gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2017 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 #include "go-gcc.h"
  41
  42 /* Language-dependent contents of a type.  */
  43
  44 struct GTY(()) lang_type
  45 {
  46   char dummy;
  47 };
  48
  49 /* Language-dependent contents of a decl.  */
  50
  51 struct GTY(()) lang_decl
  52 {
  53   char dummy;
  54 };
  55
  56 /* Language-dependent contents of an identifier.  This must include a
  57    tree_identifier.  */
  58
  59 struct GTY(()) lang_identifier
  60 {
  61   struct tree_identifier common;
  62 };
  63
  64 /* The resulting tree type.  */
  65
  66 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
  67            chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
  68 lang_tree_node
  69 {
  70   union tree_node GTY((tag ("0"),
  71                        desc ("tree_node_structure (&%h)"))) generic;
  72   struct lang_identifier GTY((tag ("1"))) identifier;
  73 };
  74
  75 /* We don't use language_function.  */
  76
  77 struct GTY(()) language_function
  78 {
  79   int dummy;
  80 };
  81
  82 /* Option information we need to pass to go_create_gogo.  */
  83
  84 static const char *go_pkgpath = NULL;
  85 static const char *go_prefix = NULL;
  86 static const char *go_relative_import_path = NULL;
  87 static const char *go_c_header = NULL;
  88
  89 /* Language hooks.  */
  90
  91 static bool
  92 go_langhook_init (void)
  93 {
  94   build_common_tree_nodes (false);
  95
  96   /* I don't know why this has to be done explicitly.  */
  97   void_list_node = build_tree_list (NULL_TREE, void_type_node);
  98
  99   /* We must create the gogo IR after calling build_common_tree_nodes
 100      (because Gogo::define_builtin_function_trees refers indirectly
 101      to, e.g., unsigned_char_type_node) but before calling
 102      build_common_builtin_nodes (because it calls, indirectly,
 103      go_type_for_size).  */
 104   struct go_create_gogo_args args;
 105   args.int_type_size = INT_TYPE_SIZE;
 106   args.pointer_size = POINTER_SIZE;
 107   args.pkgpath = go_pkgpath;
 108   args.prefix = go_prefix;
 109   args.relative_import_path = go_relative_import_path;
 110   args.c_header = go_c_header;
 111   args.check_divide_by_zero = go_check_divide_zero;
 112   args.check_divide_overflow = go_check_divide_overflow;
 113   args.compiling_runtime = go_compiling_runtime;
 114   args.debug_escape_level = go_debug_escape_level;
 115   args.nil_check_size_threshold = 4096;
 116   args.linemap = go_get_linemap();
 117   args.backend = go_get_backend();
 118   go_create_gogo (&args);
 119
 120   build_common_builtin_nodes ();
 121
 122   /* The default precision for floating point numbers.  This is used
 123      for floating point constants with abstract type.  This may
 124      eventually be controllable by a command line option.  */
 125   mpfr_set_default_prec (256);
 126
 127   /* Go uses exceptions.  */
 128   using_eh_for_cleanups ();
 129
 130   return true;
 131 }
 132
 133 /* The option mask.  */
 134
 135 static unsigned int
 136 go_langhook_option_lang_mask (void)
 137 {
 138   return CL_Go;
 139 }
 140
 141 /* Initialize the options structure.  */
 142
 143 static void
 144 go_langhook_init_options_struct (struct gcc_options *opts)
 145 {
 146   /* Go says that signed overflow is precisely defined.  */
 147   opts->x_flag_wrapv = 1;
 148
 149   /* We default to using strict aliasing, since Go pointers are safe.
 150      This is turned off for code that imports the "unsafe" package,
 151      because using unsafe.pointer violates C style aliasing
 152      requirements.  */
 153   opts->x_flag_strict_aliasing = 1;
 154
 155   /* Default to avoiding range issues for complex multiply and
 156      divide.  */
 157   opts->x_flag_complex_method = 2;
 158
 159   /* The builtin math functions should not set errno.  */
 160   opts->x_flag_errno_math = 0;
 161   opts->frontend_set_flag_errno_math = true;
 162
 163   /* Exceptions are used to handle recovering from panics.  */
 164   opts->x_flag_exceptions = 1;
 165   opts->x_flag_non_call_exceptions = 1;
 166
 167   /* We need to keep pointers live for the garbage collector.  */
 168   opts->x_flag_keep_gc_roots_live = 1;
 169
 170   /* Go programs expect runtime.Callers to work, and that uses
 171      libbacktrace that uses debug info.  Set the debug info level to 1
 172      by default.  In post_options we will set the debug type if the
 173      debug info level was not set back to 0 on the command line.  */
 174   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 175 }
 176
 177 /* Infrastructure for a vector of char * pointers.  */
 178
 179 typedef const char *go_char_p;
 180
 181 /* The list of directories to search after all the Go specific
 182    directories have been searched.  */
 183
 184 static vec<go_char_p> go_search_dirs;
 185
 186 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 187
 188 static bool
 189 go_langhook_handle_option (
 190     size_t scode,
 191     const char *arg,
 192     int value ATTRIBUTE_UNUSED,
 193     int kind ATTRIBUTE_UNUSED,
 194     location_t loc ATTRIBUTE_UNUSED,
 195     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 196 {
 197   enum opt_code code = (enum opt_code) scode;
 198   bool ret = true;
 199
 200   switch (code)
 201     {
 202     case OPT_I:
 203       go_add_search_path (arg);
 204       break;
 205
 206     case OPT_L:
 207       /* A -L option is assumed to come from the compiler driver.
 208          This is a system directory.  We search the following
 209          directories, if they exist, before this one:
 210            dir/go/VERSION
 211            dir/go/VERSION/MACHINE
 212          This is like include/c++.  */
 213       {
 214         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 215         size_t len;
 216         char *p;
 217         struct stat st;
 218
 219         len = strlen (arg);
 220         p = XALLOCAVEC (char,
 221                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 222                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 223         strcpy (p, arg);
 224         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 225           strcat (p, dir_separator_str);
 226         strcat (p, "go");
 227         strcat (p, dir_separator_str);
 228         strcat (p, DEFAULT_TARGET_VERSION);
 229         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 230           {
 231             go_add_search_path (p);
 232             strcat (p, dir_separator_str);
 233             strcat (p, DEFAULT_TARGET_MACHINE);
 234             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 235               go_add_search_path (p);
 236           }
 237
 238         /* Search ARG too, but only after we've searched to Go
 239            specific directories for all -L arguments.  */
 240         go_search_dirs.safe_push (arg);
 241       }
 242       break;
 243
 244     case OPT_fgo_dump_:
 245       ret = go_enable_dump (arg) ? true : false;
 246       break;
 247
 248     case OPT_fgo_optimize_:
 249       ret = go_enable_optimize (arg) ? true : false;
 250       break;
 251
 252     case OPT_fgo_pkgpath_:
 253       go_pkgpath = arg;
 254       break;
 255
 256     case OPT_fgo_prefix_:
 257       go_prefix = arg;
 258       break;
 259
 260     case OPT_fgo_relative_import_path_:
 261       go_relative_import_path = arg;
 262       break;
 263
 264     case OPT_fgo_c_header_:
 265       go_c_header = arg;
 266       break;
 267
 268     default:
 269       /* Just return 1 to indicate that the option is valid.  */
 270       break;
 271     }
 272
 273   return ret;
 274 }
 275
 276 /* Run after parsing options.  */
 277
 278 static bool
 279 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 280 {
 281   unsigned int ix;
 282   const char *dir;
 283
 284   gcc_assert (num_in_fnames > 0);
 285
 286   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 287     go_add_search_path (dir);
 288   go_search_dirs.release ();
 289
 290   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
 291     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 292
 293   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 294   if (!global_options_set.x_flag_optimize_sibling_calls)
 295     global_options.x_flag_optimize_sibling_calls = 0;
 296
 297   /* If the debug info level is still 1, as set in init_options, make
 298      sure that some debugging type is selected.  */
 299   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 300       && global_options.x_write_symbols == NO_DEBUG)
 301     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 302
 303   /* We turn on stack splitting if we can.  */
 304   if (!global_options_set.x_flag_split_stack
 305       && targetm_common.supports_split_stack (false, &global_options))
 306     global_options.x_flag_split_stack = 1;
 307
 308   /* If stack splitting is turned on, and the user did not explicitly
 309      request function partitioning, turn off partitioning, as it
 310      confuses the linker when trying to handle partitioned split-stack
 311      code that calls a non-split-stack function.  */
 312   if (global_options.x_flag_split_stack
 313       && global_options.x_flag_reorder_blocks_and_partition
 314       && !global_options_set.x_flag_reorder_blocks_and_partition)
 315     global_options.x_flag_reorder_blocks_and_partition = 0;
 316
 317   /* Returning false means that the backend should be used.  */
 318   return false;
 319 }
 320
 321 static void
 322 go_langhook_parse_file (void)
 323 {
 324   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 325                         go_require_return_statement);
 326
 327   /* Final processing of globals and early debug info generation.  */
 328   go_write_globals ();
 329 }
 330
 331 static tree
 332 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 333 {
 334   tree type;
 335   if (unsignedp)
 336     {
 337       if (bits == INT_TYPE_SIZE)
 338         type = unsigned_type_node;
 339       else if (bits == CHAR_TYPE_SIZE)
 340         type = unsigned_char_type_node;
 341       else if (bits == SHORT_TYPE_SIZE)
 342         type = short_unsigned_type_node;
 343       else if (bits == LONG_TYPE_SIZE)
 344         type = long_unsigned_type_node;
 345       else if (bits == LONG_LONG_TYPE_SIZE)
 346         type = long_long_unsigned_type_node;
 347       else
 348         type = make_unsigned_type(bits);
 349     }
 350   else
 351     {
 352       if (bits == INT_TYPE_SIZE)
 353         type = integer_type_node;
 354       else if (bits == CHAR_TYPE_SIZE)
 355         type = signed_char_type_node;
 356       else if (bits == SHORT_TYPE_SIZE)
 357         type = short_integer_type_node;
 358       else if (bits == LONG_TYPE_SIZE)
 359         type = long_integer_type_node;
 360       else if (bits == LONG_LONG_TYPE_SIZE)
 361         type = long_long_integer_type_node;
 362       else
 363         type = make_signed_type(bits);
 364     }
 365   return type;
 366 }
 367
 368 static tree
 369 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 370 {
 371   tree type;
 372   /* Go has no vector types.  Build them here.  FIXME: It does not
 373      make sense for the middle-end to ask the frontend for a type
 374      which the frontend does not support.  However, at least for now
 375      it is required.  See PR 46805.  */
 376   if (VECTOR_MODE_P (mode))
 377     {
 378       tree inner;
 379
 380       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 381       if (inner != NULL_TREE)
 382         return build_vector_type_for_mode (inner, mode);
 383       return NULL_TREE;
 384     }
 385
 386   scalar_int_mode imode;
 387   scalar_float_mode fmode;
 388   complex_mode cmode;
 389   if (is_int_mode (mode, &imode))
 390     return go_langhook_type_for_size (GET_MODE_BITSIZE (imode), unsignedp);
 391   else if (is_float_mode (mode, &fmode))
 392     {
 393       switch (GET_MODE_BITSIZE (fmode))
 394         {
 395         case 32:
 396           return float_type_node;
 397         case 64:
 398           return double_type_node;
 399         default:
 400           // We have to check for long double in order to support
 401           // i386 excess precision.
 402           if (fmode == TYPE_MODE(long_double_type_node))
 403             return long_double_type_node;
 404         }
 405     }
 406   else if (is_complex_float_mode (mode, &cmode))
 407     {
 408       switch (GET_MODE_BITSIZE (cmode))
 409         {
 410         case 64:
 411           return complex_float_type_node;
 412         case 128:
 413           return complex_double_type_node;
 414         default:
 415           // We have to check for long double in order to support
 416           // i386 excess precision.
 417           if (cmode == TYPE_MODE(complex_long_double_type_node))
 418             return complex_long_double_type_node;
 419         }
 420     }
 421
 422 #if HOST_BITS_PER_WIDE_INT >= 64
 423   /* The middle-end and some backends rely on TImode being supported
 424      for 64-bit HWI.  */
 425   if (mode == TImode)
 426     {
 427       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 428                                              unsignedp);
 429       if (type && TYPE_MODE (type) == TImode)
 430         return type;
 431     }
 432 #endif
 433   return NULL_TREE;
 434 }
 435
 436 /* Record a builtin function.  We just ignore builtin functions.  */
 437
 438 static tree
 439 go_langhook_builtin_function (tree decl)
 440 {
 441   return decl;
 442 }
 443
 444 /* Return true if we are in the global binding level.  */
 445
 446 static bool
 447 go_langhook_global_bindings_p (void)
 448 {
 449   return current_function_decl == NULL_TREE;
 450 }
 451
 452 /* Push a declaration into the current binding level.  We can't
 453    usefully implement this since we don't want to convert from tree
 454    back to one of our internal data structures.  I think the only way
 455    this is used is to record a decl which is to be returned by
 456    getdecls, and we could implement it for that purpose if
 457    necessary.  */
 458
 459 static tree
 460 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 461 {
 462   gcc_unreachable ();
 463 }
 464
 465 /* This hook is used to get the current list of declarations as trees.
 466    We don't support that; instead we use the write_globals hook.  This
 467    can't simply crash because it is called by -gstabs.  */
 468
 469 static tree
 470 go_langhook_getdecls (void)
 471 {
 472   return NULL;
 473 }
 474
 475 /* Go specific gimplification.  We need to gimplify
 476    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 477    it.  */
 478
 479 static int
 480 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 481 {
 482   if (TREE_CODE (*expr_p) == CALL_EXPR
 483       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 484     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 485                    is_gimple_val, fb_rvalue);
 486   return GS_UNHANDLED;
 487 }
 488
 489 /* Return a decl for the exception personality function.  The function
 490    itself is implemented in libgo/runtime/go-unwind.c.  */
 491
 492 static tree
 493 go_langhook_eh_personality (void)
 494 {
 495   static tree personality_decl;
 496   if (personality_decl == NULL_TREE)
 497     {
 498       personality_decl = build_personality_function ("gccgo");
 499       go_preserve_from_gc (personality_decl);
 500     }
 501   return personality_decl;
 502 }
 503
 504 /* Functions called directly by the generic backend.  */
 505
 506 tree
 507 convert (tree type, tree expr)
 508 {
 509   if (type == error_mark_node
 510       || expr == error_mark_node
 511       || TREE_TYPE (expr) == error_mark_node)
 512     return error_mark_node;
 513
 514   if (type == TREE_TYPE (expr))
 515     return expr;
 516
 517   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 518     return fold_convert (type, expr);
 519
 520   switch (TREE_CODE (type))
 521     {
 522     case VOID_TYPE:
 523     case BOOLEAN_TYPE:
 524       return fold_convert (type, expr);
 525     case INTEGER_TYPE:
 526       return fold (convert_to_integer (type, expr));
 527     case POINTER_TYPE:
 528       return fold (convert_to_pointer (type, expr));
 529     case REAL_TYPE:
 530       return fold (convert_to_real (type, expr));
 531     case COMPLEX_TYPE:
 532       return fold (convert_to_complex (type, expr));
 533     default:
 534       break;
 535     }
 536
 537   gcc_unreachable ();
 538 }
 539
 540 /* FIXME: This is a hack to preserve trees that we create from the
 541    garbage collector.  */
 542
 543 static GTY(()) tree go_gc_root;
 544
 545 void
 546 go_preserve_from_gc (tree t)
 547 {
 548   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 549 }
 550
 551 /* Convert an identifier for use in an error message.  */
 552
 553 const char *
 554 go_localize_identifier (const char *ident)
 555 {
 556   return identifier_to_locale (ident);
 557 }
 558
 559 #undef LANG_HOOKS_NAME
 560 #undef LANG_HOOKS_INIT
 561 #undef LANG_HOOKS_OPTION_LANG_MASK
 562 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 563 #undef LANG_HOOKS_HANDLE_OPTION
 564 #undef LANG_HOOKS_POST_OPTIONS
 565 #undef LANG_HOOKS_PARSE_FILE
 566 #undef LANG_HOOKS_TYPE_FOR_MODE
 567 #undef LANG_HOOKS_TYPE_FOR_SIZE
 568 #undef LANG_HOOKS_BUILTIN_FUNCTION
 569 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 570 #undef LANG_HOOKS_PUSHDECL
 571 #undef LANG_HOOKS_GETDECLS
 572 #undef LANG_HOOKS_GIMPLIFY_EXPR
 573 #undef LANG_HOOKS_EH_PERSONALITY
 574
 575 #define LANG_HOOKS_NAME                 "GNU Go"
 576 #define LANG_HOOKS_INIT                 go_langhook_init
 577 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 578 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 579 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 580 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 581 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 582 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 583 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 584 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 585 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 586 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 587 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 588 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 589 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 590
 591 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 592
 593 #include "gt-go-go-lang.h"
 594 #include "gtype-go.h"