gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2016 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 "coretypes.h"
  23 #include "target.h"
  24 #include "tree.h"
  25 #include "gimple-expr.h"
  26 #include "diagnostic.h"
  27 #include "opts.h"
  28 #include "fold-const.h"
  29 #include "gimplify.h"
  30 #include "stor-layout.h"
  31 #include "debug.h"
  32 #include "convert.h"
  33 #include "langhooks.h"
  34 #include "langhooks-def.h"
  35 #include "common/common-target.h"
  36
  37 #include <mpfr.h>
  38
  39 #include "go-c.h"
  40
  41 /* Language-dependent contents of a type.  */
  42
  43 struct GTY(()) lang_type
  44 {
  45   char dummy;
  46 };
  47
  48 /* Language-dependent contents of a decl.  */
  49
  50 struct GTY(()) lang_decl
  51 {
  52   char dummy;
  53 };
  54
  55 /* Language-dependent contents of an identifier.  This must include a
  56    tree_identifier.  */
  57
  58 struct GTY(()) lang_identifier
  59 {
  60   struct tree_identifier common;
  61 };
  62
  63 /* The resulting tree type.  */
  64
  65 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
  66            chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
  67 lang_tree_node
  68 {
  69   union tree_node GTY((tag ("0"),
  70                        desc ("tree_node_structure (&%h)"))) generic;
  71   struct lang_identifier GTY((tag ("1"))) identifier;
  72 };
  73
  74 /* We don't use language_function.  */
  75
  76 struct GTY(()) language_function
  77 {
  78   int dummy;
  79 };
  80
  81 /* Option information we need to pass to go_create_gogo.  */
  82
  83 static const char *go_pkgpath = NULL;
  84 static const char *go_prefix = NULL;
  85 static const char *go_relative_import_path = NULL;
  86
  87 /* Language hooks.  */
  88
  89 static bool
  90 go_langhook_init (void)
  91 {
  92   build_common_tree_nodes (false, false);
  93
  94   /* I don't know why this has to be done explicitly.  */
  95   void_list_node = build_tree_list (NULL_TREE, void_type_node);
  96
  97   /* We must create the gogo IR after calling build_common_tree_nodes
  98      (because Gogo::define_builtin_function_trees refers indirectly
  99      to, e.g., unsigned_char_type_node) but before calling
 100      build_common_builtin_nodes (because it calls, indirectly,
 101      go_type_for_size).  */
 102   go_create_gogo (INT_TYPE_SIZE, POINTER_SIZE, go_pkgpath, go_prefix,
 103                   go_relative_import_path, go_check_divide_zero,
 104                   go_check_divide_overflow);
 105
 106   build_common_builtin_nodes ();
 107
 108   /* The default precision for floating point numbers.  This is used
 109      for floating point constants with abstract type.  This may
 110      eventually be controllable by a command line option.  */
 111   mpfr_set_default_prec (256);
 112
 113   /* Go uses exceptions.  */
 114   using_eh_for_cleanups ();
 115
 116   return true;
 117 }
 118
 119 /* The option mask.  */
 120
 121 static unsigned int
 122 go_langhook_option_lang_mask (void)
 123 {
 124   return CL_Go;
 125 }
 126
 127 /* Initialize the options structure.  */
 128
 129 static void
 130 go_langhook_init_options_struct (struct gcc_options *opts)
 131 {
 132   /* Go says that signed overflow is precisely defined.  */
 133   opts->x_flag_wrapv = 1;
 134
 135   /* We default to using strict aliasing, since Go pointers are safe.
 136      This is turned off for code that imports the "unsafe" package,
 137      because using unsafe.pointer violates C style aliasing
 138      requirements.  */
 139   opts->x_flag_strict_aliasing = 1;
 140
 141   /* Default to avoiding range issues for complex multiply and
 142      divide.  */
 143   opts->x_flag_complex_method = 2;
 144
 145   /* The builtin math functions should not set errno.  */
 146   opts->x_flag_errno_math = 0;
 147   opts->frontend_set_flag_errno_math = true;
 148
 149   /* Exceptions are used to handle recovering from panics.  */
 150   opts->x_flag_exceptions = 1;
 151   opts->x_flag_non_call_exceptions = 1;
 152
 153   /* Go programs expect runtime.Callers to work, and that uses
 154      libbacktrace that uses debug info.  Set the debug info level to 1
 155      by default.  In post_options we will set the debug type if the
 156      debug info level was not set back to 0 on the command line.  */
 157   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 158 }
 159
 160 /* Infrastructure for a vector of char * pointers.  */
 161
 162 typedef const char *go_char_p;
 163
 164 /* The list of directories to search after all the Go specific
 165    directories have been searched.  */
 166
 167 static vec<go_char_p> go_search_dirs;
 168
 169 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 170
 171 static bool
 172 go_langhook_handle_option (
 173     size_t scode,
 174     const char *arg,
 175     int value ATTRIBUTE_UNUSED,
 176     int kind ATTRIBUTE_UNUSED,
 177     location_t loc ATTRIBUTE_UNUSED,
 178     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 179 {
 180   enum opt_code code = (enum opt_code) scode;
 181   bool ret = true;
 182
 183   switch (code)
 184     {
 185     case OPT_I:
 186       go_add_search_path (arg);
 187       break;
 188
 189     case OPT_L:
 190       /* A -L option is assumed to come from the compiler driver.
 191          This is a system directory.  We search the following
 192          directories, if they exist, before this one:
 193            dir/go/VERSION
 194            dir/go/VERSION/MACHINE
 195          This is like include/c++.  */
 196       {
 197         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 198         size_t len;
 199         char *p;
 200         struct stat st;
 201
 202         len = strlen (arg);
 203         p = XALLOCAVEC (char,
 204                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 205                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 206         strcpy (p, arg);
 207         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 208           strcat (p, dir_separator_str);
 209         strcat (p, "go");
 210         strcat (p, dir_separator_str);
 211         strcat (p, DEFAULT_TARGET_VERSION);
 212         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 213           {
 214             go_add_search_path (p);
 215             strcat (p, dir_separator_str);
 216             strcat (p, DEFAULT_TARGET_MACHINE);
 217             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 218               go_add_search_path (p);
 219           }
 220
 221         /* Search ARG too, but only after we've searched to Go
 222            specific directories for all -L arguments.  */
 223         go_search_dirs.safe_push (arg);
 224       }
 225       break;
 226
 227     case OPT_fgo_dump_:
 228       ret = go_enable_dump (arg) ? true : false;
 229       break;
 230
 231     case OPT_fgo_optimize_:
 232       ret = go_enable_optimize (arg) ? true : false;
 233       break;
 234
 235     case OPT_fgo_pkgpath_:
 236       go_pkgpath = arg;
 237       break;
 238
 239     case OPT_fgo_prefix_:
 240       go_prefix = arg;
 241       break;
 242
 243     case OPT_fgo_relative_import_path_:
 244       go_relative_import_path = arg;
 245       break;
 246
 247     default:
 248       /* Just return 1 to indicate that the option is valid.  */
 249       break;
 250     }
 251
 252   return ret;
 253 }
 254
 255 /* Run after parsing options.  */
 256
 257 static bool
 258 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 259 {
 260   unsigned int ix;
 261   const char *dir;
 262
 263   gcc_assert (num_in_fnames > 0);
 264
 265   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 266     go_add_search_path (dir);
 267   go_search_dirs.release ();
 268
 269   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
 270     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 271
 272   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 273   if (!global_options_set.x_flag_optimize_sibling_calls)
 274     global_options.x_flag_optimize_sibling_calls = 0;
 275
 276   /* If the debug info level is still 1, as set in init_options, make
 277      sure that some debugging type is selected.  */
 278   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 279       && global_options.x_write_symbols == NO_DEBUG)
 280     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 281
 282   /* We turn on stack splitting if we can.  */
 283   if (!global_options_set.x_flag_split_stack
 284       && targetm_common.supports_split_stack (false, &global_options))
 285     global_options.x_flag_split_stack = 1;
 286
 287   /* Returning false means that the backend should be used.  */
 288   return false;
 289 }
 290
 291 static void
 292 go_langhook_parse_file (void)
 293 {
 294   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 295                         go_require_return_statement);
 296
 297   /* Final processing of globals and early debug info generation.  */
 298   go_write_globals ();
 299 }
 300
 301 static tree
 302 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 303 {
 304   tree type;
 305   if (unsignedp)
 306     {
 307       if (bits == INT_TYPE_SIZE)
 308         type = unsigned_type_node;
 309       else if (bits == CHAR_TYPE_SIZE)
 310         type = unsigned_char_type_node;
 311       else if (bits == SHORT_TYPE_SIZE)
 312         type = short_unsigned_type_node;
 313       else if (bits == LONG_TYPE_SIZE)
 314         type = long_unsigned_type_node;
 315       else if (bits == LONG_LONG_TYPE_SIZE)
 316         type = long_long_unsigned_type_node;
 317       else
 318         type = make_unsigned_type(bits);
 319     }
 320   else
 321     {
 322       if (bits == INT_TYPE_SIZE)
 323         type = integer_type_node;
 324       else if (bits == CHAR_TYPE_SIZE)
 325         type = signed_char_type_node;
 326       else if (bits == SHORT_TYPE_SIZE)
 327         type = short_integer_type_node;
 328       else if (bits == LONG_TYPE_SIZE)
 329         type = long_integer_type_node;
 330       else if (bits == LONG_LONG_TYPE_SIZE)
 331         type = long_long_integer_type_node;
 332       else
 333         type = make_signed_type(bits);
 334     }
 335   return type;
 336 }
 337
 338 static tree
 339 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 340 {
 341   tree type;
 342   /* Go has no vector types.  Build them here.  FIXME: It does not
 343      make sense for the middle-end to ask the frontend for a type
 344      which the frontend does not support.  However, at least for now
 345      it is required.  See PR 46805.  */
 346   if (VECTOR_MODE_P (mode))
 347     {
 348       tree inner;
 349
 350       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 351       if (inner != NULL_TREE)
 352         return build_vector_type_for_mode (inner, mode);
 353       return NULL_TREE;
 354     }
 355
 356   // FIXME: This static_cast should be in machmode.h.
 357   enum mode_class mc = static_cast<enum mode_class>(GET_MODE_CLASS(mode));
 358   if (mc == MODE_INT)
 359     return go_langhook_type_for_size(GET_MODE_BITSIZE(mode), unsignedp);
 360   else if (mc == MODE_FLOAT)
 361     {
 362       switch (GET_MODE_BITSIZE (mode))
 363         {
 364         case 32:
 365           return float_type_node;
 366         case 64:
 367           return double_type_node;
 368         default:
 369           // We have to check for long double in order to support
 370           // i386 excess precision.
 371           if (mode == TYPE_MODE(long_double_type_node))
 372             return long_double_type_node;
 373         }
 374     }
 375   else if (mc == MODE_COMPLEX_FLOAT)
 376     {
 377       switch (GET_MODE_BITSIZE (mode))
 378         {
 379         case 64:
 380           return complex_float_type_node;
 381         case 128:
 382           return complex_double_type_node;
 383         default:
 384           // We have to check for long double in order to support
 385           // i386 excess precision.
 386           if (mode == TYPE_MODE(complex_long_double_type_node))
 387             return complex_long_double_type_node;
 388         }
 389     }
 390
 391 #if HOST_BITS_PER_WIDE_INT >= 64
 392   /* The middle-end and some backends rely on TImode being supported
 393      for 64-bit HWI.  */
 394   if (mode == TImode)
 395     {
 396       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 397                                              unsignedp);
 398       if (type && TYPE_MODE (type) == TImode)
 399         return type;
 400     }
 401 #endif
 402   return NULL_TREE;
 403 }
 404
 405 /* Record a builtin function.  We just ignore builtin functions.  */
 406
 407 static tree
 408 go_langhook_builtin_function (tree decl)
 409 {
 410   return decl;
 411 }
 412
 413 /* Return true if we are in the global binding level.  */
 414
 415 static bool
 416 go_langhook_global_bindings_p (void)
 417 {
 418   return current_function_decl == NULL_TREE;
 419 }
 420
 421 /* Push a declaration into the current binding level.  We can't
 422    usefully implement this since we don't want to convert from tree
 423    back to one of our internal data structures.  I think the only way
 424    this is used is to record a decl which is to be returned by
 425    getdecls, and we could implement it for that purpose if
 426    necessary.  */
 427
 428 static tree
 429 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 430 {
 431   gcc_unreachable ();
 432 }
 433
 434 /* This hook is used to get the current list of declarations as trees.
 435    We don't support that; instead we use the write_globals hook.  This
 436    can't simply crash because it is called by -gstabs.  */
 437
 438 static tree
 439 go_langhook_getdecls (void)
 440 {
 441   return NULL;
 442 }
 443
 444 /* Go specific gimplification.  We need to gimplify
 445    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 446    it.  */
 447
 448 static int
 449 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 450 {
 451   if (TREE_CODE (*expr_p) == CALL_EXPR
 452       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 453     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 454                    is_gimple_val, fb_rvalue);
 455   return GS_UNHANDLED;
 456 }
 457
 458 /* Return a decl for the exception personality function.  The function
 459    itself is implemented in libgo/runtime/go-unwind.c.  */
 460
 461 static tree
 462 go_langhook_eh_personality (void)
 463 {
 464   static tree personality_decl;
 465   if (personality_decl == NULL_TREE)
 466     {
 467       personality_decl = build_personality_function ("gccgo");
 468       go_preserve_from_gc (personality_decl);
 469     }
 470   return personality_decl;
 471 }
 472
 473 /* Functions called directly by the generic backend.  */
 474
 475 tree
 476 convert (tree type, tree expr)
 477 {
 478   if (type == error_mark_node
 479       || expr == error_mark_node
 480       || TREE_TYPE (expr) == error_mark_node)
 481     return error_mark_node;
 482
 483   if (type == TREE_TYPE (expr))
 484     return expr;
 485
 486   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 487     return fold_convert (type, expr);
 488
 489   switch (TREE_CODE (type))
 490     {
 491     case VOID_TYPE:
 492     case BOOLEAN_TYPE:
 493       return fold_convert (type, expr);
 494     case INTEGER_TYPE:
 495       return fold (convert_to_integer (type, expr));
 496     case POINTER_TYPE:
 497       return fold (convert_to_pointer (type, expr));
 498     case REAL_TYPE:
 499       return fold (convert_to_real (type, expr));
 500     case COMPLEX_TYPE:
 501       return fold (convert_to_complex (type, expr));
 502     default:
 503       break;
 504     }
 505
 506   gcc_unreachable ();
 507 }
 508
 509 /* FIXME: This is a hack to preserve trees that we create from the
 510    garbage collector.  */
 511
 512 static GTY(()) tree go_gc_root;
 513
 514 void
 515 go_preserve_from_gc (tree t)
 516 {
 517   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 518 }
 519
 520 /* Convert an identifier for use in an error message.  */
 521
 522 const char *
 523 go_localize_identifier (const char *ident)
 524 {
 525   return identifier_to_locale (ident);
 526 }
 527
 528 #undef LANG_HOOKS_NAME
 529 #undef LANG_HOOKS_INIT
 530 #undef LANG_HOOKS_OPTION_LANG_MASK
 531 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 532 #undef LANG_HOOKS_HANDLE_OPTION
 533 #undef LANG_HOOKS_POST_OPTIONS
 534 #undef LANG_HOOKS_PARSE_FILE
 535 #undef LANG_HOOKS_TYPE_FOR_MODE
 536 #undef LANG_HOOKS_TYPE_FOR_SIZE
 537 #undef LANG_HOOKS_BUILTIN_FUNCTION
 538 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 539 #undef LANG_HOOKS_PUSHDECL
 540 #undef LANG_HOOKS_GETDECLS
 541 #undef LANG_HOOKS_GIMPLIFY_EXPR
 542 #undef LANG_HOOKS_EH_PERSONALITY
 543
 544 #define LANG_HOOKS_NAME                 "GNU Go"
 545 #define LANG_HOOKS_INIT                 go_langhook_init
 546 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 547 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 548 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 549 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 550 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 551 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 552 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 553 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 554 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 555 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 556 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 557 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 558 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 559
 560 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 561
 562 #include "gt-go-go-lang.h"
 563 #include "gtype-go.h"