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 Free Software Foundation, Inc. Written by
5 Benjamin Chelf (chelf@codesourcery.com).
7 This file is part of GNU CC.
9 GNU CC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2, or (at your option)
14 GNU CC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GNU CC; see the file COPYING. If not, write to
21 the Free Software Foundation, 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
28 #include "splay-tree.h"
39 /* If non-NULL, the address of a language-specific function for
40 expanding statements. */
41 void (*lang_expand_stmt) PARAMS ((tree));
43 /* If non-NULL, the address of a language-specific function for
44 expanding a DECL_STMT. After the language-independent cases are
45 handled, this function will be called. If this function is not
46 defined, it is assumed that declarations other than those for
47 variables and labels do not require any RTL generation. */
48 void (*lang_expand_decl_stmt) PARAMS ((tree));
50 static tree prune_unused_decls PARAMS ((tree *, int *, void *));
52 /* Create an empty statement tree rooted at T. */
58 /* We create a trivial EXPR_STMT so that last_tree is never NULL in
59 what follows. We remove the extraneous statement in
61 *t = build_nt (EXPR_STMT, void_zero_node);
63 last_expr_type = NULL_TREE;
66 /* T is a statement. Add it to the statement-tree. */
72 /* Add T to the statement-tree. */
73 TREE_CHAIN (last_tree) = t;
75 /* When we expand a statement-tree, we must know whether or not the
76 statements are full-expresions. We record that fact here. */
77 STMT_IS_FULL_EXPR_P (last_tree) = stmts_are_full_exprs_p ();
81 /* Create a declaration statement for the declaration given by the
90 /* We need the type to last until instantiation time. */
91 decl_stmt = build_stmt (DECL_STMT, decl);
95 /* Add a scope-statement to the statement-tree. BEGIN_P indicates
96 whether this statements opens or closes a scope. PARTIAL_P is true
97 for a partial scope, i.e, the scope that begins after a label when
98 an object that needs a cleanup is created. If BEGIN_P is nonzero,
99 returns a new TREE_LIST representing the top of the SCOPE_STMT
100 stack. The TREE_PURPOSE is the new SCOPE_STMT. If BEGIN_P is
101 zero, returns a TREE_LIST whose TREE_VALUE is the new SCOPE_STMT,
102 and whose TREE_PURPOSE is the matching SCOPE_STMT iwth
103 SCOPE_BEGIN_P set. */
106 add_scope_stmt (begin_p, partial_p)
113 /* Build the statement. */
114 ss = build_stmt (SCOPE_STMT, NULL_TREE);
115 SCOPE_BEGIN_P (ss) = begin_p;
116 SCOPE_PARTIAL_P (ss) = partial_p;
118 /* Keep the scope stack up to date. */
121 *current_scope_stmt_stack ()
122 = tree_cons (ss, NULL_TREE, *current_scope_stmt_stack ());
123 top = *current_scope_stmt_stack ();
127 top = *current_scope_stmt_stack ();
128 TREE_VALUE (top) = ss;
129 *current_scope_stmt_stack () = TREE_CHAIN (top);
132 /* Add the new statement to the statement-tree. */
138 /* Remove declarations of internal variables that are not used from a
139 stmt tree. To qualify, the variable must have a name and must have
140 a zero DECL_SOURCE_LINE. We tried to remove all variables for
141 which TREE_USED was false, but it turns out that there's tons of
142 variables for which TREE_USED is false but that are still in fact
146 prune_unused_decls (tp, walk_subtrees, data)
148 int *walk_subtrees ATTRIBUTE_UNUSED;
149 void *data ATTRIBUTE_UNUSED;
159 if (TREE_CODE (t) == DECL_STMT)
161 tree d = DECL_STMT_DECL (t);
162 if (!TREE_USED (d) && DECL_NAME (d) && DECL_SOURCE_LINE (d) == 0)
164 *tp = TREE_CHAIN (t);
165 /* Recurse on the new value of tp, otherwise we will skip
166 the next statement. */
167 return prune_unused_decls (tp, walk_subtrees, data);
170 else if (TREE_CODE (t) == SCOPE_STMT)
172 /* Remove all unused decls from the BLOCK of this SCOPE_STMT. */
173 tree block = SCOPE_STMT_BLOCK (t);
179 for (vp = &BLOCK_VARS (block); *vp; )
182 if (! TREE_USED (v) && DECL_NAME (v) && DECL_SOURCE_LINE (v) == 0)
183 *vp = TREE_CHAIN (v); /* drop */
185 vp = &TREE_CHAIN (v); /* advance */
187 /* If there are now no variables, the entire BLOCK can be dropped.
188 (This causes SCOPE_NULLIFIED_P (t) to be true.) */
189 if (BLOCK_VARS (block) == NULL_TREE)
190 SCOPE_STMT_BLOCK (t) = NULL_TREE;
196 /* Finish the statement tree rooted at T. */
204 /* Remove the fake extra statement added in begin_stmt_tree. */
205 stmt = TREE_CHAIN (*t);
207 last_tree = NULL_TREE;
209 /* Remove unused decls from the stmt tree. */
210 walk_stmt_tree (t, prune_unused_decls, NULL);
214 /* The line-number recorded in the outermost statement in a function
215 is the line number of the end of the function. */
216 STMT_LINENO (stmt) = lineno;
217 STMT_LINENO_FOR_FN_P (stmt) = 1;
221 /* Build a generic statement based on the given type of node and
222 arguments. Similar to `build_nt', except that we set
223 TREE_COMPLEXITY to be the current line number. */
226 build_stmt VPARAMS ((enum tree_code code, ...))
228 #ifndef ANSI_PROTOTYPES
238 #ifndef ANSI_PROTOTYPES
239 code = va_arg (p, enum tree_code);
242 t = make_node (code);
243 length = TREE_CODE_LENGTH (code);
244 TREE_COMPLEXITY (t) = lineno;
246 for (i = 0; i < length; i++)
247 TREE_OPERAND (t, i) = va_arg (p, tree);
253 /* Some statements, like for-statements or if-statements, require a
254 condition. This condition can be a declaration. If T is such a
255 declaration it is processed, and an expression appropriate to use
256 as the condition is returned. Otherwise, T itself is returned. */
262 if (t && TREE_CODE (t) == TREE_LIST)
264 expand_stmt (TREE_PURPOSE (t));
265 return TREE_VALUE (t);
271 /* Create RTL for the local static variable DECL. */
274 make_rtl_for_local_static (decl)
277 const char *asmspec = NULL;
279 /* If we inlined this variable, we could see it's declaration
281 if (TREE_ASM_WRITTEN (decl))
284 if (DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl))
286 /* The only way this situaton can occur is if the
287 user specified a name for this DECL using the
288 `attribute' syntax. */
289 asmspec = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
290 DECL_ASSEMBLER_NAME (decl) = DECL_NAME (decl);
293 rest_of_decl_compilation (decl, asmspec, /*top_level=*/0, /*at_end=*/0);
296 /* Let the back-end know about DECL. */
299 emit_local_var (decl)
302 /* Create RTL for this variable. */
303 if (!DECL_RTL (decl))
305 if (DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl))
306 /* The user must have specified an assembler name for this
307 variable. Set that up now. */
308 rest_of_decl_compilation
309 (decl, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)),
310 /*top_level=*/0, /*at_end=*/0);
315 /* Actually do the initialization. */
316 if (stmts_are_full_exprs_p ())
317 expand_start_target_temps ();
319 expand_decl_init (decl);
321 if (stmts_are_full_exprs_p ())
322 expand_end_target_temps ();
325 /* Helper for generating the RTL at the beginning of a scope. */
328 genrtl_do_pushlevel ()
330 emit_line_note (input_filename, lineno);
334 /* Generate the RTL for DESTINATION, which is a GOTO_STMT. */
337 genrtl_goto_stmt (destination)
340 if (TREE_CODE (destination) == IDENTIFIER_NODE)
343 /* We warn about unused labels with -Wunused. That means we have to
344 mark the used labels as used. */
345 if (TREE_CODE (destination) == LABEL_DECL)
346 TREE_USED (destination) = 1;
348 emit_line_note (input_filename, lineno);
350 if (TREE_CODE (destination) == LABEL_DECL)
352 label_rtx (destination);
353 expand_goto (destination);
356 expand_computed_goto (destination);
359 /* Generate the RTL for EXPR, which is an EXPR_STMT. */
362 genrtl_expr_stmt (expr)
365 if (expr != NULL_TREE)
367 emit_line_note (input_filename, lineno);
369 if (stmts_are_full_exprs_p ())
370 expand_start_target_temps ();
372 if (expr != error_mark_node)
373 expand_expr_stmt (expr);
375 if (stmts_are_full_exprs_p ())
376 expand_end_target_temps ();
380 /* Generate the RTL for T, which is a DECL_STMT. */
387 emit_line_note (input_filename, lineno);
388 decl = DECL_STMT_DECL (t);
389 /* If this is a declaration for an automatic local
390 variable, initialize it. Note that we might also see a
391 declaration for a namespace-scope object (declared with
392 `extern'). We don't have to handle the initialization
393 of those objects here; they can only be declarations,
394 rather than definitions. */
395 if (TREE_CODE (decl) == VAR_DECL
396 && !TREE_STATIC (decl)
397 && !DECL_EXTERNAL (decl))
399 /* Let the back-end know about this variable. */
400 if (!anon_aggr_type_p (TREE_TYPE (decl)))
401 emit_local_var (decl);
403 expand_anon_union_decl (decl, NULL_TREE,
404 DECL_ANON_UNION_ELEMS (decl));
406 else if (TREE_CODE (decl) == VAR_DECL && TREE_STATIC (decl))
408 if (DECL_ARTIFICIAL (decl) && ! TREE_USED (decl))
409 /* Do not emit unused decls. This is not just an
410 optimization. We really do not want to emit
411 __PRETTY_FUNCTION__ etc, if they're never used. */
412 DECL_IGNORED_P (decl) = 1;
414 make_rtl_for_local_static (decl);
416 else if (TREE_CODE (decl) == LABEL_DECL
417 && C_DECLARED_LABEL_FLAG (decl))
418 declare_nonlocal_label (decl);
419 else if (lang_expand_decl_stmt)
420 (*lang_expand_decl_stmt) (t);
423 /* Generate the RTL for T, which is an IF_STMT. */
430 genrtl_do_pushlevel ();
431 cond = expand_cond (IF_COND (t));
432 emit_line_note (input_filename, lineno);
433 expand_start_cond (cond, 0);
435 expand_stmt (THEN_CLAUSE (t));
438 expand_start_else ();
439 expand_stmt (ELSE_CLAUSE (t));
444 /* Generate the RTL for T, which is a WHILE_STMT. */
447 genrtl_while_stmt (t)
452 emit_line_note (input_filename, lineno);
453 expand_start_loop (1);
454 genrtl_do_pushlevel ();
456 cond = expand_cond (WHILE_COND (t));
457 emit_line_note (input_filename, lineno);
458 expand_exit_loop_if_false (0, cond);
459 genrtl_do_pushlevel ();
461 expand_stmt (WHILE_BODY (t));
466 /* Generate the RTL for T, which is a DO_STMT. */
474 emit_line_note (input_filename, lineno);
475 expand_start_loop_continue_elsewhere (1);
477 expand_stmt (DO_BODY (t));
479 expand_loop_continue_here ();
481 cond = expand_cond (DO_COND (t));
482 emit_line_note (input_filename, lineno);
483 expand_exit_loop_if_false (0, cond);
487 /* Build the node for a return statement and return it. */
490 build_return_stmt (expr)
493 return (build_stmt (RETURN_STMT, expr));
496 /* Generate the RTL for STMT, which is a RETURN_STMT. */
499 genrtl_return_stmt (stmt)
502 tree expr = RETURN_EXPR (stmt);
504 emit_line_note (input_filename, lineno);
506 expand_null_return ();
509 expand_start_target_temps ();
510 expand_return (expr);
511 expand_end_target_temps ();
515 /* Generate the RTL for T, which is a FOR_STMT. */
522 const char *saved_filename;
525 if (NEW_FOR_SCOPE_P (t))
526 genrtl_do_pushlevel ();
528 expand_stmt (FOR_INIT_STMT (t));
530 /* Expand the initialization. */
532 emit_line_note (input_filename, lineno);
533 expand_start_loop_continue_elsewhere (1);
534 genrtl_do_pushlevel ();
535 cond = expand_cond (FOR_COND (t));
537 /* Save the filename and line number so that we expand the FOR_EXPR
538 we can reset them back to the saved values. */
539 saved_filename = input_filename;
540 saved_lineno = lineno;
542 /* Expand the condition. */
543 emit_line_note (input_filename, lineno);
545 expand_exit_loop_if_false (0, cond);
547 /* Expand the body. */
548 genrtl_do_pushlevel ();
549 expand_stmt (FOR_BODY (t));
551 /* Expand the increment expression. */
552 input_filename = saved_filename;
553 lineno = saved_lineno;
554 emit_line_note (input_filename, lineno);
555 expand_loop_continue_here ();
557 genrtl_expr_stmt (FOR_EXPR (t));
561 /* Build a break statement node and return it. */
566 return (build_stmt (BREAK_STMT));
569 /* Generate the RTL for a BREAK_STMT. */
574 emit_line_note (input_filename, lineno);
575 if ( ! expand_exit_something ())
576 error ("break statement not within loop or switch");
579 /* Build a continue statement node and return it. */
582 build_continue_stmt ()
584 return (build_stmt (CONTINUE_STMT));
587 /* Generate the RTL for a CONTINUE_STMT. */
590 genrtl_continue_stmt ()
592 emit_line_note (input_filename, lineno);
593 if (! expand_continue_loop (0))
594 error ("continue statement not within a loop");
597 /* Generate the RTL for T, which is a SCOPE_STMT. */
600 genrtl_scope_stmt (t)
603 if (!SCOPE_NO_CLEANUPS_P (t))
605 if (SCOPE_BEGIN_P (t))
606 expand_start_bindings_and_block (2 * SCOPE_NULLIFIED_P (t),
607 SCOPE_STMT_BLOCK (t));
608 else if (SCOPE_END_P (t))
609 expand_end_bindings (NULL_TREE, !SCOPE_NULLIFIED_P (t), 0);
611 else if (!SCOPE_NULLIFIED_P (t))
613 rtx note = emit_note (NULL,
615 ? NOTE_INSN_BLOCK_BEG
616 : NOTE_INSN_BLOCK_END));
617 NOTE_BLOCK (note) = SCOPE_STMT_BLOCK (t);
621 /* Generate the RTL for T, which is a SWITCH_STMT. */
624 genrtl_switch_stmt (t)
628 genrtl_do_pushlevel ();
630 cond = expand_cond (SWITCH_COND (t));
631 if (cond == error_mark_node)
632 /* The code is in error, but we don't want expand_end_case to
634 cond = boolean_false_node;
636 emit_line_note (input_filename, lineno);
637 expand_start_case (1, cond, TREE_TYPE (cond), "switch statement");
638 expand_stmt (SWITCH_BODY (t));
639 expand_end_case (cond);
642 /* Create a CASE_LABEL tree node and return it. */
645 build_case_label (low_value, high_value, label_decl)
650 return build_stmt (CASE_LABEL, low_value, high_value, label_decl);
654 /* Generate the RTL for a CASE_LABEL. */
657 genrtl_case_label (case_label)
663 cleanup = last_cleanup_this_contour ();
666 static int explained = 0;
667 warning_with_decl (TREE_PURPOSE (cleanup),
668 "destructor needed for `%#D'");
669 warning ("where case label appears here");
672 warning ("(enclose actions of previous case statements requiring destructors in their own scope.)");
677 add_case_node (CASE_LOW (case_label), CASE_HIGH (case_label),
678 CASE_LABEL_DECL (case_label), &duplicate);
681 /* Generate the RTL for T, which is a COMPOUND_STMT. */
684 genrtl_compound_stmt (t)
687 expand_stmt (COMPOUND_BODY (t));
690 /* Generate the RTL for an ASM_STMT. */
693 genrtl_asm_stmt (cv_qualifier, string, output_operands,
694 input_operands, clobbers)
697 tree output_operands;
701 if (cv_qualifier != NULL_TREE
702 && cv_qualifier != ridpointers[(int) RID_VOLATILE])
704 warning ("%s qualifier ignored on asm",
705 IDENTIFIER_POINTER (cv_qualifier));
706 cv_qualifier = NULL_TREE;
709 emit_line_note (input_filename, lineno);
710 if (output_operands != NULL_TREE || input_operands != NULL_TREE
711 || clobbers != NULL_TREE)
712 c_expand_asm_operands (string, output_operands,
715 cv_qualifier != NULL_TREE,
716 input_filename, lineno);
721 /* Generate the RTL for a DECL_CLEANUP. */
724 genrtl_decl_cleanup (decl, cleanup)
728 if (!decl || (DECL_SIZE (decl) && TREE_TYPE (decl) != error_mark_node))
729 expand_decl_cleanup (decl, cleanup);
732 /* We're about to expand T, a statement. Set up appropriate context
733 for the substitution. */
739 if (!STMT_LINENO_FOR_FN_P (t))
740 lineno = STMT_LINENO (t);
741 current_stmt_tree ()->stmts_are_full_exprs_p = STMT_IS_FULL_EXPR_P (t);
744 /* Generate the RTL for the statement T, its substatements, and any
745 other statements at its nesting level. */
751 while (t && t != error_mark_node)
753 int saved_stmts_are_full_exprs_p;
755 /* Set up context appropriately for handling this statement. */
756 saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p ();
759 switch (TREE_CODE (t))
762 genrtl_return_stmt (t);
766 genrtl_expr_stmt (EXPR_STMT_EXPR (t));
770 genrtl_decl_stmt (t);
778 genrtl_while_stmt (t);
790 genrtl_compound_stmt (t);
794 genrtl_break_stmt ();
798 genrtl_continue_stmt ();
802 genrtl_switch_stmt (t);
806 genrtl_case_label (t);
810 expand_label (LABEL_STMT_LABEL (t));
814 genrtl_goto_stmt (GOTO_DESTINATION (t));
818 genrtl_asm_stmt (ASM_CV_QUAL (t), ASM_STRING (t),
819 ASM_OUTPUTS (t), ASM_INPUTS (t), ASM_CLOBBERS (t));
823 genrtl_scope_stmt (t);
827 if (lang_expand_stmt)
828 (*lang_expand_stmt) (t);
834 /* Restore saved state. */
835 current_stmt_tree ()->stmts_are_full_exprs_p =
836 saved_stmts_are_full_exprs_p;
838 /* Go on to the next statement in this scope. */