| /* Control flow graph building code for GNU compiler. |
| Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, |
| 1999, 2000, 2001, 2002, 2003 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 |
| 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 COPYING. If not, write to the Free |
| Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
| 02111-1307, USA. */ |
| |
| /* 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 |
| - Local CFG construction |
| find_sub_basic_blocks */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "tm.h" |
| #include "tree.h" |
| #include "rtl.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 "toplev.h" |
| #include "timevar.h" |
| |
| static int count_basic_blocks (rtx); |
| static void find_basic_blocks_1 (rtx); |
| static rtx find_label_refs (rtx, rtx); |
| static void make_edges (rtx, basic_block, basic_block, int); |
| static void make_label_edge (sbitmap *, basic_block, rtx, int); |
| static void make_eh_edge (sbitmap *, basic_block, rtx); |
| static void find_bb_boundaries (basic_block); |
| static void compute_outgoing_frequencies (basic_block); |
| |
| /* Return true if insn is something that should be contained inside basic |
| block. */ |
| |
| bool |
| inside_basic_block_p (rtx insn) |
| { |
| switch (GET_CODE (insn)) |
| { |
| case CODE_LABEL: |
| /* Avoid creating of basic block for jumptables. */ |
| return (NEXT_INSN (insn) == 0 |
| || GET_CODE (NEXT_INSN (insn)) != JUMP_INSN |
| || (GET_CODE (PATTERN (NEXT_INSN (insn))) != ADDR_VEC |
| && GET_CODE (PATTERN (NEXT_INSN (insn))) != ADDR_DIFF_VEC)); |
| |
| case JUMP_INSN: |
| return (GET_CODE (PATTERN (insn)) != ADDR_VEC |
| && GET_CODE (PATTERN (insn)) != ADDR_DIFF_VEC); |
| |
| case CALL_INSN: |
| case INSN: |
| return true; |
| |
| case BARRIER: |
| case NOTE: |
| return false; |
| |
| default: |
| abort (); |
| } |
| } |
| |
| /* Return true if INSN may cause control flow transfer, so it should be last in |
| the basic block. */ |
| |
| bool |
| control_flow_insn_p (rtx insn) |
| { |
| rtx note; |
| |
| switch (GET_CODE (insn)) |
| { |
| case NOTE: |
| case CODE_LABEL: |
| return false; |
| |
| case JUMP_INSN: |
| /* Jump insn always causes control transfer except for tablejumps. */ |
| return (GET_CODE (PATTERN (insn)) != ADDR_VEC |
| && GET_CODE (PATTERN (insn)) != ADDR_DIFF_VEC); |
| |
| case CALL_INSN: |
| /* 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)); |
| |
| case INSN: |
| return (flag_non_call_exceptions && can_throw_internal (insn)); |
| |
| 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. */ |
| return false; |
| |
| default: |
| abort (); |
| } |
| } |
| |
| /* 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 ((GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == BARRIER) |
| && 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; |
| } |
| |
| /* Scan a list of insns for labels referred to other than by jumps. |
| This is used to scan the alternatives of a call placeholder. */ |
| |
| static rtx |
| find_label_refs (rtx f, rtx lvl) |
| { |
| rtx insn; |
| |
| for (insn = f; insn; insn = NEXT_INSN (insn)) |
| if (INSN_P (insn) && GET_CODE (insn) != JUMP_INSN) |
| { |
| rtx note; |
| |
| /* Make a list of all labels referred to other than by jumps |
| (which just don't have the REG_LABEL notes). |
| |
| Make a special exception for labels followed by an ADDR*VEC, |
| as this would be a part of the tablejump setup code. |
| |
| Make a special exception to registers loaded with label |
| values just before jump insns that use them. */ |
| |
| for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) |
| if (REG_NOTE_KIND (note) == REG_LABEL) |
| { |
| rtx lab = XEXP (note, 0), next; |
| |
| if ((next = next_nonnote_insn (lab)) != NULL |
| && GET_CODE (next) == JUMP_INSN |
| && (GET_CODE (PATTERN (next)) == ADDR_VEC |
| || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC)) |
| ; |
| else if (GET_CODE (lab) == NOTE) |
| ; |
| else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN |
| && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab)) |
| ; |
| else |
| lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl); |
| } |
| } |
| |
| return lvl; |
| } |
| |
| /* Create an edge between two basic blocks. FLAGS are auxiliary information |
| about the edge that is accumulated between calls. */ |
| |
| /* 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) |
| { |
| if (GET_CODE (label) != CODE_LABEL) |
| abort (); |
| |
| /* If the label was never emitted, this insn is junk, but avoid a |
| crash trying to refer to BLOCK_FOR_INSN (label). This can happen |
| as a result of a syntax error and a diagnostic has already been |
| printed. */ |
| |
| if (INSN_UID (label) == 0) |
| return; |
| |
| cached_make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags); |
| } |
| |
| /* Create the edges generated by INSN in REGION. */ |
| |
| static void |
| make_eh_edge (sbitmap *edge_cache, basic_block src, rtx insn) |
| { |
| int is_call = GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0; |
| rtx handlers, i; |
| |
| handlers = reachable_handlers (insn); |
| |
| for (i = handlers; i; i = XEXP (i, 1)) |
| make_label_edge (edge_cache, src, XEXP (i, 0), |
| EDGE_ABNORMAL | EDGE_EH | is_call); |
| |
| free_INSN_LIST_list (&handlers); |
| } |
| |
| /* 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. |
| |
| 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. */ |
| |
| static void |
| make_edges (rtx label_value_list, basic_block min, basic_block max, int update_p) |
| { |
| basic_block bb; |
| sbitmap *edge_cache = NULL; |
| |
| /* Assume no computed jump; revise as we create edges. */ |
| current_function_has_computed_jump = 0; |
| |
| /* 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 || label_value_list || 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) |
| { |
| edge e; |
| |
| for (e = bb->succ; e ; e = e->succ_next) |
| if (e->dest != EXIT_BLOCK_PTR) |
| SET_BIT (edge_cache[bb->index], e->dest->index); |
| } |
| } |
| |
| /* 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); |
| |
| FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) |
| { |
| rtx insn, x; |
| enum rtx_code code; |
| int force_fallthru = 0; |
| |
| if (GET_CODE (BB_HEAD (bb)) == CODE_LABEL |
| && LABEL_ALT_ENTRY_P (BB_HEAD (bb))) |
| cached_make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0); |
| |
| /* Examine the last instruction of the block, and discover the |
| ways we can leave the block. */ |
| |
| insn = BB_END (bb); |
| code = GET_CODE (insn); |
| |
| /* A branch. */ |
| if (code == JUMP_INSN) |
| { |
| rtx tmp; |
| |
| /* Recognize exception handling placeholders. */ |
| if (GET_CODE (PATTERN (insn)) == RESX) |
| 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)) |
| ; |
| |
| /* Recognize a tablejump and do the right thing. */ |
| else if (tablejump_p (insn, NULL, &tmp)) |
| { |
| rtvec vec; |
| int j; |
| |
| 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) |
| make_label_edge (edge_cache, bb, |
| XEXP (RTVEC_ELT (vec, j), 0), 0); |
| |
| /* Some targets (eg, ARM) emit a conditional jump that also |
| contains the out-of-range target. Scan for these and |
| add an edge if necessary. */ |
| 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) |
| make_label_edge (edge_cache, bb, |
| XEXP (XEXP (SET_SRC (tmp), 2), 0), 0); |
| |
| #ifdef CASE_DROPS_THROUGH |
| /* Silly VAXen. The ADDR_VEC is going to be in the way of |
| us naturally detecting fallthru into the next block. */ |
| force_fallthru = 1; |
| #endif |
| } |
| |
| /* If this is a computed jump, then mark it as reaching |
| everything on the label_value_list and forced_labels list. */ |
| else if (computed_jump_p (insn)) |
| { |
| current_function_has_computed_jump = 1; |
| |
| for (x = label_value_list; x; x = XEXP (x, 1)) |
| make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL); |
| |
| for (x = forced_labels; x; x = XEXP (x, 1)) |
| make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL); |
| } |
| |
| /* Returns create an exit out. */ |
| else if (returnjump_p (insn)) |
| cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0); |
| |
| /* Otherwise, we have a plain conditional or unconditional jump. */ |
| else |
| { |
| if (! JUMP_LABEL (insn)) |
| abort (); |
| make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0); |
| } |
| } |
| |
| /* If this is a sibling call insn, then this is in effect a combined call |
| and return, and so we need an edge to the exit block. No need to |
| worry about EH edges, since we wouldn't have created the sibling call |
| in the first place. */ |
| if (code == CALL_INSN && SIBLING_CALL_P (insn)) |
| cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, |
| EDGE_SIBCALL | EDGE_ABNORMAL); |
| |
| /* If this is a CALL_INSN, then mark it as reaching the active EH |
| 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) |
| { |
| /* Add any appropriate EH edges. */ |
| make_eh_edge (edge_cache, bb, insn); |
| |
| if (code == CALL_INSN && nonlocal_goto_handler_labels) |
| { |
| /* ??? 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); |
| } |
| } |
| |
| /* Find out if we can drop through to the next block. */ |
| insn = NEXT_INSN (insn); |
| while (insn |
| && GET_CODE (insn) == NOTE |
| && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK) |
| insn = NEXT_INSN (insn); |
| |
| if (!insn || (bb->next_bb == EXIT_BLOCK_PTR && force_fallthru)) |
| cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU); |
| else if (bb->next_bb != EXIT_BLOCK_PTR) |
| { |
| if (force_fallthru || insn == BB_HEAD (bb->next_bb)) |
| cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU); |
| } |
| } |
| |
| if (edge_cache) |
| 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 lvl = NULL_RTX; |
| rtx trll = 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 ((GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == BARRIER) |
| && 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 INSN: |
| case BARRIER: |
| break; |
| |
| case CALL_INSN: |
| if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER) |
| { |
| /* Scan each of the alternatives for label refs. */ |
| lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl); |
| lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl); |
| lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl); |
| /* Record its tail recursion label, if any. */ |
| if (XEXP (PATTERN (insn), 3) != NULL_RTX) |
| trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll); |
| } |
| break; |
| |
| default: |
| abort (); |
| } |
| |
| if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN) |
| { |
| rtx note; |
| |
| /* Make a list of all labels referred to other than by jumps. |
| |
| Make a special exception for labels followed by an ADDR*VEC, |
| as this would be a part of the tablejump setup code. |
| |
| Make a special exception to registers loaded with label |
| values just before jump insns that use them. */ |
| |
| for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) |
| if (REG_NOTE_KIND (note) == REG_LABEL) |
| { |
| rtx lab = XEXP (note, 0), next; |
| |
| if ((next = next_nonnote_insn (lab)) != NULL |
| && GET_CODE (next) == JUMP_INSN |
| && (GET_CODE (PATTERN (next)) == ADDR_VEC |
| || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC)) |
| ; |
| else if (GET_CODE (lab) == NOTE) |
| ; |
| else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN |
| && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab)) |
| ; |
| else |
| lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl); |
| } |
| } |
| } |
| |
| if (head != NULL_RTX) |
| create_basic_block_structure (head, end, bb_note, prev); |
| else if (bb_note) |
| delete_insn (bb_note); |
| |
| if (last_basic_block != n_basic_blocks) |
| abort (); |
| |
| label_value_list = lvl; |
| tail_recursion_label_list = trll; |
| clear_aux_for_blocks (); |
| } |
| |
| |
| /* Find basic blocks of the current function. |
| F is the first insn of the function and NREGS the number of register |
| numbers in use. */ |
| |
| void |
| find_basic_blocks (rtx f, int nregs ATTRIBUTE_UNUSED, |
| FILE *file ATTRIBUTE_UNUSED) |
| { |
| 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; |
| |
| VARRAY_FREE (basic_block_info); |
| } |
| |
| 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); |
| |
| /* Discover the edges of our cfg. */ |
| make_edges (label_value_list, 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); |
| } |
| |
| /* State of basic block as seen by find_sub_basic_blocks. */ |
| enum state {BLOCK_NEW = 0, BLOCK_ORIGINAL, BLOCK_TO_SPLIT}; |
| |
| #define STATE(BB) (enum state) ((size_t) (BB)->aux) |
| #define SET_STATE(BB, STATE) ((BB)->aux = (void *) (size_t) (STATE)) |
| |
| /* Scan basic block BB for possible BB boundaries inside the block |
| and create new basic blocks in the progress. */ |
| |
| static void |
| find_bb_boundaries (basic_block bb) |
| { |
| rtx insn = BB_HEAD (bb); |
| rtx end = BB_END (bb); |
| rtx flow_transfer_insn = NULL_RTX; |
| edge fallthru = NULL; |
| |
| if (insn == BB_END (bb)) |
| return; |
| |
| if (GET_CODE (insn) == CODE_LABEL) |
| insn = NEXT_INSN (insn); |
| |
| /* Scan insn chain and try to find new basic block boundaries. */ |
| while (1) |
| { |
| enum rtx_code code = GET_CODE (insn); |
| |
| /* On code label, split current basic block. */ |
| if (code == CODE_LABEL) |
| { |
| fallthru = split_block (bb, PREV_INSN (insn)); |
| if (flow_transfer_insn) |
| BB_END (bb) = flow_transfer_insn; |
| |
| bb = fallthru->dest; |
| remove_edge (fallthru); |
| flow_transfer_insn = NULL_RTX; |
| if (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)) |
| { |
| fallthru = split_block (bb, PREV_INSN (insn)); |
| BB_END (bb) = flow_transfer_insn; |
| bb = fallthru->dest; |
| remove_edge (fallthru); |
| flow_transfer_insn = NULL_RTX; |
| } |
| |
| if (control_flow_insn_p (insn)) |
| flow_transfer_insn = insn; |
| if (insn == end) |
| break; |
| insn = NEXT_INSN (insn); |
| } |
| |
| /* In case expander replaced normal insn by sequence terminating by |
| 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; |
| |
| /* We've possibly replaced the conditional jump by conditional jump |
| followed by cleanup at fallthru edge, so the outgoing edges may |
| be dead. */ |
| purge_dead_edges (bb); |
| } |
| |
| /* Assume that frequency of basic block B is known. Compute frequencies |
| and probabilities of outgoing edges. */ |
| |
| static void |
| compute_outgoing_frequencies (basic_block b) |
| { |
| edge e, f; |
| |
| if (b->succ && b->succ->succ_next && !b->succ->succ_next->succ_next) |
| { |
| rtx note = find_reg_note (BB_END (b), REG_BR_PROB, NULL); |
| int probability; |
| |
| if (!note) |
| return; |
| |
| probability = INTVAL (XEXP (note, 0)); |
| e = BRANCH_EDGE (b); |
| e->probability = probability; |
| e->count = ((b->count * probability + REG_BR_PROB_BASE / 2) |
| / REG_BR_PROB_BASE); |
| f = FALLTHRU_EDGE (b); |
| f->probability = REG_BR_PROB_BASE - probability; |
| f->count = b->count - e->count; |
| } |
| |
| if (b->succ && !b->succ->succ_next) |
| { |
| e = b->succ; |
| e->probability = REG_BR_PROB_BASE; |
| e->count = b->count; |
| } |
| } |
| |
| /* Assume that someone emitted code with control flow instructions to the |
| basic block. Update the data structure. */ |
| |
| void |
| find_many_sub_basic_blocks (sbitmap blocks) |
| { |
| basic_block bb, min, max; |
| |
| FOR_EACH_BB (bb) |
| SET_STATE (bb, |
| TEST_BIT (blocks, bb->index) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL); |
| |
| FOR_EACH_BB (bb) |
| if (STATE (bb) == BLOCK_TO_SPLIT) |
| find_bb_boundaries (bb); |
| |
| FOR_EACH_BB (bb) |
| if (STATE (bb) != BLOCK_ORIGINAL) |
| break; |
| |
| min = max = bb; |
| for (; bb != EXIT_BLOCK_PTR; bb = bb->next_bb) |
| if (STATE (bb) != BLOCK_ORIGINAL) |
| max = bb; |
| |
| /* Now re-scan and wire in all edges. This expect simple (conditional) |
| jumps at the end of each new basic blocks. */ |
| make_edges (NULL, min, max, 1); |
| |
| /* Update branch probabilities. Expect only (un)conditional jumps |
| to be created with only the forward edges. */ |
| FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) |
| { |
| edge e; |
| |
| if (STATE (bb) == BLOCK_ORIGINAL) |
| continue; |
| if (STATE (bb) == BLOCK_NEW) |
| { |
| bb->count = 0; |
| bb->frequency = 0; |
| for (e = bb->pred; e; e = e->pred_next) |
| { |
| bb->count += e->count; |
| bb->frequency += EDGE_FREQUENCY (e); |
| } |
| } |
| |
| compute_outgoing_frequencies (bb); |
| } |
| |
| FOR_EACH_BB (bb) |
| SET_STATE (bb, 0); |
| } |
| |
| /* Like above but for single basic block only. */ |
| |
| void |
| find_sub_basic_blocks (basic_block bb) |
| { |
| basic_block min, max, b; |
| basic_block next = bb->next_bb; |
| |
| min = bb; |
| find_bb_boundaries (bb); |
| max = next->prev_bb; |
| |
| /* Now re-scan and wire in all edges. This expect simple (conditional) |
| jumps at the end of each new basic blocks. */ |
| make_edges (NULL, min, max, 1); |
| |
| /* Update branch probabilities. Expect only (un)conditional jumps |
| to be created with only the forward edges. */ |
| FOR_BB_BETWEEN (b, min, max->next_bb, next_bb) |
| { |
| edge e; |
| |
| if (b != min) |
| { |
| b->count = 0; |
| b->frequency = 0; |
| for (e = b->pred; e; e = e->pred_next) |
| { |
| b->count += e->count; |
| b->frequency += EDGE_FREQUENCY (e); |
| } |
| } |
| |
| compute_outgoing_frequencies (b); |
| } |
| } |