1 /* This file contains the definitions and documentation for the common
2 tree codes used in the GNU C and C++ compilers (see c-common.def
3 for the standard codes).
4 Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
5 Written by Benjamin Chelf (chelf@codesourcery.com).
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 2, or (at your option) any later
14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING. If not, write to the Free
21 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
28 #include "splay-tree.h"
40 /* If non-NULL, the address of a language-specific function for
41 expanding statements. */
42 void (*lang_expand_stmt) PARAMS ((tree));
44 /* If non-NULL, the address of a language-specific function for
45 expanding a DECL_STMT. After the language-independent cases are
46 handled, this function will be called. If this function is not
47 defined, it is assumed that declarations other than those for
48 variables and labels do not require any RTL generation. */
49 void (*lang_expand_decl_stmt) PARAMS ((tree));
51 /* Create an empty statement tree rooted at T. */
57 /* We create a trivial EXPR_STMT so that last_tree is never NULL in
58 what follows. We remove the extraneous statement in
60 *t = build_nt (EXPR_STMT, void_zero_node);
62 last_expr_type = NULL_TREE;
65 /* T is a statement. Add it to the statement-tree. */
71 /* Add T to the statement-tree. */
72 TREE_CHAIN (last_tree) = t;
75 /* When we expand a statement-tree, we must know whether or not the
76 statements are full-expressions. We record that fact here. */
77 STMT_IS_FULL_EXPR_P (last_tree) = stmts_are_full_exprs_p ();
79 /* Keep track of the number of statements in this function. */
80 if (current_function_decl)
81 ++DECL_NUM_STMTS (current_function_decl);
86 /* Create a declaration statement for the declaration given by the
95 /* We need the type to last until instantiation time. */
96 decl_stmt = build_stmt (DECL_STMT, decl);
100 /* Add a scope-statement to the statement-tree. BEGIN_P indicates
101 whether this statements opens or closes a scope. PARTIAL_P is true
102 for a partial scope, i.e, the scope that begins after a label when
103 an object that needs a cleanup is created. If BEGIN_P is nonzero,
104 returns a new TREE_LIST representing the top of the SCOPE_STMT
105 stack. The TREE_PURPOSE is the new SCOPE_STMT. If BEGIN_P is
106 zero, returns a TREE_LIST whose TREE_VALUE is the new SCOPE_STMT,
107 and whose TREE_PURPOSE is the matching SCOPE_STMT with
108 SCOPE_BEGIN_P set. */
111 add_scope_stmt (begin_p, partial_p)
115 tree *stack_ptr = current_scope_stmt_stack ();
117 tree top = *stack_ptr;
119 /* Build the statement. */
120 ss = build_stmt (SCOPE_STMT, NULL_TREE);
121 SCOPE_BEGIN_P (ss) = begin_p;
122 SCOPE_PARTIAL_P (ss) = partial_p;
124 /* Keep the scope stack up to date. */
127 top = tree_cons (ss, NULL_TREE, top);
132 TREE_VALUE (top) = ss;
133 *stack_ptr = TREE_CHAIN (top);
136 /* Add the new statement to the statement-tree. */
142 /* Finish the statement tree rooted at T. */
150 /* Remove the fake extra statement added in begin_stmt_tree. */
151 stmt = TREE_CHAIN (*t);
153 last_tree = NULL_TREE;
157 /* The line-number recorded in the outermost statement in a function
158 is the line number of the end of the function. */
159 STMT_LINENO (stmt) = lineno;
160 STMT_LINENO_FOR_FN_P (stmt) = 1;
164 /* Build a generic statement based on the given type of node and
165 arguments. Similar to `build_nt', except that we set
166 STMT_LINENO to be the current line number. */
167 /* ??? This should be obsolete with the lineno_stmt productions
171 build_stmt VPARAMS ((enum tree_code code, ...))
178 VA_FIXEDARG (p, enum tree_code, code);
180 t = make_node (code);
181 length = TREE_CODE_LENGTH (code);
182 STMT_LINENO (t) = lineno;
184 for (i = 0; i < length; i++)
185 TREE_OPERAND (t, i) = va_arg (p, tree);
191 /* Some statements, like for-statements or if-statements, require a
192 condition. This condition can be a declaration. If T is such a
193 declaration it is processed, and an expression appropriate to use
194 as the condition is returned. Otherwise, T itself is returned. */
200 if (t && TREE_CODE (t) == TREE_LIST)
202 expand_stmt (TREE_PURPOSE (t));
203 return TREE_VALUE (t);
209 /* Create RTL for the local static variable DECL. */
212 make_rtl_for_local_static (decl)
215 const char *asmspec = NULL;
217 /* If we inlined this variable, we could see it's declaration
219 if (TREE_ASM_WRITTEN (decl))
222 /* If the DECL_ASSEMBLER_NAME is not the same as the DECL_NAME, then
223 either we already created RTL for this DECL (and since it was a
224 local variable, its DECL_ASSEMBLER_NAME got hacked up to prevent
225 clashes with other local statics with the same name by a previous
226 call to make_decl_rtl), or the user explicitly requested a
227 particular assembly name for this variable, using the GNU
228 extension for this purpose:
232 There's no way to know which case we're in, here. But, it turns
233 out we're safe. If there's already RTL, then
234 rest_of_decl_compilation ignores the ASMSPEC parameter, so we
235 may as well not pass it in. If there isn't RTL, then we didn't
236 already create RTL, which means that the modification to
237 DECL_ASSEMBLER_NAME came only via the explicit extension. */
238 if (DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl)
239 && !DECL_RTL_SET_P (decl))
240 asmspec = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
242 rest_of_decl_compilation (decl, asmspec, /*top_level=*/0, /*at_end=*/0);
245 /* Let the back-end know about DECL. */
248 emit_local_var (decl)
251 /* Create RTL for this variable. */
252 if (!DECL_RTL_SET_P (decl))
254 if (DECL_C_HARD_REGISTER (decl))
255 /* The user specified an assembler name for this variable.
257 rest_of_decl_compilation
258 (decl, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)),
259 /*top_level=*/0, /*at_end=*/0);
264 /* Actually do the initialization. */
265 if (stmts_are_full_exprs_p ())
266 expand_start_target_temps ();
268 expand_decl_init (decl);
270 if (stmts_are_full_exprs_p ())
271 expand_end_target_temps ();
274 /* Helper for generating the RTL at the beginning of a scope. */
277 genrtl_do_pushlevel ()
279 emit_line_note (input_filename, lineno);
283 /* Generate the RTL for DESTINATION, which is a GOTO_STMT. */
286 genrtl_goto_stmt (destination)
289 if (TREE_CODE (destination) == IDENTIFIER_NODE)
292 /* We warn about unused labels with -Wunused. That means we have to
293 mark the used labels as used. */
294 if (TREE_CODE (destination) == LABEL_DECL)
295 TREE_USED (destination) = 1;
297 emit_line_note (input_filename, lineno);
299 if (TREE_CODE (destination) == LABEL_DECL)
301 label_rtx (destination);
302 expand_goto (destination);
305 expand_computed_goto (destination);
308 /* Generate the RTL for EXPR, which is an EXPR_STMT. Provided just
309 for backward compatibility. genrtl_expr_stmt_value() should be
310 used for new code. */
313 genrtl_expr_stmt (expr)
316 genrtl_expr_stmt_value (expr, -1, 1);
319 /* Generate the RTL for EXPR, which is an EXPR_STMT. WANT_VALUE tells
320 whether to (1) save the value of the expression, (0) discard it or
321 (-1) use expr_stmts_for_value to tell. The use of -1 is
322 deprecated, and retained only for backward compatibility.
323 MAYBE_LAST is non-zero if this EXPR_STMT might be the last statement
324 in expression statement. */
327 genrtl_expr_stmt_value (expr, want_value, maybe_last)
329 int want_value, maybe_last;
331 if (expr != NULL_TREE)
333 emit_line_note (input_filename, lineno);
335 if (stmts_are_full_exprs_p ())
336 expand_start_target_temps ();
338 if (expr != error_mark_node)
339 expand_expr_stmt_value (expr, want_value, maybe_last);
341 if (stmts_are_full_exprs_p ())
342 expand_end_target_temps ();
346 /* Generate the RTL for T, which is a DECL_STMT. */
353 emit_line_note (input_filename, lineno);
354 decl = DECL_STMT_DECL (t);
355 /* If this is a declaration for an automatic local
356 variable, initialize it. Note that we might also see a
357 declaration for a namespace-scope object (declared with
358 `extern'). We don't have to handle the initialization
359 of those objects here; they can only be declarations,
360 rather than definitions. */
361 if (TREE_CODE (decl) == VAR_DECL
362 && !TREE_STATIC (decl)
363 && !DECL_EXTERNAL (decl))
365 /* Let the back-end know about this variable. */
366 if (!anon_aggr_type_p (TREE_TYPE (decl)))
367 emit_local_var (decl);
369 expand_anon_union_decl (decl, NULL_TREE,
370 DECL_ANON_UNION_ELEMS (decl));
372 else if (TREE_CODE (decl) == VAR_DECL && TREE_STATIC (decl))
373 make_rtl_for_local_static (decl);
374 else if (TREE_CODE (decl) == LABEL_DECL
375 && C_DECLARED_LABEL_FLAG (decl))
376 declare_nonlocal_label (decl);
377 else if (lang_expand_decl_stmt)
378 (*lang_expand_decl_stmt) (t);
381 /* Generate the RTL for T, which is an IF_STMT. */
388 genrtl_do_pushlevel ();
389 cond = expand_cond (IF_COND (t));
390 emit_line_note (input_filename, lineno);
391 expand_start_cond (cond, 0);
393 expand_stmt (THEN_CLAUSE (t));
396 expand_start_else ();
397 expand_stmt (ELSE_CLAUSE (t));
402 /* Generate the RTL for T, which is a WHILE_STMT. */
405 genrtl_while_stmt (t)
410 emit_line_note (input_filename, lineno);
411 expand_start_loop (1);
412 genrtl_do_pushlevel ();
414 cond = expand_cond (WHILE_COND (t));
415 emit_line_note (input_filename, lineno);
416 expand_exit_loop_if_false (0, cond);
417 genrtl_do_pushlevel ();
419 expand_stmt (WHILE_BODY (t));
424 /* Generate the RTL for T, which is a DO_STMT. */
430 tree cond = DO_COND (t);
432 /* Recognize the common special-case of do { ... } while (0) and do
433 not emit the loop widgetry in this case. In particular this
434 avoids cluttering the rtl with dummy loop notes, which can affect
435 alignment of adjacent labels. */
436 if (integer_zerop (cond))
438 expand_start_null_loop ();
439 expand_stmt (DO_BODY (t));
440 expand_end_null_loop ();
445 emit_line_note (input_filename, lineno);
446 expand_start_loop_continue_elsewhere (1);
448 expand_stmt (DO_BODY (t));
450 expand_loop_continue_here ();
451 cond = expand_cond (cond);
452 emit_line_note (input_filename, lineno);
453 expand_exit_loop_if_false (0, cond);
458 /* Build the node for a return statement and return it. */
461 build_return_stmt (expr)
464 return (build_stmt (RETURN_STMT, expr));
467 /* Generate the RTL for STMT, which is a RETURN_STMT. */
470 genrtl_return_stmt (stmt)
475 expr = RETURN_EXPR (stmt);
477 emit_line_note (input_filename, lineno);
479 expand_null_return ();
482 expand_start_target_temps ();
483 expand_return (expr);
484 expand_end_target_temps ();
488 /* Generate the RTL for T, which is a FOR_STMT. */
495 const char *saved_filename;
498 if (NEW_FOR_SCOPE_P (t))
499 genrtl_do_pushlevel ();
501 expand_stmt (FOR_INIT_STMT (t));
503 /* Expand the initialization. */
505 emit_line_note (input_filename, lineno);
506 expand_start_loop_continue_elsewhere (1);
507 genrtl_do_pushlevel ();
508 cond = expand_cond (FOR_COND (t));
510 /* Save the filename and line number so that we expand the FOR_EXPR
511 we can reset them back to the saved values. */
512 saved_filename = input_filename;
513 saved_lineno = lineno;
515 /* Expand the condition. */
516 emit_line_note (input_filename, lineno);
518 expand_exit_loop_if_false (0, cond);
520 /* Expand the body. */
521 genrtl_do_pushlevel ();
522 expand_stmt (FOR_BODY (t));
524 /* Expand the increment expression. */
525 input_filename = saved_filename;
526 lineno = saved_lineno;
527 emit_line_note (input_filename, lineno);
528 expand_loop_continue_here ();
530 genrtl_expr_stmt (FOR_EXPR (t));
534 /* Build a break statement node and return it. */
539 return (build_stmt (BREAK_STMT));
542 /* Generate the RTL for a BREAK_STMT. */
547 emit_line_note (input_filename, lineno);
548 if ( ! expand_exit_something ())
549 error ("break statement not within loop or switch");
552 /* Build a continue statement node and return it. */
555 build_continue_stmt ()
557 return (build_stmt (CONTINUE_STMT));
560 /* Generate the RTL for a CONTINUE_STMT. */
563 genrtl_continue_stmt ()
565 emit_line_note (input_filename, lineno);
566 if (! expand_continue_loop (0))
567 error ("continue statement not within a loop");
570 /* Generate the RTL for T, which is a SCOPE_STMT. */
573 genrtl_scope_stmt (t)
576 tree block = SCOPE_STMT_BLOCK (t);
578 if (!SCOPE_NO_CLEANUPS_P (t))
580 if (SCOPE_BEGIN_P (t))
581 expand_start_bindings_and_block (2 * SCOPE_NULLIFIED_P (t), block);
582 else if (SCOPE_END_P (t))
583 expand_end_bindings (NULL_TREE, !SCOPE_NULLIFIED_P (t), 0);
585 else if (!SCOPE_NULLIFIED_P (t))
587 rtx note = emit_note (NULL,
589 ? NOTE_INSN_BLOCK_BEG
590 : NOTE_INSN_BLOCK_END));
591 NOTE_BLOCK (note) = block;
594 /* If we're at the end of a scope that contains inlined nested
595 functions, we have to decide whether or not to write them out. */
596 if (block && SCOPE_END_P (t))
600 for (fn = BLOCK_VARS (block); fn; fn = TREE_CHAIN (fn))
602 if (TREE_CODE (fn) == FUNCTION_DECL
603 && DECL_CONTEXT (fn) == current_function_decl
604 && !TREE_ASM_WRITTEN (fn)
605 && TREE_ADDRESSABLE (fn))
607 push_function_context ();
608 output_inline_function (fn);
609 pop_function_context ();
615 /* Generate the RTL for T, which is a SWITCH_STMT. */
618 genrtl_switch_stmt (t)
622 genrtl_do_pushlevel ();
624 cond = expand_cond (SWITCH_COND (t));
625 if (cond == error_mark_node)
626 /* The code is in error, but we don't want expand_end_case to
628 cond = boolean_false_node;
630 emit_line_note (input_filename, lineno);
631 expand_start_case (1, cond, TREE_TYPE (cond), "switch statement");
632 expand_stmt (SWITCH_BODY (t));
633 expand_end_case (cond);
636 /* Create a CASE_LABEL tree node and return it. */
639 build_case_label (low_value, high_value, label_decl)
644 return build_stmt (CASE_LABEL, low_value, high_value, label_decl);
648 /* Generate the RTL for a CASE_LABEL. */
651 genrtl_case_label (case_label)
657 cleanup = last_cleanup_this_contour ();
660 static int explained = 0;
661 warning_with_decl (TREE_PURPOSE (cleanup),
662 "destructor needed for `%#D'");
663 warning ("where case label appears here");
666 warning ("(enclose actions of previous case statements requiring destructors in their own scope.)");
671 add_case_node (CASE_LOW (case_label), CASE_HIGH (case_label),
672 CASE_LABEL_DECL (case_label), &duplicate);
675 /* Generate the RTL for T, which is a COMPOUND_STMT. */
678 genrtl_compound_stmt (t)
681 #ifdef ENABLE_CHECKING
682 struct nesting *n = current_nesting_level ();
685 expand_stmt (COMPOUND_BODY (t));
687 #ifdef ENABLE_CHECKING
688 /* Make sure that we've pushed and popped the same number of levels. */
689 if (n != current_nesting_level ())
694 /* Generate the RTL for an ASM_STMT. */
697 genrtl_asm_stmt (cv_qualifier, string, output_operands,
698 input_operands, clobbers, asm_input_p)
701 tree output_operands;
706 if (cv_qualifier != NULL_TREE
707 && cv_qualifier != ridpointers[(int) RID_VOLATILE])
709 warning ("%s qualifier ignored on asm",
710 IDENTIFIER_POINTER (cv_qualifier));
711 cv_qualifier = NULL_TREE;
714 emit_line_note (input_filename, lineno);
718 c_expand_asm_operands (string, output_operands, input_operands,
719 clobbers, cv_qualifier != NULL_TREE,
720 input_filename, lineno);
723 /* Generate the RTL for a DECL_CLEANUP. */
726 genrtl_decl_cleanup (decl, cleanup)
730 if (!decl || (DECL_SIZE (decl) && TREE_TYPE (decl) != error_mark_node))
731 expand_decl_cleanup (decl, cleanup);
734 /* We're about to expand T, a statement. Set up appropriate context
735 for the substitution. */
741 if (!STMT_LINENO_FOR_FN_P (t))
742 lineno = STMT_LINENO (t);
743 current_stmt_tree ()->stmts_are_full_exprs_p = STMT_IS_FULL_EXPR_P (t);
746 /* Generate the RTL for the statement T, its substatements, and any
747 other statements at its nesting level. */
753 while (t && t != error_mark_node)
755 int saved_stmts_are_full_exprs_p;
757 /* Set up context appropriately for handling this statement. */
758 saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p ();
761 switch (TREE_CODE (t))
764 genrtl_return_stmt (t);
768 genrtl_expr_stmt_value (EXPR_STMT_EXPR (t), TREE_ADDRESSABLE (t),
769 TREE_CHAIN (t) == NULL
770 || (TREE_CODE (TREE_CHAIN (t)) == SCOPE_STMT
771 && TREE_CHAIN (TREE_CHAIN (t)) == NULL));
775 genrtl_decl_stmt (t);
783 genrtl_while_stmt (t);
795 genrtl_compound_stmt (t);
799 genrtl_break_stmt ();
803 genrtl_continue_stmt ();
807 genrtl_switch_stmt (t);
811 genrtl_case_label (t);
815 expand_label (LABEL_STMT_LABEL (t));
819 genrtl_goto_stmt (GOTO_DESTINATION (t));
823 genrtl_asm_stmt (ASM_CV_QUAL (t), ASM_STRING (t),
824 ASM_OUTPUTS (t), ASM_INPUTS (t),
825 ASM_CLOBBERS (t), ASM_INPUT_P (t));
829 genrtl_scope_stmt (t);
833 if (lang_expand_stmt)
834 (*lang_expand_stmt) (t);
840 /* Restore saved state. */
841 current_stmt_tree ()->stmts_are_full_exprs_p
842 = saved_stmts_are_full_exprs_p;
844 /* Go on to the next statement in this scope. */