diff options
Diffstat (limited to 'gcc/cfglayout.c')
-rw-r--r-- | gcc/cfglayout.c | 246 |
1 files changed, 112 insertions, 134 deletions
diff --git a/gcc/cfglayout.c b/gcc/cfglayout.c index 12cc255..a576f0e 100644 --- a/gcc/cfglayout.c +++ b/gcc/cfglayout.c @@ -34,13 +34,16 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "cfgloop.h" #include "target.h" #include "ggc.h" +#include "alloc-pool.h" /* The contents of the current function definition are allocated in this obstack, and all are freed at the end of the function. */ extern struct obstack flow_obstack; +alloc_pool cfg_layout_pool; + /* Holds the interesting trailing notes for the function. */ -rtx cfg_layout_function_footer; +rtx cfg_layout_function_footer, cfg_layout_function_header; static rtx skip_insns_after_block (basic_block); static void record_effective_endpoints (void); @@ -51,7 +54,6 @@ static void set_block_levels (tree, int); static void change_scope (rtx, tree, tree); void verify_insn_chain (void); -static void cleanup_unconditional_jumps (struct loops *); static void fixup_fallthru_exit_predecessor (void); static rtx duplicate_insn_chain (rtx, rtx); static void break_superblocks (void); @@ -189,19 +191,38 @@ label_for_bb (basic_block bb) static void record_effective_endpoints (void) { - rtx next_insn = get_insns (); + rtx next_insn; basic_block bb; + rtx insn; + + for (insn = get_insns (); + NEXT_INSN (insn) && GET_CODE (insn) == NOTE; + insn = NEXT_INSN (insn)) + { + if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK) + { + insn = NULL; + break; + } + if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG) + break; + } + if (insn) + cfg_layout_function_header = unlink_insn_chain (get_insns (), insn); + else + cfg_layout_function_header = NULL_RTX; + next_insn = get_insns (); FOR_EACH_BB (bb) { rtx end; if (PREV_INSN (bb->head) && next_insn != bb->head) - RBI (bb)->header = unlink_insn_chain (next_insn, + bb->rbi->header = unlink_insn_chain (next_insn, PREV_INSN (bb->head)); end = skip_insns_after_block (bb); if (NEXT_INSN (bb->end) && bb->end != end) - RBI (bb)->footer = unlink_insn_chain (NEXT_INSN (bb->end), end); + bb->rbi->footer = unlink_insn_chain (NEXT_INSN (bb->end), end); next_insn = NEXT_INSN (bb->end); } @@ -529,21 +550,29 @@ fixup_reorder_chain (void) int index; rtx insn = NULL; + if (cfg_layout_function_header) + { + set_first_insn (cfg_layout_function_header); + insn = cfg_layout_function_header; + while (NEXT_INSN (insn)) + insn = NEXT_INSN (insn); + } + /* First do the bulk reordering -- rechain the blocks without regard to the needed changes to jumps and labels. */ for (bb = ENTRY_BLOCK_PTR->next_bb, index = 0; bb != 0; - bb = RBI (bb)->next, index++) + bb = bb->rbi->next, index++) { - if (RBI (bb)->header) + if (bb->rbi->header) { if (insn) - NEXT_INSN (insn) = RBI (bb)->header; + NEXT_INSN (insn) = bb->rbi->header; else - set_first_insn (RBI (bb)->header); - PREV_INSN (RBI (bb)->header) = insn; - insn = RBI (bb)->header; + set_first_insn (bb->rbi->header); + PREV_INSN (bb->rbi->header) = insn; + insn = bb->rbi->header; while (NEXT_INSN (insn)) insn = NEXT_INSN (insn); } @@ -553,10 +582,10 @@ fixup_reorder_chain (void) set_first_insn (bb->head); PREV_INSN (bb->head) = insn; insn = bb->end; - if (RBI (bb)->footer) + if (bb->rbi->footer) { - NEXT_INSN (insn) = RBI (bb)->footer; - PREV_INSN (RBI (bb)->footer) = insn; + NEXT_INSN (insn) = bb->rbi->footer; + PREV_INSN (bb->rbi->footer) = insn; while (NEXT_INSN (insn)) insn = NEXT_INSN (insn); } @@ -580,7 +609,7 @@ fixup_reorder_chain (void) /* Now add jumps and labels as needed to match the blocks new outgoing edges. */ - for (bb = ENTRY_BLOCK_PTR->next_bb; bb ; bb = RBI (bb)->next) + for (bb = ENTRY_BLOCK_PTR->next_bb; bb ; bb = bb->rbi->next) { edge e_fall, e_taken, e; rtx bb_end_insn; @@ -604,8 +633,8 @@ fixup_reorder_chain (void) if (any_condjump_p (bb_end_insn)) { /* If the old fallthru is still next, nothing to do. */ - if (RBI (bb)->next == e_fall->dest - || (!RBI (bb)->next + if (bb->rbi->next == e_fall->dest + || (!bb->rbi->next && e_fall->dest == EXIT_BLOCK_PTR)) continue; @@ -645,7 +674,7 @@ fixup_reorder_chain (void) such as happens at the very end of a function, then we'll need to add a new unconditional jump. Choose the taken edge based on known or assumed probability. */ - else if (RBI (bb)->next != e_taken->dest) + else if (bb->rbi->next != e_taken->dest) { rtx note = find_reg_note (bb_end_insn, REG_BR_PROB, 0); @@ -684,7 +713,7 @@ fixup_reorder_chain (void) #ifdef CASE_DROPS_THROUGH /* Except for VAX. Since we didn't have predication for the tablejump, the fallthru block should not have moved. */ - if (RBI (bb)->next == e_fall->dest) + if (bb->rbi->next == e_fall->dest) continue; bb_end_insn = skip_insns_after_block (bb); #else @@ -701,11 +730,11 @@ fixup_reorder_chain (void) continue; /* If the fallthru block is still next, nothing to do. */ - if (RBI (bb)->next == e_fall->dest) + if (bb->rbi->next == e_fall->dest) continue; /* A fallthru to exit block. */ - if (!RBI (bb)->next && e_fall->dest == EXIT_BLOCK_PTR) + if (!bb->rbi->next && e_fall->dest == EXIT_BLOCK_PTR) continue; } @@ -713,10 +742,10 @@ fixup_reorder_chain (void) nb = force_nonfallthru (e_fall); if (nb) { - alloc_aux_for_block (nb, sizeof (struct reorder_block_def)); - RBI (nb)->visited = 1; - RBI (nb)->next = RBI (bb)->next; - RBI (bb)->next = nb; + cfg_layout_initialize_rbi (nb); + nb->rbi->visited = 1; + nb->rbi->next = bb->rbi->next; + bb->rbi->next = nb; /* Don't process this new block. */ bb = nb; } @@ -727,12 +756,12 @@ fixup_reorder_chain (void) if (rtl_dump_file) { fprintf (rtl_dump_file, "Reordered sequence:\n"); - for (bb = ENTRY_BLOCK_PTR->next_bb, index = 0; bb; bb = RBI (bb)->next, index ++) + for (bb = ENTRY_BLOCK_PTR->next_bb, index = 0; bb; bb = bb->rbi->next, index ++) { fprintf (rtl_dump_file, " %i ", index); - if (RBI (bb)->original) + if (bb->rbi->original) fprintf (rtl_dump_file, "duplicate of %i ", - RBI (bb)->original->index); + bb->rbi->original->index); else if (forwarder_block_p (bb) && GET_CODE (bb->head) != CODE_LABEL) fprintf (rtl_dump_file, "compensation "); else @@ -745,7 +774,7 @@ fixup_reorder_chain (void) bb = ENTRY_BLOCK_PTR->next_bb; index = 0; - for (; bb; prev_bb = bb, bb = RBI (bb)->next, index ++) + for (; bb; prev_bb = bb, bb = bb->rbi->next, index ++) { bb->index = index; BASIC_BLOCK (index) = bb; @@ -755,6 +784,16 @@ fixup_reorder_chain (void) } prev_bb->next_bb = EXIT_BLOCK_PTR; EXIT_BLOCK_PTR->prev_bb = prev_bb; + + /* Anoying special case - jump around dead jumptables left in the code. */ + FOR_EACH_BB (bb) + { + edge e; + for (e = bb->succ; e && !(e->flags & EDGE_FALLTHRU); e = e->succ_next) + continue; + if (e && !can_fallthru (e->src, e->dest)) + force_nonfallthru (e); + } } /* Perform sanity checks on the insn chain. @@ -788,87 +827,6 @@ verify_insn_chain (void) abort (); } -/* Remove any unconditional jumps and forwarder block creating fallthru - edges instead. During BB reordering, fallthru edges are not required - to target next basic block in the linear CFG layout, so the unconditional - jumps are not needed. If LOOPS is not null, also update loop structure & - dominators. */ - -static void -cleanup_unconditional_jumps (struct loops *loops) -{ - basic_block bb; - - FOR_EACH_BB (bb) - { - if (!bb->succ) - continue; - if (bb->succ->flags & EDGE_FALLTHRU) - continue; - if (!bb->succ->succ_next) - { - rtx insn; - if (GET_CODE (bb->head) != CODE_LABEL && forwarder_block_p (bb) - && bb->prev_bb != ENTRY_BLOCK_PTR) - { - basic_block prev = bb->prev_bb; - - if (rtl_dump_file) - fprintf (rtl_dump_file, "Removing forwarder BB %i\n", - bb->index); - - if (loops) - { - /* bb cannot be loop header, as it only has one entry - edge. It could be a loop latch. */ - if (bb->loop_father->header == bb) - abort (); - - if (bb->loop_father->latch == bb) - bb->loop_father->latch = bb->pred->src; - - if (get_immediate_dominator - (loops->cfg.dom, bb->succ->dest) == bb) - set_immediate_dominator - (loops->cfg.dom, bb->succ->dest, bb->pred->src); - - remove_bb_from_loops (bb); - delete_from_dominance_info (loops->cfg.dom, bb); - } - - redirect_edge_succ_nodup (bb->pred, bb->succ->dest); - delete_block (bb); - bb = prev; - } - else if (simplejump_p (bb->end)) - { - rtx jump = bb->end; - - if (rtl_dump_file) - fprintf (rtl_dump_file, "Removing jump %i in BB %i\n", - INSN_UID (jump), bb->index); - delete_insn (jump); - bb->succ->flags |= EDGE_FALLTHRU; - } - else - continue; - - insn = NEXT_INSN (bb->end); - while (insn - && (GET_CODE (insn) != NOTE - || NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK)) - { - rtx next = NEXT_INSN (insn); - - if (GET_CODE (insn) == BARRIER) - delete_barrier (insn); - - insn = next; - } - } - } -} - /* The block falling through to exit must be the last one in the reordered chain. Ensure that this condition is met. */ static void @@ -881,19 +839,19 @@ fixup_fallthru_exit_predecessor (void) if (e->flags & EDGE_FALLTHRU) bb = e->src; - if (bb && RBI (bb)->next) + if (bb && bb->rbi->next) { basic_block c = ENTRY_BLOCK_PTR->next_bb; - while (RBI (c)->next != bb) - c = RBI (c)->next; + while (c->rbi->next != bb) + c = c->rbi->next; - RBI (c)->next = RBI (bb)->next; - while (RBI (c)->next) - c = RBI (c)->next; + c->rbi->next = bb->rbi->next; + while (c->rbi->next) + c = c->rbi->next; - RBI (c)->next = bb; - RBI (bb)->next = NULL; + c->rbi->next = bb; + bb->rbi->next = NULL; } } @@ -1050,26 +1008,25 @@ cfg_layout_duplicate_bb (basic_block bb, edge e) new_bb = create_basic_block (insn, insn ? get_last_insn () : NULL, EXIT_BLOCK_PTR->prev_bb); - alloc_aux_for_block (new_bb, sizeof (struct reorder_block_def)); - if (RBI (bb)->header) + if (bb->rbi->header) { - insn = RBI (bb)->header; + insn = bb->rbi->header; while (NEXT_INSN (insn)) insn = NEXT_INSN (insn); - insn = duplicate_insn_chain (RBI (bb)->header, insn); + insn = duplicate_insn_chain (bb->rbi->header, insn); if (insn) - RBI (new_bb)->header = unlink_insn_chain (insn, get_last_insn ()); + new_bb->rbi->header = unlink_insn_chain (insn, get_last_insn ()); } - if (RBI (bb)->footer) + if (bb->rbi->footer) { - insn = RBI (bb)->footer; + insn = bb->rbi->footer; while (NEXT_INSN (insn)) insn = NEXT_INSN (insn); - insn = duplicate_insn_chain (RBI (bb)->footer, insn); + insn = duplicate_insn_chain (bb->rbi->footer, insn); if (insn) - RBI (new_bb)->footer = unlink_insn_chain (insn, get_last_insn ()); + new_bb->rbi->footer = unlink_insn_chain (insn, get_last_insn ()); } if (bb->global_live_at_start) @@ -1113,25 +1070,42 @@ cfg_layout_duplicate_bb (basic_block bb, edge e) if (bb->frequency < 0) bb->frequency = 0; - RBI (new_bb)->original = bb; - RBI (bb)->copy = new_bb; + new_bb->rbi->original = bb; + bb->rbi->copy = new_bb; return new_bb; } +void +cfg_layout_initialize_rbi (bb) + basic_block bb; +{ + if (bb->rbi) + abort (); + bb->rbi = pool_alloc (cfg_layout_pool); + memset (bb->rbi, 0, sizeof (struct reorder_block_def)); +} + /* Main entry point to this module - initialize the datastructures for CFG layout changes. It keeps LOOPS up-to-date if not null. */ void -cfg_layout_initialize (struct loops *loops) +cfg_layout_initialize () { + basic_block bb; + /* Our algorithm depends on fact that there are now dead jumptables around the code. */ - alloc_aux_for_blocks (sizeof (struct reorder_block_def)); - cfg_layout_rtl_register_cfg_hooks (); + cfg_layout_pool = + create_alloc_pool ("cfg layout pool", sizeof (struct reorder_block_def), + n_basic_blocks + 2); + FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb) + cfg_layout_initialize_rbi (bb); - cleanup_unconditional_jumps (loops); + cfg_layout_rtl_register_cfg_hooks (); record_effective_endpoints (); + + cleanup_cfg (CLEANUP_CFGLAYOUT); } /* Splits superblocks. */ @@ -1169,6 +1143,8 @@ break_superblocks (void) void cfg_layout_finalize (void) { + basic_block bb; + #ifdef ENABLE_CHECKING verify_flow_info (); #endif @@ -1180,7 +1156,9 @@ cfg_layout_finalize (void) verify_insn_chain (); #endif - free_aux_for_blocks (); + free_alloc_pool (cfg_layout_pool); + FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb) + bb->rbi = NULL; break_superblocks (); |