1106 lines
26 KiB
C
1106 lines
26 KiB
C
/* Basic block reordering routines for the GNU compiler.
|
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Copyright (C) 2000, 2001 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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02111-1307, USA. */
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#include "config.h"
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#include "system.h"
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#include "rtl.h"
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#include "hard-reg-set.h"
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#include "basic-block.h"
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#include "insn-config.h"
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#include "output.h"
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#include "function.h"
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#include "obstack.h"
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#include "cfglayout.h"
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/* The contents of the current function definition are allocated
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in this obstack, and all are freed at the end of the function.
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For top-level functions, this is temporary_obstack.
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Separate obstacks are made for nested functions. */
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extern struct obstack flow_obstack;
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/* Structure to hold information about lexical scopes. */
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struct scope_def
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{
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int level;
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/* The NOTE_INSN_BLOCK_BEG that started this scope. */
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rtx note_beg;
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/* The NOTE_INSN_BLOCK_END that ended this scope. */
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rtx note_end;
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/* The bb containing note_beg (if any). */
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basic_block bb_beg;
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/* The bb containing note_end (if any). */
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basic_block bb_end;
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/* List of basic blocks contained within this scope. */
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basic_block *bbs;
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/* Number of blocks contained within this scope. */
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int num_bbs;
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/* The outer scope or NULL if outermost scope. */
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struct scope_def *outer;
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/* The first inner scope or NULL if innermost scope. */
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struct scope_def *inner;
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/* The last inner scope or NULL if innermost scope. */
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struct scope_def *inner_last;
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/* Link to the next (sibling) scope. */
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struct scope_def *next;
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};
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/* Structure to hold information about the scope forest. */
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typedef struct
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{
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/* Number of trees in forest. */
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int num_trees;
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/* List of tree roots. */
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scope *trees;
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} scope_forest_info;
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/* Holds the interesting trailing notes for the function. */
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static rtx function_tail_eff_head;
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/* The scope forest of current function. */
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static scope_forest_info forest;
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static rtx skip_insns_after_block PARAMS ((basic_block));
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static void record_effective_endpoints PARAMS ((void));
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static rtx label_for_bb PARAMS ((basic_block));
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static void fixup_reorder_chain PARAMS ((void));
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static void relate_bbs_with_scopes PARAMS ((scope));
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static scope make_new_scope PARAMS ((int, rtx));
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static void build_scope_forest PARAMS ((scope_forest_info *));
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static void remove_scope_notes PARAMS ((void));
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static void insert_intra_1 PARAMS ((scope, rtx *, basic_block));
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static void insert_intra_bb_scope_notes PARAMS ((basic_block));
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static void insert_inter_bb_scope_notes PARAMS ((basic_block, basic_block));
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static void rebuild_scope_notes PARAMS ((scope_forest_info *));
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static void free_scope_forest_1 PARAMS ((scope));
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static void free_scope_forest PARAMS ((scope_forest_info *));
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void dump_scope_forest PARAMS ((scope_forest_info *));
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static void dump_scope_forest_1 PARAMS ((scope, int));
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static rtx get_next_bb_note PARAMS ((rtx));
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static rtx get_prev_bb_note PARAMS ((rtx));
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void verify_insn_chain PARAMS ((void));
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static void fixup_fallthru_exit_predecessor PARAMS ((void));
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/* Skip over inter-block insns occurring after BB which are typically
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associated with BB (e.g., barriers). If there are any such insns,
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we return the last one. Otherwise, we return the end of BB. */
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static rtx
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skip_insns_after_block (bb)
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basic_block bb;
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{
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rtx insn, last_insn, next_head, prev;
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next_head = NULL_RTX;
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if (bb->index + 1 != n_basic_blocks)
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next_head = BASIC_BLOCK (bb->index + 1)->head;
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for (last_insn = insn = bb->end; (insn = NEXT_INSN (insn)); )
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{
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if (insn == next_head)
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break;
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switch (GET_CODE (insn))
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{
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case BARRIER:
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last_insn = insn;
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continue;
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case NOTE:
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switch (NOTE_LINE_NUMBER (insn))
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{
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case NOTE_INSN_LOOP_END:
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case NOTE_INSN_BLOCK_END:
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last_insn = insn;
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continue;
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case NOTE_INSN_DELETED:
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case NOTE_INSN_DELETED_LABEL:
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continue;
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default:
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continue;
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break;
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}
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break;
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case CODE_LABEL:
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if (NEXT_INSN (insn)
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&& GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
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&& (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
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|| GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
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{
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insn = NEXT_INSN (insn);
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last_insn = insn;
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continue;
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}
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break;
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default:
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break;
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}
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break;
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}
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/* It is possible to hit contradicting sequence. For instance:
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jump_insn
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NOTE_INSN_LOOP_BEG
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barrier
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Where barrier belongs to jump_insn, but the note does not.
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This can be created by removing the basic block originally
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following NOTE_INSN_LOOP_BEG.
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In such case reorder the notes. */
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for (insn = last_insn; insn != bb->end; insn = prev)
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{
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prev = PREV_INSN (insn);
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if (GET_CODE (insn) == NOTE)
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switch (NOTE_LINE_NUMBER (insn))
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{
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case NOTE_INSN_LOOP_END:
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case NOTE_INSN_BLOCK_END:
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case NOTE_INSN_DELETED:
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case NOTE_INSN_DELETED_LABEL:
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continue;
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default:
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reorder_insns (insn, insn, last_insn);
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}
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}
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return last_insn;
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}
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/* Locate or create a label for a given basic block. */
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static rtx
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label_for_bb (bb)
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basic_block bb;
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{
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rtx label = bb->head;
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if (GET_CODE (label) != CODE_LABEL)
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{
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if (rtl_dump_file)
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fprintf (rtl_dump_file, "Emitting label for block %d\n",
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bb->index);
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label = block_label (bb);
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if (bb->head == PREV_INSN (RBI (bb)->eff_head))
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RBI (bb)->eff_head = label;
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}
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return label;
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}
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/* Locate the effective beginning and end of the insn chain for each
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block, as defined by skip_insns_after_block above. */
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static void
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record_effective_endpoints ()
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{
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rtx next_insn = get_insns ();
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int i;
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for (i = 0; i < n_basic_blocks; ++i)
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{
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basic_block bb = BASIC_BLOCK (i);
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rtx end;
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RBI (bb)->eff_head = next_insn;
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end = skip_insns_after_block (bb);
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RBI (bb)->eff_end = end;
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next_insn = NEXT_INSN (end);
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}
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function_tail_eff_head = next_insn;
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}
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static rtx
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get_next_bb_note (x)
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rtx x;
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{
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while (x)
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{
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if (NOTE_INSN_BASIC_BLOCK_P (x))
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return x;
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x = NEXT_INSN (x);
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}
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return NULL;
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}
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static rtx
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get_prev_bb_note (x)
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rtx x;
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{
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while (x)
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{
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if (NOTE_INSN_BASIC_BLOCK_P (x))
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return x;
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x = PREV_INSN (x);
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}
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return NULL;
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}
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/* Determine and record the relationships between basic blocks and
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scopes in scope tree S. */
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static void
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relate_bbs_with_scopes (s)
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scope s;
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{
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scope p;
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int i, bbi1, bbi2, bbs_spanned;
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rtx bbnote;
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for (p = s->inner; p; p = p->next)
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relate_bbs_with_scopes (p);
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bbi1 = bbi2 = -1;
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bbs_spanned = 0;
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/* If the begin and end notes are both inside the same basic block,
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or if they are both outside of basic blocks, then we know immediately
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how they are related. Otherwise, we need to poke around to make the
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determination. */
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if (s->bb_beg != s->bb_end)
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{
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if (s->bb_beg && s->bb_end)
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{
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/* Both notes are in different bbs. This implies that all the
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basic blocks spanned by the pair of notes are contained in
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this scope. */
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bbi1 = s->bb_beg->index;
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bbi2 = s->bb_end->index;
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bbs_spanned = 1;
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}
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else if (! s->bb_beg)
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{
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/* First note is outside of a bb. If the scope spans more than
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one basic block, then they all are contained within this
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scope. Otherwise, this scope is contained within the basic
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block. */
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bbnote = get_next_bb_note (s->note_beg);
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if (! bbnote)
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abort ();
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if (NOTE_BASIC_BLOCK (bbnote) == s->bb_end)
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{
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bbs_spanned = 0;
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s->bb_beg = NOTE_BASIC_BLOCK (bbnote);
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}
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else
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{
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bbi1 = NOTE_BASIC_BLOCK (bbnote)->index;
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bbi2 = s->bb_end->index;
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s->bb_end = NULL;
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bbs_spanned = 1;
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}
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}
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else /* ! s->bb_end */
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{
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/* Second note is outside of a bb. If the scope spans more than
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one basic block, then they all are contained within this
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scope. Otherwise, this scope is contained within the basic
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block. */
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bbnote = get_prev_bb_note (s->note_end);
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if (! bbnote)
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abort ();
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if (NOTE_BASIC_BLOCK (bbnote) == s->bb_beg)
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{
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bbs_spanned = 0;
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s->bb_end = NOTE_BASIC_BLOCK (bbnote);
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||
}
|
||
else
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{
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bbi1 = s->bb_beg->index;
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bbi2 = NOTE_BASIC_BLOCK (bbnote)->index;
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s->bb_beg = NULL;
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bbs_spanned = 1;
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||
}
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}
|
||
}
|
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else
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{
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if (s->bb_beg)
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/* Both notes are in the same bb, which implies the block
|
||
contains this scope. */
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bbs_spanned = 0;
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else
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{
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rtx x1, x2;
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||
/* Both notes are outside of any bbs. This implies that all the
|
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basic blocks spanned by the pair of notes are contained in
|
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this scope.
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There is a degenerate case to consider. If the notes do not
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span any basic blocks, then it is an empty scope that can
|
||
safely be deleted or ignored. Mark these with level = -1. */
|
||
|
||
x1 = get_next_bb_note (s->note_beg);
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x2 = get_prev_bb_note (s->note_end);
|
||
if (! (x1 && x2))
|
||
{
|
||
s->level = -1;
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||
bbs_spanned = 0;
|
||
}
|
||
else
|
||
{
|
||
bbi1 = NOTE_BASIC_BLOCK (x1)->index;
|
||
bbi2 = NOTE_BASIC_BLOCK (x2)->index;
|
||
bbs_spanned = 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If the scope spans one or more basic blocks, we record them. We
|
||
only record the bbs that are immediately contained within this
|
||
scope. Note that if a scope is contained within a bb, we can tell
|
||
by checking that bb_beg = bb_end and that they are non-null. */
|
||
if (bbs_spanned)
|
||
{
|
||
int j = 0;
|
||
|
||
s->num_bbs = 0;
|
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for (i = bbi1; i <= bbi2; i++)
|
||
if (! RBI (BASIC_BLOCK (i))->scope)
|
||
s->num_bbs++;
|
||
|
||
s->bbs = xmalloc (s->num_bbs * sizeof (basic_block));
|
||
for (i = bbi1; i <= bbi2; i++)
|
||
{
|
||
basic_block curr_bb = BASIC_BLOCK (i);
|
||
if (! RBI (curr_bb)->scope)
|
||
{
|
||
s->bbs[j++] = curr_bb;
|
||
RBI (curr_bb)->scope = s;
|
||
}
|
||
}
|
||
}
|
||
else
|
||
s->num_bbs = 0;
|
||
}
|
||
|
||
/* Allocate and initialize a new scope structure with scope level LEVEL,
|
||
and record the NOTE beginning the scope. */
|
||
|
||
static scope
|
||
make_new_scope (level, note)
|
||
int level;
|
||
rtx note;
|
||
{
|
||
scope new_scope = xcalloc (1, sizeof (struct scope_def));
|
||
new_scope->level = level;
|
||
new_scope->note_beg = note;
|
||
return new_scope;
|
||
}
|
||
|
||
|
||
/* Build a forest representing the scope structure of the function.
|
||
Return a pointer to a structure describing the forest. */
|
||
|
||
static void
|
||
build_scope_forest (forest)
|
||
scope_forest_info *forest;
|
||
{
|
||
rtx x;
|
||
int level, bbi, i;
|
||
basic_block curr_bb;
|
||
scope root, curr_scope = 0;
|
||
|
||
forest->num_trees = 0;
|
||
forest->trees = NULL;
|
||
level = -1;
|
||
root = NULL;
|
||
curr_bb = NULL;
|
||
bbi = 0;
|
||
for (x = get_insns (); x; x = NEXT_INSN (x))
|
||
{
|
||
if (bbi < n_basic_blocks && x == BASIC_BLOCK (bbi)->head)
|
||
curr_bb = BASIC_BLOCK (bbi);
|
||
|
||
if (GET_CODE (x) == NOTE)
|
||
{
|
||
if (NOTE_LINE_NUMBER (x) == NOTE_INSN_BLOCK_BEG)
|
||
{
|
||
if (root)
|
||
{
|
||
scope new_scope;
|
||
if (! curr_scope)
|
||
abort();
|
||
level++;
|
||
new_scope = make_new_scope (level, x);
|
||
new_scope->outer = curr_scope;
|
||
new_scope->next = NULL;
|
||
if (! curr_scope->inner)
|
||
{
|
||
curr_scope->inner = new_scope;
|
||
curr_scope->inner_last = new_scope;
|
||
}
|
||
else
|
||
{
|
||
curr_scope->inner_last->next = new_scope;
|
||
curr_scope->inner_last = new_scope;
|
||
}
|
||
curr_scope = curr_scope->inner_last;
|
||
}
|
||
else
|
||
{
|
||
int ntrees = forest->num_trees;
|
||
level++;
|
||
curr_scope = make_new_scope (level, x);
|
||
root = curr_scope;
|
||
forest->trees = xrealloc (forest->trees,
|
||
sizeof (scope) * (ntrees + 1));
|
||
forest->trees[forest->num_trees++] = root;
|
||
}
|
||
curr_scope->bb_beg = curr_bb;
|
||
}
|
||
else if (NOTE_LINE_NUMBER (x) == NOTE_INSN_BLOCK_END)
|
||
{
|
||
curr_scope->bb_end = curr_bb;
|
||
curr_scope->note_end = x;
|
||
level--;
|
||
curr_scope = curr_scope->outer;
|
||
if (level == -1)
|
||
root = NULL;
|
||
}
|
||
} /* if note */
|
||
|
||
if (curr_bb && curr_bb->end == x)
|
||
{
|
||
curr_bb = NULL;
|
||
bbi++;
|
||
}
|
||
|
||
} /* for */
|
||
|
||
for (i = 0; i < forest->num_trees; i++)
|
||
relate_bbs_with_scopes (forest->trees[i]);
|
||
}
|
||
|
||
/* Remove all the NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes from
|
||
the insn chain. */
|
||
|
||
static void
|
||
remove_scope_notes ()
|
||
{
|
||
rtx x, next;
|
||
basic_block currbb = NULL;
|
||
|
||
for (x = get_insns (); x; x = next)
|
||
{
|
||
next = NEXT_INSN (x);
|
||
if (NOTE_INSN_BASIC_BLOCK_P (x))
|
||
currbb = NOTE_BASIC_BLOCK (x);
|
||
|
||
if (GET_CODE (x) == NOTE
|
||
&& (NOTE_LINE_NUMBER (x) == NOTE_INSN_BLOCK_BEG
|
||
|| NOTE_LINE_NUMBER (x) == NOTE_INSN_BLOCK_END))
|
||
{
|
||
/* Check if the scope note happens to be the end of a bb. */
|
||
if (currbb && x == currbb->end)
|
||
currbb->end = PREV_INSN (x);
|
||
if (currbb && x == currbb->head)
|
||
abort ();
|
||
|
||
if (PREV_INSN (x))
|
||
{
|
||
NEXT_INSN (PREV_INSN (x)) = next;
|
||
PREV_INSN (next) = PREV_INSN (x);
|
||
|
||
NEXT_INSN (x) = NULL;
|
||
PREV_INSN (x) = NULL;
|
||
}
|
||
else
|
||
abort ();
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Insert scope note pairs for a contained scope tree S after insn IP. */
|
||
|
||
static void
|
||
insert_intra_1 (s, ip, bb)
|
||
scope s;
|
||
rtx *ip;
|
||
basic_block bb;
|
||
{
|
||
scope p;
|
||
|
||
if (NOTE_BLOCK (s->note_beg))
|
||
{
|
||
*ip = emit_note_after (NOTE_INSN_BLOCK_BEG, *ip);
|
||
NOTE_BLOCK (*ip) = NOTE_BLOCK (s->note_beg);
|
||
}
|
||
|
||
for (p = s->inner; p; p = p->next)
|
||
insert_intra_1 (p, ip, bb);
|
||
|
||
if (NOTE_BLOCK (s->note_beg))
|
||
{
|
||
*ip = emit_note_after (NOTE_INSN_BLOCK_END, *ip);
|
||
NOTE_BLOCK (*ip) = NOTE_BLOCK (s->note_end);
|
||
}
|
||
}
|
||
|
||
|
||
/* Insert NOTE_INSN_BLOCK_END notes and NOTE_INSN_BLOCK_BEG notes for
|
||
scopes that are contained within BB. */
|
||
|
||
static void
|
||
insert_intra_bb_scope_notes (bb)
|
||
basic_block bb;
|
||
{
|
||
scope s = RBI (bb)->scope;
|
||
scope p;
|
||
rtx ip;
|
||
|
||
if (! s)
|
||
return;
|
||
|
||
ip = bb->head;
|
||
if (GET_CODE (ip) == CODE_LABEL)
|
||
ip = NEXT_INSN (ip);
|
||
|
||
for (p = s->inner; p; p = p->next)
|
||
{
|
||
if (p->bb_beg != NULL && p->bb_beg == p->bb_end && p->bb_beg == bb)
|
||
insert_intra_1 (p, &ip, bb);
|
||
}
|
||
}
|
||
|
||
|
||
/* Given two consecutive basic blocks BB1 and BB2 with different scopes,
|
||
insert NOTE_INSN_BLOCK_END notes after BB1 and NOTE_INSN_BLOCK_BEG
|
||
notes before BB2 such that the notes are correctly balanced. If BB1 or
|
||
BB2 is NULL, we are inserting scope notes for the first and last basic
|
||
blocks, respectively. */
|
||
|
||
static void
|
||
insert_inter_bb_scope_notes (bb1, bb2)
|
||
basic_block bb1;
|
||
basic_block bb2;
|
||
{
|
||
rtx ip;
|
||
scope com;
|
||
|
||
/* It is possible that a basic block is not contained in any scope.
|
||
In that case, we either open or close a scope but not both. */
|
||
if (bb1 && bb2)
|
||
{
|
||
scope s1 = RBI (bb1)->scope;
|
||
scope s2 = RBI (bb2)->scope;
|
||
if (! s1 && ! s2)
|
||
return;
|
||
if (! s1)
|
||
bb1 = NULL;
|
||
else if (! s2)
|
||
bb2 = NULL;
|
||
}
|
||
|
||
/* Find common ancestor scope. */
|
||
if (bb1 && bb2)
|
||
{
|
||
scope s1 = RBI (bb1)->scope;
|
||
scope s2 = RBI (bb2)->scope;
|
||
while (s1 != s2)
|
||
{
|
||
if (! (s1 && s2))
|
||
abort ();
|
||
if (s1->level > s2->level)
|
||
s1 = s1->outer;
|
||
else if (s2->level > s1->level)
|
||
s2 = s2->outer;
|
||
else
|
||
{
|
||
s1 = s1->outer;
|
||
s2 = s2->outer;
|
||
}
|
||
}
|
||
com = s1;
|
||
}
|
||
else
|
||
com = NULL;
|
||
|
||
/* Close scopes. */
|
||
if (bb1)
|
||
{
|
||
rtx end = bb1->end;
|
||
|
||
scope s = RBI (bb1)->scope;
|
||
ip = RBI (bb1)->eff_end;
|
||
while (s != com)
|
||
{
|
||
if (NOTE_BLOCK (s->note_beg))
|
||
{
|
||
ip = emit_note_after (NOTE_INSN_BLOCK_END, ip);
|
||
NOTE_BLOCK (ip) = NOTE_BLOCK (s->note_end);
|
||
}
|
||
s = s->outer;
|
||
}
|
||
/* Emitting note may move the end of basic block to unwanted place. */
|
||
bb1->end = end;
|
||
}
|
||
|
||
/* Open scopes. */
|
||
if (bb2)
|
||
{
|
||
scope s = RBI (bb2)->scope;
|
||
ip = bb2->head;
|
||
while (s != com)
|
||
{
|
||
if (NOTE_BLOCK (s->note_beg))
|
||
{
|
||
ip = emit_note_before (NOTE_INSN_BLOCK_BEG, ip);
|
||
NOTE_BLOCK (ip) = NOTE_BLOCK (s->note_beg);
|
||
}
|
||
s = s->outer;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
/* Rebuild all the NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes based
|
||
on the scope forest and the newly reordered basic blocks. */
|
||
|
||
static void
|
||
rebuild_scope_notes (forest)
|
||
scope_forest_info *forest;
|
||
{
|
||
int i;
|
||
|
||
if (forest->num_trees == 0)
|
||
return;
|
||
|
||
/* Start by opening the scopes before the first basic block. */
|
||
insert_inter_bb_scope_notes (NULL, BASIC_BLOCK (0));
|
||
|
||
/* Then, open and close scopes as needed between blocks. */
|
||
for (i = 0; i < n_basic_blocks - 1; i++)
|
||
{
|
||
basic_block bb1 = BASIC_BLOCK (i);
|
||
basic_block bb2 = BASIC_BLOCK (i + 1);
|
||
if (RBI (bb1)->scope != RBI (bb2)->scope)
|
||
insert_inter_bb_scope_notes (bb1, bb2);
|
||
insert_intra_bb_scope_notes (bb1);
|
||
}
|
||
|
||
/* Finally, close the scopes after the last basic block. */
|
||
insert_inter_bb_scope_notes (BASIC_BLOCK (n_basic_blocks - 1), NULL);
|
||
insert_intra_bb_scope_notes (BASIC_BLOCK (n_basic_blocks - 1));
|
||
}
|
||
|
||
/* Free the storage associated with the scope tree at S. */
|
||
|
||
static void
|
||
free_scope_forest_1 (s)
|
||
scope s;
|
||
{
|
||
scope p, next;
|
||
|
||
for (p = s->inner; p; p = next)
|
||
{
|
||
next = p->next;
|
||
free_scope_forest_1 (p);
|
||
}
|
||
|
||
if (s->bbs)
|
||
free (s->bbs);
|
||
free (s);
|
||
}
|
||
|
||
/* Free the storage associated with the scope forest. */
|
||
|
||
static void
|
||
free_scope_forest (forest)
|
||
scope_forest_info *forest;
|
||
{
|
||
int i;
|
||
for (i = 0; i < forest->num_trees; i++)
|
||
free_scope_forest_1 (forest->trees[i]);
|
||
}
|
||
|
||
/* Visualize the scope forest. */
|
||
|
||
void
|
||
dump_scope_forest (forest)
|
||
scope_forest_info *forest;
|
||
{
|
||
if (forest->num_trees == 0)
|
||
fprintf (stderr, "\n< Empty scope forest >\n");
|
||
else
|
||
{
|
||
int i;
|
||
fprintf (stderr, "\n< Scope forest >\n");
|
||
for (i = 0; i < forest->num_trees; i++)
|
||
dump_scope_forest_1 (forest->trees[i], 0);
|
||
}
|
||
}
|
||
|
||
/* Recursive portion of dump_scope_forest. */
|
||
|
||
static void
|
||
dump_scope_forest_1 (s, indent)
|
||
scope s;
|
||
int indent;
|
||
{
|
||
scope p;
|
||
int i;
|
||
|
||
if (s->bb_beg != NULL && s->bb_beg == s->bb_end
|
||
&& RBI (s->bb_beg)->scope
|
||
&& RBI (s->bb_beg)->scope->level + 1 == s->level)
|
||
{
|
||
fprintf (stderr, "%*s", indent, "");
|
||
fprintf (stderr, "BB%d:\n", s->bb_beg->index);
|
||
}
|
||
|
||
fprintf (stderr, "%*s", indent, "");
|
||
fprintf (stderr, "{ level %d (block %p)\n", s->level,
|
||
(PTR) NOTE_BLOCK (s->note_beg));
|
||
|
||
fprintf (stderr, "%*s%s", indent, "", "bbs:");
|
||
for (i = 0; i < s->num_bbs; i++)
|
||
fprintf (stderr, " %d", s->bbs[i]->index);
|
||
fprintf (stderr, "\n");
|
||
|
||
for (p = s->inner; p; p = p->next)
|
||
dump_scope_forest_1 (p, indent + 2);
|
||
|
||
fprintf (stderr, "%*s", indent, "");
|
||
fprintf (stderr, "}\n");
|
||
}
|
||
|
||
/* Given a reorder chain, rearrange the code to match. */
|
||
|
||
static void
|
||
fixup_reorder_chain ()
|
||
{
|
||
basic_block bb, last_bb;
|
||
int index;
|
||
rtx insn;
|
||
int old_n_basic_blocks = n_basic_blocks;
|
||
|
||
/* First do the bulk reordering -- rechain the blocks without regard to
|
||
the needed changes to jumps and labels. */
|
||
|
||
last_bb = BASIC_BLOCK (0);
|
||
bb = RBI (last_bb)->next;
|
||
index = 1;
|
||
while (bb)
|
||
{
|
||
rtx last_e = RBI (last_bb)->eff_end;
|
||
rtx curr_h = RBI (bb)->eff_head;
|
||
|
||
NEXT_INSN (last_e) = curr_h;
|
||
PREV_INSN (curr_h) = last_e;
|
||
|
||
last_bb = bb;
|
||
bb = RBI (bb)->next;
|
||
index++;
|
||
}
|
||
|
||
if (index != n_basic_blocks)
|
||
abort ();
|
||
|
||
insn = RBI (last_bb)->eff_end;
|
||
|
||
NEXT_INSN (insn) = function_tail_eff_head;
|
||
if (function_tail_eff_head)
|
||
PREV_INSN (function_tail_eff_head) = insn;
|
||
|
||
while (NEXT_INSN (insn))
|
||
insn = NEXT_INSN (insn);
|
||
set_last_insn (insn);
|
||
#ifdef ENABLE_CHECKING
|
||
verify_insn_chain ();
|
||
#endif
|
||
|
||
/* Now add jumps and labels as needed to match the blocks new
|
||
outgoing edges. */
|
||
|
||
for (bb = BASIC_BLOCK (0); bb ; bb = RBI (bb)->next)
|
||
{
|
||
edge e_fall, e_taken, e;
|
||
rtx bb_end_insn;
|
||
basic_block nb;
|
||
|
||
if (bb->succ == NULL)
|
||
continue;
|
||
|
||
/* Find the old fallthru edge, and another non-EH edge for
|
||
a taken jump. */
|
||
e_taken = e_fall = NULL;
|
||
for (e = bb->succ; e ; e = e->succ_next)
|
||
if (e->flags & EDGE_FALLTHRU)
|
||
e_fall = e;
|
||
else if (! (e->flags & EDGE_EH))
|
||
e_taken = e;
|
||
|
||
bb_end_insn = bb->end;
|
||
if (GET_CODE (bb_end_insn) == JUMP_INSN)
|
||
{
|
||
if (any_condjump_p (bb_end_insn))
|
||
{
|
||
/* If the old fallthru is still next, nothing to do. */
|
||
if (RBI (bb)->next == e_fall->dest
|
||
|| (!RBI (bb)->next
|
||
&& e_fall->dest == EXIT_BLOCK_PTR))
|
||
continue;
|
||
|
||
/* There is one special case: if *neither* block is next,
|
||
such as happens at the very end of a function, then we'll
|
||
need to add a new unconditional jump. Choose the taken
|
||
edge based on known or assumed probability. */
|
||
if (RBI (bb)->next != e_taken->dest)
|
||
{
|
||
rtx note = find_reg_note (bb_end_insn, REG_BR_PROB, 0);
|
||
if (note
|
||
&& INTVAL (XEXP (note, 0)) < REG_BR_PROB_BASE / 2
|
||
&& invert_jump (bb_end_insn,
|
||
label_for_bb (e_fall->dest), 0))
|
||
{
|
||
e_fall->flags &= ~EDGE_FALLTHRU;
|
||
e_taken->flags |= EDGE_FALLTHRU;
|
||
e = e_fall, e_fall = e_taken, e_taken = e;
|
||
}
|
||
}
|
||
|
||
/* Otherwise we can try to invert the jump. This will
|
||
basically never fail, however, keep up the pretense. */
|
||
else if (invert_jump (bb_end_insn,
|
||
label_for_bb (e_fall->dest), 0))
|
||
{
|
||
e_fall->flags &= ~EDGE_FALLTHRU;
|
||
e_taken->flags |= EDGE_FALLTHRU;
|
||
continue;
|
||
}
|
||
}
|
||
else if (returnjump_p (bb_end_insn))
|
||
continue;
|
||
else
|
||
{
|
||
/* Otherwise we have some switch or computed jump. In the
|
||
99% case, there should not have been a fallthru edge. */
|
||
if (! e_fall)
|
||
continue;
|
||
#ifdef CASE_DROPS_THROUGH
|
||
/* Except for VAX. Since we didn't have predication for the
|
||
tablejump, the fallthru block should not have moved. */
|
||
if (RBI (bb)->next == e_fall->dest)
|
||
continue;
|
||
bb_end_insn = skip_insns_after_block (bb);
|
||
#else
|
||
abort ();
|
||
#endif
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* No fallthru implies a noreturn function with EH edges, or
|
||
something similarly bizarre. In any case, we don't need to
|
||
do anything. */
|
||
if (! e_fall)
|
||
continue;
|
||
|
||
/* If the fallthru block is still next, nothing to do. */
|
||
if (RBI (bb)->next == e_fall->dest)
|
||
continue;
|
||
|
||
/* An fallthru to exit block. */
|
||
if (!RBI (bb)->next && e_fall->dest == EXIT_BLOCK_PTR)
|
||
continue;
|
||
}
|
||
|
||
/* We got here if we need to add a new jump insn. */
|
||
|
||
nb = force_nonfallthru (e_fall);
|
||
|
||
if (nb)
|
||
{
|
||
alloc_aux_for_block (nb, sizeof (struct reorder_block_def));
|
||
RBI (nb)->eff_head = nb->head;
|
||
RBI (nb)->eff_end = NEXT_INSN (nb->end);
|
||
RBI (nb)->scope = RBI (bb)->scope;
|
||
RBI (nb)->visited = 1;
|
||
RBI (nb)->next = RBI (bb)->next;
|
||
RBI (bb)->next = nb;
|
||
/* Don't process this new block. */
|
||
bb = nb;
|
||
}
|
||
}
|
||
|
||
/* Put basic_block_info in the new order. */
|
||
bb = BASIC_BLOCK (0);
|
||
index = 0;
|
||
|
||
if (rtl_dump_file)
|
||
fprintf (rtl_dump_file, "Reordered sequence:\n");
|
||
while (bb)
|
||
{
|
||
if (rtl_dump_file)
|
||
fprintf (rtl_dump_file, " %i %sbb %i freq %i\n", index,
|
||
bb->index >= old_n_basic_blocks ? "compensation " : "",
|
||
bb->index,
|
||
bb->frequency);
|
||
bb->index = index;
|
||
BASIC_BLOCK (index) = bb;
|
||
|
||
bb = RBI (bb)->next;
|
||
index++;
|
||
}
|
||
}
|
||
|
||
/* Perform sanity checks on the insn chain.
|
||
1. Check that next/prev pointers are consistent in both the forward and
|
||
reverse direction.
|
||
2. Count insns in chain, going both directions, and check if equal.
|
||
3. Check that get_last_insn () returns the actual end of chain. */
|
||
|
||
void
|
||
verify_insn_chain ()
|
||
{
|
||
rtx x,
|
||
prevx,
|
||
nextx;
|
||
int insn_cnt1,
|
||
insn_cnt2;
|
||
|
||
prevx = NULL;
|
||
insn_cnt1 = 1;
|
||
for (x = get_insns (); x; x = NEXT_INSN (x))
|
||
{
|
||
if (PREV_INSN (x) != prevx)
|
||
{
|
||
fprintf (stderr, "Forward traversal: insn chain corrupt.\n");
|
||
fprintf (stderr, "previous insn:\n");
|
||
debug_rtx (prevx);
|
||
fprintf (stderr, "current insn:\n");
|
||
debug_rtx (x);
|
||
abort ();
|
||
}
|
||
++insn_cnt1;
|
||
prevx = x;
|
||
}
|
||
|
||
if (prevx != get_last_insn ())
|
||
{
|
||
fprintf (stderr, "last_insn corrupt.\n");
|
||
abort ();
|
||
}
|
||
|
||
nextx = NULL;
|
||
insn_cnt2 = 1;
|
||
for (x = get_last_insn (); x; x = PREV_INSN (x))
|
||
{
|
||
if (NEXT_INSN (x) != nextx)
|
||
{
|
||
fprintf (stderr, "Reverse traversal: insn chain corrupt.\n");
|
||
fprintf (stderr, "current insn:\n");
|
||
debug_rtx (x);
|
||
fprintf (stderr, "next insn:\n");
|
||
debug_rtx (nextx);
|
||
abort ();
|
||
}
|
||
++insn_cnt2;
|
||
nextx = x;
|
||
}
|
||
|
||
if (insn_cnt1 != insn_cnt2)
|
||
{
|
||
fprintf (stderr, "insn_cnt1 (%d) not equal to insn_cnt2 (%d).\n",
|
||
insn_cnt1, insn_cnt2);
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* The block falling through to exit must be the last one in the
|
||
reordered chain. Ensure that this condition is met. */
|
||
static void
|
||
fixup_fallthru_exit_predecessor ()
|
||
{
|
||
edge e;
|
||
basic_block bb = NULL;
|
||
|
||
for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
|
||
if (e->flags & EDGE_FALLTHRU)
|
||
bb = e->src;
|
||
if (bb && RBI (bb)->next)
|
||
{
|
||
basic_block c = BASIC_BLOCK (0);
|
||
while (RBI (c)->next != bb)
|
||
c = RBI (c)->next;
|
||
RBI (c)->next = RBI (bb)->next;
|
||
while (RBI (c)->next)
|
||
c = RBI (c)->next;
|
||
RBI (c)->next = bb;
|
||
RBI (bb)->next = NULL;
|
||
}
|
||
}
|
||
|
||
/* Main entry point to this module - initialize the datastructures for
|
||
CFG layout changes. */
|
||
|
||
void
|
||
cfg_layout_initialize ()
|
||
{
|
||
alloc_aux_for_blocks (sizeof (struct reorder_block_def));
|
||
|
||
build_scope_forest (&forest);
|
||
remove_scope_notes ();
|
||
|
||
record_effective_endpoints ();
|
||
}
|
||
|
||
/* Finalize the changes - reorder insn list according to the sequence,
|
||
enter compensation code, rebuild scope forest. */
|
||
|
||
void
|
||
cfg_layout_finalize ()
|
||
{
|
||
fixup_fallthru_exit_predecessor ();
|
||
fixup_reorder_chain ();
|
||
#ifdef ENABLE_CHECKING
|
||
verify_insn_chain ();
|
||
#endif
|
||
|
||
rebuild_scope_notes (&forest);
|
||
free_scope_forest (&forest);
|
||
reorder_blocks ();
|
||
|
||
free_aux_for_blocks ();
|
||
|
||
#ifdef ENABLE_CHECKING
|
||
verify_flow_info ();
|
||
#endif
|
||
}
|