/* 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, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
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. */
/* find_basic_blocks divides the current function's rtl into basic
blocks and constructs the CFG. The blocks are recorded in the
Available functionality:
- CFG construction
- find_basic_blocks
- - Local CFG construction
- find_sub_basic_blocks
- */
+ find_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_label_edge PARAMS ((sbitmap *, basic_block,
- rtx, int));
-static void make_eh_edge PARAMS ((sbitmap *, basic_block, rtx));
-
-/* Count the basic blocks of the function. */
+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 find_bb_boundaries (basic_block);
+static void compute_outgoing_frequencies (basic_block);
+\f
+/* Return true if insn is something that should be contained inside basic
+ block. */
-static int
-count_basic_blocks (f)
- rtx f;
+bool
+inside_basic_block_p (rtx insn)
{
- register rtx insn;
- register RTX_CODE prev_code;
- register int count = 0;
- int saw_abnormal_edge = 0;
-
- prev_code = JUMP_INSN;
- for (insn = f; insn; insn = NEXT_INSN (insn))
+ switch (GET_CODE (insn))
{
- enum rtx_code code = GET_CODE (insn);
-
- if (code == CODE_LABEL
- || (GET_RTX_CLASS (code) == 'i'
- && (prev_code == JUMP_INSN
- || prev_code == BARRIER
- || saw_abnormal_edge)))
- {
- saw_abnormal_edge = 0;
- count++;
- }
-
- /* Record whether this insn created an edge. */
- if (code == CALL_INSN)
- {
- rtx note;
-
- /* If there is a nonlocal goto label and the specified
- region number isn't -1, we have an edge. */
- if (nonlocal_goto_handler_labels
- && ((note = find_reg_note (insn, REG_EH_REGION, NULL_RTX)) == 0
- || INTVAL (XEXP (note, 0)) >= 0))
- saw_abnormal_edge = 1;
+ case CODE_LABEL:
+ /* Avoid creating of basic block for jumptables. */
+ return (NEXT_INSN (insn) == 0
+ || !JUMP_P (NEXT_INSN (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:
+ gcc_unreachable ();
+ }
+}
- else if (can_throw_internal (insn))
- saw_abnormal_edge = 1;
- }
- else if (flag_non_call_exceptions
- && code == INSN
- && can_throw_internal (insn))
- saw_abnormal_edge = 1;
+/* Return true if INSN may cause control flow transfer, so it should be last in
+ the basic block. */
- if (code != NOTE)
- prev_code = code;
- }
+bool
+control_flow_insn_p (rtx insn)
+{
+ rtx note;
- /* 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)
+ switch (GET_CODE (insn))
{
- emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
- count = 1;
+ 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:
+ /* Noreturn and sibling call instructions terminate the basic blocks
+ (but only if they happen unconditionally). */
+ if ((SIBLING_CALL_P (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));
+
+ 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:
+ gcc_unreachable ();
}
-
- 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 (f, lvl)
- rtx f;
- rtx lvl;
+/* Count the basic blocks of the function. */
+
+static int
+count_basic_blocks (rtx f)
{
+ int count = NUM_FIXED_BLOCKS;
+ bool saw_insn = false;
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.
+ {
+ /* 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;
+ }
- Make a special exception to registers loaded with label
- values just before jump insns that use them. */
+ if (saw_insn)
+ count++;
- 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);
- }
- }
+ /* 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 == NUM_FIXED_BLOCKS)
+ {
+ emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
+ count = NUM_FIXED_BLOCKS + 1;
+ }
- return lvl;
+ return count;
}
\f
/* Create an edge between two basic blocks. FLAGS are auxiliary information
/* Create an edge from a basic block to a label. */
static void
-make_label_edge (edge_cache, src, label, flags)
- sbitmap *edge_cache;
- basic_block src;
- rtx label;
- int flags;
+make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags)
{
- if (GET_CODE (label) != CODE_LABEL)
- abort ();
+ gcc_assert (LABEL_P (label));
/* 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
if (INSN_UID (label) == 0)
return;
- make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
+ cached_make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
}
/* Create the edges generated by INSN in REGION. */
-static void
-make_eh_edge (edge_cache, src, insn)
- sbitmap *edge_cache;
- basic_block src;
- rtx insn;
+void
+rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx insn)
{
- int is_call = (GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
+ int is_call = CALL_P (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
- that are otherwise unreachable may be reachable with a non-local goto.
+/* 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))
- 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. */
+/* Used internally by purge_dead_tablejump_edges, ORed into state. */
+#define BLOCK_USED_BY_TABLEJUMP 32
+#define FULL_STATE(BB) ((size_t) (BB)->aux)
+
+/* 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.
+
+ UPDATE_P should be nonzero if we are updating CFG and zero if we
+ are building CFG from scratch. */
static void
-make_edges (label_value_list, min, max, update_p)
- rtx label_value_list;
- int min, max, update_p;
+make_edges (basic_block min, basic_block max, int update_p)
{
- int i;
- sbitmap *edge_cache = NULL;
-
- /* Assume no computed jump; revise as we create edges. */
- current_function_has_computed_jump = 0;
+ basic_block bb;
+ 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 || label_value_list)
- {
- edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
- sbitmap_vector_zero (edge_cache, n_basic_blocks);
-
- if (update_p)
- for (i = min; i <= max; ++i)
- {
- edge e;
- for (e = BASIC_BLOCK (i)->succ; e ; e = e->succ_next)
- if (e->dest != EXIT_BLOCK_PTR)
- SET_BIT (edge_cache[i], e->dest->index);
- }
- }
+ if (forced_labels || cfun->max_jumptable_ents > 100)
+ edge_cache = sbitmap_alloc (last_basic_block);
- /* By nature of the way these get numbered, block 0 is always the entry. */
- 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)
+ make_edge (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;
+ edge e;
+ edge_iterator ei;
- if (GET_CODE (bb->head) == CODE_LABEL
- && LABEL_ALTERNATE_NAME (bb->head))
- make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
+ 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);
/* Examine the last instruction of the block, and discover the
ways we can leave the block. */
- insn = bb->end;
+ insn = BB_END (bb);
code = GET_CODE (insn);
/* A branch. */
/* Recognize exception handling placeholders. */
if (GET_CODE (PATTERN (insn)) == RESX)
- make_eh_edge (edge_cache, bb, insn);
+ 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))
;
- /* ??? 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;
&& 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. */
+ everything on the 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))
- make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
+ 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 ();
+ gcc_assert (JUMP_LABEL (insn));
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 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))
- make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
- EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
+ 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);
+ rtl_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),
}
/* 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))
- make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
- else if (i + 1 < n_basic_blocks)
+ insn = NEXT_INSN (insn);
+ e = find_edge (bb, EXIT_BLOCK_PTR);
+ if (e && e->flags & EDGE_FALLTHRU)
+ insn = NULL;
+
+ while (insn
+ && NOTE_P (insn)
+ && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK)
+ insn = NEXT_INSN (insn);
+
+ if (!insn)
+ cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
+ 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)
- make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
+ if (insn == BB_HEAD (bb->next_bb))
+ cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU);
}
}
will be used in make_edges for use with computed gotos. */
static void
-find_basic_blocks_1 (f)
- rtx f;
+find_basic_blocks_1 (rtx f)
{
- register rtx insn, next;
- int i = 0;
+ 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
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:
if (bb_note == NULL_RTX)
bb_note = insn;
else
- next = flow_delete_insn (insn);
+ next = delete_insn (insn);
}
break;
}
case CODE_LABEL:
- /* A basic block starts at a label. If we've closed one off due
- to a barrier or some such, no need to do it again. */
- if (head != NULL_RTX)
- {
- create_basic_block (i++, head, end, bb_note);
- bb_note = NULL_RTX;
- }
-
- head = end = insn;
- break;
-
case JUMP_INSN:
- /* A basic block ends at a jump. */
- if (head == NULL_RTX)
- head = insn;
- else
- {
- /* ??? Make a special check for table jumps. The way this
- happens is truly and amazingly gross. We are about to
- create a basic block that contains just a code label and
- an addr*vec jump insn. Worse, an addr_diff_vec creates
- its own natural loop.
-
- Prevent this bit of brain damage, pasting things together
- correctly in make_edges.
-
- The correct solution involves emitting the table directly
- on the tablejump instruction as a note, or JUMP_LABEL. */
-
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- {
- head = end = NULL;
- n_basic_blocks--;
- break;
- }
- }
- end = insn;
- goto new_bb_inclusive;
-
- case BARRIER:
- /* A basic block ends at a barrier. It may be that an unconditional
- jump already closed the basic block -- no need to do it again. */
- if (head == NULL_RTX)
- break;
- goto new_bb_exclusive;
-
case CALL_INSN:
- {
- /* Record whether this call created an edge. */
- rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
- int region = (note ? INTVAL (XEXP (note, 0)) : 0);
-
- 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);
- }
-
- /* A basic block ends at a call that can either throw or
- do a non-local goto. */
- if ((nonlocal_goto_handler_labels && region >= 0)
- || can_throw_internal (insn))
- {
- new_bb_inclusive:
- if (head == NULL_RTX)
- head = insn;
- end = insn;
-
- new_bb_exclusive:
- create_basic_block (i++, head, end, bb_note);
- head = end = NULL_RTX;
- bb_note = NULL_RTX;
- break;
- }
- }
- /* Fall through. */
-
case INSN:
- /* Non-call exceptions generate new blocks just like calls. */
- if (flag_non_call_exceptions && can_throw_internal (insn))
- goto new_bb_inclusive;
-
- if (head == NULL_RTX)
- head = insn;
- end = insn;
+ case BARRIER:
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);
- }
+ gcc_unreachable ();
}
}
if (head != NULL_RTX)
- create_basic_block (i++, head, end, bb_note);
+ create_basic_block_structure (head, end, bb_note, prev);
else if (bb_note)
- flow_delete_insn (bb_note);
+ delete_insn (bb_note);
- if (i != n_basic_blocks)
- abort ();
+ gcc_assert (last_basic_block == n_basic_blocks);
- 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. */
+ F is the first insn of the function. */
void
-find_basic_blocks (f, nregs, file)
- rtx f;
- int nregs ATTRIBUTE_UNUSED;
- FILE *file ATTRIBUTE_UNUSED;
+find_basic_blocks (rtx f)
{
- int max_uid;
+ basic_block bb;
+
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);
+ basic_block_info = NULL;
}
n_basic_blocks = count_basic_blocks (f);
+ last_basic_block = NUM_FIXED_BLOCKS;
+ 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
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");
+ basic_block_info = VEC_alloc (basic_block, gc, n_basic_blocks);
+ VEC_safe_grow (basic_block, gc, basic_block_info, n_basic_blocks);
+ memset (VEC_address (basic_block, basic_block_info), 0,
+ sizeof (basic_block) * n_basic_blocks);
+ SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
+ SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
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. */
+ profile_status = PROFILE_ABSENT;
- 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);
+ /* Tell make_edges to examine every block for out-going edges. */
+ FOR_EACH_BB (bb)
+ SET_STATE (bb, BLOCK_NEW);
/* Discover the edges of our cfg. */
- make_edges (label_value_list, 0, n_basic_blocks - 1, 0);
+ 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 ();
- mark_critical_edges ();
-
#ifdef ENABLE_CHECKING
verify_flow_info ();
#endif
timevar_pop (TV_CFG);
}
\f
-/* Assume that someone emitted code with control flow instructions to the
- basic block. Update the data structure. */
-void
-find_sub_basic_blocks (bb)
- basic_block bb;
+static void
+mark_tablejump_edge (rtx label)
+{
+ basic_block bb;
+
+ gcc_assert (LABEL_P (label));
+ /* See comment in make_label_edge. */
+ if (INSN_UID (label) == 0)
+ return;
+ bb = BLOCK_FOR_INSN (label);
+ SET_STATE (bb, FULL_STATE (bb) | BLOCK_USED_BY_TABLEJUMP);
+}
+
+static void
+purge_dead_tablejump_edges (basic_block bb, rtx table)
+{
+ rtx insn = BB_END (bb), tmp;
+ rtvec vec;
+ int j;
+ edge_iterator ei;
+ edge e;
+
+ if (GET_CODE (PATTERN (table)) == ADDR_VEC)
+ vec = XVEC (PATTERN (table), 0);
+ else
+ vec = XVEC (PATTERN (table), 1);
+
+ for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
+ mark_tablejump_edge (XEXP (RTVEC_ELT (vec, j), 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)
+ mark_tablejump_edge (XEXP (XEXP (SET_SRC (tmp), 2), 0));
+
+ 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);
+ else if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
+ {
+ remove_edge (e);
+ continue;
+ }
+ ei_next (&ei);
+ }
+}
+
+/* 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;
- rtx end = bb->end;
- rtx jump_insn = NULL_RTX;
- edge falltru = 0;
- basic_block first_bb = bb;
- int i;
-
- if (insn == bb->end)
+ basic_block orig_bb = bb;
+ rtx insn = BB_HEAD (bb);
+ rtx end = BB_END (bb);
+ rtx table;
+ rtx flow_transfer_insn = NULL_RTX;
+ edge fallthru = NULL;
+
+ if (insn == BB_END (bb))
return;
- if (GET_CODE (insn) == CODE_LABEL)
+ if (LABEL_P (insn))
insn = NEXT_INSN (insn);
/* Scan insn chain and try to find new basic block boundaries. */
while (1)
{
enum rtx_code code = GET_CODE (insn);
- switch (code)
+
+ /* On code label, split current basic block. */
+ if (code == CODE_LABEL)
{
- case BARRIER:
- if (!jump_insn)
- abort ();
- break;
- /* On code label, split current basic block. */
- case CODE_LABEL:
- falltru = split_block (bb, PREV_INSN (insn));
- if (jump_insn)
- bb->end = jump_insn;
- bb = falltru->dest;
- remove_edge (falltru);
- jump_insn = 0;
- if (LABEL_ALTERNATE_NAME (insn))
- make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
- break;
- case INSN:
- case JUMP_INSN:
- /* In case we've previously split insn on the JUMP_INSN, move the
- block header to proper place. */
- if (jump_insn)
- {
- falltru = split_block (bb, PREV_INSN (insn));
- bb->end = jump_insn;
- bb = falltru->dest;
- remove_edge (falltru);
- jump_insn = 0;
- }
- /* We need some special care for those expressions. */
- if (GET_CODE (insn) == JUMP_INSN)
- {
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- abort();
- jump_insn = insn;
- }
- break;
- default:
- break;
+ 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 (jump_insn && GET_CODE (bb->end) != JUMP_INSN)
- bb->end = jump_insn;
+ 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);
- /* Now re-scan and wire in all edges. This expect simple (conditional)
- jumps at the end of each new basic blocks. */
- make_edges (NULL, first_bb->index, bb->index, 1);
+ /* purge_dead_edges doesn't handle tablejump's, but if we have split the
+ basic block, we might need to kill some edges. */
+ if (bb != orig_bb && tablejump_p (BB_END (bb), NULL, &table))
+ purge_dead_tablejump_edges (bb, table);
+}
- /* Update branch probabilities. Expect only (un)conditional jumps
- to be created with only the forward edges. */
- for (i = first_bb->index; i <= bb->index; i++)
+/* 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;
+ edge_iterator ei;
+
+ if (EDGE_COUNT (b->succs) == 2)
{
- edge e,f;
- basic_block b = BASIC_BLOCK (i);
- if (b != first_bb)
- {
- b->count = 0;
- b->frequency = 0;
- for (e = b->pred; e; e=e->pred_next)
- {
- b->count += e->count;
- b->frequency += EDGE_FREQUENCY (e);
- }
- }
- 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)
{
- rtx note = find_reg_note (b->end, REG_BR_PROB, NULL);
- int probability;
-
- if (!note)
- continue;
- probability = INTVAL (XEXP (find_reg_note (b->end,
- REG_BR_PROB,
- NULL), 0));
+ probability = INTVAL (XEXP (note, 0));
e = BRANCH_EDGE (b);
e->probability = probability;
e->count = ((b->count * probability + REG_BR_PROB_BASE / 2)
f = FALLTHRU_EDGE (b);
f->probability = REG_BR_PROB_BASE - probability;
f->count = b->count - e->count;
+ return;
}
- if (b->succ && !b->succ->succ_next)
- {
- e = b->succ;
- e->probability = REG_BR_PROB_BASE;
- e->count = b->count;
- }
}
+
+ if (single_succ_p (b))
+ {
+ e = single_succ_edge (b);
+ e->probability = REG_BR_PROB_BASE;
+ e->count = b->count;
+ return;
+ }
+ guess_outgoing_edge_probabilities (b);
+ if (b->count)
+ FOR_EACH_EDGE (e, ei, b->succs)
+ e->count = ((b->count * e->probability + REG_BR_PROB_BASE / 2)
+ / REG_BR_PROB_BASE);
+}
+
+/* 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)
+{
+ 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 (min, max, 1);
+
+ /* Update branch probabilities. Expect only (un)conditional jumps
+ to be created with only the forward edges. */
+ if (profile_status != PROFILE_ABSENT)
+ FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
+ {
+ edge e;
+ edge_iterator ei;
+
+ if (STATE (bb) == BLOCK_ORIGINAL)
+ continue;
+ if (STATE (bb) == BLOCK_NEW)
+ {
+ bb->count = 0;
+ bb->frequency = 0;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ bb->count += e->count;
+ bb->frequency += EDGE_FREQUENCY (e);
+ }
+ }
+
+ compute_outgoing_frequencies (bb);
+ }
+
+ FOR_EACH_BB (bb)
+ SET_STATE (bb, 0);
}
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