X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Fcfgbuild.c;h=692fea8a17b3d87b1e7e6ef9b8a1f28228eb120c;hb=eec86b214a56292b6b65834f0caff7ae2bda9cc9;hp=a4882e2fca14f66b70911d67d527120c4f457e77;hpb=ea091dfdfe023dacb0c7c2af37bdd75e23c530f4;p=pf3gnuchains%2Fgcc-fork.git diff --git a/gcc/cfgbuild.c b/gcc/cfgbuild.c index a4882e2fca1..692fea8a17b 100644 --- a/gcc/cfgbuild.c +++ b/gcc/cfgbuild.c @@ -1,12 +1,13 @@ /* Control flow graph building code for GNU compiler. Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, - 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. + 1999, 2000, 2001, 2002, 2003, 2004, 2005, 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 2, or (at your option) any later +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 @@ -15,20 +16,9 @@ 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 COPYING. If not, write to the Free -Software Foundation, 59 Temple Place - Suite 330, Boston, MA -02111-1307, USA. */ +along with GCC; see the file COPYING3. If not see +. */ -/* find_basic_blocks divides the current function's rtl into basic - blocks and constructs the CFG. The blocks are recorded in the - basic_block_info array; the CFG exists in the edge structures - referenced by the blocks. - - find_basic_blocks also finds any unreachable loops and deletes them. - - Available functionality: - - CFG construction - find_basic_blocks */ #include "config.h" #include "system.h" @@ -43,13 +33,13 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "output.h" #include "function.h" #include "except.h" -#include "toplev.h" +#include "expr.h" +#include "diagnostic-core.h" #include "timevar.h" +#include "sbitmap.h" -static int count_basic_blocks (rtx); -static void find_basic_blocks_1 (rtx); static void make_edges (basic_block, basic_block, int); -static void make_label_edge (sbitmap *, basic_block, rtx, int); +static void make_label_edge (sbitmap, basic_block, rtx, int); static void find_bb_boundaries (basic_block); static void compute_outgoing_frequencies (basic_block); @@ -57,7 +47,7 @@ static void compute_outgoing_frequencies (basic_block); block. */ bool -inside_basic_block_p (rtx insn) +inside_basic_block_p (const_rtx insn) { switch (GET_CODE (insn)) { @@ -74,6 +64,7 @@ inside_basic_block_p (rtx insn) case CALL_INSN: case INSN: + case DEBUG_INSN: return true; case BARRIER: @@ -89,14 +80,13 @@ inside_basic_block_p (rtx insn) the basic block. */ bool -control_flow_insn_p (rtx insn) +control_flow_insn_p (const_rtx insn) { - rtx note; - switch (GET_CODE (insn)) { case NOTE: case CODE_LABEL: + case DEBUG_INSN: return false; case JUMP_INSN: @@ -111,67 +101,34 @@ control_flow_insn_p (rtx insn) || find_reg_note (insn, REG_NORETURN, 0)) && GET_CODE (PATTERN (insn)) != COND_EXEC) return true; + /* Call insn may return to the nonlocal goto handler. */ - return ((nonlocal_goto_handler_labels - && (0 == (note = find_reg_note (insn, REG_EH_REGION, - NULL_RTX)) - || INTVAL (XEXP (note, 0)) >= 0)) - /* Or may trap. */ - || can_throw_internal (insn)); + if (can_nonlocal_goto (insn)) + return true; + break; case INSN: - return (flag_non_call_exceptions && can_throw_internal (insn)); + /* Treat trap instructions like noreturn calls (same provision). */ + if (GET_CODE (PATTERN (insn)) == TRAP_IF + && XEXP (PATTERN (insn), 0) == const1_rtx) + return true; + if (!cfun->can_throw_non_call_exceptions) + return false; + break; case BARRIER: /* It is nonsense to reach barrier when looking for the - end of basic block, but before dead code is eliminated - this may happen. */ + end of basic block, but before dead code is eliminated + this may happen. */ return false; default: gcc_unreachable (); } -} - -/* Count the basic blocks of the function. */ - -static int -count_basic_blocks (rtx f) -{ - int count = 0; - bool saw_insn = false; - rtx insn; - - for (insn = f; insn; insn = NEXT_INSN (insn)) - { - /* Code labels and barriers causes current basic block to be - terminated at previous real insn. */ - if ((LABEL_P (insn) || BARRIER_P (insn)) - && saw_insn) - count++, saw_insn = false; - - /* Start basic block if needed. */ - if (!saw_insn && inside_basic_block_p (insn)) - saw_insn = true; - - /* Control flow insn causes current basic block to be terminated. */ - if (saw_insn && control_flow_insn_p (insn)) - count++, saw_insn = false; - } - if (saw_insn) - count++; - - /* The rest of the compiler works a bit smoother when we don't have to - check for the edge case of do-nothing functions with no basic blocks. */ - if (count == 0) - { - emit_insn (gen_rtx_USE (VOIDmode, const0_rtx)); - count = 1; - } - - return count; + return can_throw_internal (insn); } + /* Create an edge between two basic blocks. FLAGS are auxiliary information about the edge that is accumulated between calls. */ @@ -179,7 +136,7 @@ count_basic_blocks (rtx f) /* Create an edge from a basic block to a label. */ static void -make_label_edge (sbitmap *edge_cache, basic_block src, rtx label, int flags) +make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags) { gcc_assert (LABEL_P (label)); @@ -197,22 +154,44 @@ make_label_edge (sbitmap *edge_cache, basic_block src, rtx label, int flags) /* Create the edges generated by INSN in REGION. */ void -rtl_make_eh_edge (sbitmap *edge_cache, basic_block src, rtx insn) +rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx insn) { - int is_call = CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0; - rtx handlers, i; + eh_landing_pad lp = get_eh_landing_pad_from_rtx (insn); - handlers = reachable_handlers (insn); + if (lp) + { + rtx label = lp->landing_pad; - for (i = handlers; i; i = XEXP (i, 1)) - make_label_edge (edge_cache, src, XEXP (i, 0), - EDGE_ABNORMAL | EDGE_EH | is_call); + /* During initial rtl generation, use the post_landing_pad. */ + if (label == NULL) + { + gcc_assert (lp->post_landing_pad); + label = label_rtx (lp->post_landing_pad); + } - free_INSN_LIST_list (&handlers); + make_label_edge (edge_cache, src, label, + EDGE_ABNORMAL | EDGE_EH + | (CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0)); + } } -/* State of basic block as seen by find_many_sub_basic_blocks. */ -enum state {BLOCK_NEW = 0, BLOCK_ORIGINAL, BLOCK_TO_SPLIT}; +/* States of basic block as seen by find_many_sub_basic_blocks. */ +enum state { + /* Basic blocks created via split_block belong to this state. + make_edges will examine these basic blocks to see if we need to + create edges going out of them. */ + BLOCK_NEW = 0, + + /* Basic blocks that do not need examining belong to this state. + These blocks will be left intact. In particular, make_edges will + not create edges going out of these basic blocks. */ + BLOCK_ORIGINAL, + + /* Basic blocks that may need splitting (due to a label appearing in + the middle, etc) belong to this state. After splitting them, + make_edges will create edges going out of them as needed. */ + BLOCK_TO_SPLIT +}; #define STATE(BB) (enum state) ((size_t) (BB)->aux) #define SET_STATE(BB, STATE) ((BB)->aux = (void *) (size_t) (STATE)) @@ -221,58 +200,52 @@ enum state {BLOCK_NEW = 0, BLOCK_ORIGINAL, BLOCK_TO_SPLIT}; #define BLOCK_USED_BY_TABLEJUMP 32 #define FULL_STATE(BB) ((size_t) (BB)->aux) -/* Identify the edges between basic blocks MIN to MAX. - - NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks - that are otherwise unreachable may be reachable with a non-local goto. +/* Identify the edges going out of basic blocks between MIN and MAX, + inclusive, that have their states set to BLOCK_NEW or + BLOCK_TO_SPLIT. - BB_EH_END is an array indexed by basic block number in which we record - the list of exception regions active at the end of the basic block. */ + UPDATE_P should be nonzero if we are updating CFG and zero if we + are building CFG from scratch. */ static void make_edges (basic_block min, basic_block max, int update_p) { basic_block bb; - sbitmap *edge_cache = NULL; + sbitmap edge_cache = NULL; /* Heavy use of computed goto in machine-generated code can lead to nearly fully-connected CFGs. In that case we spend a significant amount of time searching the edge lists for duplicates. */ - if (forced_labels || cfun->max_jumptable_ents > 100) - { - edge_cache = sbitmap_vector_alloc (last_basic_block, last_basic_block); - sbitmap_vector_zero (edge_cache, last_basic_block); - - if (update_p) - { - FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) - if (STATE (bb) != BLOCK_ORIGINAL) - { - edge e; - edge_iterator ei; - - FOR_EACH_EDGE (e, ei, bb->succs) - if (e->dest != EXIT_BLOCK_PTR) - SET_BIT (edge_cache[bb->index], e->dest->index); - } - } - } + if (forced_labels || cfun->cfg->max_jumptable_ents > 100) + edge_cache = sbitmap_alloc (last_basic_block); /* By nature of the way these get numbered, ENTRY_BLOCK_PTR->next_bb block is always the entry. */ if (min == ENTRY_BLOCK_PTR->next_bb) - cached_make_edge (edge_cache, ENTRY_BLOCK_PTR, min, - EDGE_FALLTHRU); + make_edge (ENTRY_BLOCK_PTR, min, EDGE_FALLTHRU); FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) { rtx insn, x; enum rtx_code code; edge e; + edge_iterator ei; if (STATE (bb) == BLOCK_ORIGINAL) continue; + /* If we have an edge cache, cache edges going out of BB. */ + if (edge_cache) + { + sbitmap_zero (edge_cache); + if (update_p) + { + FOR_EACH_EDGE (e, ei, bb->succs) + if (e->dest != EXIT_BLOCK_PTR) + SET_BIT (edge_cache, e->dest->index); + } + } + if (LABEL_P (BB_HEAD (bb)) && LABEL_ALT_ENTRY_P (BB_HEAD (bb))) cached_make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0); @@ -288,13 +261,9 @@ make_edges (basic_block min, basic_block max, int update_p) { rtx tmp; - /* Recognize exception handling placeholders. */ - if (GET_CODE (PATTERN (insn)) == RESX) - rtl_make_eh_edge (edge_cache, bb, insn); - /* Recognize a non-local goto as a branch outside the current function. */ - else if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX)) + if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX)) ; /* Recognize a tablejump and do the right thing. */ @@ -335,6 +304,15 @@ make_edges (basic_block min, basic_block max, int update_p) else if (returnjump_p (insn)) cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0); + /* Recognize asm goto and do the right thing. */ + else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL) + { + int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp); + for (i = 0; i < n; ++i) + make_label_edge (edge_cache, bb, + XEXP (ASM_OPERANDS_LABEL (tmp, i), 0), 0); + } + /* Otherwise, we have a plain conditional or unconditional jump. */ else { @@ -355,28 +333,35 @@ make_edges (basic_block min, basic_block max, int update_p) handler for this CALL_INSN. If we're handling non-call exceptions then any insn can reach any of the active handlers. Also mark the CALL_INSN as reaching any nonlocal goto handler. */ - else if (code == CALL_INSN || flag_non_call_exceptions) + else if (code == CALL_INSN || cfun->can_throw_non_call_exceptions) { /* Add any appropriate EH edges. */ rtl_make_eh_edge (edge_cache, bb, insn); - if (code == CALL_INSN && nonlocal_goto_handler_labels) + if (code == CALL_INSN) { - /* ??? This could be made smarter: in some cases it's possible - to tell that certain calls will not do a nonlocal goto. - For example, if the nested functions that do the nonlocal - gotos do not have their addresses taken, then only calls to - those functions or to other nested functions that use them - could possibly do nonlocal gotos. */ - - /* We do know that a REG_EH_REGION note with a value less - than 0 is guaranteed not to perform a non-local goto. */ - rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX); - - if (!note || INTVAL (XEXP (note, 0)) >= 0) - for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1)) - make_label_edge (edge_cache, bb, XEXP (x, 0), - EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); + if (can_nonlocal_goto (insn)) + { + /* ??? This could be made smarter: in some cases it's + possible to tell that certain calls will not do a + nonlocal goto. For example, if the nested functions + that do the nonlocal gotos do not have their addresses + taken, then only calls to those functions or to other + nested functions that use them could possibly do + nonlocal gotos. */ + for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1)) + make_label_edge (edge_cache, bb, XEXP (x, 0), + EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); + } + + if (flag_tm) + { + rtx note; + for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) + if (REG_NOTE_KIND (note) == REG_TM) + make_label_edge (edge_cache, bb, XEXP (note, 0), + EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); + } } } @@ -388,7 +373,7 @@ make_edges (basic_block min, basic_block max, int update_p) while (insn && NOTE_P (insn) - && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK) + && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK) insn = NEXT_INSN (insn); if (!insn) @@ -404,156 +389,6 @@ make_edges (basic_block min, basic_block max, int update_p) sbitmap_vector_free (edge_cache); } -/* Find all basic blocks of the function whose first insn is F. - - Collect and return a list of labels whose addresses are taken. This - will be used in make_edges for use with computed gotos. */ - -static void -find_basic_blocks_1 (rtx f) -{ - rtx insn, next; - rtx bb_note = NULL_RTX; - rtx head = NULL_RTX; - rtx end = NULL_RTX; - basic_block prev = ENTRY_BLOCK_PTR; - - /* We process the instructions in a slightly different way than we did - previously. This is so that we see a NOTE_BASIC_BLOCK after we have - closed out the previous block, so that it gets attached at the proper - place. Since this form should be equivalent to the previous, - count_basic_blocks continues to use the old form as a check. */ - - for (insn = f; insn; insn = next) - { - enum rtx_code code = GET_CODE (insn); - - next = NEXT_INSN (insn); - - if ((LABEL_P (insn) || BARRIER_P (insn)) - && head) - { - prev = create_basic_block_structure (head, end, bb_note, prev); - head = end = NULL_RTX; - bb_note = NULL_RTX; - } - - if (inside_basic_block_p (insn)) - { - if (head == NULL_RTX) - head = insn; - end = insn; - } - - if (head && control_flow_insn_p (insn)) - { - prev = create_basic_block_structure (head, end, bb_note, prev); - head = end = NULL_RTX; - bb_note = NULL_RTX; - } - - switch (code) - { - case NOTE: - { - int kind = NOTE_LINE_NUMBER (insn); - - /* Look for basic block notes with which to keep the - basic_block_info pointers stable. Unthread the note now; - we'll put it back at the right place in create_basic_block. - Or not at all if we've already found a note in this block. */ - if (kind == NOTE_INSN_BASIC_BLOCK) - { - if (bb_note == NULL_RTX) - bb_note = insn; - else - next = delete_insn (insn); - } - break; - } - - case CODE_LABEL: - case JUMP_INSN: - case CALL_INSN: - case INSN: - case BARRIER: - break; - - default: - gcc_unreachable (); - } - } - - if (head != NULL_RTX) - create_basic_block_structure (head, end, bb_note, prev); - else if (bb_note) - delete_insn (bb_note); - - gcc_assert (last_basic_block == n_basic_blocks); - - clear_aux_for_blocks (); -} - - -/* Find basic blocks of the current function. - F is the first insn of the function. */ - -void -find_basic_blocks (rtx f) -{ - basic_block bb; - - timevar_push (TV_CFG); - - /* Flush out existing data. */ - if (basic_block_info != NULL) - { - clear_edges (); - - /* Clear bb->aux on all extant basic blocks. We'll use this as a - tag for reuse during create_basic_block, just in case some pass - copies around basic block notes improperly. */ - FOR_EACH_BB (bb) - bb->aux = NULL; - - basic_block_info = NULL; - } - - n_basic_blocks = count_basic_blocks (f); - last_basic_block = 0; - ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR; - EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR; - - /* Size the basic block table. The actual structures will be allocated - by find_basic_blocks_1, since we want to keep the structure pointers - stable across calls to find_basic_blocks. */ - /* ??? This whole issue would be much simpler if we called find_basic_blocks - exactly once, and thereafter we don't have a single long chain of - instructions at all until close to the end of compilation when we - actually lay them out. */ - - VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info"); - - find_basic_blocks_1 (f); - - profile_status = PROFILE_ABSENT; - - FOR_EACH_BB (bb) - SET_STATE (bb, BLOCK_NEW); - - /* Discover the edges of our cfg. */ - make_edges (ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR->prev_bb, 0); - - /* Do very simple cleanup now, for the benefit of code that runs between - here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */ - tidy_fallthru_edges (); - -#ifdef ENABLE_CHECKING - verify_flow_info (); -#endif - timevar_pop (TV_CFG); -} - static void mark_tablejump_edge (rtx label) { @@ -596,13 +431,13 @@ purge_dead_tablejump_edges (basic_block bb, rtx table) for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) { if (FULL_STATE (e->dest) & BLOCK_USED_BY_TABLEJUMP) - SET_STATE (e->dest, FULL_STATE (e->dest) - & ~(size_t) BLOCK_USED_BY_TABLEJUMP); + SET_STATE (e->dest, FULL_STATE (e->dest) + & ~(size_t) BLOCK_USED_BY_TABLEJUMP); else if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH))) - { - remove_edge (e); - continue; - } + { + remove_edge (e); + continue; + } ei_next (&ei); } } @@ -615,7 +450,7 @@ find_bb_boundaries (basic_block bb) { basic_block orig_bb = bb; rtx insn = BB_HEAD (bb); - rtx end = BB_END (bb); + rtx end = BB_END (bb), x; rtx table; rtx flow_transfer_insn = NULL_RTX; edge fallthru = NULL; @@ -631,29 +466,37 @@ find_bb_boundaries (basic_block bb) { enum rtx_code code = GET_CODE (insn); - /* On code label, split current basic block. */ - if (code == CODE_LABEL) + /* In case we've previously seen an insn that effects a control + flow transfer, split the block. */ + if ((flow_transfer_insn || code == CODE_LABEL) + && inside_basic_block_p (insn)) { fallthru = split_block (bb, PREV_INSN (insn)); if (flow_transfer_insn) - BB_END (bb) = flow_transfer_insn; + { + BB_END (bb) = flow_transfer_insn; + + /* Clean up the bb field for the insns between the blocks. */ + for (x = NEXT_INSN (flow_transfer_insn); + x != BB_HEAD (fallthru->dest); + x = NEXT_INSN (x)) + if (!BARRIER_P (x)) + set_block_for_insn (x, NULL); + } bb = fallthru->dest; remove_edge (fallthru); flow_transfer_insn = NULL_RTX; - if (LABEL_ALT_ENTRY_P (insn)) + if (code == CODE_LABEL && LABEL_ALT_ENTRY_P (insn)) make_edge (ENTRY_BLOCK_PTR, bb, 0); } - - /* In case we've previously seen an insn that effects a control - flow transfer, split the block. */ - if (flow_transfer_insn && inside_basic_block_p (insn)) + else if (code == BARRIER) { - fallthru = split_block (bb, PREV_INSN (insn)); - BB_END (bb) = flow_transfer_insn; - bb = fallthru->dest; - remove_edge (fallthru); - flow_transfer_insn = NULL_RTX; + /* __builtin_unreachable () may cause a barrier to be emitted in + the middle of a BB. We need to split it in the same manner as + if the barrier were preceded by a control_flow_insn_p insn. */ + if (!flow_transfer_insn) + flow_transfer_insn = prev_nonnote_insn_bb (insn); } if (control_flow_insn_p (insn)) @@ -667,7 +510,18 @@ find_bb_boundaries (basic_block bb) return and barrier, or possibly other sequence not behaving like ordinary jump, we need to take care and move basic block boundary. */ if (flow_transfer_insn) - BB_END (bb) = flow_transfer_insn; + { + BB_END (bb) = flow_transfer_insn; + + /* Clean up the bb field for the insns that do not belong to BB. */ + x = flow_transfer_insn; + while (x != end) + { + x = NEXT_INSN (x); + if (!BARRIER_P (x)) + set_block_for_insn (x, NULL); + } + } /* We've possibly replaced the conditional jump by conditional jump followed by cleanup at fallthru edge, so the outgoing edges may @@ -722,8 +576,9 @@ compute_outgoing_frequencies (basic_block b) / REG_BR_PROB_BASE); } -/* Assume that someone emitted code with control flow instructions to the - basic block. Update the data structure. */ +/* Assume that some pass has inserted labels or control flow + instructions within a basic block. Split basic blocks as needed + and create edges. */ void find_many_sub_basic_blocks (sbitmap blocks)