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 */
+ find_basic_blocks */
\f
#include "config.h"
#include "system.h"
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. */
+ end of basic block, but before dead code is eliminated
+ this may happen. */
return false;
default:
static int
count_basic_blocks (rtx f)
{
- int count = 0;
+ int count = NUM_FIXED_BLOCKS;
bool saw_insn = false;
rtx insn;
for (insn = f; insn; insn = NEXT_INSN (insn))
{
/* Code labels and barriers causes current basic block to be
- terminated at previous real insn. */
+ terminated at previous real insn. */
if ((LABEL_P (insn) || BARRIER_P (insn))
&& saw_insn)
count++, saw_insn = false;
/* 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)
+ if (count == NUM_FIXED_BLOCKS)
{
emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
- count = 1;
+ count = NUM_FIXED_BLOCKS + 1;
}
return count;
free_INSN_LIST_list (&handlers);
}
-/* State of basic block as seen by find_many_sub_basic_blocks. */
-enum state {BLOCK_NEW = 0, BLOCK_ORIGINAL, BLOCK_TO_SPLIT};
+/* 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))
#define BLOCK_USED_BY_TABLEJUMP 32
#define FULL_STATE(BB) ((size_t) (BB)->aux)
-/* Identify the edges between basic blocks MIN to MAX.
+/* 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.
- 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.
-
- 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. */
+ 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)
}
n_basic_blocks = count_basic_blocks (f);
- last_basic_block = 0;
+ 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
stable across calls to find_basic_blocks. */
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);
profile_status = PROFILE_ABSENT;
+ /* Tell make_edges to examine every block for out-going edges. */
FOR_EACH_BB (bb)
SET_STATE (bb, BLOCK_NEW);
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);
+ 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;
- }
+ {
+ remove_edge (e);
+ continue;
+ }
ei_next (&ei);
}
}
/ 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)