EACH_BB (bb)
+ if (!flag_reorder_blocks_and_partition)
+ return;
+
+ FOR_EACH_BB (bb)
{
if (!first_partition)
first_partition = BB_PARTITION (bb);
if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1)
return 0;
+ df_set_flags (DF_DEFER_INSN_RESCAN);
+
crossing_edges = find_rarely_executed_basic_blocks_and_crossing_edges ();
if (crossing_edges == NULL)
return 0;
add_reg_crossing_jump_notes ();
+ /* Clear bb->aux fields that the above routines were using. */
+ clear_aux_for_blocks ();
+
VEC_free (edge, heap, crossing_edges);
+ /* ??? FIXME: DF generates the bb info for a block immediately.
+ And by immediately, I mean *during* creation of the block.
+
+ #0 df_bb_refs_collect
+ #1 in df_bb_refs_record
+ #2 in create_basic_block_structure
+
+ Which means that the bb_has_eh_pred test in df_bb_refs_collect
+ will *always* fail, because no edges can have been added to the
+ block yet. Which of course means we don't add the right
+ artificial refs, which means we fail df_verify (much) later.
+
+ Cleanest solution would seem to make DF_DEFER_INSN_RESCAN imply
+ that we also shouldn't grab data from the new blocks those new
+ insns are in either. In this way one can create the block, link
+ it up properly, and have everything Just Work later, when deferred
+ insns are processed.
+
+ In the meantime, we have no other option but to throw away all
+ of the DF data and recompute it all. */
+ if (cfun->eh->lp_array)
+ {
+ df_finish_pass (true);
+ df_scan_alloc (NULL);
+ df_scan_blocks ();
+ /* Not all post-landing pads use all of the EH_RETURN_DATA_REGNO
+ data. We blindly generated all of them when creating the new
+ landing pad. Delete those assignments we don't use. */
+ df_set_flags (DF_LR_RUN_DCE);
+ df_analyze ();
+ }
+
return TODO_verify_flow | TODO_verify_rtl_sharing;
}
\f
{
if (targetm.cannot_modify_jumps_p ())
return false;
- return (optimize > 0);
+ /* Don't reorder blocks when optimizing for size because extra jump insns may
+ be created; also barrier may create extra padding.
+
+ More correctly we should have a block reordering mode that tried to
+ minimize the combined size of all the jumps. This would more or less
+ automatically remove extra jumps, but would also try to use more short
+ jumps instead of long jumps. */
+ if (!optimize_function_for_speed_p (cfun))
+ return false;
+ return (optimize > 0
+ && (flag_reorder_blocks || flag_reorder_blocks_and_partition));
}
splitting possibly introduced more crossjumping opportunities. */
cfg_layout_initialize (CLEANUP_EXPENSIVE);
- if ((flag_reorder_blocks || flag_reorder_blocks_and_partition)
- /* Don't reorder blocks when optimizing for size because extra jump insns may
- be created; also barrier may create extra padding.
-
- More correctly we should have a block reordering mode that tried to
- minimize the combined size of all the jumps. This would more or less
- automatically remove extra jumps, but would also try to use more short
- jumps instead of long jumps. */
- && optimize_function_for_speed_p (cfun))
- {
- reorder_basic_blocks ();
- cleanup_cfg (CLEANUP_EXPENSIVE);
- }
+ reorder_basic_blocks ();
+ cleanup_cfg (CLEANUP_EXPENSIVE);
FOR_EACH_BB (bb)
if (bb->next_bb != EXIT_BLOCK_PTR)
arises. */
return (flag_reorder_blocks_and_partition
&& optimize
+ /* See gate_handle_reorder_blocks. We should not partition if
+ we are going to omit the reordering. */
+ && optimize_function_for_speed_p (cfun)
&& !DECL_ONE_ONLY (current_function_decl)
&& !user_defined_section_attribute);
}
OSDN Git Service
