/* Control flow graph building code for GNU compiler.
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
This file is part of GCC.
- CFG construction
find_basic_blocks
- Local CFG construction
- find_sub_basic_blocks
- */
+ find_sub_basic_blocks */
\f
#include "config.h"
#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "hard-reg-set.h"
#include "toplev.h"
#include "timevar.h"
-#include "obstack.h"
static int count_basic_blocks PARAMS ((rtx));
static void find_basic_blocks_1 PARAMS ((rtx));
static rtx find_label_refs PARAMS ((rtx, rtx));
-static void make_edges PARAMS ((rtx, int, int, int));
+static void make_edges PARAMS ((rtx, basic_block,
+ basic_block, int));
static void make_label_edge PARAMS ((sbitmap *, basic_block,
rtx, int));
static void make_eh_edge PARAMS ((sbitmap *, basic_block, rtx));
static void find_bb_boundaries PARAMS ((basic_block));
static void compute_outgoing_frequencies PARAMS ((basic_block));
-static bool inside_basic_block_p PARAMS ((rtx));
-static bool control_flow_insn_p PARAMS ((rtx));
-
+\f
/* Return true if insn is something that should be contained inside basic
block. */
-static bool
+bool
inside_basic_block_p (insn)
rtx insn;
{
{
case CODE_LABEL:
/* Avoid creating of basic block for jumptables. */
- if (NEXT_INSN (insn)
- && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
- && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
- || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
- return false;
- return true;
+ 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:
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- return false;
- return true;
+ return (GET_CODE (PATTERN (insn)) != ADDR_VEC
+ && GET_CODE (PATTERN (insn)) != ADDR_DIFF_VEC);
case CALL_INSN:
case INSN:
}
}
-/* Return true if INSN may cause control flow transfer, so
- it should be last in the basic block. */
+/* Return true if INSN may cause control flow transfer, so it should be last in
+ the basic block. */
-static bool
+bool
control_flow_insn_p (insn)
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. */
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- return false;
- return true;
-
- case CALL_INSN:
- /* Call insn may return to the nonlocal goto handler. */
- if (nonlocal_goto_handler_labels
- && ((note = find_reg_note (insn, REG_EH_REGION, NULL_RTX)) == 0
- || INTVAL (XEXP (note, 0)) >= 0))
- return true;
- /* Or may trap. */
- return can_throw_internal (insn);
-
- case INSN:
- return (flag_non_call_exceptions
- && can_throw_internal (insn));
-
- case BARRIER:
- /* It is nonsence to reach barrier when looking for the
- end of basic block, but before dead code is elliminated
- this may happen. */
- return false;
-
- default:
- abort ();
+ 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 nonsence to reach barrier when looking for the
+ end of basic block, but before dead code is eliminated
+ this may happen. */
+ return false;
+
+ default:
+ abort ();
}
}
for (insn = f; insn; insn = NEXT_INSN (insn))
{
- /* Code labels and barriers causes curent basic block to be
+ /* 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;
if (saw_insn && control_flow_insn_p (insn))
count++, saw_insn = false;
}
+
if (saw_insn)
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 (f, lvl)
rtx f;
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))
+ && GET_CODE (next) == JUMP_INSN
+ && (GET_CODE (PATTERN (next)) == ADDR_VEC
+ || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
;
else if (GET_CODE (lab) == NOTE)
;
basic_block src;
rtx insn;
{
- int is_call = (GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
+ int is_call = GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0;
rtx handlers, i;
handlers = reachable_handlers (insn);
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
static void
make_edges (label_value_list, min, max, update_p)
rtx label_value_list;
- int min, max, update_p;
+ basic_block min, max;
+ int update_p;
{
- int i;
+ basic_block bb;
sbitmap *edge_cache = NULL;
/* Assume no computed jump; revise as we create edges. */
/* 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)
+ if (forced_labels || label_value_list || cfun->max_jumptable_ents > 100)
{
- edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
- sbitmap_vector_zero (edge_cache, n_basic_blocks);
+ edge_cache = sbitmap_vector_alloc (last_basic_block, last_basic_block);
+ sbitmap_vector_zero (edge_cache, last_basic_block);
if (update_p)
- for (i = min; i <= max; ++i)
+ FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
{
edge e;
- for (e = BASIC_BLOCK (i)->succ; e ; e = e->succ_next)
+
+ for (e = bb->succ; e ; e = e->succ_next)
if (e->dest != EXIT_BLOCK_PTR)
- SET_BIT (edge_cache[i], e->dest->index);
+ SET_BIT (edge_cache[bb->index], e->dest->index);
}
}
- /* By nature of the way these get numbered, block 0 is always the entry. */
- if (min == 0)
- cached_make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
+ /* 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 (i = min; i <= max; ++i)
+ FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
{
- basic_block bb = BASIC_BLOCK (i);
rtx insn, x;
enum rtx_code code;
int force_fallthru = 0;
- if (GET_CODE (bb->head) == CODE_LABEL
- && LABEL_ALTERNATE_NAME (bb->head))
+ if (GET_CODE (bb->head) == CODE_LABEL && LABEL_ALT_ENTRY_P (bb->head))
cached_make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
/* Examine the last instruction of the block, and discover the
else if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
;
- /* ??? Recognize a tablejump and do the right thing. */
- else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
- && (tmp = NEXT_INSN (tmp)) != NULL_RTX
- && GET_CODE (tmp) == JUMP_INSN
- && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
- || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
+ /* Recognize a tablejump and do the right thing. */
+ else if (tablejump_p (insn, NULL, &tmp))
{
rtvec vec;
int j;
}
}
- /* 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 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_ABNORMAL | EDGE_ABNORMAL_CALL);
+ cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_SIBCALL);
/* 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. */
{
/* ??? 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),
}
/* Find out if we can drop through to the next block. */
- insn = next_nonnote_insn (insn);
- if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
+ 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 (i + 1 < n_basic_blocks)
+ else if (bb->next_bb != EXIT_BLOCK_PTR)
{
- rtx tmp = BLOCK_HEAD (i + 1);
- if (GET_CODE (tmp) == NOTE)
- tmp = next_nonnote_insn (tmp);
- if (force_fallthru || insn == tmp)
- cached_make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
+ if (force_fallthru || insn == bb->next_bb->head)
+ cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU);
}
}
rtx f;
{
rtx insn, next;
- int i = 0;
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
if ((GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == BARRIER)
&& head)
{
- create_basic_block_structure (i++, head, end, bb_note);
+ 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))
{
- create_basic_block_structure (i++, head, end, bb_note);
+ prev = create_basic_block_structure (head, end, bb_note, prev);
head = end = NULL_RTX;
bb_note = NULL_RTX;
}
}
if (head != NULL_RTX)
- create_basic_block_structure (i++, head, end, bb_note);
+ create_basic_block_structure (head, end, bb_note, prev);
else if (bb_note)
delete_insn (bb_note);
- if (i != n_basic_blocks)
+ if (last_basic_block != n_basic_blocks)
abort ();
label_value_list = lvl;
tail_recursion_label_list = trll;
+ clear_aux_for_blocks ();
}
int nregs ATTRIBUTE_UNUSED;
FILE *file ATTRIBUTE_UNUSED;
{
- int max_uid;
- timevar_push (TV_CFG);
+ basic_block bb;
- basic_block_for_insn = 0;
+ timevar_push (TV_CFG);
/* Flush out existing data. */
if (basic_block_info != NULL)
{
- int i;
-
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 (i = 0; i < n_basic_blocks; ++i)
- BASIC_BLOCK (i)->aux = NULL;
+ 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
find_basic_blocks_1 (f);
- /* Record the block to which an insn belongs. */
- /* ??? This should be done another way, by which (perhaps) a label is
- tagged directly with the basic block that it starts. It is used for
- more than that currently, but IMO that is the only valid use. */
-
- max_uid = get_max_uid ();
-#ifdef AUTO_INC_DEC
- /* Leave space for insns life_analysis makes in some cases for auto-inc.
- These cases are rare, so we don't need too much space. */
- max_uid += max_uid / 10;
-#endif
-
- compute_bb_for_insn (max_uid);
-
/* Discover the edges of our cfg. */
- make_edges (label_value_list, 0, n_basic_blocks - 1, 0);
+ 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. */
}
\f
/* 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)
+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. */
fallthru = split_block (bb, PREV_INSN (insn));
if (flow_transfer_insn)
bb->end = flow_transfer_insn;
+
bb = fallthru->dest;
remove_edge (fallthru);
flow_transfer_insn = NULL_RTX;
- if (LABEL_ALTERNATE_NAME (insn))
+ 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))
remove_edge (fallthru);
flow_transfer_insn = NULL_RTX;
}
+
if (control_flow_insn_p (insn))
flow_transfer_insn = insn;
if (insn == end)
basic_block b;
{
edge e, f;
+
if (b->succ && b->succ->succ_next && !b->succ->succ_next->succ_next)
{
rtx note = find_reg_note (b->end, REG_BR_PROB, NULL);
if (!note)
return;
+
probability = INTVAL (XEXP (find_reg_note (b->end,
- REG_BR_PROB, NULL), 0));
+ REG_BR_PROB, NULL),
+ 0));
e = BRANCH_EDGE (b);
e->probability = probability;
e->count = ((b->count * probability + REG_BR_PROB_BASE / 2)
f->probability = REG_BR_PROB_BASE - probability;
f->count = b->count - e->count;
}
+
if (b->succ && !b->succ->succ_next)
{
e = b->succ;
find_many_sub_basic_blocks (blocks)
sbitmap blocks;
{
- int i;
- int min, max;
+ basic_block bb, min, max;
- for (i = 0; i < n_basic_blocks; i++)
- SET_STATE (BASIC_BLOCK (i),
- TEST_BIT (blocks, i) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL);
+ FOR_EACH_BB (bb)
+ SET_STATE (bb,
+ TEST_BIT (blocks, bb->index) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL);
- for (i = 0; i < n_basic_blocks; i++)
- {
- basic_block bb = BASIC_BLOCK (i);
- if (STATE (bb) == BLOCK_TO_SPLIT)
- find_bb_boundaries (bb);
- }
+ FOR_EACH_BB (bb)
+ if (STATE (bb) == BLOCK_TO_SPLIT)
+ find_bb_boundaries (bb);
- for (i = 0; i < n_basic_blocks; i++)
- if (STATE (BASIC_BLOCK (i)) != BLOCK_ORIGINAL)
+ FOR_EACH_BB (bb)
+ if (STATE (bb) != BLOCK_ORIGINAL)
break;
- min = max = i;
- for (; i < n_basic_blocks; i++)
- if (STATE (BASIC_BLOCK (i)) != BLOCK_ORIGINAL)
- max = i;
+
+ 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. */
/* Update branch probabilities. Expect only (un)conditional jumps
to be created with only the forward edges. */
- for (i = min; i <= max; i++)
+ FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
{
edge e;
- basic_block b = BASIC_BLOCK (i);
- if (STATE (b) == BLOCK_ORIGINAL)
+ if (STATE (bb) == BLOCK_ORIGINAL)
continue;
- if (STATE (b) == BLOCK_NEW)
+ if (STATE (bb) == BLOCK_NEW)
{
- b->count = 0;
- b->frequency = 0;
- for (e = b->pred; e; e=e->pred_next)
+ bb->count = 0;
+ bb->frequency = 0;
+ for (e = bb->pred; e; e = e->pred_next)
{
- b->count += e->count;
- b->frequency += EDGE_FREQUENCY (e);
+ bb->count += e->count;
+ bb->frequency += EDGE_FREQUENCY (e);
}
}
- compute_outgoing_frequencies (b);
+
+ compute_outgoing_frequencies (bb);
}
- for (i = 0; i < n_basic_blocks; i++)
- SET_STATE (BASIC_BLOCK (i), 0);
+
+ FOR_EACH_BB (bb)
+ SET_STATE (bb, 0);
}
/* Like above but for single basic block only. */
void
find_sub_basic_blocks (bb)
- basic_block bb;
+ basic_block bb;
{
- int i;
- int min, max;
- basic_block next = (bb->index == n_basic_blocks - 1
- ? NULL : BASIC_BLOCK (bb->index + 1));
+ basic_block min, max, b;
+ basic_block next = bb->next_bb;
- min = bb->index;
+ min = bb;
find_bb_boundaries (bb);
- max = (next ? next->index : n_basic_blocks) - 1;
+ 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. */
/* Update branch probabilities. Expect only (un)conditional jumps
to be created with only the forward edges. */
- for (i = min; i <= max; i++)
+ FOR_BB_BETWEEN (b, min, max->next_bb, next_bb)
{
edge e;
- basic_block b = BASIC_BLOCK (i);
- if (i != min)
+ if (b != min)
{
b->count = 0;
b->frequency = 0;
- for (e = b->pred; e; e=e->pred_next)
+ for (e = b->pred; e; e = e->pred_next)
{
b->count += e->count;
b->frequency += EDGE_FREQUENCY (e);
}
}
+
compute_outgoing_frequencies (b);
}
}
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