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Diffstat (limited to 'gcc/cfgrtl.c')
| -rw-r--r-- | gcc/cfgrtl.c | 3240 |
1 files changed, 3240 insertions, 0 deletions
diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c new file mode 100644 index 000000000..f86f0a35c --- /dev/null +++ b/gcc/cfgrtl.c @@ -0,0 +1,3240 @@ +/* Control flow graph manipulation code for GNU compiler. + Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, + 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 + 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 + + 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 "tm.h" +#include "tree.h" +#include "hard-reg-set.h" +#include "basic-block.h" +#include "regs.h" +#include "flags.h" +#include "output.h" +#include "function.h" +#include "except.h" +#include "rtl-error.h" +#include "tm_p.h" +#include "obstack.h" +#include "insn-attr.h" +#include "insn-config.h" +#include "cfglayout.h" +#include "expr.h" +#include "target.h" +#include "cfgloop.h" +#include "ggc.h" +#include "tree-pass.h" +#include "df.h" + +static int can_delete_note_p (const_rtx); +static int can_delete_label_p (const_rtx); +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 (basic_block, FILE *, int, int); +static int rtl_verify_flow_info_1 (void); +static void rtl_make_forwarder_block (edge); + +/* 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) +{ + 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 label) +{ + return (!LABEL_PRESERVE_P (label) + /* User declared labels must be preserved. */ + && LABEL_NAME (label) == 0 + && !in_expr_list_p (forced_labels, label)); +} + +/* Delete INSN by patching it out. Return the next insn. */ + +rtx +delete_insn (rtx insn) +{ + rtx next = NEXT_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 (insn)) + { + const char *name = LABEL_NAME (insn); + + really_delete = false; + PUT_CODE (insn, NOTE); + NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL; + NOTE_DELETED_LABEL_NAME (insn) = name; + } + + remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels); + } + + if (really_delete) + { + /* If this insn has already been deleted, something is very wrong. */ + gcc_assert (!INSN_DELETED_P (insn)); + remove_insn (insn); + INSN_DELETED_P (insn) = 1; + } + + /* 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 (JUMP_TABLE_DATA_P (insn)) + { + rtx pat = PATTERN (insn); + int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC; + int len = XVECLEN (pat, diff_vec_p); + int i; + + for (i = 0; i < len; i++) + { + rtx label = XEXP (XVECEXP (pat, diff_vec_p, 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)--; + } + } + + return next; +} + +/* Like delete_insn but also purge dead edges from BB. */ + +rtx +delete_insn_and_edges (rtx insn) +{ + rtx x; + bool purge = false; + + if (INSN_P (insn) + && BLOCK_FOR_INSN (insn) + && BB_END (BLOCK_FOR_INSN (insn)) == insn) + purge = true; + x = delete_insn (insn); + if (purge) + purge_dead_edges (BLOCK_FOR_INSN (insn)); + return x; +} + +/* 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 finish, bool clear_bb) +{ + rtx next; + + /* 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. */ + while (1) + { + next = NEXT_INSN (start); + if (NOTE_P (start) && !can_delete_note_p (start)) + ; + else + next = delete_insn (start); + + if (clear_bb && !INSN_DELETED_P (start)) + set_block_for_insn (start, NULL); + + if (start == finish) + break; + start = next; + } +} + +/* 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 head, rtx end, rtx 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 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++; + bb->flags = BB_NEW | BB_RTL; + link_block (bb, after); + SET_BASIC_BLOCK (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 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. */ + +static basic_block +rtl_create_basic_block (void *headp, void *endp, basic_block after) +{ + rtx head = (rtx) headp, end = (rtx) endp; + basic_block bb; + + /* Grow the basic block array if needed. */ + if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info)) + { + size_t new_size = last_basic_block + (last_basic_block + 3) / 4; + VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size); + } + + n_basic_blocks++; + + 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, 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 (bb) + { + rtx end = BB_END (bb); + rtx 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; + for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) + if (!BARRIER_P (insn)) + BLOCK_FOR_INSN (insn) = NULL; + return 0; +} + +static unsigned int +rest_of_pass_free_cfg (void) +{ +#ifdef DELAY_SLOTS + /* 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 (optimize > 0 && flag_delayed_branch) + { + df_note_add_problem (); + df_analyze (); + } +#endif + + free_bb_for_insn (); + return 0; +} + +struct rtl_opt_pass pass_free_cfg = +{ + { + RTL_PASS, + "*free_cfg", /* name */ + NULL, /* gate */ + rest_of_pass_free_cfg, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + TV_NONE, /* tv_id */ + 0, /* properties_required */ + 0, /* properties_provided */ + PROP_cfg, /* properties_destroyed */ + 0, /* todo_flags_start */ + 0, /* todo_flags_finish */ + } +}; + +/* Return RTX to emit after when we want to emit code on the entry of function. */ +rtx +entry_of_function (void) +{ + return (n_basic_blocks > NUM_FIXED_BLOCKS ? + BB_HEAD (ENTRY_BLOCK_PTR->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->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 begin, rtx end, basic_block bb) +{ + rtx 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); +} + + +/* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK + note associated with the BLOCK. */ + +static rtx +first_insn_after_basic_block_note (basic_block block) +{ + rtx insn; + + /* Get the first instruction in the block. */ + insn = BB_HEAD (block); + + if (insn == NULL_RTX) + return NULL_RTX; + 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 B by splitting + everything after specified instruction I. */ + +static basic_block +rtl_split_block (basic_block bb, void *insnp) +{ + basic_block new_bb; + rtx insn = (rtx) insnp; + edge e; + edge_iterator ei; + + if (!insn) + { + insn = first_insn_after_basic_block_note (bb); + + if (insn) + { + rtx 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; +} + +/* 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) +{ + rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a); + rtx del_first = NULL_RTX, del_last = NULL_RTX; + rtx b_debug_start = b_end, b_debug_end = b_end; + bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0; + 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 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; + +#ifdef HAVE_cc0 + /* If this was a conditional jump, we need to also delete + the insn that set cc0. */ + if (only_sets_cc0_p (prev)) + { + rtx tmp = prev; + + prev = prev_nonnote_insn (prev); + if (!prev) + prev = BB_HEAD (a); + del_first = tmp; + } +#endif + + 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_HEAD (b) = NULL; + delete_insn_chain (del_first, del_last, true); + + /* Reassociate the insns of B with A. */ + if (!b_empty) + { + update_bb_for_insn_chain (a_end, b_debug_end, a); + + a_end = b_debug_end; + } + 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); + a_end = b_debug_end; + } + + df_bb_delete (b->index); + BB_END (a) = a_end; + + /* If B was a forwarder block, propagate the locus on the edge. */ + if (forwarder_p && !EDGE_SUCC (b, 0)->goto_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; + + /* 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 && b != EXIT_BLOCK_PTR + /* 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 +block_label (basic_block block) +{ + if (block == EXIT_BLOCK_PTR) + return NULL_RTX; + + if (!LABEL_P (BB_HEAD (block))) + { + BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block)); + } + + return BB_HEAD (block); +} + +/* 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 = BB_END (src), kill_from; + 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 (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX) + || 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; + + /* In case we zap a conditional jump, we'll need to kill + the cc0 setter too. */ + kill_from = insn; +#ifdef HAVE_cc0 + if (reg_mentioned_p (cc0_rtx, PATTERN (insn)) + && only_sets_cc0_p (PREV_INSN (insn))) + kill_from = PREV_INSN (insn); +#endif + + /* 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) + { + rtx insn = src->il.rtl->footer; + + delete_insn_chain (kill_from, BB_END (src), false); + + /* Remove barriers but keep jumptables. */ + while (insn) + { + if (BARRIER_P (insn)) + { + if (PREV_INSN (insn)) + NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); + else + src->il.rtl->footer = NEXT_INSN (insn); + if (NEXT_INSN (insn)) + PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); + } + if (LABEL_P (insn)) + break; + insn = NEXT_INSN (insn); + } + } + else + delete_insn_chain (kill_from, 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 (insn, block_label (target), 0)) + { + gcc_assert (target == EXIT_BLOCK_PTR); + return NULL; + } + } + + /* Cannot do anything for target exit block. */ + else if (target == EXIT_BLOCK_PTR) + return NULL; + + /* Or replace possibly complicated jump insn by simple jump insn. */ + else + { + rtx target_label = block_label (target); + rtx barrier, label, table; + + emit_jump_insn_after_noloc (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 (kill_from, 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_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 new_insn = BB_END (src); + + update_bb_for_insn_chain (NEXT_INSN (BB_END (src)), + PREV_INSN (barrier), src); + + NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn); + PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn); + + NEXT_INSN (new_insn) = barrier; + NEXT_INSN (PREV_INSN (barrier)) = new_insn; + + PREV_INSN (new_insn) = PREV_INSN (barrier); + 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 = REG_BR_PROB_BASE; + e->count = src->count; + + 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, rtx old_label, basic_block new_bb) +{ + rtx tmp; + /* Recognize a tablejump and adjust all matching cases. */ + if (tablejump_p (insn, NULL, &tmp)) + { + rtvec vec; + int j; + rtx new_label = block_label (new_bb); + + if (new_bb == EXIT_BLOCK_PTR) + return false; + if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) + vec = XVEC (PATTERN (tmp), 0); + else + vec = XVEC (PATTERN (tmp), 1); + + 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 = single_set (insn)) != NULL + && SET_DEST (tmp) == pc_rtx + && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE + && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF + && XEXP (XEXP (SET_SRC (tmp), 2), 0) == 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 new_label, note; + + if (new_bb == EXIT_BLOCK_PTR) + return false; + 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. */ + if (!redirect_jump (insn, block_label (new_bb), 0)) + { + gcc_assert (new_bb == EXIT_BLOCK_PTR); + 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 old_label = BB_HEAD (e->dest); + basic_block src = e->src; + rtx 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 (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 (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; +} + +/* 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; + + if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) + return NULL; + + if (e->dest == target) + return e; + + if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL) + { + df_set_bb_dirty (src); + return ret; + } + + ret = redirect_branch_edge (e, target); + if (!ret) + return NULL; + + df_set_bb_dirty (src); + return ret; +} + +/* Like force_nonfallthru below, but additionally performs redirection + Used by redirect_edge_and_branch_force. */ + +static basic_block +force_nonfallthru_and_redirect (edge e, basic_block target) +{ + 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 && e->dest != EXIT_BLOCK_PTR + && 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 (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 = INTVAL (XEXP (note, 0)); + + b->probability = prob; + b->count = e->count * prob / REG_BR_PROB_BASE; + e->probability -= e->probability; + e->count -= b->count; + if (e->probability < 0) + e->probability = 0; + if (e->count < 0) + e->count = 0; + } + } + + 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 | EDGE_CAN_FALLTHRU); + e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU; + } + else + { + gcc_assert (e->flags & EDGE_FALLTHRU); + if (e->src == ENTRY_BLOCK_PTR) + { + /* 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); + + /* 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->succs); (tmp = ei_safe_edge (ei)); ) + { + if (tmp == e) + { + VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index); + found = true; + break; + } + else + ei_next (&ei); + } + + gcc_assert (found); + + VEC_safe_push (edge, gc, bb->succs, e); + make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU); + } + } + + /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs + don't point to target label. */ + if (JUMP_P (BB_END (e->src)) + && target != EXIT_BLOCK_PTR + && e->dest == target + && (e->flags & EDGE_FALLTHRU) + && (note = extract_asm_operands (PATTERN (BB_END (e->src))))) + { + int i, n = ASM_OPERANDS_LABEL_LENGTH (note); + + for (i = 0; i < n; ++i) + if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (target)) + { + asm_goto_edge = true; + break; + } + } + + if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags || asm_goto_edge) + { + gcov_type count = e->count; + int 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. */ + if (!tablejump_p (BB_END (e->src), NULL, ¬e)) + note = BB_END (e->src); + note = NEXT_INSN (note); + + jump_block = create_basic_block (note, NULL, e->src); + jump_block->count = count; + jump_block->frequency = EDGE_FREQUENCY (e); + jump_block->loop_depth = target->loop_depth; + + /* Make sure new block ends up in correct hot/cold section. */ + + BB_COPY_PARTITION (jump_block, e->src); + if (flag_reorder_blocks_and_partition + && targetm.have_named_sections + && JUMP_P (BB_END (jump_block)) + && !any_condjump_p (BB_END (jump_block)) + && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING)) + add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX); + + /* Wire edge in. */ + new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU); + new_edge->probability = probability; + new_edge->count = count; + + /* Redirect old edge. */ + redirect_edge_pred (e, jump_block); + e->probability = REG_BR_PROB_BASE; + + /* 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 /= 2; + new_edge->count /= 2; + jump_block->count /= 2; + jump_block->frequency /= 2; + new_edge = make_edge (new_edge->src, target, + e->flags & ~EDGE_FALLTHRU); + new_edge->probability = probability - probability / 2; + new_edge->count = count - count / 2; + } + + new_bb = jump_block; + } + else + jump_block = e->src; + + if (e->goto_locus && e->goto_block == NULL) + loc = e->goto_locus; + else + loc = 0; + e->flags &= ~EDGE_FALLTHRU; + if (target == EXIT_BLOCK_PTR) + { +#ifdef HAVE_return + emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc); +#else + gcc_unreachable (); +#endif + } + else + { + rtx label = block_label (target); + emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc); + JUMP_LABEL (BB_END (jump_block)) = label; + LABEL_NUSES (label)++; + } + + emit_barrier_after (BB_END (jump_block)); + redirect_edge_succ_nodup (e, target); + + if (abnormal_edge_flags) + make_edge (src, target, abnormal_edge_flags); + + df_mark_solutions_dirty (); + 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. */ + +basic_block +force_nonfallthru (edge e) +{ + return force_nonfallthru_and_redirect (e, e->dest); +} + +/* 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); +} + +/* 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 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 (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))) + { +#ifdef HAVE_cc0 + /* If this was a conditional jump, we need to also delete + the insn that set cc0. */ + if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q))) + q = PREV_INSN (q); +#endif + + q = PREV_INSN (q); + } + + /* 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; +} + +/* 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; + rtx 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) + before = BB_HEAD (edge_in->dest); + else + before = NULL_RTX; + + /* If this is a fall through edge to the exit block, the blocks might be + not adjacent, and the right place is the after the source. */ + if (edge_in->flags & EDGE_FALLTHRU && edge_in->dest == EXIT_BLOCK_PTR) + { + 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 + { + bb = create_basic_block (before, NULL, edge_in->dest->prev_bb); + /* ??? Why not edge_in->dest->prev_bb here? */ + BB_COPY_PARTITION (bb, edge_in->dest); + } + + make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU); + + /* 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 asm goto even splitting of fallthru edge might + need insn patching, as other labels might point to the + old label. */ + rtx last = BB_END (edge_in->src); + if (last + && JUMP_P (last) + && edge_in->dest != EXIT_BLOCK_PTR + && extract_asm_operands (PATTERN (last)) != NULL_RTX + && 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 before = NULL_RTX, after = NULL_RTX, insns, tmp, last; + basic_block bb = NULL; + + /* Pull the insns off the edge now since the edge might go away. */ + insns = e->insns.r; + e->insns.r = NULL_RTX; + + if (!before && !after) + { + /* Figure out where to put these things. If the destination has + one predecessor, insert there. Except for the exit block. */ + if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR) + { + 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. */ + else if ((e->flags & EDGE_ABNORMAL) == 0 + && single_succ_p (e->src) + && e->src != ENTRY_BLOCK_PTR) + { + 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); + after = BB_END (bb); + + if (flag_reorder_blocks_and_partition + && targetm.have_named_sections + && e->src != ENTRY_BLOCK_PTR + && BB_PARTITION (e->src) == BB_COLD_PARTITION + && !(e->flags & EDGE_CROSSING) + && JUMP_P (after) + && !any_condjump_p (after) + && (single_succ_edge (bb)->flags & EDGE_CROSSING)) + add_reg_note (after, REG_CROSSING_JUMP, NULL_RTX); + } + } + + /* 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 + && 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)); + + /* Mark the basic block for find_many_sub_basic_blocks. */ + if (current_ir_type () != IR_RTL_CFGLAYOUT) + bb->aux = &bb->aux; +} + +/* Update the CFG for all queued instructions. */ + +void +commit_edge_insertions (void) +{ + basic_block bb; + sbitmap blocks; + bool changed = false; + +#ifdef ENABLE_CHECKING + verify_flow_info (); +#endif + + FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) + { + edge e; + edge_iterator ei; + + FOR_EACH_EDGE (e, ei, bb->succs) + if (e->insns.r) + { + changed = true; + commit_one_edge_insertion (e); + } + } + + if (!changed) + return; + + /* In the old rtl CFG API, it was OK to insert control flow on an + edge, apparently? In cfglayout mode, this will *not* work, and + the caller is responsible for making sure that control flow is + valid at all times. */ + if (current_ir_type () == IR_RTL_CFGLAYOUT) + return; + + blocks = sbitmap_alloc (last_basic_block); + sbitmap_zero (blocks); + FOR_EACH_BB (bb) + if (bb->aux) + { + SET_BIT (blocks, bb->index); + /* Check for forgotten bb->aux values before commit_edge_insertions + call. */ + gcc_assert (bb->aux == &bb->aux); + bb->aux = NULL; + } + find_many_sub_basic_blocks (blocks); + sbitmap_free (blocks); +} + + +/* Print out RTL-specific basic block information (live information + at start and end). */ + +static void +rtl_dump_bb (basic_block bb, FILE *outf, int indent, int flags ATTRIBUTE_UNUSED) +{ + rtx insn; + rtx last; + char *s_indent; + + s_indent = (char *) alloca ((size_t) indent + 1); + memset (s_indent, ' ', (size_t) indent); + s_indent[indent] = '\0'; + + if (df) + { + df_dump_top (bb, outf); + putc ('\n', outf); + } + + if (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK) + for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last; + insn = NEXT_INSN (insn)) + print_rtl_single (outf, insn); + + if (df) + { + df_dump_bottom (bb, outf); + putc ('\n', outf); + } + +} + +/* Like print_rtl, but also print out live information for the start of each + basic block. */ + +void +print_rtl_with_bb (FILE *outf, const_rtx rtx_first) +{ + const_rtx 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; + + if (df) + df_dump_start (outf); + + FOR_EACH_BB_REVERSE (bb) + { + rtx x; + + start[INSN_UID (BB_HEAD (bb))] = bb; + end[INSN_UID (BB_END (bb))] = bb; + 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; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx)) + { + int did_output; + if ((bb = start[INSN_UID (tmp_rtx)]) != NULL) + { + edge e; + edge_iterator ei; + + fprintf (outf, ";; Start of basic block ("); + FOR_EACH_EDGE (e, ei, bb->preds) + fprintf (outf, " %d", e->src->index); + fprintf (outf, ") -> %d\n", bb->index); + + if (df) + { + df_dump_top (bb, outf); + putc ('\n', outf); + } + FOR_EACH_EDGE (e, ei, bb->preds) + { + fputs (";; Pred edge ", outf); + dump_edge_info (outf, e, 0); + fputc ('\n', 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"); + + did_output = print_rtl_single (outf, tmp_rtx); + + if ((bb = end[INSN_UID (tmp_rtx)]) != NULL) + { + edge e; + edge_iterator ei; + + fprintf (outf, ";; End of basic block %d -> (", bb->index); + FOR_EACH_EDGE (e, ei, bb->succs) + fprintf (outf, " %d", e->dest->index); + fprintf (outf, ")\n"); + + if (df) + { + df_dump_bottom (bb, outf); + putc ('\n', outf); + } + putc ('\n', outf); + FOR_EACH_EDGE (e, ei, bb->succs) + { + fputs (";; Succ edge ", outf); + dump_edge_info (outf, e, 1); + fputc ('\n', outf); + } + } + if (did_output) + putc ('\n', outf); + } + + free (start); + free (end); + free (in_bb_p); + } + + if (crtl->epilogue_delay_list != 0) + { + fprintf (outf, "\n;; Insns in epilogue delay list:\n\n"); + for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0; + tmp_rtx = XEXP (tmp_rtx, 1)) + print_rtl_single (outf, XEXP (tmp_rtx, 0)); + } +} + +void +update_br_prob_note (basic_block bb) +{ + rtx note; + if (!JUMP_P (BB_END (bb))) + return; + note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX); + if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability) + return; + XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability); +} + +/* Get the last insn associated with block BB (that includes barriers and + tablejumps after BB). */ +rtx +get_last_bb_insn (basic_block bb) +{ + rtx tmp; + rtx end = BB_END (bb); + + /* Include any jump table following the basic block. */ + if (tablejump_p (end, NULL, &tmp)) + end = tmp; + + /* Include any barriers that may follow the basic block. */ + tmp = next_nonnote_insn_bb (end); + while (tmp && BARRIER_P (tmp)) + { + end = tmp; + tmp = next_nonnote_insn_bb (end); + } + + return end; +} + +/* 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 + + 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) +{ + rtx x; + int err = 0; + basic_block bb; + + /* Check the general integrity of the basic blocks. */ + FOR_EACH_BB_REVERSE (bb) + { + rtx 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->il.rtl->header; 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->il.rtl->footer; 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; + } + } + + /* Now check the basic blocks (boundaries etc.) */ + FOR_EACH_BB_REVERSE (bb) + { + int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0; + edge e, fallthru = NULL; + rtx note; + edge_iterator ei; + + 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 (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability + && profile_status != PROFILE_ABSENT) + { + error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i", + INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability); + err = 1; + } + } + FOR_EACH_EDGE (e, ei, bb->succs) + { + if (e->flags & EDGE_FALLTHRU) + { + n_fallthru++, fallthru = e; + if ((e->flags & EDGE_CROSSING) + || (BB_PARTITION (e->src) != BB_PARTITION (e->dest) + && e->src != ENTRY_BLOCK_PTR + && e->dest != EXIT_BLOCK_PTR)) + { + error ("fallthru edge crosses section boundary (bb %i)", + e->src->index); + err = 1; + } + } + + if ((e->flags & ~(EDGE_DFS_BACK + | EDGE_CAN_FALLTHRU + | EDGE_IRREDUCIBLE_LOOP + | EDGE_LOOP_EXIT + | EDGE_CROSSING)) == 0) + n_branch++; + + if (e->flags & EDGE_ABNORMAL_CALL) + n_call++; + + if (e->flags & EDGE_EH) + n_eh++; + else if (e->flags & EDGE_ABNORMAL) + n_abnormal++; + } + + if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX)) + { + error ("missing REG_EH_REGION note in the end of bb %i", bb->index); + err = 1; + } + if (n_eh > 1) + { + error ("too many eh edges %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 %i", bb->index); + err = 1; + } + if (n_branch != 1 && any_uncondjump_p (BB_END (bb))) + { + error ("wrong number of branch edges after unconditional jump %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 %i", + bb->index); + err = 1; + } + if (n_call && !CALL_P (BB_END (bb))) + { + error ("call edges for non-call insn in bb %i", bb->index); + err = 1; + } + if (n_abnormal + && (!CALL_P (BB_END (bb)) && n_call != n_abnormal) + && (!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; + } + + for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x)) + /* We may have a barrier inside a basic block before dead code + elimination. There is no BLOCK_FOR_INSN field in a barrier. */ + if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb) + { + debug_rtx (x); + if (! BLOCK_FOR_INSN (x)) + error + ("insn %d inside basic block %d but block_for_insn is NULL", + INSN_UID (x), bb->index); + else + error + ("insn %d inside basic block %d but block_for_insn is %i", + INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index); + + err = 1; + } + + /* OK pointers are correct. 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 the CFG and RTL consistency common for both underlying RTL and + cfglayout RTL. + + Currently it does following checks: + - all checks of rtl_verify_flow_info_1 + - test head/end pointers + - 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. */ + +static int +rtl_verify_flow_info (void) +{ + basic_block bb; + int err = rtl_verify_flow_info_1 (); + rtx x; + rtx last_head = get_last_insn (); + basic_block *bb_info; + int num_bb_notes; + const rtx rtx_first = get_insns (); + basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL; + const int max_uid = get_max_uid (); + + bb_info = XCNEWVEC (basic_block, max_uid); + + FOR_EACH_BB_REVERSE (bb) + { + edge e; + rtx head = BB_HEAD (bb); + rtx 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); + + e = find_fallthru_edge (bb->succs); + if (!e) + { + rtx 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 + && e->dest != EXIT_BLOCK_PTR) + { + rtx 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) || 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; + } + } + } + + 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); + + num_bb_notes = 0; + last_bb_seen = ENTRY_BLOCK_PTR; + + 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) + && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x)))) + 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 - NUM_FIXED_BLOCKS) + internal_error + ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)", + num_bb_notes, n_basic_blocks); + + 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 = BB_END (bb), note; + bool purged = false; + bool found; + edge_iterator ei; + + if (DEBUG_INSN_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 + 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 + && 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 && returnjump_p (insn)) + /* If the destination block is the exit block, and this + instruction is a return, then keep the edge. */ + { + ei_next (&ei); + continue; + } + else if ((e->flags & EDGE_EH) && can_throw_internal (insn)) + /* Keep the edges that correspond to exceptions thrown by + this instruction and rematerialize the EDGE_ABNORMAL + flag we just cleared above. */ + { + e->flags |= EDGE_ABNORMAL; + ei_next (&ei); + continue; + } + + /* We do not need this edge. */ + df_set_bb_dirty (bb); + purged = true; + remove_edge (e); + } + + if (EDGE_COUNT (bb->succs) == 0 || !purged) + return purged; + + if (dump_file) + fprintf (dump_file, "Purged edges from bb %i\n", bb->index); + + if (!optimize) + return purged; + + /* Redistribute probabilities. */ + if (single_succ_p (bb)) + { + single_succ_edge (bb)->probability = REG_BR_PROB_BASE; + single_succ_edge (bb)->count = bb->count; + } + else + { + note = find_reg_note (insn, REG_BR_PROB, NULL); + if (!note) + return purged; + + b = BRANCH_EDGE (bb); + f = FALLTHRU_EDGE (bb); + b->probability = INTVAL (XEXP (note, 0)); + f->probability = REG_BR_PROB_BASE - b->probability; + b->count = bb->count * b->probability / REG_BR_PROB_BASE; + f->count = bb->count * f->probability / REG_BR_PROB_BASE; + } + + return purged; + } + else if (CALL_P (insn) && SIBLING_CALL_P (insn)) + { + /* First, there should not be any EH or ABCALL edges resulting + from non-local gotos and the like. If there were, we shouldn't + have created the sibcall in the first place. Second, there + should of course never have been a fallthru edge. */ + gcc_assert (single_succ_p (bb)); + gcc_assert (single_succ_edge (bb)->flags + == (EDGE_SIBCALL | EDGE_ABNORMAL)); + + return 0; + } + + /* If we don't see a jump insn, we don't know exactly why the block would + have been broken at this point. Look for a simple, non-fallthru edge, + as these are only created by conditional branches. If we find such an + edge we know that there used to be a jump here and can then safely + remove all non-fallthru edges. */ + found = false; + FOR_EACH_EDGE (e, ei, bb->succs) + if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))) + { + found = true; + break; + } + + if (!found) + return purged; + + /* Remove all but the fake and fallthru edges. The fake edge may be + the only successor for this block in the case of noreturn + calls. */ + for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) + { + if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE))) + { + df_set_bb_dirty (bb); + remove_edge (e); + purged = true; + } + else + ei_next (&ei); + } + + gcc_assert (single_succ_p (bb)); + + single_succ_edge (bb)->probability = REG_BR_PROB_BASE; + single_succ_edge (bb)->count = bb->count; + + if (dump_file) + fprintf (dump_file, "Purged non-fallthru edges from bb %i\n", + bb->index); + return purged; +} + +/* Search all basic blocks for potentially dead edges and purge them. Return + true if some edge has been eliminated. */ + +bool +purge_all_dead_edges (void) +{ + int purged = false; + basic_block bb; + + FOR_EACH_BB (bb) + { + bool purged_here = purge_dead_edges (bb); + + purged |= purged_here; + } + + return purged; +} + +/* Same as split_block but update cfg_layout structures. */ + +static basic_block +cfg_layout_split_block (basic_block bb, void *insnp) +{ + rtx insn = (rtx) insnp; + basic_block new_bb = rtl_split_block (bb, insn); + + new_bb->il.rtl->footer = bb->il.rtl->footer; + bb->il.rtl->footer = NULL; + + return new_bb; +} + +/* Redirect Edge to DEST. */ +static edge +cfg_layout_redirect_edge_and_branch (edge e, basic_block dest) +{ + basic_block src = e->src; + edge ret; + + if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) + return NULL; + + if (e->dest == dest) + return e; + + if (e->src != ENTRY_BLOCK_PTR + && (ret = try_redirect_by_replacing_jump (e, dest, true))) + { + df_set_bb_dirty (src); + return ret; + } + + if (e->src == ENTRY_BLOCK_PTR + && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX)) + { + if (dump_file) + fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n", + e->src->index, dest->index); + + df_set_bb_dirty (e->src); + redirect_edge_succ (e, dest); + return e; + } + + /* Redirect_edge_and_branch may decide to turn branch into fallthru edge + in the case the basic block appears to be in sequence. Avoid this + transformation. */ + + if (e->flags & EDGE_FALLTHRU) + { + /* Redirect any branch edges unified with the fallthru one. */ + if (JUMP_P (BB_END (src)) + && label_is_jump_target_p (BB_HEAD (e->dest), + BB_END (src))) + { + edge redirected; + + if (dump_file) + fprintf (dump_file, "Fallthru edge unified with branch " + "%i->%i redirected to %i\n", + e->src->index, e->dest->index, dest->index); + e->flags &= ~EDGE_FALLTHRU; + redirected = redirect_branch_edge (e, dest); + gcc_assert (redirected); + e->flags |= EDGE_FALLTHRU; + df_set_bb_dirty (e->src); + return e; + } + /* In case we are redirecting fallthru edge to the branch edge + of conditional jump, remove it. */ + if (EDGE_COUNT (src->succs) == 2) + { + /* Find the edge that is different from E. */ + edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e); + + if (s->dest == dest + && any_condjump_p (BB_END (src)) + && onlyjump_p (BB_END (src))) + delete_insn (BB_END (src)); + } + ret = redirect_edge_succ_nodup (e, dest); + if (dump_file) + fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n", + e->src->index, e->dest->index, dest->index); + } + else + ret = redirect_branch_edge (e, dest); + + /* We don't want simplejumps in the insn stream during cfglayout. */ + gcc_assert (!simplejump_p (BB_END (src))); + + df_set_bb_dirty (src); + return ret; +} + +/* Simple wrapper as we always can redirect fallthru edges. */ +static basic_block +cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest) +{ + edge redirected = cfg_layout_redirect_edge_and_branch (e, dest); + + gcc_assert (redirected); + return NULL; +} + +/* Same as delete_basic_block but update cfg_layout structures. */ + +static void +cfg_layout_delete_block (basic_block bb) +{ + rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints; + + if (bb->il.rtl->header) + { + next = BB_HEAD (bb); + if (prev) + NEXT_INSN (prev) = bb->il.rtl->header; + else + set_first_insn (bb->il.rtl->header); + PREV_INSN (bb->il.rtl->header) = prev; + insn = bb->il.rtl->header; + while (NEXT_INSN (insn)) + insn = NEXT_INSN (insn); + NEXT_INSN (insn) = next; + PREV_INSN (next) = insn; + } + next = NEXT_INSN (BB_END (bb)); + if (bb->il.rtl->footer) + { + insn = bb->il.rtl->footer; + while (insn) + { + if (BARRIER_P (insn)) + { + if (PREV_INSN (insn)) + NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); + else + bb->il.rtl->footer = NEXT_INSN (insn); + if (NEXT_INSN (insn)) + PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); + } + if (LABEL_P (insn)) + break; + insn = NEXT_INSN (insn); + } + if (bb->il.rtl->footer) + { + insn = BB_END (bb); + NEXT_INSN (insn) = bb->il.rtl->footer; + PREV_INSN (bb->il.rtl->footer) = insn; + while (NEXT_INSN (insn)) + insn = NEXT_INSN (insn); + NEXT_INSN (insn) = next; + if (next) + PREV_INSN (next) = insn; + else + set_last_insn (insn); + } + } + if (bb->next_bb != EXIT_BLOCK_PTR) + to = &bb->next_bb->il.rtl->header; + else + to = &cfg_layout_function_footer; + + rtl_delete_block (bb); + + if (prev) + prev = NEXT_INSN (prev); + else + prev = get_insns (); + if (next) + next = PREV_INSN (next); + else + next = get_last_insn (); + + if (next && NEXT_INSN (next) != prev) + { + remaints = unlink_insn_chain (prev, next); + insn = remaints; + while (NEXT_INSN (insn)) + insn = NEXT_INSN (insn); + NEXT_INSN (insn) = *to; + if (*to) + PREV_INSN (*to) = insn; + *to = remaints; + } +} + +/* Return true when blocks A and B can be safely merged. */ + +static bool +cfg_layout_can_merge_blocks_p (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; + + /* There must be exactly one edge in between the blocks. */ + return (single_succ_p (a) + && single_succ (a) == b + && single_pred_p (b) == 1 + && a != b + /* Must be simple edge. */ + && !(single_succ_edge (a)->flags & EDGE_COMPLEX) + && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR + /* If the jump insn has side effects, we can't kill the edge. + When not optimizing, try_redirect_by_replacing_jump will + not allow us to redirect an edge by replacing a table jump. */ + && (!JUMP_P (BB_END (a)) + || ((!optimize || reload_completed) + ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a))))); +} + +/* Merge block A and B. The blocks must be mergeable. */ + +static void +cfg_layout_merge_blocks (basic_block a, basic_block b) +{ + bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0; + + gcc_checking_assert (cfg_layout_can_merge_blocks_p (a, b)); + + if (dump_file) + fprintf (dump_file, "Merging block %d into block %d...\n", b->index, + a->index); + + /* If there was a CODE_LABEL beginning B, delete it. */ + if (LABEL_P (BB_HEAD (b))) + { + delete_insn (BB_HEAD (b)); + } + + /* We should have fallthru edge in a, or we can do dummy redirection to get + it cleaned up. */ + if (JUMP_P (BB_END (a))) + try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true); + gcc_assert (!JUMP_P (BB_END (a))); + + /* When not optimizing and the edge is the only place in RTL which holds + some unique locus, emit a nop with that locus in between. */ + if (!optimize && EDGE_SUCC (a, 0)->goto_locus) + { + rtx insn = BB_END (a), end = PREV_INSN (BB_HEAD (a)); + int goto_locus = EDGE_SUCC (a, 0)->goto_locus; + + while (insn != end && (!INSN_P (insn) || INSN_LOCATOR (insn) == 0)) + insn = PREV_INSN (insn); + if (insn != end && locator_eq (INSN_LOCATOR (insn), goto_locus)) + goto_locus = 0; + else + { + insn = BB_HEAD (b); + end = NEXT_INSN (BB_END (b)); + while (insn != end && !INSN_P (insn)) + insn = NEXT_INSN (insn); + if (insn != end && INSN_LOCATOR (insn) != 0 + && locator_eq (INSN_LOCATOR (insn), goto_locus)) + goto_locus = 0; + } + if (goto_locus) + { + BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a); + INSN_LOCATOR (BB_END (a)) = goto_locus; + } + } + + /* Possible line number notes should appear in between. */ + if (b->il.rtl->header) + { + rtx first = BB_END (a), last; + + last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a), a); + /* The above might add a BARRIER as BB_END, but as barriers + aren't valid parts of a bb, remove_insn doesn't update + BB_END if it is a barrier. So adjust BB_END here. */ + while (BB_END (a) != first && BARRIER_P (BB_END (a))) + BB_END (a) = PREV_INSN (BB_END (a)); + delete_insn_chain (NEXT_INSN (first), last, false); + b->il.rtl->header = NULL; + } + + /* In the case basic blocks are not adjacent, move them around. */ + if (NEXT_INSN (BB_END (a)) != BB_HEAD (b)) + { + rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b)); + + emit_insn_after_noloc (first, BB_END (a), a); + /* Skip possible DELETED_LABEL insn. */ + if (!NOTE_INSN_BASIC_BLOCK_P (first)) + first = NEXT_INSN (first); + gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first)); + BB_HEAD (b) = NULL; + + /* emit_insn_after_noloc doesn't call df_insn_change_bb. + We need to explicitly call. */ + update_bb_for_insn_chain (NEXT_INSN (first), + BB_END (b), + a); + + delete_insn (first); + } + /* Otherwise just re-associate the instructions. */ + else + { + rtx insn; + + update_bb_for_insn_chain (BB_HEAD (b), BB_END (b), a); + + insn = BB_HEAD (b); + /* Skip possible DELETED_LABEL insn. */ + if (!NOTE_INSN_BASIC_BLOCK_P (insn)) + insn = NEXT_INSN (insn); + gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn)); + BB_HEAD (b) = NULL; + BB_END (a) = BB_END (b); + delete_insn (insn); + } + + df_bb_delete (b->index); + + /* Possible tablejumps and barriers should appear after the block. */ + if (b->il.rtl->footer) + { + if (!a->il.rtl->footer) + a->il.rtl->footer = b->il.rtl->footer; + else + { + rtx last = a->il.rtl->footer; + + while (NEXT_INSN (last)) + last = NEXT_INSN (last); + NEXT_INSN (last) = b->il.rtl->footer; + PREV_INSN (b->il.rtl->footer) = last; + } + b->il.rtl->footer = NULL; + } + + /* If B was a forwarder block, propagate the locus on the edge. */ + if (forwarder_p && !EDGE_SUCC (b, 0)->goto_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); +} + +/* Split edge E. */ + +static basic_block +cfg_layout_split_edge (edge e) +{ + basic_block new_bb = + create_basic_block (e->src != ENTRY_BLOCK_PTR + ? NEXT_INSN (BB_END (e->src)) : get_insns (), + NULL_RTX, e->src); + + if (e->dest == EXIT_BLOCK_PTR) + BB_COPY_PARTITION (new_bb, e->src); + else + BB_COPY_PARTITION (new_bb, e->dest); + make_edge (new_bb, e->dest, EDGE_FALLTHRU); + redirect_edge_and_branch_force (e, new_bb); + + return new_bb; +} + +/* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */ + +static void +rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED) +{ +} + +/* Return 1 if BB ends with a call, possibly followed by some + instructions that must stay with the call, 0 otherwise. */ + +static bool +rtl_block_ends_with_call_p (basic_block bb) +{ + rtx insn = BB_END (bb); + + while (!CALL_P (insn) + && insn != BB_HEAD (bb) + && (keep_with_call_p (insn) + || NOTE_P (insn) + || DEBUG_INSN_P (insn))) + insn = PREV_INSN (insn); + return (CALL_P (insn)); +} + +/* Return 1 if BB ends with a conditional branch, 0 otherwise. */ + +static bool +rtl_block_ends_with_condjump_p (const_basic_block bb) +{ + return any_condjump_p (BB_END (bb)); +} + +/* Return true if we need to add fake edge to exit. + Helper function for rtl_flow_call_edges_add. */ + +static bool +need_fake_edge_p (const_rtx insn) +{ + if (!INSN_P (insn)) + return false; + + if ((CALL_P (insn) + && !SIBLING_CALL_P (insn) + && !find_reg_note (insn, REG_NORETURN, NULL) + && !(RTL_CONST_OR_PURE_CALL_P (insn)))) + return true; + + return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS + && MEM_VOLATILE_P (PATTERN (insn))) + || (GET_CODE (PATTERN (insn)) == PARALLEL + && asm_noperands (insn) != -1 + && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0))) + || GET_CODE (PATTERN (insn)) == ASM_INPUT); +} + +/* Add fake edges to the function exit for any non constant and non noreturn + calls, volatile inline assembly in the bitmap of blocks specified by + BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks + that were split. + + The goal is to expose cases in which entering a basic block does not imply + that all subsequent instructions must be executed. */ + +static int +rtl_flow_call_edges_add (sbitmap blocks) +{ + int i; + int blocks_split = 0; + int last_bb = last_basic_block; + bool check_last_block = false; + + if (n_basic_blocks == NUM_FIXED_BLOCKS) + return 0; + + if (! blocks) + check_last_block = true; + else + check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index); + + /* In the last basic block, before epilogue generation, there will be + a fallthru edge to EXIT. Special care is required if the last insn + of the last basic block is a call because make_edge folds duplicate + edges, which would result in the fallthru edge also being marked + fake, which would result in the fallthru edge being removed by + remove_fake_edges, which would result in an invalid CFG. + + Moreover, we can't elide the outgoing fake edge, since the block + profiler needs to take this into account in order to solve the minimal + spanning tree in the case that the call doesn't return. + + Handle this by adding a dummy instruction in a new last basic block. */ + if (check_last_block) + { + basic_block bb = EXIT_BLOCK_PTR->prev_bb; + rtx insn = BB_END (bb); + + /* Back up past insns that must be kept in the same block as a call. */ + while (insn != BB_HEAD (bb) + && keep_with_call_p (insn)) + insn = PREV_INSN (insn); + + if (need_fake_edge_p (insn)) + { + edge e; + + e = find_edge (bb, EXIT_BLOCK_PTR); + if (e) + { + insert_insn_on_edge (gen_use (const0_rtx), e); + commit_edge_insertions (); + } + } + } + + /* Now add fake edges to the function exit for any non constant + calls since there is no way that we can determine if they will + return or not... */ + + for (i = NUM_FIXED_BLOCKS; i < last_bb; i++) + { + basic_block bb = BASIC_BLOCK (i); + rtx insn; + rtx prev_insn; + + if (!bb) + continue; + + if (blocks && !TEST_BIT (blocks, i)) + continue; + + for (insn = BB_END (bb); ; insn = prev_insn) + { + prev_insn = PREV_INSN (insn); + if (need_fake_edge_p (insn)) + { + edge e; + rtx split_at_insn = insn; + + /* Don't split the block between a call and an insn that should + remain in the same block as the call. */ + if (CALL_P (insn)) + while (split_at_insn != BB_END (bb) + && keep_with_call_p (NEXT_INSN (split_at_insn))) + split_at_insn = NEXT_INSN (split_at_insn); + + /* The handling above of the final block before the epilogue + should be enough to verify that there is no edge to the exit + block in CFG already. Calling make_edge in such case would + cause us to mark that edge as fake and remove it later. */ + +#ifdef ENABLE_CHECKING + if (split_at_insn == BB_END (bb)) + { + e = find_edge (bb, EXIT_BLOCK_PTR); + gcc_assert (e == NULL); + } +#endif + + /* Note that the following may create a new basic block + and renumber the existing basic blocks. */ + if (split_at_insn != BB_END (bb)) + { + e = split_block (bb, split_at_insn); + if (e) + blocks_split++; + } + + make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE); + } + + if (insn == BB_HEAD (bb)) + break; + } + } + + if (blocks_split) + verify_flow_info (); + + return blocks_split; +} + +/* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is + the conditional branch target, SECOND_HEAD should be the fall-thru + there is no need to handle this here the loop versioning code handles + this. the reason for SECON_HEAD is that it is needed for condition + in trees, and this should be of the same type since it is a hook. */ +static void +rtl_lv_add_condition_to_bb (basic_block first_head , + basic_block second_head ATTRIBUTE_UNUSED, + basic_block cond_bb, void *comp_rtx) +{ + rtx label, seq, jump; + rtx op0 = XEXP ((rtx)comp_rtx, 0); + rtx op1 = XEXP ((rtx)comp_rtx, 1); + enum rtx_code comp = GET_CODE ((rtx)comp_rtx); + enum machine_mode mode; + + + label = block_label (first_head); + mode = GET_MODE (op0); + if (mode == VOIDmode) + mode = GET_MODE (op1); + + start_sequence (); + op0 = force_operand (op0, NULL_RTX); + op1 = force_operand (op1, NULL_RTX); + do_compare_rtx_and_jump (op0, op1, comp, 0, + mode, NULL_RTX, NULL_RTX, label, -1); + jump = get_last_insn (); + JUMP_LABEL (jump) = label; + LABEL_NUSES (label)++; + seq = get_insns (); + end_sequence (); + + /* Add the new cond , in the new head. */ + emit_insn_after(seq, BB_END(cond_bb)); +} + + +/* Given a block B with unconditional branch at its end, get the + store the return the branch edge and the fall-thru edge in + BRANCH_EDGE and FALLTHRU_EDGE respectively. */ +static void +rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge, + edge *fallthru_edge) +{ + edge e = EDGE_SUCC (b, 0); + + if (e->flags & EDGE_FALLTHRU) + { + *fallthru_edge = e; + *branch_edge = EDGE_SUCC (b, 1); + } + else + { + *branch_edge = e; + *fallthru_edge = EDGE_SUCC (b, 1); + } +} + +void +init_rtl_bb_info (basic_block bb) +{ + gcc_assert (!bb->il.rtl); + bb->il.rtl = ggc_alloc_cleared_rtl_bb_info (); +} + +/* Returns true if it is possible to remove edge E by redirecting + it to the destination of the other edge from E->src. */ + +static bool +rtl_can_remove_branch_p (const_edge e) +{ + const_basic_block src = e->src; + const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest; + const_rtx insn = BB_END (src), set; + + /* The conditions are taken from try_redirect_by_replacing_jump. */ + if (target == EXIT_BLOCK_PTR) + return false; + + if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) + return false; + + if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX) + || BB_PARTITION (src) != BB_PARTITION (target)) + return false; + + if (!onlyjump_p (insn) + || tablejump_p (insn, NULL, NULL)) + return false; + + set = single_set (insn); + if (!set || side_effects_p (set)) + return false; + + return true; +} + +/* Implementation of CFG manipulation for linearized RTL. */ +struct cfg_hooks rtl_cfg_hooks = { + "rtl", + rtl_verify_flow_info, + rtl_dump_bb, + rtl_create_basic_block, + rtl_redirect_edge_and_branch, + rtl_redirect_edge_and_branch_force, + rtl_can_remove_branch_p, + rtl_delete_block, + rtl_split_block, + rtl_move_block_after, + rtl_can_merge_blocks, /* can_merge_blocks_p */ + rtl_merge_blocks, + rtl_predict_edge, + rtl_predicted_by_p, + NULL, /* can_duplicate_block_p */ + NULL, /* duplicate_block */ + rtl_split_edge, + rtl_make_forwarder_block, + rtl_tidy_fallthru_edge, + rtl_block_ends_with_call_p, + rtl_block_ends_with_condjump_p, + rtl_flow_call_edges_add, + NULL, /* execute_on_growing_pred */ + NULL, /* execute_on_shrinking_pred */ + NULL, /* duplicate loop for trees */ + NULL, /* lv_add_condition_to_bb */ + NULL, /* lv_adjust_loop_header_phi*/ + NULL, /* extract_cond_bb_edges */ + NULL /* flush_pending_stmts */ +}; + +/* Implementation of CFG manipulation for cfg layout RTL, where + basic block connected via fallthru edges does not have to be adjacent. + This representation will hopefully become the default one in future + version of the compiler. */ + +/* We do not want to declare these functions in a header file, since they + should only be used through the cfghooks interface, and we do not want to + move them here since it would require also moving quite a lot of related + code. They are in cfglayout.c. */ +extern bool cfg_layout_can_duplicate_bb_p (const_basic_block); +extern basic_block cfg_layout_duplicate_bb (basic_block); + +struct cfg_hooks cfg_layout_rtl_cfg_hooks = { + "cfglayout mode", + rtl_verify_flow_info_1, + rtl_dump_bb, + cfg_layout_create_basic_block, + cfg_layout_redirect_edge_and_branch, + cfg_layout_redirect_edge_and_branch_force, + rtl_can_remove_branch_p, + cfg_layout_delete_block, + cfg_layout_split_block, + rtl_move_block_after, + cfg_layout_can_merge_blocks_p, + cfg_layout_merge_blocks, + rtl_predict_edge, + rtl_predicted_by_p, + cfg_layout_can_duplicate_bb_p, + cfg_layout_duplicate_bb, + cfg_layout_split_edge, + rtl_make_forwarder_block, + NULL, + rtl_block_ends_with_call_p, + rtl_block_ends_with_condjump_p, + rtl_flow_call_edges_add, + NULL, /* execute_on_growing_pred */ + NULL, /* execute_on_shrinking_pred */ + duplicate_loop_to_header_edge, /* duplicate loop for trees */ + rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */ + NULL, /* lv_adjust_loop_header_phi*/ + rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */ + NULL /* flush_pending_stmts */ +}; |