gcc/ada/misc.c

   1 /****************************************************************************
   2  *                                                                          *
   3  *                         GNAT COMPILER COMPONENTS                         *
   4  *                                                                          *
   5  *                                 M I S C                                  *
   6  *                                                                          *
   7  *                           C Implementation File                          *
   8  *                                                                          *
   9  *          Copyright (C) 1992-2005, Free Software Foundation, Inc.         *
  10  *                                                                          *
  11  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  12  * terms of the  GNU General Public License as published  by the Free Soft- *
  13  * ware  Foundation;  either version 2,  or (at your option) any later ver- *
  14  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  15  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  16  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
  17  * for  more details.  You should have  received  a copy of the GNU General *
  18  * Public License  distributed with GNAT;  see file COPYING.  If not, write *
  19  * to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, *
  20  * MA 02111-1307, USA.                                                      *
  21  *                                                                          *
  22  * As a  special  exception,  if you  link  this file  with other  files to *
  23  * produce an executable,  this file does not by itself cause the resulting *
  24  * executable to be covered by the GNU General Public License. This except- *
  25  * ion does not  however invalidate  any other reasons  why the  executable *
  26  * file might be covered by the  GNU Public License.                        *
  27  *                                                                          *
  28  * GNAT was originally developed  by the GNAT team at  New York University. *
  29  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  30  *                                                                          *
  31  ****************************************************************************/
  32
  33 /* This file contains parts of the compiler that are required for interfacing
  34    with GCC but otherwise do nothing and parts of Gigi that need to know
  35    about RTL.  */
  36
  37 #include "config.h"
  38 #include "system.h"
  39 #include "coretypes.h"
  40 #include "tm.h"
  41 #include "tree.h"
  42 #include "real.h"
  43 #include "rtl.h"
  44 #include "errors.h"
  45 #include "diagnostic.h"
  46 #include "expr.h"
  47 #include "libfuncs.h"
  48 #include "ggc.h"
  49 #include "flags.h"
  50 #include "debug.h"
  51 #include "cgraph.h"
  52 #include "tree-inline.h"
  53 #include "insn-codes.h"
  54 #include "insn-flags.h"
  55 #include "insn-config.h"
  56 #include "optabs.h"
  57 #include "recog.h"
  58 #include "toplev.h"
  59 #include "output.h"
  60 #include "except.h"
  61 #include "tm_p.h"
  62 #include "langhooks.h"
  63 #include "langhooks-def.h"
  64 #include "target.h"
  65
  66 #include "ada.h"
  67 #include "types.h"
  68 #include "atree.h"
  69 #include "elists.h"
  70 #include "namet.h"
  71 #include "nlists.h"
  72 #include "stringt.h"
  73 #include "uintp.h"
  74 #include "fe.h"
  75 #include "sinfo.h"
  76 #include "einfo.h"
  77 #include "ada-tree.h"
  78 #include "gigi.h"
  79 #include "adadecode.h"
  80 #include "opts.h"
  81 #include "options.h"
  82
  83 extern FILE *asm_out_file;
  84
  85 /* The largest alignment, in bits, that is needed for using the widest
  86    move instruction.  */
  87 unsigned int largest_move_alignment;
  88
  89 static bool gnat_init                   (void);
  90 static void gnat_finish_incomplete_decl (tree);
  91 static unsigned int gnat_init_options   (unsigned int, const char **);
  92 static int gnat_handle_option           (size_t, const char *, int);
  93 static bool gnat_post_options           (const char **);
  94 static HOST_WIDE_INT gnat_get_alias_set (tree);
  95 static void gnat_print_decl             (FILE *, tree, int);
  96 static void gnat_print_type             (FILE *, tree, int);
  97 static const char *gnat_printable_name  (tree, int);
  98 static tree gnat_eh_runtime_type        (tree);
  99 static int gnat_eh_type_covers          (tree, tree);
 100 static void gnat_parse_file             (int);
 101 static rtx gnat_expand_expr             (tree, rtx, enum machine_mode, int,
 102                                          rtx *);
 103 static void gnat_expand_body            (tree);
 104 static void internal_error_function     (const char *, va_list *);
 105 static void gnat_adjust_rli             (record_layout_info);
 106 static tree gnat_type_max_size          (tree);
 107
 108 /* Definitions for our language-specific hooks.  */
 109
 110 #undef  LANG_HOOKS_NAME
 111 #define LANG_HOOKS_NAME                 "GNU Ada"
 112 #undef  LANG_HOOKS_IDENTIFIER_SIZE
 113 #define LANG_HOOKS_IDENTIFIER_SIZE      sizeof (struct tree_identifier)
 114 #undef  LANG_HOOKS_INIT
 115 #define LANG_HOOKS_INIT                 gnat_init
 116 #undef  LANG_HOOKS_INIT_OPTIONS
 117 #define LANG_HOOKS_INIT_OPTIONS         gnat_init_options
 118 #undef  LANG_HOOKS_HANDLE_OPTION
 119 #define LANG_HOOKS_HANDLE_OPTION        gnat_handle_option
 120 #undef  LANG_HOOKS_POST_OPTIONS
 121 #define LANG_HOOKS_POST_OPTIONS         gnat_post_options
 122 #undef  LANG_HOOKS_PARSE_FILE
 123 #define LANG_HOOKS_PARSE_FILE           gnat_parse_file
 124 #undef  LANG_HOOKS_HASH_TYPES
 125 #define LANG_HOOKS_HASH_TYPES           false
 126 #undef  LANG_HOOKS_GETDECLS
 127 #define LANG_HOOKS_GETDECLS             lhd_return_null_tree_v
 128 #undef  LANG_HOOKS_PUSHDECL
 129 #define LANG_HOOKS_PUSHDECL             lhd_return_tree
 130 #undef  LANG_HOOKS_FINISH_INCOMPLETE_DECL
 131 #define LANG_HOOKS_FINISH_INCOMPLETE_DECL gnat_finish_incomplete_decl
 132 #undef  LANG_HOOKS_REDUCE_BIT_FIELD_OPERATIONS
 133 #define LANG_HOOKS_REDUCE_BIT_FIELD_OPERATIONS true
 134 #undef  LANG_HOOKS_GET_ALIAS_SET
 135 #define LANG_HOOKS_GET_ALIAS_SET        gnat_get_alias_set
 136 #undef  LANG_HOOKS_EXPAND_EXPR
 137 #define LANG_HOOKS_EXPAND_EXPR          gnat_expand_expr
 138 #undef  LANG_HOOKS_MARK_ADDRESSABLE
 139 #define LANG_HOOKS_MARK_ADDRESSABLE     gnat_mark_addressable
 140 #undef  LANG_HOOKS_TRUTHVALUE_CONVERSION
 141 #define LANG_HOOKS_TRUTHVALUE_CONVERSION gnat_truthvalue_conversion
 142 #undef  LANG_HOOKS_PRINT_DECL
 143 #define LANG_HOOKS_PRINT_DECL           gnat_print_decl
 144 #undef  LANG_HOOKS_PRINT_TYPE
 145 #define LANG_HOOKS_PRINT_TYPE           gnat_print_type
 146 #undef  LANG_HOOKS_TYPE_MAX_SIZE
 147 #define LANG_HOOKS_TYPE_MAX_SIZE        gnat_type_max_size
 148 #undef  LANG_HOOKS_DECL_PRINTABLE_NAME
 149 #define LANG_HOOKS_DECL_PRINTABLE_NAME  gnat_printable_name
 150 #undef  LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION
 151 #define LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION gnat_expand_body
 152 #undef  LANG_HOOKS_GIMPLIFY_EXPR
 153 #define LANG_HOOKS_GIMPLIFY_EXPR        gnat_gimplify_expr
 154 #undef  LANG_HOOKS_TYPE_FOR_MODE
 155 #define LANG_HOOKS_TYPE_FOR_MODE        gnat_type_for_mode
 156 #undef  LANG_HOOKS_TYPE_FOR_SIZE
 157 #define LANG_HOOKS_TYPE_FOR_SIZE        gnat_type_for_size
 158 #undef  LANG_HOOKS_SIGNED_TYPE
 159 #define LANG_HOOKS_SIGNED_TYPE          gnat_signed_type
 160 #undef  LANG_HOOKS_UNSIGNED_TYPE
 161 #define LANG_HOOKS_UNSIGNED_TYPE        gnat_unsigned_type
 162 #undef  LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE
 163 #define LANG_HOOKS_SIGNED_OR_UNSIGNED_TYPE gnat_signed_or_unsigned_type
 164
 165 const struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 166
 167 /* Tables describing GCC tree codes used only by GNAT.
 168
 169    Table indexed by tree code giving a string containing a character
 170    classifying the tree code.  Possibilities are
 171    t, d, s, c, r, <, 1 and 2.  See cp-tree.def for details.  */
 172
 173 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
 174
 175 const enum tree_code_class tree_code_type[] = {
 176 #include "tree.def"
 177   tcc_exceptional,
 178 #include "ada-tree.def"
 179 };
 180 #undef DEFTREECODE
 181
 182 /* Table indexed by tree code giving number of expression
 183    operands beyond the fixed part of the node structure.
 184    Not used for types or decls.  */
 185
 186 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
 187
 188 const unsigned char tree_code_length[] = {
 189 #include "tree.def"
 190   0,
 191 #include "ada-tree.def"
 192 };
 193 #undef DEFTREECODE
 194
 195 /* Names of tree components.
 196    Used for printing out the tree and error messages.  */
 197 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
 198
 199 const char *const tree_code_name[] = {
 200 #include "tree.def"
 201   "@@dummy",
 202 #include "ada-tree.def"
 203 };
 204 #undef DEFTREECODE
 205
 206 /* Command-line argc and argv.
 207    These variables are global, since they are imported and used in
 208    back_end.adb  */
 209
 210 unsigned int save_argc;
 211 const char **save_argv;
 212
 213 /* gnat standard argc argv */
 214
 215 extern int gnat_argc;
 216 extern char **gnat_argv;
 217
 218 \f
 219 /* Declare functions we use as part of startup.  */
 220 extern void __gnat_initialize           (void *);
 221 extern void __gnat_install_SEH_handler  (void *);
 222 extern void adainit                     (void);
 223 extern void _ada_gnat1drv               (void);
 224
 225 /* The parser for the language.  For us, we process the GNAT tree.  */
 226
 227 static void
 228 gnat_parse_file (int set_yydebug ATTRIBUTE_UNUSED)
 229 {
 230   int seh[2];
 231
 232   /* call the target specific initializations */
 233   __gnat_initialize (NULL);
 234
 235   /* ??? call the SEH initialization routine, this is to workaround a
 236   bootstrap path problem. The call below should be removed at some point and
 237   the seh pointer passed to __gnat_initialize() above.  */
 238
 239   __gnat_install_SEH_handler((void *)seh);
 240
 241   /* Call the front-end elaboration procedures */
 242   adainit ();
 243
 244   /* Call the front end */
 245   _ada_gnat1drv ();
 246
 247   cgraph_finalize_compilation_unit ();
 248   cgraph_optimize ();
 249 }
 250
 251 /* Decode all the language specific options that cannot be decoded by GCC.
 252    The option decoding phase of GCC calls this routine on the flags that
 253    it cannot decode.  This routine returns the number of consecutive arguments
 254    from ARGV that it successfully decoded; 0 indicates failure.  */
 255
 256 static int
 257 gnat_handle_option (size_t scode, const char *arg, int value ATTRIBUTE_UNUSED)
 258 {
 259   const struct cl_option *option = &cl_options[scode];
 260   enum opt_code code = (enum opt_code) scode;
 261   char *q;
 262
 263   if (arg == NULL && (option->flags & (CL_JOINED | CL_SEPARATE)))
 264     {
 265       error ("missing argument to \"-%s\"", option->opt_text);
 266       return 1;
 267     }
 268
 269   switch (code)
 270     {
 271     default:
 272       abort ();
 273
 274     case OPT_I:
 275       q = xmalloc (sizeof("-I") + strlen (arg));
 276       strcpy (q, "-I");
 277       strcat (q, arg);
 278       gnat_argv[gnat_argc] = q;
 279       gnat_argc++;
 280       break;
 281
 282       /* All front ends are expected to accept this.  */
 283     case OPT_Wall:
 284       /* These are used in the GCC Makefile.  */
 285     case OPT_Wmissing_prototypes:
 286     case OPT_Wstrict_prototypes:
 287     case OPT_Wwrite_strings:
 288     case OPT_Wlong_long:
 289       break;
 290
 291       /* This is handled by the front-end.  */
 292     case OPT_nostdinc:
 293       break;
 294
 295     case OPT_nostdlib:
 296       gnat_argv[gnat_argc] = xstrdup ("-nostdlib");
 297       gnat_argc++;
 298       break;
 299
 300     case OPT_fRTS_:
 301       gnat_argv[gnat_argc] = xstrdup ("-fRTS");
 302       gnat_argc++;
 303       break;
 304
 305     case OPT_gant:
 306       warning ("%<-gnat%> misspelled as %<-gant%>");
 307
 308       /* ... fall through ... */
 309
 310     case OPT_gnat:
 311       /* Recopy the switches without the 'gnat' prefix.  */
 312       gnat_argv[gnat_argc] = xmalloc (strlen (arg) + 2);
 313       gnat_argv[gnat_argc][0] = '-';
 314       strcpy (gnat_argv[gnat_argc] + 1, arg);
 315       gnat_argc++;
 316       break;
 317
 318     case OPT_gnatO:
 319       gnat_argv[gnat_argc] = xstrdup ("-O");
 320       gnat_argc++;
 321       gnat_argv[gnat_argc] = xstrdup (arg);
 322       gnat_argc++;
 323       break;
 324     }
 325
 326   return 1;
 327 }
 328
 329 /* Initialize for option processing.  */
 330
 331 static unsigned int
 332 gnat_init_options (unsigned int argc, const char **argv)
 333 {
 334   /* Initialize gnat_argv with save_argv size.  */
 335   gnat_argv = (char **) xmalloc ((argc + 1) * sizeof (argv[0]));
 336   gnat_argv[0] = xstrdup (argv[0]);     /* name of the command */
 337   gnat_argc = 1;
 338
 339   save_argc = argc;
 340   save_argv = argv;
 341
 342   /* Uninitialized really means uninitialized in Ada.  */
 343   flag_zero_initialized_in_bss = 0;
 344
 345   return CL_Ada;
 346 }
 347
 348 /* Post-switch processing.  */
 349
 350 bool
 351 gnat_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 352 {
 353   flag_inline_trees = 1;
 354
 355   if (!flag_no_inline)
 356     flag_no_inline = 1;
 357   if (flag_inline_functions)
 358     flag_inline_trees = 2;
 359
 360   flag_tree_salias = 0;
 361
 362   return false;
 363 }
 364
 365 /* Here is the function to handle the compiler error processing in GCC.  */
 366
 367 static void
 368 internal_error_function (const char *msgid, va_list *ap)
 369 {
 370   char buffer[1000];            /* Assume this is big enough.  */
 371   char *p;
 372   String_Template temp;
 373   Fat_Pointer fp;
 374
 375   vsprintf (buffer, msgid, *ap);
 376
 377   /* Go up to the first newline.  */
 378   for (p = buffer; *p; p++)
 379     if (*p == '\n')
 380       {
 381         *p = '\0';
 382         break;
 383       }
 384
 385   temp.Low_Bound = 1, temp.High_Bound = strlen (buffer);
 386   fp.Array = buffer, fp.Bounds = &temp;
 387
 388   Current_Error_Node = error_gnat_node;
 389   Compiler_Abort (fp, -1);
 390 }
 391
 392 /* Perform all the initialization steps that are language-specific.  */
 393
 394 static bool
 395 gnat_init (void)
 396 {
 397   /* Initialize translations and the outer statement group.  */
 398   gnat_init_stmt_group ();
 399
 400   /* Performs whatever initialization steps needed by the language-dependent
 401      lexical analyzer.  */
 402   gnat_init_decl_processing ();
 403
 404   /* Add the input filename as the last argument.  */
 405   gnat_argv[gnat_argc] = (char *) main_input_filename;
 406   gnat_argc++;
 407   gnat_argv[gnat_argc] = 0;
 408
 409   global_dc->internal_error = &internal_error_function;
 410
 411   /* Show that REFERENCE_TYPEs are internal and should be Pmode.  */
 412   internal_reference_types ();
 413
 414   set_lang_adjust_rli (gnat_adjust_rli);
 415
 416   return true;
 417 }
 418
 419 /* This function is called indirectly from toplev.c to handle incomplete
 420    declarations, i.e. VAR_DECL nodes whose DECL_SIZE is zero.  To be precise,
 421    compile_file in toplev.c makes an indirect call through the function pointer
 422    incomplete_decl_finalize_hook which is initialized to this routine in
 423    init_decl_processing.  */
 424
 425 static void
 426 gnat_finish_incomplete_decl (tree dont_care ATTRIBUTE_UNUSED)
 427 {
 428   abort ();
 429 }
 430 \f
 431 /* Compute the alignment of the largest mode that can be used for copying
 432    objects.  */
 433
 434 void
 435 gnat_compute_largest_alignment (void)
 436 {
 437   enum machine_mode mode;
 438
 439   for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
 440        mode = GET_MODE_WIDER_MODE (mode))
 441     if (mov_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing)
 442       largest_move_alignment = MIN (BIGGEST_ALIGNMENT,
 443                                     MAX (largest_move_alignment,
 444                                          GET_MODE_ALIGNMENT (mode)));
 445 }
 446
 447 /* If we are using the GCC mechanism to process exception handling, we
 448    have to register the personality routine for Ada and to initialize
 449    various language dependent hooks.  */
 450
 451 void
 452 gnat_init_gcc_eh (void)
 453 {
 454   /* We shouldn't do anything if the No_Exceptions_Handler pragma is set,
 455      though. This could for instance lead to the emission of tables with
 456      references to symbols (such as the Ada eh personality routine) within
 457      libraries we won't link against.  */
 458   if (No_Exception_Handlers_Set ())
 459     return;
 460
 461   /* Tell GCC we are handling cleanup actions through exception propagation.
 462      This opens possibilities that we don't take advantage of yet, but is
 463      nonetheless necessary to ensure that fixup code gets assigned to the
 464      right exception regions.  */
 465   using_eh_for_cleanups ();
 466
 467   eh_personality_libfunc = init_one_libfunc ("__gnat_eh_personality");
 468   lang_eh_type_covers = gnat_eh_type_covers;
 469   lang_eh_runtime_type = gnat_eh_runtime_type;
 470
 471   /* Turn on -fexceptions and -fnon-call-exceptions. The first one triggers
 472      the generation of the necessary exception runtime tables. The second one
 473      is useful for two reasons: 1/ we map some asynchronous signals like SEGV
 474      to exceptions, so we need to ensure that the insns which can lead to such
 475      signals are correctly attached to the exception region they pertain to,
 476      2/ Some calls to pure subprograms are handled as libcall blocks and then
 477      marked as "cannot trap" if the flag is not set (see emit_libcall_block).
 478      We should not let this be since it is possible for such calls to actually
 479      raise in Ada.  */
 480
 481   flag_exceptions = 1;
 482   flag_non_call_exceptions = 1;
 483
 484   init_eh ();
 485 #ifdef DWARF2_UNWIND_INFO
 486   if (dwarf2out_do_frame ())
 487     dwarf2out_frame_init ();
 488 #endif
 489 }
 490
 491 /* Language hooks, first one to print language-specific items in a DECL.  */
 492
 493 static void
 494 gnat_print_decl (FILE *file, tree node, int indent)
 495 {
 496   switch (TREE_CODE (node))
 497     {
 498     case CONST_DECL:
 499       print_node (file, "const_corresponding_var",
 500                   DECL_CONST_CORRESPONDING_VAR (node), indent + 4);
 501       break;
 502
 503     case FIELD_DECL:
 504       print_node (file, "original_field", DECL_ORIGINAL_FIELD (node),
 505                   indent + 4);
 506       break;
 507
 508     case VAR_DECL:
 509       print_node (file, "renamed_object", DECL_RENAMED_OBJECT (node),
 510                   indent + 4);
 511       break;
 512
 513     default:
 514       break;
 515     }
 516 }
 517
 518 static void
 519 gnat_print_type (FILE *file, tree node, int indent)
 520 {
 521   switch (TREE_CODE (node))
 522     {
 523     case FUNCTION_TYPE:
 524       print_node (file, "ci_co_list", TYPE_CI_CO_LIST (node), indent + 4);
 525       break;
 526
 527     case ENUMERAL_TYPE:
 528       print_node (file, "RM size", TYPE_RM_SIZE_NUM (node), indent + 4);
 529       break;
 530
 531     case INTEGER_TYPE:
 532       if (TYPE_MODULAR_P (node))
 533         print_node (file, "modulus", TYPE_MODULUS (node), indent + 4);
 534       else if (TYPE_HAS_ACTUAL_BOUNDS_P (node))
 535         print_node (file, "actual bounds", TYPE_ACTUAL_BOUNDS (node),
 536                     indent + 4);
 537       else if (TYPE_VAX_FLOATING_POINT_P (node))
 538         ;
 539       else
 540         print_node (file, "index type", TYPE_INDEX_TYPE (node), indent + 4);
 541
 542       print_node (file, "RM size", TYPE_RM_SIZE_NUM (node), indent + 4);
 543       break;
 544
 545     case ARRAY_TYPE:
 546       print_node (file,"actual bounds", TYPE_ACTUAL_BOUNDS (node), indent + 4);
 547       break;
 548
 549     case RECORD_TYPE:
 550       if (TYPE_IS_FAT_POINTER_P (node) || TYPE_CONTAINS_TEMPLATE_P (node))
 551         print_node (file, "unconstrained array",
 552                     TYPE_UNCONSTRAINED_ARRAY (node), indent + 4);
 553       else
 554         print_node (file, "Ada size", TYPE_ADA_SIZE (node), indent + 4);
 555       break;
 556
 557     case UNION_TYPE:
 558     case QUAL_UNION_TYPE:
 559       print_node (file, "Ada size", TYPE_ADA_SIZE (node), indent + 4);
 560       break;
 561
 562     default:
 563       break;
 564     }
 565 }
 566
 567 static const char *
 568 gnat_printable_name (tree decl, int verbosity)
 569 {
 570   const char *coded_name = IDENTIFIER_POINTER (DECL_NAME (decl));
 571   char *ada_name = (char *) ggc_alloc (strlen (coded_name) * 2 + 60);
 572
 573   __gnat_decode (coded_name, ada_name, 0);
 574
 575   if (verbosity == 2)
 576     {
 577       Set_Identifier_Casing (ada_name, (char *) DECL_SOURCE_FILE (decl));
 578       ada_name = Name_Buffer;
 579     }
 580
 581   return (const char *) ada_name;
 582 }
 583
 584 /* Expands GNAT-specific GCC tree nodes.  The only ones we support
 585    here are  and NULL_EXPR.  */
 586
 587 static rtx
 588 gnat_expand_expr (tree exp, rtx target, enum machine_mode tmode,
 589                   int modifier, rtx *alt_rtl)
 590 {
 591   tree type = TREE_TYPE (exp);
 592   tree new;
 593
 594   /* If this is a statement, call the expansion routine for statements.  */
 595   if (IS_STMT (exp))
 596     {
 597       gnat_expand_stmt (exp);
 598       return const0_rtx;
 599     }
 600
 601   /* Update EXP to be the new expression to expand.  */
 602   switch (TREE_CODE (exp))
 603     {
 604 #if 0
 605     case ALLOCATE_EXPR:
 606       return
 607         allocate_dynamic_stack_space
 608           (expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, TYPE_MODE (sizetype),
 609                         EXPAND_NORMAL),
 610            NULL_RTX, tree_low_cst (TREE_OPERAND (exp, 1), 1));
 611 #endif
 612
 613     case UNCONSTRAINED_ARRAY_REF:
 614       /* If we are evaluating just for side-effects, just evaluate our
 615          operand.  Otherwise, abort since this code should never appear
 616          in a tree to be evaluated (objects aren't unconstrained).  */
 617       if (target == const0_rtx || TREE_CODE (type) == VOID_TYPE)
 618         return expand_expr (TREE_OPERAND (exp, 0), const0_rtx,
 619                             VOIDmode, modifier);
 620
 621       /* ... fall through ... */
 622
 623     default:
 624       abort ();
 625     }
 626
 627   return expand_expr_real (new, target, tmode, modifier, alt_rtl);
 628 }
 629
 630 /* Generate the RTL for the body of GNU_DECL.  */
 631
 632 static void
 633 gnat_expand_body (tree gnu_decl)
 634 {
 635   if (!DECL_INITIAL (gnu_decl) || DECL_INITIAL (gnu_decl) == error_mark_node)
 636     return;
 637
 638   tree_rest_of_compilation (gnu_decl);
 639 }
 640
 641 /* Adjusts the RLI used to layout a record after all the fields have been
 642    added.  We only handle the packed case and cause it to use the alignment
 643    that will pad the record at the end.  */
 644
 645 static void
 646 gnat_adjust_rli (record_layout_info rli ATTRIBUTE_UNUSED)
 647 {
 648 #if 0
 649   /* ??? This code seems to have no actual effect; record_align should already
 650      reflect the largest alignment desired by a field.  jason 2003-04-01  */
 651   unsigned int record_align = rli->unpadded_align;
 652   tree field;
 653
 654   /* If an alignment has been specified, don't use anything larger unless we
 655      have to.  */
 656   if (TYPE_ALIGN (rli->t) != 0 && TYPE_ALIGN (rli->t) < record_align)
 657     record_align = MAX (rli->record_align, TYPE_ALIGN (rli->t));
 658
 659   /* If any fields have variable size, we need to force the record to be at
 660      least as aligned as the alignment of that type.  */
 661   for (field = TYPE_FIELDS (rli->t); field; field = TREE_CHAIN (field))
 662     if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST)
 663       record_align = MAX (record_align, DECL_ALIGN (field));
 664
 665   if (TYPE_PACKED (rli->t))
 666     rli->record_align = record_align;
 667 #endif
 668 }
 669 \f
 670 /* These routines are used in conjunction with GCC exception handling.  */
 671
 672 /* Map compile-time to run-time tree for GCC exception handling scheme.  */
 673
 674 static tree
 675 gnat_eh_runtime_type (tree type)
 676 {
 677   return type;
 678 }
 679
 680 /* Return true if type A catches type B. Callback for flow analysis from
 681    the exception handling part of the back-end.  */
 682
 683 static int
 684 gnat_eh_type_covers (tree a, tree b)
 685 {
 686   /* a catches b if they represent the same exception id or if a
 687      is an "others".
 688
 689      ??? integer_zero_node for "others" is hardwired in too many places
 690      currently.  */
 691   return (a == b || a == integer_zero_node);
 692 }
 693 \f
 694 /* Get the alias set corresponding to a type or expression.  */
 695
 696 static HOST_WIDE_INT
 697 gnat_get_alias_set (tree type)
 698 {
 699   /* If this is a padding type, use the type of the first field.  */
 700   if (TREE_CODE (type) == RECORD_TYPE
 701       && TYPE_IS_PADDING_P (type))
 702     return get_alias_set (TREE_TYPE (TYPE_FIELDS (type)));
 703
 704   /* If the type is an unconstrained array, use the type of the
 705      self-referential array we make.  */
 706   else if (TREE_CODE (type) == UNCONSTRAINED_ARRAY_TYPE)
 707     return
 708       get_alias_set (TREE_TYPE (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (type)))));
 709
 710
 711   return -1;
 712 }
 713
 714 /* GNU_TYPE is a type.  Return its maxium size in bytes, if known.  */
 715
 716 static tree
 717 gnat_type_max_size (gnu_type)
 718      tree gnu_type;
 719 {
 720   return max_size (TYPE_SIZE_UNIT (gnu_type), true);
 721 }
 722
 723 /* GNU_TYPE is a type. Determine if it should be passed by reference by
 724    default.  */
 725
 726 bool
 727 default_pass_by_ref (tree gnu_type)
 728 {
 729   /* We pass aggregates by reference if they are sufficiently large.  The
 730      choice of constant here is somewhat arbitrary.  We also pass by
 731      reference if the target machine would either pass or return by
 732      reference.  Strictly speaking, we need only check the return if this
 733      is an In Out parameter, but it's probably best to err on the side of
 734      passing more things by reference.  */
 735
 736   if (pass_by_reference (NULL, TYPE_MODE (gnu_type), gnu_type, 1))
 737     return true;
 738
 739   if (targetm.calls.return_in_memory (gnu_type, NULL_TREE))
 740     return true;
 741
 742   if (AGGREGATE_TYPE_P (gnu_type)
 743       && (!host_integerp (TYPE_SIZE (gnu_type), 1)
 744           || 0 < compare_tree_int (TYPE_SIZE (gnu_type),
 745                                    8 * TYPE_ALIGN (gnu_type))))
 746     return true;
 747
 748   return false;
 749 }
 750
 751 /* GNU_TYPE is the type of a subprogram parameter.  Determine from the type if
 752    it should be passed by reference. */
 753
 754 bool
 755 must_pass_by_ref (tree gnu_type)
 756 {
 757   /* We pass only unconstrained objects, those required by the language
 758      to be passed by reference, and objects of variable size.  The latter
 759      is more efficient, avoids problems with variable size temporaries,
 760      and does not produce compatibility problems with C, since C does
 761      not have such objects.  */
 762   return (TREE_CODE (gnu_type) == UNCONSTRAINED_ARRAY_TYPE
 763           || (AGGREGATE_TYPE_P (gnu_type) && TYPE_BY_REFERENCE_P (gnu_type))
 764           || (TYPE_SIZE (gnu_type)
 765               && TREE_CODE (TYPE_SIZE (gnu_type)) != INTEGER_CST));
 766 }
 767
 768 /* This function is called by the front end to enumerate all the supported
 769    modes for the machine.  We pass a function which is called back with
 770    the following integer parameters:
 771
 772    FLOAT_P      nonzero if this represents a floating-point mode
 773    COMPLEX_P    nonzero is this represents a complex mode
 774    COUNT        count of number of items, nonzero for vector mode
 775    PRECISION    number of bits in data representation
 776    MANTISSA     number of bits in mantissa, if FP and known, else zero.
 777    SIZE         number of bits used to store data
 778    ALIGN        number of bits to which mode is aligned.  */
 779
 780 void
 781 enumerate_modes (void (*f) (int, int, int, int, int, int, unsigned int))
 782 {
 783   enum machine_mode i;
 784
 785   for (i = 0; i < NUM_MACHINE_MODES; i++)
 786     {
 787       enum machine_mode j;
 788       bool float_p = 0;
 789       bool complex_p = 0;
 790       bool vector_p = 0;
 791       bool skip_p = 0;
 792       int mantissa = 0;
 793       enum machine_mode inner_mode = i;
 794
 795       switch (GET_MODE_CLASS (i))
 796         {
 797         case MODE_INT:
 798           break;
 799         case MODE_FLOAT:
 800           float_p = 1;
 801           break;
 802         case MODE_COMPLEX_INT:
 803           complex_p = 1;
 804           inner_mode = GET_MODE_INNER (i);
 805           break;
 806         case MODE_COMPLEX_FLOAT:
 807           float_p = 1;
 808           complex_p = 1;
 809           inner_mode = GET_MODE_INNER (i);
 810           break;
 811         case MODE_VECTOR_INT:
 812           vector_p = 1;
 813           inner_mode = GET_MODE_INNER (i);
 814           break;
 815         case MODE_VECTOR_FLOAT:
 816           float_p = 1;
 817           vector_p = 1;
 818           inner_mode = GET_MODE_INNER (i);
 819           break;
 820         default:
 821           skip_p = 1;
 822         }
 823
 824       /* Skip this mode if it's one the front end doesn't need to know about
 825          (e.g., the CC modes) or if there is no add insn for that mode (or
 826          any wider mode), meaning it is not supported by the hardware.  If
 827          this a complex or vector mode, we care about the inner mode.  */
 828       for (j = inner_mode; j != VOIDmode; j = GET_MODE_WIDER_MODE (j))
 829         if (add_optab->handlers[j].insn_code != CODE_FOR_nothing)
 830           break;
 831
 832       if (float_p)
 833         {
 834           const struct real_format *fmt = REAL_MODE_FORMAT (inner_mode);
 835
 836           mantissa = fmt->p * fmt->log2_b;
 837         }
 838
 839       if (!skip_p && j != VOIDmode)
 840         (*f) (float_p, complex_p, vector_p ? GET_MODE_NUNITS (i) : 0,
 841               GET_MODE_BITSIZE (i), mantissa,
 842               GET_MODE_SIZE (i) * BITS_PER_UNIT, GET_MODE_ALIGNMENT (i));
 843     }
 844 }
 845
 846 int
 847 fp_prec_to_size (int prec)
 848 {
 849   enum machine_mode mode;
 850
 851   for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); mode != VOIDmode;
 852        mode = GET_MODE_WIDER_MODE (mode))
 853     if (GET_MODE_PRECISION (mode) == prec)
 854       return GET_MODE_BITSIZE (mode);
 855
 856   abort ();
 857 }
 858
 859 int
 860 fp_size_to_prec (int size)
 861 {
 862   enum machine_mode mode;
 863
 864   for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); mode != VOIDmode;
 865        mode = GET_MODE_WIDER_MODE (mode))
 866     if (GET_MODE_BITSIZE (mode) == size)
 867       return GET_MODE_PRECISION (mode);
 868
 869   abort ();
 870 }