+ /* The GIMPLE_BIND no longer carries any useful information -- kill it. */
+ gsi_insert_seq_before (gsi, gimple_bind_body (stmt), GSI_SAME_STMT);
+ gsi_remove (gsi, false);
+}
+
+/* Try to determine whether a TRY_CATCH expression can fall through.
+ This is a subroutine of block_may_fallthru. */
+
+static bool
+try_catch_may_fallthru (const_tree stmt)
+{
+ tree_stmt_iterator i;
+
+ /* If the TRY block can fall through, the whole TRY_CATCH can
+ fall through. */
+ if (block_may_fallthru (TREE_OPERAND (stmt, 0)))
+ return true;
+
+ i = tsi_start (TREE_OPERAND (stmt, 1));
+ switch (TREE_CODE (tsi_stmt (i)))
+ {
+ case CATCH_EXPR:
+ /* We expect to see a sequence of CATCH_EXPR trees, each with a
+ catch expression and a body. The whole TRY_CATCH may fall
+ through iff any of the catch bodies falls through. */
+ for (; !tsi_end_p (i); tsi_next (&i))
+ {
+ if (block_may_fallthru (CATCH_BODY (tsi_stmt (i))))
+ return true;
+ }
+ return false;
+
+ case EH_FILTER_EXPR:
+ /* The exception filter expression only matters if there is an
+ exception. If the exception does not match EH_FILTER_TYPES,
+ we will execute EH_FILTER_FAILURE, and we will fall through
+ if that falls through. If the exception does match
+ EH_FILTER_TYPES, the stack unwinder will continue up the
+ stack, so we will not fall through. We don't know whether we
+ will throw an exception which matches EH_FILTER_TYPES or not,
+ so we just ignore EH_FILTER_TYPES and assume that we might
+ throw an exception which doesn't match. */
+ return block_may_fallthru (EH_FILTER_FAILURE (tsi_stmt (i)));
+
+ default:
+ /* This case represents statements to be executed when an
+ exception occurs. Those statements are implicitly followed
+ by a RESX statement to resume execution after the exception.
+ So in this case the TRY_CATCH never falls through. */
+ return false;
+ }
+}
+
+
+/* Same as above, but for a GIMPLE_TRY_CATCH. */
+
+static bool
+gimple_try_catch_may_fallthru (gimple stmt)
+{
+ gimple_stmt_iterator i;
+
+ /* We don't handle GIMPLE_TRY_FINALLY. */
+ gcc_assert (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH);
+
+ /* If the TRY block can fall through, the whole TRY_CATCH can
+ fall through. */
+ if (gimple_seq_may_fallthru (gimple_try_eval (stmt)))
+ return true;
+
+ i = gsi_start (gimple_try_cleanup (stmt));
+ switch (gimple_code (gsi_stmt (i)))
+ {
+ case GIMPLE_CATCH:
+ /* We expect to see a sequence of GIMPLE_CATCH stmts, each with a
+ catch expression and a body. The whole try/catch may fall
+ through iff any of the catch bodies falls through. */
+ for (; !gsi_end_p (i); gsi_next (&i))
+ {
+ if (gimple_seq_may_fallthru (gimple_catch_handler (gsi_stmt (i))))
+ return true;
+ }
+ return false;
+
+ case GIMPLE_EH_FILTER:
+ /* The exception filter expression only matters if there is an
+ exception. If the exception does not match EH_FILTER_TYPES,
+ we will execute EH_FILTER_FAILURE, and we will fall through
+ if that falls through. If the exception does match
+ EH_FILTER_TYPES, the stack unwinder will continue up the
+ stack, so we will not fall through. We don't know whether we
+ will throw an exception which matches EH_FILTER_TYPES or not,
+ so we just ignore EH_FILTER_TYPES and assume that we might
+ throw an exception which doesn't match. */
+ return gimple_seq_may_fallthru (gimple_eh_filter_failure (gsi_stmt (i)));
+
+ default:
+ /* This case represents statements to be executed when an
+ exception occurs. Those statements are implicitly followed
+ by a GIMPLE_RESX to resume execution after the exception. So
+ in this case the try/catch never falls through. */
+ return false;
+ }
OSDN Git Service
