along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
-/* find_basic_blocks divides the current function's rtl into basic
- blocks and constructs the CFG. The blocks are recorded in the
- basic_block_info array; the CFG exists in the edge structures
- referenced by the blocks.
-
- find_basic_blocks also finds any unreachable loops and deletes them.
-
- Available functionality:
- - CFG construction
- find_basic_blocks */
\f
#include "config.h"
#include "system.h"
#include "toplev.h"
#include "timevar.h"
-static int count_basic_blocks (const_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);
}
}
-/* Count the basic blocks of the function. */
-
-static int
-count_basic_blocks (const_rtx f)
-{
- int count = NUM_FIXED_BLOCKS;
- bool saw_insn = false;
- const_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. */
- 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;
- }
-
- if (saw_insn)
- count++;
-
- /* 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_use (const0_rtx);
- count = NUM_FIXED_BLOCKS + 1;
- }
-
- return count;
-}
\f
/* Create an edge between two basic blocks. FLAGS are auxiliary information
about the edge that is accumulated between calls. */
sbitmap_vector_free (edge_cache);
}
\f
-/* Find all basic blocks of the function whose first insn is F.
-
- Collect and return a list of labels whose addresses are taken. This
- will be used in make_edges for use with computed gotos. */
-
-static void
-find_basic_blocks_1 (rtx f)
-{
- rtx insn, next;
- rtx bb_note = 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
- closed out the previous block, so that it gets attached at the proper
- place. Since this form should be equivalent to the previous,
- count_basic_blocks continues to use the old form as a check. */
-
- for (insn = f; insn; insn = next)
- {
- enum rtx_code code = GET_CODE (insn);
-
- 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:
- /* Look for basic block notes with which to keep the
- basic_block_info pointers stable. Unthread the note now;
- we'll put it back at the right place in create_basic_block.
- Or not at all if we've already found a note in this block. */
- if (NOTE_INSN_BASIC_BLOCK_P (insn))
- {
- if (bb_note == NULL_RTX)
- bb_note = insn;
- else
- next = delete_insn (insn);
- }
- break;
-
- case CODE_LABEL:
- case JUMP_INSN:
- case CALL_INSN:
- case INSN:
- case BARRIER:
- break;
-
- default:
- gcc_unreachable ();
- }
- }
-
- if (head != NULL_RTX)
- create_basic_block_structure (head, end, bb_note, prev);
- else if (bb_note)
- delete_insn (bb_note);
-
- gcc_assert (last_basic_block == n_basic_blocks);
-
- clear_aux_for_blocks ();
-}
-
-
-/* Find basic blocks of the current function.
- F is the first insn of the function. */
-
-void
-find_basic_blocks (rtx f)
-{
- basic_block bb;
-
- timevar_push (TV_CFG);
-
- /* Flush out existing data. */
- if (basic_block_info != NULL)
- {
- 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_EACH_BB (bb)
- bb->aux = NULL;
-
- 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
- stable across calls to find_basic_blocks. */
- /* ??? This whole issue would be much simpler if we called find_basic_blocks
- exactly once, and thereafter we don't have a single long chain of
- instructions at all until close to the end of compilation when we
- actually lay them out. */
-
- basic_block_info = VEC_alloc (basic_block, gc, n_basic_blocks);
- VEC_safe_grow_cleared (basic_block, gc, basic_block_info, 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);
-
- /* Discover the edges of our cfg. */
- 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 ();
-
-#ifdef ENABLE_CHECKING
- verify_flow_info ();
-#endif
- timevar_pop (TV_CFG);
-}
-\f
static void
mark_tablejump_edge (rtx label)
{
free (lp_info);
}
-void
+/* After initial rtl generation, call back to finish generating
+ exception support code. */
+
+static void
finish_eh_generation (void)
{
basic_block bb;
if (cfun->eh->region_tree == NULL)
return;
- /* The object here is to provide find_basic_blocks with detailed
- information (via reachable_handlers) on how exception control
- flows within the function. In this first pass, we can include
- type information garnered from ERT_THROW and ERT_ALLOWED_EXCEPTIONS
- regions, and hope that it will be useful in deleting unreachable
- handlers. Subsequently, we will generate landing pads which will
- connect many of the handlers, and then type information will not
- be effective. Still, this is a win over previous implementations. */
+ /* The object here is to provide detailed information (via
+ reachable_handlers) on how exception control flows within the
+ function for the CFG construction. In this first pass, we can
+ include type information garnered from ERT_THROW and
+ ERT_ALLOWED_EXCEPTIONS regions, and hope that it will be useful
+ in deleting unreachable handlers. Subsequently, we will generate
+ landing pads which will connect many of the handlers, and then
+ type information will not be effective. Still, this is a win
+ over previous implementations. */
/* These registers are used by the landing pads. Make sure they
have been generated. */
projects / platform / upstream / gcc.git / commitdiff