/* Control flow graph building code for GNU compiler.
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003, 2004 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"
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 make_label_edge (sbitmap, basic_block, rtx, int);
static void find_bb_boundaries (basic_block);
static void compute_outgoing_frequencies (basic_block);
\f
/* Create an edge from a basic block to a label. */
static void
-make_label_edge (sbitmap *edge_cache, basic_block src, rtx label, int flags)
+make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags)
{
gcc_assert (LABEL_P (label));
/* Create the edges generated by INSN in REGION. */
void
-rtl_make_eh_edge (sbitmap *edge_cache, basic_block src, rtx insn)
+rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx insn)
{
int is_call = CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0;
rtx handlers, i;
free_INSN_LIST_list (&handlers);
}
-/* Identify the edges between basic blocks MIN to MAX.
+/* 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,
- 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.
+ /* 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,
- 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. */
+ /* 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))
+
+/* 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 (basic_block min, basic_block max, int update_p)
{
basic_block bb;
- sbitmap *edge_cache = NULL;
-
- /* Assume no computed jump; revise as we create edges. */
- current_function_has_computed_jump = 0;
-
- /* If we are partitioning hot and cold basic blocks into separate
- sections, we cannot assume there is no computed jump (partitioning
- sometimes requires the use of indirect jumps; see comments about
- partitioning at the top of bb-reorder.c:partition_hot_cold_basic_blocks
- for complete details). */
-
- if (flag_reorder_blocks_and_partition)
- current_function_has_computed_jump = 1;
+ 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 || cfun->max_jumptable_ents > 100)
- {
- edge_cache = sbitmap_vector_alloc (last_basic_block, last_basic_block);
- sbitmap_vector_zero (edge_cache, last_basic_block);
-
- if (update_p)
- FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
- {
- edge e;
- edge_iterator ei;
-
- FOR_EACH_EDGE (e, ei, bb->succs)
- if (e->dest != EXIT_BLOCK_PTR)
- SET_BIT (edge_cache[bb->index], e->dest->index);
- }
- }
+ edge_cache = sbitmap_alloc (last_basic_block);
/* 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);
+ make_edge (ENTRY_BLOCK_PTR, min, EDGE_FALLTHRU);
FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
{
rtx insn, x;
enum rtx_code code;
edge e;
+ edge_iterator ei;
+
+ 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)))
everything on the forced_labels list. */
else if (computed_jump_p (insn))
{
- current_function_has_computed_jump = 1;
-
for (x = forced_labels; x; x = XEXP (x, 1))
make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
}
/* 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 (rtx f, int nregs ATTRIBUTE_UNUSED,
- FILE *file ATTRIBUTE_UNUSED)
+find_basic_blocks (rtx f)
{
basic_block bb;
profile_status = PROFILE_ABSENT;
+ /* 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 (ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR->prev_bb, 0);
timevar_pop (TV_CFG);
}
\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))
-
-/* Used internally by purge_dead_tablejump_edges, ORed into state. */
-#define BLOCK_USED_BY_TABLEJUMP 32
-#define FULL_STATE(BB) ((size_t) (BB)->aux)
-
static void
mark_tablejump_edge (rtx label)
{
}
}
- if (EDGE_COUNT (b->succs) == 1)
+ if (single_succ_p (b))
{
- e = EDGE_SUCC (b, 0);
+ e = single_succ_edge (b);
e->probability = REG_BR_PROB_BASE;
e->count = b->count;
return;
/ REG_BR_PROB_BASE);
}
-/* Assume that someone emitted code with control flow instructions to the
- basic block. Update the data structure. */
+/* 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)
FOR_EACH_BB (bb)
SET_STATE (bb, 0);
}
-
-/* Like above but for single basic block only. */
-
-void
-find_sub_basic_blocks (basic_block bb)
-{
- basic_block min, max, b;
- basic_block next = bb->next_bb;
-
- min = bb;
- find_bb_boundaries (bb);
- max = next->prev_bb;
-
- /* Now re-scan and wire in all edges. This expect simple (conditional)
- jumps at the end of each new basic blocks. */
- make_edges (min, max, 1);
-
- /* Update branch probabilities. Expect only (un)conditional jumps
- to be created with only the forward edges. */
- FOR_BB_BETWEEN (b, min, max->next_bb, next_bb)
- {
- edge e;
- edge_iterator ei;
-
- if (b != min)
- {
- b->count = 0;
- b->frequency = 0;
- FOR_EACH_EDGE (e, ei, b->preds)
- {
- b->count += e->count;
- b->frequency += EDGE_FREQUENCY (e);
- }
- }
-
- compute_outgoing_frequencies (b);
- }
-}
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