gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2013 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "ansidecl.h"
  23 #include "coretypes.h"
  24 #include "opts.h"
  25 #include "tree.h"
  26 #include "gimple.h"
  27 #include "gimplify.h"
  28 #include "stor-layout.h"
  29 #include "ggc.h"
  30 #include "toplev.h"
  31 #include "debug.h"
  32 #include "options.h"
  33 #include "flags.h"
  34 #include "convert.h"
  35 #include "diagnostic.h"
  36 #include "langhooks.h"
  37 #include "langhooks-def.h"
  38 #include "target.h"
  39 #include "common/common-target.h"
  40
  41 #include <mpfr.h>
  42
  43 #include "go-c.h"
  44
  45 /* Language-dependent contents of a type.  */
  46
  47 struct GTY(()) lang_type
  48 {
  49   char dummy;
  50 };
  51
  52 /* Language-dependent contents of a decl.  */
  53
  54 struct GTY((variable_size)) lang_decl
  55 {
  56   char dummy;
  57 };
  58
  59 /* Language-dependent contents of an identifier.  This must include a
  60    tree_identifier.  */
  61
  62 struct GTY(()) lang_identifier
  63 {
  64   struct tree_identifier common;
  65 };
  66
  67 /* The resulting tree type.  */
  68
  69 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
  70            chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
  71 lang_tree_node
  72 {
  73   union tree_node GTY((tag ("0"),
  74                        desc ("tree_node_structure (&%h)"))) generic;
  75   struct lang_identifier GTY((tag ("1"))) identifier;
  76 };
  77
  78 /* We don't use language_function.  */
  79
  80 struct GTY(()) language_function
  81 {
  82   int dummy;
  83 };
  84
  85 /* Option information we need to pass to go_create_gogo.  */
  86
  87 static const char *go_pkgpath = NULL;
  88 static const char *go_prefix = NULL;
  89 static const char *go_relative_import_path = NULL;
  90
  91 /* Language hooks.  */
  92
  93 static bool
  94 go_langhook_init (void)
  95 {
  96   build_common_tree_nodes (false, false);
  97
  98   /* I don't know why this has to be done explicitly.  */
  99   void_list_node = build_tree_list (NULL_TREE, void_type_node);
 100
 101   /* We must create the gogo IR after calling build_common_tree_nodes
 102      (because Gogo::define_builtin_function_trees refers indirectly
 103      to, e.g., unsigned_char_type_node) but before calling
 104      build_common_builtin_nodes (because it calls, indirectly,
 105      go_type_for_size).  */
 106   go_create_gogo (INT_TYPE_SIZE, POINTER_SIZE, go_pkgpath, go_prefix,
 107                   go_relative_import_path);
 108
 109   build_common_builtin_nodes ();
 110
 111   /* The default precision for floating point numbers.  This is used
 112      for floating point constants with abstract type.  This may
 113      eventually be controllable by a command line option.  */
 114   mpfr_set_default_prec (256);
 115
 116   /* Go uses exceptions.  */
 117   using_eh_for_cleanups ();
 118
 119   return true;
 120 }
 121
 122 /* The option mask.  */
 123
 124 static unsigned int
 125 go_langhook_option_lang_mask (void)
 126 {
 127   return CL_Go;
 128 }
 129
 130 /* Initialize the options structure.  */
 131
 132 static void
 133 go_langhook_init_options_struct (struct gcc_options *opts)
 134 {
 135   /* Go says that signed overflow is precisely defined.  */
 136   opts->x_flag_wrapv = 1;
 137
 138   /* We default to using strict aliasing, since Go pointers are safe.
 139      This is turned off for code that imports the "unsafe" package,
 140      because using unsafe.pointer violates C style aliasing
 141      requirements.  */
 142   opts->x_flag_strict_aliasing = 1;
 143
 144   /* Default to avoiding range issues for complex multiply and
 145      divide.  */
 146   opts->x_flag_complex_method = 2;
 147
 148   /* The builtin math functions should not set errno.  */
 149   opts->x_flag_errno_math = 0;
 150   opts->frontend_set_flag_errno_math = true;
 151
 152   /* We turn on stack splitting if we can.  */
 153   if (targetm_common.supports_split_stack (false, opts))
 154     opts->x_flag_split_stack = 1;
 155
 156   /* Exceptions are used to handle recovering from panics.  */
 157   opts->x_flag_exceptions = 1;
 158   opts->x_flag_non_call_exceptions = 1;
 159 }
 160
 161 /* Infrastructure for a vector of char * pointers.  */
 162
 163 typedef const char *go_char_p;
 164
 165 /* The list of directories to search after all the Go specific
 166    directories have been searched.  */
 167
 168 static vec<go_char_p> go_search_dirs;
 169
 170 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 171
 172 static bool
 173 go_langhook_handle_option (
 174     size_t scode,
 175     const char *arg,
 176     int value ATTRIBUTE_UNUSED,
 177     int kind ATTRIBUTE_UNUSED,
 178     location_t loc ATTRIBUTE_UNUSED,
 179     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 180 {
 181   enum opt_code code = (enum opt_code) scode;
 182   bool ret = true;
 183
 184   switch (code)
 185     {
 186     case OPT_I:
 187       go_add_search_path (arg);
 188       break;
 189
 190     case OPT_L:
 191       /* A -L option is assumed to come from the compiler driver.
 192          This is a system directory.  We search the following
 193          directories, if they exist, before this one:
 194            dir/go/VERSION
 195            dir/go/VERSION/MACHINE
 196          This is like include/c++.  */
 197       {
 198         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 199         size_t len;
 200         char *p;
 201         struct stat st;
 202
 203         len = strlen (arg);
 204         p = XALLOCAVEC (char,
 205                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 206                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 207         strcpy (p, arg);
 208         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 209           strcat (p, dir_separator_str);
 210         strcat (p, "go");
 211         strcat (p, dir_separator_str);
 212         strcat (p, DEFAULT_TARGET_VERSION);
 213         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 214           {
 215             go_add_search_path (p);
 216             strcat (p, dir_separator_str);
 217             strcat (p, DEFAULT_TARGET_MACHINE);
 218             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 219               go_add_search_path (p);
 220           }
 221
 222         /* Search ARG too, but only after we've searched to Go
 223            specific directories for all -L arguments.  */
 224         go_search_dirs.safe_push (arg);
 225       }
 226       break;
 227
 228     case OPT_fgo_dump_:
 229       ret = go_enable_dump (arg) ? true : false;
 230       break;
 231
 232     case OPT_fgo_optimize_:
 233       ret = go_enable_optimize (arg) ? true : false;
 234       break;
 235
 236     case OPT_fgo_pkgpath_:
 237       go_pkgpath = arg;
 238       break;
 239
 240     case OPT_fgo_prefix_:
 241       go_prefix = arg;
 242       break;
 243
 244     case OPT_fgo_relative_import_path_:
 245       go_relative_import_path = arg;
 246       break;
 247
 248     default:
 249       /* Just return 1 to indicate that the option is valid.  */
 250       break;
 251     }
 252
 253   return ret;
 254 }
 255
 256 /* Run after parsing options.  */
 257
 258 static bool
 259 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 260 {
 261   unsigned int ix;
 262   const char *dir;
 263
 264   gcc_assert (num_in_fnames > 0);
 265
 266   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 267     go_add_search_path (dir);
 268   go_search_dirs.release ();
 269
 270   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
 271     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 272
 273   /* The isolate_erroneous_paths optimization can change a nil
 274      dereference from a panic to a trap, so we have to disable it for
 275      Go, even though it is normally enabled by -O2.  */
 276   if (!global_options_set.x_flag_isolate_erroneous_paths)
 277     global_options.x_flag_isolate_erroneous_paths = 0;
 278
 279   /* Returning false means that the backend should be used.  */
 280   return false;
 281 }
 282
 283 static void
 284 go_langhook_parse_file (void)
 285 {
 286   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 287                         go_require_return_statement);
 288 }
 289
 290 static tree
 291 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 292 {
 293   return go_type_for_size (bits, unsignedp);
 294 }
 295
 296 static tree
 297 go_langhook_type_for_mode (enum machine_mode mode, int unsignedp)
 298 {
 299   tree type;
 300   /* Go has no vector types.  Build them here.  FIXME: It does not
 301      make sense for the middle-end to ask the frontend for a type
 302      which the frontend does not support.  However, at least for now
 303      it is required.  See PR 46805.  */
 304   if (VECTOR_MODE_P (mode))
 305     {
 306       tree inner;
 307
 308       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 309       if (inner != NULL_TREE)
 310         return build_vector_type_for_mode (inner, mode);
 311       return NULL_TREE;
 312     }
 313
 314   type = go_type_for_mode (mode, unsignedp);
 315   if (type)
 316     return type;
 317
 318 #if HOST_BITS_PER_WIDE_INT >= 64
 319   /* The middle-end and some backends rely on TImode being supported
 320      for 64-bit HWI.  */
 321   if (mode == TImode)
 322     {
 323       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 324                                              unsignedp);
 325       if (type && TYPE_MODE (type) == TImode)
 326         return type;
 327     }
 328 #endif
 329   return NULL_TREE;
 330 }
 331
 332 /* Record a builtin function.  We just ignore builtin functions.  */
 333
 334 static tree
 335 go_langhook_builtin_function (tree decl)
 336 {
 337   return decl;
 338 }
 339
 340 /* Return true if we are in the global binding level.  */
 341
 342 static bool
 343 go_langhook_global_bindings_p (void)
 344 {
 345   return current_function_decl == NULL_TREE;
 346 }
 347
 348 /* Push a declaration into the current binding level.  We can't
 349    usefully implement this since we don't want to convert from tree
 350    back to one of our internal data structures.  I think the only way
 351    this is used is to record a decl which is to be returned by
 352    getdecls, and we could implement it for that purpose if
 353    necessary.  */
 354
 355 static tree
 356 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 357 {
 358   gcc_unreachable ();
 359 }
 360
 361 /* This hook is used to get the current list of declarations as trees.
 362    We don't support that; instead we use the write_globals hook.  This
 363    can't simply crash because it is called by -gstabs.  */
 364
 365 static tree
 366 go_langhook_getdecls (void)
 367 {
 368   return NULL;
 369 }
 370
 371 /* Write out globals.  */
 372
 373 static void
 374 go_langhook_write_globals (void)
 375 {
 376   go_write_globals ();
 377 }
 378
 379 /* Go specific gimplification.  We need to gimplify
 380    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 381    it.  */
 382
 383 static int
 384 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 385 {
 386   if (TREE_CODE (*expr_p) == CALL_EXPR
 387       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 388     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 389                    is_gimple_val, fb_rvalue);
 390   return GS_UNHANDLED;
 391 }
 392
 393 /* Return a decl for the exception personality function.  The function
 394    itself is implemented in libgo/runtime/go-unwind.c.  */
 395
 396 static tree
 397 go_langhook_eh_personality (void)
 398 {
 399   static tree personality_decl;
 400   if (personality_decl == NULL_TREE)
 401     {
 402       personality_decl = build_personality_function ("gccgo");
 403       go_preserve_from_gc (personality_decl);
 404     }
 405   return personality_decl;
 406 }
 407
 408 /* Functions called directly by the generic backend.  */
 409
 410 tree
 411 convert (tree type, tree expr)
 412 {
 413   if (type == error_mark_node
 414       || expr == error_mark_node
 415       || TREE_TYPE (expr) == error_mark_node)
 416     return error_mark_node;
 417
 418   if (type == TREE_TYPE (expr))
 419     return expr;
 420
 421   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 422     return fold_convert (type, expr);
 423
 424   switch (TREE_CODE (type))
 425     {
 426     case VOID_TYPE:
 427     case BOOLEAN_TYPE:
 428       return fold_convert (type, expr);
 429     case INTEGER_TYPE:
 430       return fold (convert_to_integer (type, expr));
 431     case POINTER_TYPE:
 432       return fold (convert_to_pointer (type, expr));
 433     case REAL_TYPE:
 434       return fold (convert_to_real (type, expr));
 435     case COMPLEX_TYPE:
 436       return fold (convert_to_complex (type, expr));
 437     default:
 438       break;
 439     }
 440
 441   gcc_unreachable ();
 442 }
 443
 444 /* FIXME: This is a hack to preserve trees that we create from the
 445    garbage collector.  */
 446
 447 static GTY(()) tree go_gc_root;
 448
 449 void
 450 go_preserve_from_gc (tree t)
 451 {
 452   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 453 }
 454
 455 /* Convert an identifier for use in an error message.  */
 456
 457 const char *
 458 go_localize_identifier (const char *ident)
 459 {
 460   return identifier_to_locale (ident);
 461 }
 462
 463 #undef LANG_HOOKS_NAME
 464 #undef LANG_HOOKS_INIT
 465 #undef LANG_HOOKS_OPTION_LANG_MASK
 466 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 467 #undef LANG_HOOKS_HANDLE_OPTION
 468 #undef LANG_HOOKS_POST_OPTIONS
 469 #undef LANG_HOOKS_PARSE_FILE
 470 #undef LANG_HOOKS_TYPE_FOR_MODE
 471 #undef LANG_HOOKS_TYPE_FOR_SIZE
 472 #undef LANG_HOOKS_BUILTIN_FUNCTION
 473 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 474 #undef LANG_HOOKS_PUSHDECL
 475 #undef LANG_HOOKS_GETDECLS
 476 #undef LANG_HOOKS_WRITE_GLOBALS
 477 #undef LANG_HOOKS_GIMPLIFY_EXPR
 478 #undef LANG_HOOKS_EH_PERSONALITY
 479
 480 #define LANG_HOOKS_NAME                 "GNU Go"
 481 #define LANG_HOOKS_INIT                 go_langhook_init
 482 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 483 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 484 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 485 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 486 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 487 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 488 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 489 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 490 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 491 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 492 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 493 #define LANG_HOOKS_WRITE_GLOBALS        go_langhook_write_globals
 494 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 495 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 496
 497 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 498
 499 #include "gt-go-go-lang.h"
 500 #include "gtype-go.h"