From 1f9ea4d0a40cca64d60cf4dab152349da7b9dddf Mon Sep 17 00:00:00 2001 From: kan Date: Sat, 19 May 2007 01:19:51 +0000 Subject: GCC 4.2.0 release. --- contrib/gcc/cfganal.c | 782 ++++++++++++++++++++++---------------------------- 1 file changed, 351 insertions(+), 431 deletions(-) (limited to 'contrib/gcc/cfganal.c') diff --git a/contrib/gcc/cfganal.c b/contrib/gcc/cfganal.c index aa3965c..467c399 100644 --- a/contrib/gcc/cfganal.c +++ b/contrib/gcc/cfganal.c @@ -1,6 +1,6 @@ /* Control flow graph analysis code for GNU compiler. Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, - 1999, 2000, 2001, 2003 Free Software Foundation, Inc. + 1999, 2000, 2001, 2003, 2004, 2005 Free Software Foundation, Inc. This file is part of GCC. @@ -16,8 +16,8 @@ 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. */ +Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301, USA. */ /* This file contains various simple utilities to analyze the CFG. */ #include "config.h" @@ -25,12 +25,14 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "coretypes.h" #include "tm.h" #include "rtl.h" +#include "obstack.h" #include "hard-reg-set.h" #include "basic-block.h" #include "insn-config.h" #include "recog.h" #include "toplev.h" #include "tm_p.h" +#include "timevar.h" /* Store the data structures necessary for depth-first search. */ struct depth_first_search_dsS { @@ -49,10 +51,9 @@ typedef struct depth_first_search_dsS *depth_first_search_ds; static void flow_dfs_compute_reverse_init (depth_first_search_ds); static void flow_dfs_compute_reverse_add_bb (depth_first_search_ds, basic_block); -static basic_block flow_dfs_compute_reverse_execute (depth_first_search_ds); +static basic_block flow_dfs_compute_reverse_execute (depth_first_search_ds, + basic_block); static void flow_dfs_compute_reverse_finish (depth_first_search_ds); -static void remove_fake_successors (basic_block); -static bool need_fake_edge_p (rtx); static bool flow_active_insn_p (rtx); /* Like active_insn_p, except keep the return value clobber around @@ -68,9 +69,9 @@ flow_active_insn_p (rtx insn) programs that fail to return a value. Its effect is to keep the return value from being live across the entire function. If we allow it to be skipped, we introduce the - possibility for register livetime aborts. */ + possibility for register lifetime confusion. */ if (GET_CODE (PATTERN (insn)) == CLOBBER - && GET_CODE (XEXP (PATTERN (insn), 0)) == REG + && REG_P (XEXP (PATTERN (insn), 0)) && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0))) return true; @@ -86,7 +87,7 @@ forwarder_block_p (basic_block bb) rtx insn; if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR - || !bb->succ || bb->succ->succ_next) + || !single_succ_p (bb)) return false; for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn)) @@ -94,7 +95,7 @@ forwarder_block_p (basic_block bb) return false; return (!INSN_P (insn) - || (GET_CODE (insn) == JUMP_INSN && simplejump_p (insn)) + || (JUMP_P (insn) && simplejump_p (insn)) || !flow_active_insn_p (insn)); } @@ -104,17 +105,44 @@ bool can_fallthru (basic_block src, basic_block target) { rtx insn = BB_END (src); - rtx insn2 = target == EXIT_BLOCK_PTR ? NULL : BB_HEAD (target); + rtx insn2; + edge e; + edge_iterator ei; + if (target == EXIT_BLOCK_PTR) + return true; if (src->next_bb != target) return 0; + FOR_EACH_EDGE (e, ei, src->succs) + if (e->dest == EXIT_BLOCK_PTR + && e->flags & EDGE_FALLTHRU) + return 0; + insn2 = BB_HEAD (target); if (insn2 && !active_insn_p (insn2)) insn2 = next_active_insn (insn2); /* ??? Later we may add code to move jump tables offline. */ return next_active_insn (insn) == insn2; } + +/* Return nonzero if we could reach target from src by falling through, + if the target was made adjacent. If we already have a fall-through + edge to the exit block, we can't do that. */ +bool +could_fall_through (basic_block src, basic_block target) +{ + edge e; + edge_iterator ei; + + if (target == EXIT_BLOCK_PTR) + return true; + FOR_EACH_EDGE (e, ei, src->succs) + if (e->dest == EXIT_BLOCK_PTR + && e->flags & EDGE_FALLTHRU) + return 0; + return true; +} /* Mark the back edges in DFS traversal. Return nonzero if a loop (natural or otherwise) is present. @@ -124,12 +152,12 @@ can_fallthru (basic_block src, basic_block target) Steven Muchnick Morgan Kaufmann, 1997 - and heavily borrowed from flow_depth_first_order_compute. */ + and heavily borrowed from pre_and_rev_post_order_compute. */ bool mark_dfs_back_edges (void) { - edge *stack; + edge_iterator *stack; int *pre; int *post; int sp; @@ -139,11 +167,11 @@ mark_dfs_back_edges (void) bool found = false; /* Allocate the preorder and postorder number arrays. */ - pre = xcalloc (last_basic_block, sizeof (int)); - post = xcalloc (last_basic_block, sizeof (int)); + pre = XCNEWVEC (int, last_basic_block); + post = XCNEWVEC (int, last_basic_block); /* Allocate stack for back-tracking up CFG. */ - stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge)); + stack = XNEWVEC (edge_iterator, n_basic_blocks + 1); sp = 0; /* Allocate bitmap to track nodes that have been visited. */ @@ -153,19 +181,19 @@ mark_dfs_back_edges (void) sbitmap_zero (visited); /* Push the first edge on to the stack. */ - stack[sp++] = ENTRY_BLOCK_PTR->succ; + stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs); while (sp) { - edge e; + edge_iterator ei; basic_block src; basic_block dest; /* Look at the edge on the top of the stack. */ - e = stack[sp - 1]; - src = e->src; - dest = e->dest; - e->flags &= ~EDGE_DFS_BACK; + ei = stack[sp - 1]; + src = ei_edge (ei)->src; + dest = ei_edge (ei)->dest; + ei_edge (ei)->flags &= ~EDGE_DFS_BACK; /* Check if the edge destination has been visited yet. */ if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)) @@ -174,11 +202,11 @@ mark_dfs_back_edges (void) SET_BIT (visited, dest->index); pre[dest->index] = prenum++; - if (dest->succ) + if (EDGE_COUNT (dest->succs) > 0) { /* Since the DEST node has been visited for the first time, check its successors. */ - stack[sp++] = dest->succ; + stack[sp++] = ei_start (dest->succs); } else post[dest->index] = postnum++; @@ -188,13 +216,13 @@ mark_dfs_back_edges (void) if (dest != EXIT_BLOCK_PTR && src != ENTRY_BLOCK_PTR && pre[src->index] >= pre[dest->index] && post[dest->index] == 0) - e->flags |= EDGE_DFS_BACK, found = true; + ei_edge (ei)->flags |= EDGE_DFS_BACK, found = true; - if (! e->succ_next && src != ENTRY_BLOCK_PTR) + if (ei_one_before_end_p (ei) && src != ENTRY_BLOCK_PTR) post[src->index] = postnum++; - if (e->succ_next) - stack[sp - 1] = e->succ_next; + if (!ei_one_before_end_p (ei)) + ei_next (&stack[sp - 1]); else sp--; } @@ -218,8 +246,9 @@ set_edge_can_fallthru_flag (void) FOR_EACH_BB (bb) { edge e; + edge_iterator ei; - for (e = bb->succ; e; e = e->succ_next) + FOR_EACH_EDGE (e, ei, bb->succs) { e->flags &= ~EDGE_CAN_FALLTHRU; @@ -230,179 +259,16 @@ set_edge_can_fallthru_flag (void) /* If the BB ends with an invertible condjump all (2) edges are CAN_FALLTHRU edges. */ - if (!bb->succ || !bb->succ->succ_next || bb->succ->succ_next->succ_next) + if (EDGE_COUNT (bb->succs) != 2) continue; if (!any_condjump_p (BB_END (bb))) continue; if (!invert_jump (BB_END (bb), JUMP_LABEL (BB_END (bb)), 0)) continue; invert_jump (BB_END (bb), JUMP_LABEL (BB_END (bb)), 0); - bb->succ->flags |= EDGE_CAN_FALLTHRU; - bb->succ->succ_next->flags |= EDGE_CAN_FALLTHRU; - } -} - -/* Return true if we need to add fake edge to exit. - Helper function for the flow_call_edges_add. */ - -static bool -need_fake_edge_p (rtx insn) -{ - if (!INSN_P (insn)) - return false; - - if ((GET_CODE (insn) == CALL_INSN - && !SIBLING_CALL_P (insn) - && !find_reg_note (insn, REG_NORETURN, NULL) - && !find_reg_note (insn, REG_ALWAYS_RETURN, NULL) - && !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. */ - -int -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 == 0) - 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; - - for (e = bb->succ; e; e = e->succ_next) - if (e->dest == EXIT_BLOCK_PTR) - { - insert_insn_on_edge (gen_rtx_USE (VOIDmode, const0_rtx), e); - commit_edge_insertions (); - break; - } - } - } - - /* 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 = 0; i < last_bb; i++) - { - basic_block bb = BASIC_BLOCK (i); - rtx libcall_end = NULL_RTX; - 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 libcalls. */ - if (libcall_end) - split_at_insn = libcall_end; - - /* Don't split the block between a call and an insn that should - remain in the same block as the call. */ - else if (GET_CODE (insn) == CALL_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)) - for (e = bb->succ; e; e = e->succ_next) - if (e->dest == EXIT_BLOCK_PTR) - abort (); -#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); - } - - /* Watch out for REG_LIBCALL/REG_RETVAL notes so that we know - whether we are currently in a libcall or not. Remember that - we are scanning backwards! */ - if (find_reg_note (insn, REG_RETVAL, NULL_RTX)) - libcall_end = insn; - if (find_reg_note (insn, REG_LIBCALL, NULL_RTX)) - libcall_end = NULL_RTX; - - if (insn == BB_HEAD (bb)) - break; - } + EDGE_SUCC (bb, 0)->flags |= EDGE_CAN_FALLTHRU; + EDGE_SUCC (bb, 1)->flags |= EDGE_CAN_FALLTHRU; } - - if (blocks_split) - verify_flow_info (); - - return blocks_split; } /* Find unreachable blocks. An unreachable block will have 0 in @@ -413,9 +279,10 @@ void find_unreachable_blocks (void) { edge e; + edge_iterator ei; basic_block *tos, *worklist, bb; - tos = worklist = xmalloc (sizeof (basic_block) * n_basic_blocks); + tos = worklist = XNEWVEC (basic_block, n_basic_blocks); /* Clear all the reachability flags. */ @@ -426,7 +293,7 @@ find_unreachable_blocks (void) be only one. It isn't inconceivable that we might one day directly support Fortran alternate entry points. */ - for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next) + FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs) { *tos++ = e->dest; @@ -440,12 +307,16 @@ find_unreachable_blocks (void) { basic_block b = *--tos; - for (e = b->succ; e; e = e->succ_next) - if (!(e->dest->flags & BB_REACHABLE)) - { - *tos++ = e->dest; - e->dest->flags |= BB_REACHABLE; - } + FOR_EACH_EDGE (e, ei, b->succs) + { + basic_block dest = e->dest; + + if (!(dest->flags & BB_REACHABLE)) + { + *tos++ = dest; + dest->flags |= BB_REACHABLE; + } + } } free (worklist); @@ -472,8 +343,9 @@ create_edge_list (void) int num_edges; int block_count; basic_block bb; + edge_iterator ei; - block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */ + block_count = n_basic_blocks; /* Include the entry and exit blocks. */ num_edges = 0; @@ -481,20 +353,19 @@ create_edge_list (void) edges on each basic block. */ FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) { - for (e = bb->succ; e; e = e->succ_next) - num_edges++; + num_edges += EDGE_COUNT (bb->succs); } - elist = xmalloc (sizeof (struct edge_list)); + elist = XNEW (struct edge_list); elist->num_blocks = block_count; elist->num_edges = num_edges; - elist->index_to_edge = xmalloc (sizeof (edge) * num_edges); + elist->index_to_edge = XNEWVEC (edge, num_edges); num_edges = 0; /* Follow successors of blocks, and register these edges. */ FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) - for (e = bb->succ; e; e = e->succ_next) + FOR_EACH_EDGE (e, ei, bb->succs) elist->index_to_edge[num_edges++] = e; return elist; @@ -520,7 +391,7 @@ print_edge_list (FILE *f, struct edge_list *elist) int x; fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n", - elist->num_blocks - 2, elist->num_edges); + elist->num_blocks, elist->num_edges); for (x = 0; x < elist->num_edges; x++) { @@ -547,10 +418,11 @@ verify_edge_list (FILE *f, struct edge_list *elist) int pred, succ, index; edge e; basic_block bb, p, s; + edge_iterator ei; FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) { - for (e = bb->succ; e; e = e->succ_next) + FOR_EACH_EDGE (e, ei, bb->succs) { pred = e->src->index; succ = e->dest->index; @@ -578,14 +450,14 @@ verify_edge_list (FILE *f, struct edge_list *elist) { int found_edge = 0; - for (e = p->succ; e; e = e->succ_next) + FOR_EACH_EDGE (e, ei, p->succs) if (e->dest == s) { found_edge = 1; break; } - for (e = s->pred; e; e = e->pred_next) + FOR_EACH_EDGE (e, ei, s->preds) if (e->src == p) { found_edge = 1; @@ -603,6 +475,31 @@ verify_edge_list (FILE *f, struct edge_list *elist) } } +/* Given PRED and SUCC blocks, return the edge which connects the blocks. + If no such edge exists, return NULL. */ + +edge +find_edge (basic_block pred, basic_block succ) +{ + edge e; + edge_iterator ei; + + if (EDGE_COUNT (pred->succs) <= EDGE_COUNT (succ->preds)) + { + FOR_EACH_EDGE (e, ei, pred->succs) + if (e->dest == succ) + return e; + } + else + { + FOR_EACH_EDGE (e, ei, succ->preds) + if (e->src == pred) + return e; + } + + return NULL; +} + /* This routine will determine what, if any, edge there is between a specified predecessor and successor. */ @@ -624,13 +521,15 @@ find_edge_index (struct edge_list *edge_list, basic_block pred, basic_block succ void flow_nodes_print (const char *str, const sbitmap nodes, FILE *file) { - int node; + unsigned int node = 0; + sbitmap_iterator sbi; if (! nodes) return; fprintf (file, "%s { ", str); - EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);}); + EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, sbi) + fprintf (file, "%d ", node); fputs ("}\n", file); } @@ -653,22 +552,22 @@ flow_edge_list_print (const char *str, const edge *edge_list, int num_edges, FIL } -/* This routine will remove any fake successor edges for a basic block. - When the edge is removed, it is also removed from whatever predecessor +/* This routine will remove any fake predecessor edges for a basic block. + When the edge is removed, it is also removed from whatever successor list it is in. */ static void -remove_fake_successors (basic_block bb) +remove_fake_predecessors (basic_block bb) { edge e; + edge_iterator ei; - for (e = bb->succ; e;) + for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) { - edge tmp = e; - - e = e->succ_next; - if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE) - remove_edge (tmp); + if ((e->flags & EDGE_FAKE) == EDGE_FAKE) + remove_edge (e); + else + ei_next (&ei); } } @@ -681,10 +580,19 @@ remove_fake_edges (void) { basic_block bb; - FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) - remove_fake_successors (bb); + FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb, NULL, next_bb) + remove_fake_predecessors (bb); } +/* This routine will remove all fake edges to the EXIT_BLOCK. */ + +void +remove_fake_exit_edges (void) +{ + remove_fake_predecessors (EXIT_BLOCK_PTR); +} + + /* This function will add a fake edge between any block which has no successors, and the exit block. Some data flow equations require these edges to exist. */ @@ -695,7 +603,7 @@ add_noreturn_fake_exit_edges (void) basic_block bb; FOR_EACH_BB (bb) - if (bb->succ == NULL) + if (EDGE_COUNT (bb->succs) == 0) make_single_succ_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE); } @@ -713,7 +621,7 @@ add_noreturn_fake_exit_edges (void) void connect_infinite_loops_to_exit (void) { - basic_block unvisited_block; + basic_block unvisited_block = EXIT_BLOCK_PTR; struct depth_first_search_dsS dfs_ds; /* Perform depth-first search in the reverse graph to find nodes @@ -724,7 +632,8 @@ connect_infinite_loops_to_exit (void) /* Repeatedly add fake edges, updating the unreachable nodes. */ while (1) { - unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds); + unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds, + unvisited_block); if (!unvisited_block) break; @@ -736,18 +645,22 @@ connect_infinite_loops_to_exit (void) return; } -/* Compute reverse top sort order. */ +/* Compute reverse top sort order. + This is computing a post order numbering of the graph. */ -void -flow_reverse_top_sort_order_compute (int *rts_order) +int +post_order_compute (int *post_order, bool include_entry_exit) { - edge *stack; + edge_iterator *stack; int sp; - int postnum = 0; + int post_order_num = 0; sbitmap visited; + if (include_entry_exit) + post_order[post_order_num++] = EXIT_BLOCK; + /* Allocate stack for back-tracking up CFG. */ - stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge)); + stack = XNEWVEC (edge_iterator, n_basic_blocks + 1); sp = 0; /* Allocate bitmap to track nodes that have been visited. */ @@ -757,18 +670,18 @@ flow_reverse_top_sort_order_compute (int *rts_order) sbitmap_zero (visited); /* Push the first edge on to the stack. */ - stack[sp++] = ENTRY_BLOCK_PTR->succ; + stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs); while (sp) { - edge e; + edge_iterator ei; basic_block src; basic_block dest; /* Look at the edge on the top of the stack. */ - e = stack[sp - 1]; - src = e->src; - dest = e->dest; + ei = stack[sp - 1]; + src = ei_edge (ei)->src; + dest = ei_edge (ei)->dest; /* Check if the edge destination has been visited yet. */ if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)) @@ -776,49 +689,69 @@ flow_reverse_top_sort_order_compute (int *rts_order) /* Mark that we have visited the destination. */ SET_BIT (visited, dest->index); - if (dest->succ) + if (EDGE_COUNT (dest->succs) > 0) /* Since the DEST node has been visited for the first time, check its successors. */ - stack[sp++] = dest->succ; + stack[sp++] = ei_start (dest->succs); else - rts_order[postnum++] = dest->index; + post_order[post_order_num++] = dest->index; } else { - if (! e->succ_next && src != ENTRY_BLOCK_PTR) - rts_order[postnum++] = src->index; + if (ei_one_before_end_p (ei) && src != ENTRY_BLOCK_PTR) + post_order[post_order_num++] = src->index; - if (e->succ_next) - stack[sp - 1] = e->succ_next; + if (!ei_one_before_end_p (ei)) + ei_next (&stack[sp - 1]); else sp--; } } + if (include_entry_exit) + post_order[post_order_num++] = ENTRY_BLOCK; + free (stack); sbitmap_free (visited); + return post_order_num; } /* Compute the depth first search order and store in the array - DFS_ORDER if nonzero, marking the nodes visited in VISITED. If - RC_ORDER is nonzero, return the reverse completion number for each + PRE_ORDER if nonzero, marking the nodes visited in VISITED. If + REV_POST_ORDER is nonzero, return the reverse completion number for each node. Returns the number of nodes visited. A depth first search tries to get as far away from the starting point as quickly as - possible. */ + possible. + + pre_order is a really a preorder numbering of the graph. + rev_post_order is really a reverse postorder numbering of the graph. + */ int -flow_depth_first_order_compute (int *dfs_order, int *rc_order) +pre_and_rev_post_order_compute (int *pre_order, int *rev_post_order, + bool include_entry_exit) { - edge *stack; + edge_iterator *stack; int sp; - int dfsnum = 0; - int rcnum = n_basic_blocks - 1; + int pre_order_num = 0; + int rev_post_order_num = n_basic_blocks - 1; sbitmap visited; /* Allocate stack for back-tracking up CFG. */ - stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge)); + stack = XNEWVEC (edge_iterator, n_basic_blocks + 1); sp = 0; + if (include_entry_exit) + { + if (pre_order) + pre_order[pre_order_num] = ENTRY_BLOCK; + pre_order_num++; + if (rev_post_order) + rev_post_order[rev_post_order_num--] = ENTRY_BLOCK; + } + else + rev_post_order_num -= NUM_FIXED_BLOCKS; + /* Allocate bitmap to track nodes that have been visited. */ visited = sbitmap_alloc (last_basic_block); @@ -826,18 +759,18 @@ flow_depth_first_order_compute (int *dfs_order, int *rc_order) sbitmap_zero (visited); /* Push the first edge on to the stack. */ - stack[sp++] = ENTRY_BLOCK_PTR->succ; + stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs); while (sp) { - edge e; + edge_iterator ei; basic_block src; basic_block dest; /* Look at the edge on the top of the stack. */ - e = stack[sp - 1]; - src = e->src; - dest = e->dest; + ei = stack[sp - 1]; + src = ei_edge (ei)->src; + dest = ei_edge (ei)->dest; /* Check if the edge destination has been visited yet. */ if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)) @@ -845,30 +778,30 @@ flow_depth_first_order_compute (int *dfs_order, int *rc_order) /* Mark that we have visited the destination. */ SET_BIT (visited, dest->index); - if (dfs_order) - dfs_order[dfsnum] = dest->index; + if (pre_order) + pre_order[pre_order_num] = dest->index; - dfsnum++; + pre_order_num++; - if (dest->succ) + if (EDGE_COUNT (dest->succs) > 0) /* Since the DEST node has been visited for the first time, check its successors. */ - stack[sp++] = dest->succ; - else if (rc_order) + stack[sp++] = ei_start (dest->succs); + else if (rev_post_order) /* There are no successors for the DEST node so assign its reverse completion number. */ - rc_order[rcnum--] = dest->index; + rev_post_order[rev_post_order_num--] = dest->index; } else { - if (! e->succ_next && src != ENTRY_BLOCK_PTR - && rc_order) + if (ei_one_before_end_p (ei) && src != ENTRY_BLOCK_PTR + && rev_post_order) /* There are no more successors for the SRC node so assign its reverse completion number. */ - rc_order[rcnum--] = src->index; + rev_post_order[rev_post_order_num--] = src->index; - if (e->succ_next) - stack[sp - 1] = e->succ_next; + if (!ei_one_before_end_p (ei)) + ei_next (&stack[sp - 1]); else sp--; } @@ -877,140 +810,22 @@ flow_depth_first_order_compute (int *dfs_order, int *rc_order) free (stack); sbitmap_free (visited); - /* The number of nodes visited should not be greater than - n_basic_blocks. */ - if (dfsnum > n_basic_blocks) - abort (); - - /* There are some nodes left in the CFG that are unreachable. */ - if (dfsnum < n_basic_blocks) - abort (); - - return dfsnum; -} - -struct dfst_node -{ - unsigned nnodes; - struct dfst_node **node; - struct dfst_node *up; -}; - -/* Compute a preorder transversal ordering such that a sub-tree which - is the source of a cross edge appears before the sub-tree which is - the destination of the cross edge. This allows for easy detection - of all the entry blocks for a loop. - - The ordering is compute by: - - 1) Generating a depth first spanning tree. - - 2) Walking the resulting tree from right to left. */ - -void -flow_preorder_transversal_compute (int *pot_order) -{ - edge e; - edge *stack; - int i; - int max_successors; - int sp; - sbitmap visited; - struct dfst_node *node; - struct dfst_node *dfst; - basic_block bb; - - /* Allocate stack for back-tracking up CFG. */ - stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge)); - sp = 0; - - /* Allocate the tree. */ - dfst = xcalloc (last_basic_block, sizeof (struct dfst_node)); - - FOR_EACH_BB (bb) - { - max_successors = 0; - for (e = bb->succ; e; e = e->succ_next) - max_successors++; - - dfst[bb->index].node - = (max_successors - ? xcalloc (max_successors, sizeof (struct dfst_node *)) : NULL); - } - - /* Allocate bitmap to track nodes that have been visited. */ - visited = sbitmap_alloc (last_basic_block); - - /* None of the nodes in the CFG have been visited yet. */ - sbitmap_zero (visited); - - /* Push the first edge on to the stack. */ - stack[sp++] = ENTRY_BLOCK_PTR->succ; - - while (sp) + if (include_entry_exit) { - basic_block src; - basic_block dest; - - /* Look at the edge on the top of the stack. */ - e = stack[sp - 1]; - src = e->src; - dest = e->dest; - - /* Check if the edge destination has been visited yet. */ - if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)) - { - /* Mark that we have visited the destination. */ - SET_BIT (visited, dest->index); - - /* Add the destination to the preorder tree. */ - if (src != ENTRY_BLOCK_PTR) - { - dfst[src->index].node[dfst[src->index].nnodes++] - = &dfst[dest->index]; - dfst[dest->index].up = &dfst[src->index]; - } - - if (dest->succ) - /* Since the DEST node has been visited for the first - time, check its successors. */ - stack[sp++] = dest->succ; - } - - else if (e->succ_next) - stack[sp - 1] = e->succ_next; - else - sp--; + if (pre_order) + pre_order[pre_order_num] = EXIT_BLOCK; + pre_order_num++; + if (rev_post_order) + rev_post_order[rev_post_order_num--] = EXIT_BLOCK; + /* The number of nodes visited should be the number of blocks. */ + gcc_assert (pre_order_num == n_basic_blocks); } + else + /* The number of nodes visited should be the number of blocks minus + the entry and exit blocks which are not visited here. */ + gcc_assert (pre_order_num == n_basic_blocks - NUM_FIXED_BLOCKS); - free (stack); - sbitmap_free (visited); - - /* Record the preorder transversal order by - walking the tree from right to left. */ - - i = 0; - node = &dfst[ENTRY_BLOCK_PTR->next_bb->index]; - pot_order[i++] = 0; - - while (node) - { - if (node->nnodes) - { - node = node->node[--node->nnodes]; - pot_order[i++] = node - dfst; - } - else - node = node->up; - } - - /* Free the tree. */ - - for (i = 0; i < last_basic_block; i++) - if (dfst[i].node) - free (dfst[i].node); - - free (dfst); + return pre_order_num; } /* Compute the depth first search order on the _reverse_ graph and @@ -1047,12 +862,11 @@ static void flow_dfs_compute_reverse_init (depth_first_search_ds data) { /* Allocate stack for back-tracking up CFG. */ - data->stack = xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1)) - * sizeof (basic_block)); + data->stack = XNEWVEC (basic_block, n_basic_blocks); data->sp = 0; /* Allocate bitmap to track nodes that have been visited. */ - data->visited_blocks = sbitmap_alloc (last_basic_block - (INVALID_BLOCK + 1)); + data->visited_blocks = sbitmap_alloc (last_basic_block); /* None of the nodes in the CFG have been visited yet. */ sbitmap_zero (data->visited_blocks); @@ -1068,7 +882,7 @@ static void flow_dfs_compute_reverse_add_bb (depth_first_search_ds data, basic_block bb) { data->stack[data->sp++] = bb; - SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)); + SET_BIT (data->visited_blocks, bb->index); } /* Continue the depth-first search through the reverse graph starting with the @@ -1077,25 +891,26 @@ flow_dfs_compute_reverse_add_bb (depth_first_search_ds data, basic_block bb) available. */ static basic_block -flow_dfs_compute_reverse_execute (depth_first_search_ds data) +flow_dfs_compute_reverse_execute (depth_first_search_ds data, + basic_block last_unvisited) { basic_block bb; edge e; + edge_iterator ei; while (data->sp > 0) { bb = data->stack[--data->sp]; /* Perform depth-first search on adjacent vertices. */ - for (e = bb->pred; e; e = e->pred_next) - if (!TEST_BIT (data->visited_blocks, - e->src->index - (INVALID_BLOCK + 1))) + FOR_EACH_EDGE (e, ei, bb->preds) + if (!TEST_BIT (data->visited_blocks, e->src->index)) flow_dfs_compute_reverse_add_bb (data, e->src); } /* Determine if there are unvisited basic blocks. */ - FOR_BB_BETWEEN (bb, EXIT_BLOCK_PTR, NULL, prev_bb) - if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1))) + FOR_BB_BETWEEN (bb, last_unvisited, NULL, prev_bb) + if (!TEST_BIT (data->visited_blocks, bb->index)) return bb; return NULL; @@ -1121,39 +936,144 @@ dfs_enumerate_from (basic_block bb, int reverse, { basic_block *st, lbb; int sp = 0, tv = 0; + unsigned size; + + /* A bitmap to keep track of visited blocks. Allocating it each time + this function is called is not possible, since dfs_enumerate_from + is often used on small (almost) disjoint parts of cfg (bodies of + loops), and allocating a large sbitmap would lead to quadratic + behavior. */ + static sbitmap visited; + static unsigned v_size; + +#define MARK_VISITED(BB) (SET_BIT (visited, (BB)->index)) +#define UNMARK_VISITED(BB) (RESET_BIT (visited, (BB)->index)) +#define VISITED_P(BB) (TEST_BIT (visited, (BB)->index)) + + /* Resize the VISITED sbitmap if necessary. */ + size = last_basic_block; + if (size < 10) + size = 10; + + if (!visited) + { + + visited = sbitmap_alloc (size); + sbitmap_zero (visited); + v_size = size; + } + else if (v_size < size) + { + /* Ensure that we increase the size of the sbitmap exponentially. */ + if (2 * v_size > size) + size = 2 * v_size; - st = xcalloc (rslt_max, sizeof (basic_block)); + visited = sbitmap_resize (visited, size, 0); + v_size = size; + } + + st = XCNEWVEC (basic_block, rslt_max); rslt[tv++] = st[sp++] = bb; - bb->flags |= BB_VISITED; + MARK_VISITED (bb); while (sp) { edge e; + edge_iterator ei; lbb = st[--sp]; if (reverse) - { - for (e = lbb->pred; e; e = e->pred_next) - if (!(e->src->flags & BB_VISITED) && predicate (e->src, data)) + { + FOR_EACH_EDGE (e, ei, lbb->preds) + if (!VISITED_P (e->src) && predicate (e->src, data)) { - if (tv == rslt_max) - abort (); - rslt[tv++] = st[sp++] = e->src; - e->src->flags |= BB_VISITED; + gcc_assert (tv != rslt_max); + rslt[tv++] = st[sp++] = e->src; + MARK_VISITED (e->src); } - } + } else - { - for (e = lbb->succ; e; e = e->succ_next) - if (!(e->dest->flags & BB_VISITED) && predicate (e->dest, data)) + { + FOR_EACH_EDGE (e, ei, lbb->succs) + if (!VISITED_P (e->dest) && predicate (e->dest, data)) { - if (tv == rslt_max) - abort (); - rslt[tv++] = st[sp++] = e->dest; - e->dest->flags |= BB_VISITED; + gcc_assert (tv != rslt_max); + rslt[tv++] = st[sp++] = e->dest; + MARK_VISITED (e->dest); } } } free (st); for (sp = 0; sp < tv; sp++) - rslt[sp]->flags &= ~BB_VISITED; + UNMARK_VISITED (rslt[sp]); return tv; +#undef MARK_VISITED +#undef UNMARK_VISITED +#undef VISITED_P } + + +/* Compute dominance frontiers, ala Harvey, Ferrante, et al. + + This algorithm can be found in Timothy Harvey's PhD thesis, at + http://www.cs.rice.edu/~harv/dissertation.pdf in the section on iterative + dominance algorithms. + + First, we identify each join point, j (any node with more than one + incoming edge is a join point). + + We then examine each predecessor, p, of j and walk up the dominator tree + starting at p. + + We stop the walk when we reach j's immediate dominator - j is in the + dominance frontier of each of the nodes in the walk, except for j's + immediate dominator. Intuitively, all of the rest of j's dominators are + shared by j's predecessors as well. + Since they dominate j, they will not have j in their dominance frontiers. + + The number of nodes touched by this algorithm is equal to the size + of the dominance frontiers, no more, no less. +*/ + + +static void +compute_dominance_frontiers_1 (bitmap *frontiers) +{ + edge p; + edge_iterator ei; + basic_block b; + FOR_EACH_BB (b) + { + if (EDGE_COUNT (b->preds) >= 2) + { + FOR_EACH_EDGE (p, ei, b->preds) + { + basic_block runner = p->src; + basic_block domsb; + if (runner == ENTRY_BLOCK_PTR) + continue; + + domsb = get_immediate_dominator (CDI_DOMINATORS, b); + while (runner != domsb) + { + if (bitmap_bit_p (frontiers[runner->index], b->index)) + break; + bitmap_set_bit (frontiers[runner->index], + b->index); + runner = get_immediate_dominator (CDI_DOMINATORS, + runner); + } + } + } + } +} + + +void +compute_dominance_frontiers (bitmap *frontiers) +{ + timevar_push (TV_DOM_FRONTIERS); + + compute_dominance_frontiers_1 (frontiers); + + timevar_pop (TV_DOM_FRONTIERS); +} + -- cgit v1.1