/* C++-specific tree lowering bits; see also c-gimplify.c and tree-gimple.c.
- Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
Contributed by Jason Merrill <jason@redhat.com>
This file is part of GCC.
#include "hashtab.h"
#include "pointer-set.h"
+/* Local declarations. */
+
+enum bc_t { bc_break = 0, bc_continue = 1 };
+
+static struct cp_gimplify_ctx
+{
+ /* Stack of labels which are targets for "break" or "continue",
+ linked through TREE_CHAIN. */
+ tree current_label[2];
+} *ctxp;
+
+static void
+push_context (void)
+{
+ gcc_assert (!ctxp);
+ ctxp = ((struct cp_gimplify_ctx *)
+ xcalloc (1, sizeof (struct cp_gimplify_ctx)));
+}
+
+static void
+pop_context (void)
+{
+ gcc_assert (ctxp
+ && !ctxp->current_label[0]
+ && !ctxp->current_label[1]);
+ free (ctxp);
+ ctxp = NULL;
+}
+
+/* Begin a scope which can be exited by a break or continue statement. BC
+ indicates which.
+
+ Just creates a label and pushes it into the current context. */
+
+static tree
+begin_bc_block (enum bc_t bc)
+{
+ tree label = create_artificial_label ();
+ TREE_CHAIN (label) = ctxp->current_label[bc];
+ ctxp->current_label[bc] = label;
+ return label;
+}
+
+/* Finish a scope which can be exited by a break or continue statement.
+ LABEL was returned from the most recent call to begin_bc_block. BODY is
+ an expression for the contents of the scope.
+
+ If we saw a break (or continue) in the scope, append a LABEL_EXPR to
+ body. Otherwise, just forget the label. */
+
+static tree
+finish_bc_block (enum bc_t bc, tree label, tree body)
+{
+ gcc_assert (label == ctxp->current_label[bc]);
+
+ if (TREE_USED (label))
+ {
+ tree t, sl = NULL;
+
+ t = build1 (LABEL_EXPR, void_type_node, label);
+
+ append_to_statement_list (body, &sl);
+ append_to_statement_list (t, &sl);
+ body = sl;
+ }
+
+ ctxp->current_label[bc] = TREE_CHAIN (label);
+ TREE_CHAIN (label) = NULL_TREE;
+ return body;
+}
+
+/* Build a GOTO_EXPR to represent a break or continue statement. BC
+ indicates which. */
+
+static tree
+build_bc_goto (enum bc_t bc)
+{
+ tree label = ctxp->current_label[bc];
+
+ if (label == NULL_TREE)
+ {
+ if (bc == bc_break)
+ error ("break statement not within loop or switch");
+ else
+ error ("continue statement not within loop or switch");
+
+ return NULL_TREE;
+ }
+
+ /* Mark the label used for finish_bc_block. */
+ TREE_USED (label) = 1;
+ return build1 (GOTO_EXPR, void_type_node, label);
+}
+
/* Genericize a TRY_BLOCK. */
static void
*stmt_p = stmt;
}
+/* Build a generic representation of one of the C loop forms. COND is the
+ loop condition or NULL_TREE. BODY is the (possibly compound) statement
+ controlled by the loop. INCR is the increment expression of a for-loop,
+ or NULL_TREE. COND_IS_FIRST indicates whether the condition is
+ evaluated before the loop body as in while and for loops, or after the
+ loop body as in do-while loops. */
+
+static tree
+gimplify_cp_loop (tree cond, tree body, tree incr, bool cond_is_first)
+{
+ tree top, entry, exit, cont_block, break_block, stmt_list, t;
+ location_t stmt_locus;
+
+ stmt_locus = input_location;
+ stmt_list = NULL_TREE;
+ entry = NULL_TREE;
+
+ break_block = begin_bc_block (bc_break);
+ cont_block = begin_bc_block (bc_continue);
+
+ /* If condition is zero don't generate a loop construct. */
+ if (cond && integer_zerop (cond))
+ {
+ top = NULL_TREE;
+ exit = NULL_TREE;
+ if (cond_is_first)
+ {
+ t = build_bc_goto (bc_break);
+ append_to_statement_list (t, &stmt_list);
+ }
+ }
+ else
+ {
+ /* If we use a LOOP_EXPR here, we have to feed the whole thing
+ back through the main gimplifier to lower it. Given that we
+ have to gimplify the loop body NOW so that we can resolve
+ break/continue stmts, seems easier to just expand to gotos. */
+ top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
+
+ /* If we have an exit condition, then we build an IF with gotos either
+ out of the loop, or to the top of it. If there's no exit condition,
+ then we just build a jump back to the top. */
+ exit = build_and_jump (&LABEL_EXPR_LABEL (top));
+ if (cond && !integer_nonzerop (cond))
+ {
+ t = build_bc_goto (bc_break);
+ exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
+ exit = fold (exit);
+ gimplify_stmt (&exit);
+
+ if (cond_is_first)
+ {
+ if (incr)
+ {
+ entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
+ t = build_and_jump (&LABEL_EXPR_LABEL (entry));
+ }
+ else
+ t = build_bc_goto (bc_continue);
+ append_to_statement_list (t, &stmt_list);
+ }
+ }
+ }
+
+ gimplify_stmt (&body);
+ gimplify_stmt (&incr);
+
+ body = finish_bc_block (bc_continue, cont_block, body);
+
+ append_to_statement_list (top, &stmt_list);
+ append_to_statement_list (body, &stmt_list);
+ append_to_statement_list (incr, &stmt_list);
+ append_to_statement_list (entry, &stmt_list);
+ append_to_statement_list (exit, &stmt_list);
+
+ annotate_all_with_locus (&stmt_list, stmt_locus);
+
+ return finish_bc_block (bc_break, break_block, stmt_list);
+}
+
+/* Gimplify a FOR_STMT node. Move the stuff in the for-init-stmt into the
+ prequeue and hand off to gimplify_cp_loop. */
+
+static void
+gimplify_for_stmt (tree *stmt_p, tree *pre_p)
+{
+ tree stmt = *stmt_p;
+
+ if (FOR_INIT_STMT (stmt))
+ gimplify_and_add (FOR_INIT_STMT (stmt), pre_p);
+
+ *stmt_p = gimplify_cp_loop (FOR_COND (stmt), FOR_BODY (stmt),
+ FOR_EXPR (stmt), 1);
+}
+
+/* Gimplify a WHILE_STMT node. */
+
+static void
+gimplify_while_stmt (tree *stmt_p)
+{
+ tree stmt = *stmt_p;
+ *stmt_p = gimplify_cp_loop (WHILE_COND (stmt), WHILE_BODY (stmt),
+ NULL_TREE, 1);
+}
+
+/* Gimplify a DO_STMT node. */
+
+static void
+gimplify_do_stmt (tree *stmt_p)
+{
+ tree stmt = *stmt_p;
+ *stmt_p = gimplify_cp_loop (DO_COND (stmt), DO_BODY (stmt),
+ NULL_TREE, 0);
+}
+
+/* Genericize a SWITCH_STMT by turning it into a SWITCH_EXPR. */
+
+static void
+gimplify_switch_stmt (tree *stmt_p)
+{
+ tree stmt = *stmt_p;
+ tree break_block, body;
+ location_t stmt_locus = input_location;
+
+ break_block = begin_bc_block (bc_break);
+
+ body = SWITCH_STMT_BODY (stmt);
+ if (!body)
+ body = build_empty_stmt ();
+
+ *stmt_p = build3 (SWITCH_EXPR, SWITCH_STMT_TYPE (stmt),
+ SWITCH_STMT_COND (stmt), body, NULL_TREE);
+ SET_EXPR_LOCATION (*stmt_p, stmt_locus);
+ gimplify_stmt (stmt_p);
+
+ *stmt_p = finish_bc_block (bc_break, break_block, *stmt_p);
+}
+
/* Gimplify initialization from an AGGR_INIT_EXPR. */
static void
ret = GS_OK;
break;
+ case FOR_STMT:
+ gimplify_for_stmt (expr_p, pre_p);
+ ret = GS_ALL_DONE;
+ break;
+
+ case WHILE_STMT:
+ gimplify_while_stmt (expr_p);
+ ret = GS_ALL_DONE;
+ break;
+
+ case DO_STMT:
+ gimplify_do_stmt (expr_p);
+ ret = GS_ALL_DONE;
+ break;
+
+ case SWITCH_STMT:
+ gimplify_switch_stmt (expr_p);
+ ret = GS_ALL_DONE;
+ break;
+
+ case CONTINUE_STMT:
+ *expr_p = build_bc_goto (bc_continue);
+ ret = GS_ALL_DONE;
+ break;
+
+ case BREAK_STMT:
+ *expr_p = build_bc_goto (bc_break);
+ ret = GS_ALL_DONE;
+ break;
+
default:
ret = c_gimplify_expr (expr_p, pre_p, post_p);
break;
pointer_set_destroy (p_set);
/* Do everything else. */
+ push_context ();
c_genericize (fndecl);
+ pop_context ();
}
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