gcc/c-semantics.c

   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 Free Software Foundation, Inc.
   5    Written by Benjamin Chelf (chelf@codesourcery.com).
   6
   7 This file is part of GNU CC.
   8
   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)
  12 any later version.
  13
  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.
  18
  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.  */
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "tree.h"
  27 #include "function.h"
  28 #include "splay-tree.h"
  29 #include "varray.h"
  30 #include "c-common.h"
  31 #include "except.h"
  32 #include "toplev.h"
  33 #include "flags.h"
  34 #include "ggc.h"
  35 #include "rtl.h"
  36 #include "output.h"
  37 #include "timevar.h"
  38
  39 /* If non-NULL, the address of a language-specific function for
  40    expanding statements.  */
  41 void (*lang_expand_stmt) PARAMS ((tree));
  42
  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));
  49
  50 static tree prune_unused_decls PARAMS ((tree *, int *, void *));
  51
  52 /* Create an empty statement tree rooted at T.  */
  53
  54 void
  55 begin_stmt_tree (t)
  56      tree *t;
  57 {
  58   /* We create a trivial EXPR_STMT so that last_tree is never NULL in
  59      what follows.  We remove the extraneous statement in
  60      finish_stmt_tree.  */
  61   *t = build_nt (EXPR_STMT, void_zero_node);
  62   last_tree = *t;
  63   last_expr_type = NULL_TREE;
  64 }
  65
  66 /* T is a statement.  Add it to the statement-tree.  */
  67
  68 tree
  69 add_stmt (t)
  70      tree t;
  71 {
  72   /* Add T to the statement-tree.  */
  73   TREE_CHAIN (last_tree) = t;
  74   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 ();
  78   return t;
  79 }
  80
  81 /* Create a declaration statement for the declaration given by the
  82    DECL.  */
  83
  84 void
  85 add_decl_stmt (decl)
  86      tree decl;
  87 {
  88   tree decl_stmt;
  89
  90   /* We need the type to last until instantiation time.  */
  91   decl_stmt = build_stmt (DECL_STMT, decl);
  92   add_stmt (decl_stmt);
  93 }
  94
  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.  */
 104
 105 tree
 106 add_scope_stmt (begin_p, partial_p)
 107      int begin_p;
 108      int partial_p;
 109 {
 110   tree ss;
 111   tree top;
 112
 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;
 117
 118   /* Keep the scope stack up to date.  */
 119   if (begin_p)
 120     {
 121       *current_scope_stmt_stack ()
 122         = tree_cons (ss, NULL_TREE, *current_scope_stmt_stack ());
 123       top = *current_scope_stmt_stack ();
 124     }
 125   else
 126     {
 127       top = *current_scope_stmt_stack ();
 128       TREE_VALUE (top) = ss;
 129       *current_scope_stmt_stack () = TREE_CHAIN (top);
 130     }
 131
 132   /* Add the new statement to the statement-tree.  */
 133   add_stmt (ss);
 134
 135   return top;
 136 }
 137
 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
 143    used.  */
 144
 145 static tree
 146 prune_unused_decls (tp, walk_subtrees, data)
 147      tree *tp;
 148      int *walk_subtrees ATTRIBUTE_UNUSED;
 149      void *data ATTRIBUTE_UNUSED;
 150 {
 151   tree t = *tp;
 152
 153   if (t == NULL_TREE)
 154     return error_mark_node;
 155
 156   if (TREE_CODE (t) == DECL_STMT)
 157     {
 158       tree d = DECL_STMT_DECL (t);
 159       if (!TREE_USED (d) && DECL_NAME (d) && DECL_SOURCE_LINE (d) == 0)
 160         {
 161           *tp = TREE_CHAIN (t);
 162           /* Recurse on the new value of tp, otherwise we will skip
 163              the next statement.  */
 164           return prune_unused_decls (tp, walk_subtrees, data);
 165         }
 166     }
 167   else if (TREE_CODE (t) == SCOPE_STMT)
 168     {
 169       /* Remove all unused decls from the BLOCK of this SCOPE_STMT.  */
 170       tree block = SCOPE_STMT_BLOCK (t);
 171
 172       if (block)
 173         {
 174           tree *vp;
 175
 176           for (vp = &BLOCK_VARS (block); *vp; )
 177             {
 178               tree v = *vp;
 179               if (! TREE_USED (v) && DECL_NAME (v) && DECL_SOURCE_LINE (v) == 0)
 180                 *vp = TREE_CHAIN (v);  /* drop */
 181               else
 182                 vp = &TREE_CHAIN (v);  /* advance */
 183             }
 184           /* If there are now no variables, the entire BLOCK can be dropped.
 185              (This causes SCOPE_NULLIFIED_P (t) to be true.)  */
 186           if (BLOCK_VARS (block) == NULL_TREE)
 187             SCOPE_STMT_BLOCK (t) = NULL_TREE;
 188         }
 189     }
 190   return NULL_TREE;
 191 }
 192
 193 /* Finish the statement tree rooted at T.  */
 194
 195 void
 196 finish_stmt_tree (t)
 197      tree *t;
 198 {
 199   tree stmt;
 200
 201   /* Remove the fake extra statement added in begin_stmt_tree.  */
 202   stmt = TREE_CHAIN (*t);
 203   *t = stmt;
 204   last_tree = NULL_TREE;
 205
 206   /* Remove unused decls from the stmt tree.  */
 207   walk_stmt_tree (t, prune_unused_decls, NULL);
 208
 209   if (cfun && stmt)
 210     {
 211       /* The line-number recorded in the outermost statement in a function
 212          is the line number of the end of the function.  */
 213       STMT_LINENO (stmt) = lineno;
 214       STMT_LINENO_FOR_FN_P (stmt) = 1;
 215     }
 216 }
 217
 218 /* Build a generic statement based on the given type of node and
 219    arguments. Similar to `build_nt', except that we set
 220    STMT_LINENO to be the current line number.  */
 221 /* ??? This should be obsolete with the lineno_stmt productions
 222    in the grammar.  */
 223
 224 tree
 225 build_stmt VPARAMS ((enum tree_code code, ...))
 226 {
 227 #ifndef ANSI_PROTOTYPES
 228   enum tree_code code;
 229 #endif
 230   va_list p;
 231   register tree t;
 232   register int length;
 233   register int i;
 234
 235   VA_START (p, code);
 236
 237 #ifndef ANSI_PROTOTYPES
 238   code = va_arg (p, enum tree_code);
 239 #endif
 240
 241   t = make_node (code);
 242   length = TREE_CODE_LENGTH (code);
 243   STMT_LINENO (t) = lineno;
 244
 245   for (i = 0; i < length; i++)
 246     TREE_OPERAND (t, i) = va_arg (p, tree);
 247
 248   va_end (p);
 249   return t;
 250 }
 251
 252 /* Some statements, like for-statements or if-statements, require a
 253    condition.  This condition can be a declaration.  If T is such a
 254    declaration it is processed, and an expression appropriate to use
 255    as the condition is returned.  Otherwise, T itself is returned.  */
 256
 257 tree
 258 expand_cond (t)
 259      tree t;
 260 {
 261   if (t && TREE_CODE (t) == TREE_LIST)
 262     {
 263       expand_stmt (TREE_PURPOSE (t));
 264       return TREE_VALUE (t);
 265     }
 266   else
 267     return t;
 268 }
 269
 270 /* Create RTL for the local static variable DECL.  */
 271
 272 void
 273 make_rtl_for_local_static (decl)
 274      tree decl;
 275 {
 276   const char *asmspec = NULL;
 277
 278   /* If we inlined this variable, we could see it's declaration
 279      again.  */
 280   if (TREE_ASM_WRITTEN (decl))
 281     return;
 282
 283   /* If the DECL_ASSEMBLER_NAME is not the same as the DECL_NAME, then
 284      either we already created RTL for this DECL (and since it was a
 285      local variable, its DECL_ASSEMBLER_NAME got hacked up to prevent
 286      clashes with other local statics with the same name by a previous
 287      call to make_decl_rtl), or the user explicitly requested a
 288      particular assembly name for this variable, using the GNU
 289      extension for this purpose:
 290
 291        int i asm ("j");
 292
 293      There's no way to know which case we're in, here.  But, it turns
 294      out we're safe.  If there's already RTL, then
 295      rest_of_decl_compilation ignores the ASMSPEC parameter, so we
 296      may as well not pass it in.  If there isn't RTL, then we didn't
 297      already create RTL, which means that the modification to
 298      DECL_ASSEMBLER_NAME came only via the explicit extension.  */
 299   if (DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl)
 300       && !DECL_RTL (decl))
 301     asmspec = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 302
 303   rest_of_decl_compilation (decl, asmspec, /*top_level=*/0, /*at_end=*/0);
 304 }
 305
 306 /* Let the back-end know about DECL.  */
 307
 308 void
 309 emit_local_var (decl)
 310      tree decl;
 311 {
 312   /* Create RTL for this variable.  */
 313   if (!DECL_RTL_SET_P (decl))
 314     {
 315       if (DECL_C_HARD_REGISTER (decl))
 316         /* The user specified an assembler name for this variable.
 317            Set that up now.  */
 318         rest_of_decl_compilation
 319           (decl, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)),
 320            /*top_level=*/0, /*at_end=*/0);
 321       else
 322         expand_decl (decl);
 323     }
 324
 325   /* Actually do the initialization.  */
 326   if (stmts_are_full_exprs_p ())
 327     expand_start_target_temps ();
 328
 329   expand_decl_init (decl);
 330
 331   if (stmts_are_full_exprs_p ())
 332     expand_end_target_temps ();
 333 }
 334
 335 /* Helper for generating the RTL at the beginning of a scope. */
 336
 337 void
 338 genrtl_do_pushlevel ()
 339 {
 340   emit_line_note (input_filename, lineno);
 341   clear_last_expr ();
 342 }
 343
 344 /* Generate the RTL for DESTINATION, which is a GOTO_STMT. */
 345
 346 void
 347 genrtl_goto_stmt (destination)
 348      tree destination;
 349 {
 350   if (TREE_CODE (destination) == IDENTIFIER_NODE)
 351     abort ();
 352
 353   /* We warn about unused labels with -Wunused.  That means we have to
 354      mark the used labels as used.  */
 355   if (TREE_CODE (destination) == LABEL_DECL)
 356     TREE_USED (destination) = 1;
 357
 358   emit_line_note (input_filename, lineno);
 359
 360   if (TREE_CODE (destination) == LABEL_DECL)
 361     {
 362       label_rtx (destination);
 363       expand_goto (destination);
 364     }
 365   else
 366     expand_computed_goto (destination);
 367 }
 368
 369 /* Generate the RTL for EXPR, which is an EXPR_STMT. */
 370
 371 void
 372 genrtl_expr_stmt (expr)
 373      tree expr;
 374 {
 375   if (expr != NULL_TREE)
 376     {
 377       emit_line_note (input_filename, lineno);
 378
 379       if (stmts_are_full_exprs_p ())
 380         expand_start_target_temps ();
 381
 382       if (expr != error_mark_node)
 383         expand_expr_stmt (expr);
 384
 385       if (stmts_are_full_exprs_p ())
 386         expand_end_target_temps ();
 387     }
 388 }
 389
 390 /* Generate the RTL for T, which is a DECL_STMT. */
 391
 392 void
 393 genrtl_decl_stmt (t)
 394      tree t;
 395 {
 396   tree decl;
 397   emit_line_note (input_filename, lineno);
 398   decl = DECL_STMT_DECL (t);
 399   /* If this is a declaration for an automatic local
 400      variable, initialize it.  Note that we might also see a
 401      declaration for a namespace-scope object (declared with
 402      `extern').  We don't have to handle the initialization
 403      of those objects here; they can only be declarations,
 404      rather than definitions.  */
 405   if (TREE_CODE (decl) == VAR_DECL
 406       && !TREE_STATIC (decl)
 407       && !DECL_EXTERNAL (decl))
 408     {
 409       /* Let the back-end know about this variable.  */
 410       if (!anon_aggr_type_p (TREE_TYPE (decl)))
 411         emit_local_var (decl);
 412       else
 413         expand_anon_union_decl (decl, NULL_TREE,
 414                                 DECL_ANON_UNION_ELEMS (decl));
 415     }
 416   else if (TREE_CODE (decl) == VAR_DECL && TREE_STATIC (decl))
 417     {
 418       if (DECL_ARTIFICIAL (decl) && ! TREE_USED (decl))
 419         /* Do not emit unused decls. This is not just an
 420            optimization. We really do not want to emit
 421            __PRETTY_FUNCTION__ etc, if they're never used.  */
 422         DECL_IGNORED_P (decl) = 1;
 423       else
 424         make_rtl_for_local_static (decl);
 425     }
 426   else if (TREE_CODE (decl) == LABEL_DECL
 427            && C_DECLARED_LABEL_FLAG (decl))
 428     declare_nonlocal_label (decl);
 429   else if (lang_expand_decl_stmt)
 430     (*lang_expand_decl_stmt) (t);
 431 }
 432
 433 /* Generate the RTL for T, which is an IF_STMT. */
 434
 435 void
 436 genrtl_if_stmt (t)
 437      tree t;
 438 {
 439   tree cond;
 440   genrtl_do_pushlevel ();
 441   cond = expand_cond (IF_COND (t));
 442   emit_line_note (input_filename, lineno);
 443   expand_start_cond (cond, 0);
 444   if (THEN_CLAUSE (t))
 445     expand_stmt (THEN_CLAUSE (t));
 446   if (ELSE_CLAUSE (t))
 447     {
 448       expand_start_else ();
 449       expand_stmt (ELSE_CLAUSE (t));
 450     }
 451   expand_end_cond ();
 452 }
 453
 454 /* Generate the RTL for T, which is a WHILE_STMT. */
 455
 456 void
 457 genrtl_while_stmt (t)
 458      tree t;
 459 {
 460   tree cond;
 461   emit_nop ();
 462   emit_line_note (input_filename, lineno);
 463   expand_start_loop (1);
 464   genrtl_do_pushlevel ();
 465
 466   cond = expand_cond (WHILE_COND (t));
 467   emit_line_note (input_filename, lineno);
 468   expand_exit_loop_if_false (0, cond);
 469   genrtl_do_pushlevel ();
 470
 471   expand_stmt (WHILE_BODY (t));
 472
 473   expand_end_loop ();
 474 }
 475
 476 /* Generate the RTL for T, which is a DO_STMT. */
 477
 478 void
 479 genrtl_do_stmt (t)
 480      tree t;
 481 {
 482   tree cond = DO_COND (t);
 483
 484   /* Recognize the common special-case of do { ... } while (0) and do
 485      not emit the loop widgetry in this case.  In particular this
 486      avoids cluttering the rtl with dummy loop notes, which can affect
 487      alignment of adjacent labels.  */
 488   if (integer_zerop (cond))
 489     {
 490       expand_start_null_loop ();
 491       expand_stmt (DO_BODY (t));
 492       expand_end_null_loop ();
 493     }
 494   else
 495     {
 496       emit_nop ();
 497       emit_line_note (input_filename, lineno);
 498       expand_start_loop_continue_elsewhere (1);
 499
 500       expand_stmt (DO_BODY (t));
 501
 502       expand_loop_continue_here ();
 503       cond = expand_cond (cond);
 504       emit_line_note (input_filename, lineno);
 505       expand_exit_loop_if_false (0, cond);
 506       expand_end_loop ();
 507     }
 508 }
 509
 510 /* Build the node for a return statement and return it. */
 511
 512 tree
 513 build_return_stmt (expr)
 514      tree expr;
 515 {
 516   return (build_stmt (RETURN_STMT, expr));
 517 }
 518
 519 /* Generate the RTL for STMT, which is a RETURN_STMT. */
 520
 521 void
 522 genrtl_return_stmt (stmt)
 523      tree stmt;
 524 {
 525   tree expr = RETURN_EXPR (stmt);
 526
 527   emit_line_note (input_filename, lineno);
 528   if (!expr)
 529     expand_null_return ();
 530   else
 531     {
 532       expand_start_target_temps ();
 533       expand_return (expr);
 534       expand_end_target_temps ();
 535     }
 536 }
 537
 538 /* Generate the RTL for T, which is a FOR_STMT. */
 539
 540 void
 541 genrtl_for_stmt (t)
 542      tree t;
 543 {
 544   tree cond;
 545   const char *saved_filename;
 546   int saved_lineno;
 547
 548   if (NEW_FOR_SCOPE_P (t))
 549     genrtl_do_pushlevel ();
 550
 551   expand_stmt (FOR_INIT_STMT (t));
 552
 553   /* Expand the initialization.  */
 554   emit_nop ();
 555   emit_line_note (input_filename, lineno);
 556   expand_start_loop_continue_elsewhere (1);
 557   genrtl_do_pushlevel ();
 558   cond = expand_cond (FOR_COND (t));
 559
 560   /* Save the filename and line number so that we expand the FOR_EXPR
 561      we can reset them back to the saved values.  */
 562   saved_filename = input_filename;
 563   saved_lineno = lineno;
 564
 565   /* Expand the condition.  */
 566   emit_line_note (input_filename, lineno);
 567   if (cond)
 568     expand_exit_loop_if_false (0, cond);
 569
 570   /* Expand the body.  */
 571   genrtl_do_pushlevel ();
 572   expand_stmt (FOR_BODY (t));
 573
 574   /* Expand the increment expression.  */
 575   input_filename = saved_filename;
 576   lineno = saved_lineno;
 577   emit_line_note (input_filename, lineno);
 578   expand_loop_continue_here ();
 579   if (FOR_EXPR (t))
 580     genrtl_expr_stmt (FOR_EXPR (t));
 581   expand_end_loop ();
 582 }
 583
 584 /* Build a break statement node and return it. */
 585
 586 tree
 587 build_break_stmt ()
 588 {
 589   return (build_stmt (BREAK_STMT));
 590 }
 591
 592 /* Generate the RTL for a BREAK_STMT. */
 593
 594 void
 595 genrtl_break_stmt ()
 596 {
 597   emit_line_note (input_filename, lineno);
 598   if ( ! expand_exit_something ())
 599     error ("break statement not within loop or switch");
 600 }
 601
 602 /* Build a continue statement node and return it. */
 603
 604 tree
 605 build_continue_stmt ()
 606 {
 607   return (build_stmt (CONTINUE_STMT));
 608 }
 609
 610 /* Generate the RTL for a CONTINUE_STMT. */
 611
 612 void
 613 genrtl_continue_stmt ()
 614 {
 615   emit_line_note (input_filename, lineno);
 616   if (! expand_continue_loop (0))
 617     error ("continue statement not within a loop");
 618 }
 619
 620 /* Generate the RTL for T, which is a SCOPE_STMT. */
 621
 622 void
 623 genrtl_scope_stmt (t)
 624      tree t;
 625 {
 626   if (!SCOPE_NO_CLEANUPS_P (t))
 627     {
 628       if (SCOPE_BEGIN_P (t))
 629         expand_start_bindings_and_block (2 * SCOPE_NULLIFIED_P (t),
 630                                          SCOPE_STMT_BLOCK (t));
 631       else if (SCOPE_END_P (t))
 632         expand_end_bindings (NULL_TREE, !SCOPE_NULLIFIED_P (t), 0);
 633     }
 634   else if (!SCOPE_NULLIFIED_P (t))
 635     {
 636       rtx note = emit_note (NULL,
 637                             (SCOPE_BEGIN_P (t)
 638                              ? NOTE_INSN_BLOCK_BEG
 639                              : NOTE_INSN_BLOCK_END));
 640       NOTE_BLOCK (note) = SCOPE_STMT_BLOCK (t);
 641     }
 642 }
 643
 644 /* Generate the RTL for T, which is a SWITCH_STMT. */
 645
 646 void
 647 genrtl_switch_stmt (t)
 648      tree t;
 649 {
 650   tree cond;
 651   genrtl_do_pushlevel ();
 652
 653   cond = expand_cond (SWITCH_COND (t));
 654   if (cond == error_mark_node)
 655     /* The code is in error, but we don't want expand_end_case to
 656        crash. */
 657     cond = boolean_false_node;
 658
 659   emit_line_note (input_filename, lineno);
 660   expand_start_case (1, cond, TREE_TYPE (cond), "switch statement");
 661   expand_stmt (SWITCH_BODY (t));
 662   expand_end_case (cond);
 663 }
 664
 665 /* Create a CASE_LABEL tree node and return it. */
 666
 667 tree
 668 build_case_label (low_value, high_value, label_decl)
 669      tree low_value;
 670      tree high_value;
 671      tree label_decl;
 672 {
 673   return build_stmt (CASE_LABEL, low_value, high_value, label_decl);
 674 }
 675
 676
 677 /* Generate the RTL for a CASE_LABEL. */
 678
 679 void
 680 genrtl_case_label (case_label)
 681      tree case_label;
 682 {
 683   tree duplicate;
 684   tree cleanup;
 685
 686   cleanup = last_cleanup_this_contour ();
 687   if (cleanup)
 688     {
 689       static int explained = 0;
 690       warning_with_decl (TREE_PURPOSE (cleanup),
 691                          "destructor needed for `%#D'");
 692       warning ("where case label appears here");
 693       if (!explained)
 694         {
 695           warning ("(enclose actions of previous case statements requiring destructors in their own scope.)");
 696           explained = 1;
 697         }
 698     }
 699
 700   add_case_node (CASE_LOW (case_label), CASE_HIGH (case_label),
 701                  CASE_LABEL_DECL (case_label), &duplicate);
 702 }
 703
 704 /* Generate the RTL for T, which is a COMPOUND_STMT. */
 705
 706 void
 707 genrtl_compound_stmt (t)
 708     tree t;
 709 {
 710   expand_stmt (COMPOUND_BODY (t));
 711 }
 712
 713 /* Generate the RTL for an ASM_STMT. */
 714
 715 void
 716 genrtl_asm_stmt (cv_qualifier, string, output_operands,
 717                  input_operands, clobbers, asm_input_p)
 718      tree cv_qualifier;
 719      tree string;
 720      tree output_operands;
 721      tree input_operands;
 722      tree clobbers;
 723      int asm_input_p;
 724 {
 725   if (cv_qualifier != NULL_TREE
 726       && cv_qualifier != ridpointers[(int) RID_VOLATILE])
 727     {
 728       warning ("%s qualifier ignored on asm",
 729                IDENTIFIER_POINTER (cv_qualifier));
 730       cv_qualifier = NULL_TREE;
 731     }
 732
 733   emit_line_note (input_filename, lineno);
 734   if (asm_input_p)
 735     expand_asm (string);
 736   else
 737     c_expand_asm_operands (string, output_operands, input_operands,
 738                            clobbers, cv_qualifier != NULL_TREE,
 739                            input_filename, lineno);
 740 }
 741
 742 /* Generate the RTL for a DECL_CLEANUP. */
 743
 744 void
 745 genrtl_decl_cleanup (decl, cleanup)
 746      tree decl;
 747      tree cleanup;
 748 {
 749   if (!decl || (DECL_SIZE (decl) && TREE_TYPE (decl) != error_mark_node))
 750     expand_decl_cleanup (decl, cleanup);
 751 }
 752
 753 /* We're about to expand T, a statement.  Set up appropriate context
 754    for the substitution.  */
 755
 756 void
 757 prep_stmt (t)
 758      tree t;
 759 {
 760   if (!STMT_LINENO_FOR_FN_P (t))
 761     lineno = STMT_LINENO (t);
 762   current_stmt_tree ()->stmts_are_full_exprs_p = STMT_IS_FULL_EXPR_P (t);
 763 }
 764
 765 /* Generate the RTL for the statement T, its substatements, and any
 766    other statements at its nesting level. */
 767
 768 void
 769 expand_stmt (t)
 770      tree t;
 771 {
 772   while (t && t != error_mark_node)
 773     {
 774       int saved_stmts_are_full_exprs_p;
 775
 776       /* Set up context appropriately for handling this statement.  */
 777       saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p ();
 778       prep_stmt (t);
 779
 780       switch (TREE_CODE (t))
 781         {
 782         case RETURN_STMT:
 783           genrtl_return_stmt (t);
 784           break;
 785
 786         case EXPR_STMT:
 787           genrtl_expr_stmt (EXPR_STMT_EXPR (t));
 788           break;
 789
 790         case DECL_STMT:
 791           genrtl_decl_stmt (t);
 792           break;
 793
 794         case FOR_STMT:
 795           genrtl_for_stmt (t);
 796           break;
 797
 798         case WHILE_STMT:
 799           genrtl_while_stmt (t);
 800           break;
 801
 802         case DO_STMT:
 803           genrtl_do_stmt (t);
 804           break;
 805
 806         case IF_STMT:
 807           genrtl_if_stmt (t);
 808           break;
 809
 810         case COMPOUND_STMT:
 811           genrtl_compound_stmt (t);
 812           break;
 813
 814         case BREAK_STMT:
 815           genrtl_break_stmt ();
 816           break;
 817
 818         case CONTINUE_STMT:
 819           genrtl_continue_stmt ();
 820           break;
 821
 822         case SWITCH_STMT:
 823           genrtl_switch_stmt (t);
 824           break;
 825
 826         case CASE_LABEL:
 827           genrtl_case_label (t);
 828           break;
 829
 830         case LABEL_STMT:
 831           expand_label (LABEL_STMT_LABEL (t));
 832           break;
 833
 834         case GOTO_STMT:
 835           genrtl_goto_stmt (GOTO_DESTINATION (t));
 836           break;
 837
 838         case ASM_STMT:
 839           genrtl_asm_stmt (ASM_CV_QUAL (t), ASM_STRING (t),
 840                            ASM_OUTPUTS (t), ASM_INPUTS (t),
 841                            ASM_CLOBBERS (t), ASM_INPUT_P (t));
 842           break;
 843
 844         case SCOPE_STMT:
 845           genrtl_scope_stmt (t);
 846           break;
 847
 848         default:
 849           if (lang_expand_stmt)
 850             (*lang_expand_stmt) (t);
 851           else
 852             abort ();
 853           break;
 854         }
 855
 856       /* Restore saved state.  */
 857       current_stmt_tree ()->stmts_are_full_exprs_p
 858         = saved_stmts_are_full_exprs_p;
 859
 860       /* Go on to the next statement in this scope.  */
 861       t = TREE_CHAIN (t);
 862     }
 863 }
 864