gcc/go/go-lang.cc

   1 /* go-lang.cc -- Go frontend gcc interface.
   2    Copyright (C) 2009-2022 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 #ifndef TARGET_AIX
  43 #define TARGET_AIX 0
  44 #endif
  45
  46 /* Language-dependent contents of a type.  */
  47
  48 struct GTY(()) lang_type
  49 {
  50   char dummy;
  51 };
  52
  53 /* Language-dependent contents of a decl.  */
  54
  55 struct GTY(()) lang_decl
  56 {
  57   char dummy;
  58 };
  59
  60 /* Language-dependent contents of an identifier.  This must include a
  61    tree_identifier.  */
  62
  63 struct GTY(()) lang_identifier
  64 {
  65   struct tree_identifier common;
  66 };
  67
  68 /* The resulting tree type.  */
  69
  70 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
  71            chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
  72 lang_tree_node
  73 {
  74   union tree_node GTY((tag ("0"),
  75                        desc ("tree_node_structure (&%h)"))) generic;
  76   struct lang_identifier GTY((tag ("1"))) identifier;
  77 };
  78
  79 /* We don't use language_function.  */
  80
  81 struct GTY(()) language_function
  82 {
  83   int dummy;
  84 };
  85
  86 /* Option information we need to pass to go_create_gogo.  */
  87
  88 static const char *go_pkgpath = NULL;
  89 static const char *go_prefix = NULL;
  90 static const char *go_relative_import_path = NULL;
  91 static const char *go_c_header = NULL;
  92 static const char *go_embedcfg = NULL;
  93
  94 /* Language hooks.  */
  95
  96 static bool
  97 go_langhook_init (void)
  98 {
  99   build_common_tree_nodes (false);
 100
 101   /* I don't know why this has to be done explicitly.  */
 102   void_list_node = build_tree_list (NULL_TREE, void_type_node);
 103
 104   /* We must create the gogo IR after calling build_common_tree_nodes
 105      (because Gogo::define_builtin_function_trees refers indirectly
 106      to, e.g., unsigned_char_type_node) but before calling
 107      build_common_builtin_nodes (because it calls, indirectly,
 108      go_type_for_size).  */
 109   struct go_create_gogo_args args;
 110   args.int_type_size = INT_TYPE_SIZE;
 111   args.pointer_size = POINTER_SIZE;
 112   args.pkgpath = go_pkgpath;
 113   args.prefix = go_prefix;
 114   args.relative_import_path = go_relative_import_path;
 115   args.c_header = go_c_header;
 116   args.embedcfg = go_embedcfg;
 117   args.check_divide_by_zero = go_check_divide_zero;
 118   args.check_divide_overflow = go_check_divide_overflow;
 119   args.compiling_runtime = go_compiling_runtime;
 120   args.debug_escape_level = go_debug_escape_level;
 121   args.debug_escape_hash = go_debug_escape_hash;
 122   args.nil_check_size_threshold = TARGET_AIX ? -1 : 4096;
 123   args.debug_optimization = go_debug_optimization;
 124   args.need_eqtype = TARGET_AIX ? true : false;
 125   args.linemap = go_get_linemap();
 126   args.backend = go_get_backend();
 127   go_create_gogo (&args);
 128
 129   build_common_builtin_nodes ();
 130
 131   /* The default precision for floating point numbers.  This is used
 132      for floating point constants with abstract type.  This may
 133      eventually be controllable by a command line option.  */
 134   mpfr_set_default_prec (256);
 135
 136   /* If necessary, override GCC's choice of minimum and maximum
 137      exponents.  This should only affect GCC middle-end
 138      compilation-time, not correctness.  */
 139   mpfr_exp_t exp = mpfr_get_emax ();
 140   if (exp < (1 << 16) - 1)
 141     mpfr_set_emax ((1 << 16) - 1);
 142   exp = mpfr_get_emin ();
 143   if (exp > - ((1 << 16) - 1))
 144     mpfr_set_emin (- ((1 << 16) - 1));
 145
 146   /* Go uses exceptions.  */
 147   using_eh_for_cleanups ();
 148
 149   return true;
 150 }
 151
 152 /* The option mask.  */
 153
 154 static unsigned int
 155 go_langhook_option_lang_mask (void)
 156 {
 157   return CL_Go;
 158 }
 159
 160 /* Initialize the options structure.  */
 161
 162 static void
 163 go_langhook_init_options_struct (struct gcc_options *opts)
 164 {
 165   /* Go says that signed overflow is precisely defined.  */
 166   opts->x_flag_wrapv = 1;
 167
 168   /* We default to using strict aliasing, since Go pointers are safe.
 169      This is turned off for code that imports the "unsafe" package,
 170      because using unsafe.pointer violates C style aliasing
 171      requirements.  */
 172   opts->x_flag_strict_aliasing = 1;
 173
 174   /* Default to avoiding range issues for complex multiply and
 175      divide.  */
 176   opts->x_flag_complex_method = 2;
 177   opts->x_flag_default_complex_method = opts->x_flag_complex_method;
 178
 179   /* The builtin math functions should not set errno.  */
 180   opts->x_flag_errno_math = 0;
 181   opts->frontend_set_flag_errno_math = true;
 182
 183   /* Exceptions are used to handle recovering from panics.  */
 184   opts->x_flag_exceptions = 1;
 185   opts->x_flag_non_call_exceptions = 1;
 186
 187   /* We need to keep pointers live for the garbage collector.  */
 188   opts->x_flag_keep_gc_roots_live = 1;
 189
 190   /* Go programs expect runtime.Callers to work, and that uses
 191      libbacktrace that uses debug info.  Set the debug info level to 1
 192      by default.  In post_options we will set the debug type if the
 193      debug info level was not set back to 0 on the command line.  */
 194   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 195 }
 196
 197 /* Infrastructure for a vector of char * pointers.  */
 198
 199 typedef const char *go_char_p;
 200
 201 /* The list of directories to search after all the Go specific
 202    directories have been searched.  */
 203
 204 static vec<go_char_p> go_search_dirs;
 205
 206 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 207
 208 static bool
 209 go_langhook_handle_option (
 210     size_t scode,
 211     const char *arg,
 212     HOST_WIDE_INT value,
 213     int kind ATTRIBUTE_UNUSED,
 214     location_t loc ATTRIBUTE_UNUSED,
 215     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 216 {
 217   enum opt_code code = (enum opt_code) scode;
 218   bool ret = true;
 219
 220   switch (code)
 221     {
 222     case OPT_I:
 223       go_add_search_path (arg);
 224       break;
 225
 226     case OPT_L:
 227       /* A -L option is assumed to come from the compiler driver.
 228          This is a system directory.  We search the following
 229          directories, if they exist, before this one:
 230            dir/go/VERSION
 231            dir/go/VERSION/MACHINE
 232          This is like include/c++.  */
 233       {
 234         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 235         size_t len;
 236         char *p;
 237         struct stat st;
 238
 239         len = strlen (arg);
 240         p = XALLOCAVEC (char,
 241                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 242                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 243         strcpy (p, arg);
 244         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 245           strcat (p, dir_separator_str);
 246         strcat (p, "go");
 247         strcat (p, dir_separator_str);
 248         strcat (p, DEFAULT_TARGET_VERSION);
 249         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 250           {
 251             go_add_search_path (p);
 252             strcat (p, dir_separator_str);
 253             strcat (p, DEFAULT_TARGET_MACHINE);
 254             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 255               go_add_search_path (p);
 256           }
 257
 258         /* Search ARG too, but only after we've searched to Go
 259            specific directories for all -L arguments.  */
 260         go_search_dirs.safe_push (arg);
 261       }
 262       break;
 263
 264     case OPT_fgo_dump_:
 265       ret = go_enable_dump (arg) ? true : false;
 266       break;
 267
 268     case OPT_fgo_optimize_:
 269       ret = go_enable_optimize (arg, value) ? true : false;
 270       break;
 271
 272     case OPT_fgo_pkgpath_:
 273       go_pkgpath = arg;
 274       break;
 275
 276     case OPT_fgo_prefix_:
 277       go_prefix = arg;
 278       break;
 279
 280     case OPT_fgo_relative_import_path_:
 281       go_relative_import_path = arg;
 282       break;
 283
 284     case OPT_fgo_c_header_:
 285       go_c_header = arg;
 286       break;
 287
 288     case OPT_fgo_embedcfg_:
 289       go_embedcfg = arg;
 290       break;
 291
 292     default:
 293       /* Just return 1 to indicate that the option is valid.  */
 294       break;
 295     }
 296
 297   return ret;
 298 }
 299
 300 /* Run after parsing options.  */
 301
 302 static bool
 303 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 304 {
 305   unsigned int ix;
 306   const char *dir;
 307
 308   gcc_assert (num_in_fnames > 0);
 309
 310   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 311     go_add_search_path (dir);
 312   go_search_dirs.release ();
 313
 314   if (flag_excess_precision == EXCESS_PRECISION_DEFAULT)
 315     flag_excess_precision = EXCESS_PRECISION_STANDARD;
 316
 317   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 318   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 319                        flag_optimize_sibling_calls, 0);
 320
 321   /* Partial inlining can confuses uses of runtime.Callers.
 322      See https://gcc.gnu.org/PR91663.  */
 323   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 324                        flag_partial_inlining, 0);
 325
 326   /* Go programs expect runtime.Callers to give the right answers,
 327      which means that we can't combine functions even if they look the
 328      same.  */
 329   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 330                        flag_ipa_icf_functions, 0);
 331
 332   /* If the debug info level is still 1, as set in init_options, make
 333      sure that some debugging type is selected.  */
 334   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 335       && global_options.x_write_symbols == NO_DEBUG)
 336     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 337
 338   /* We turn on stack splitting if we can.  */
 339   if (targetm_common.supports_split_stack (false, &global_options))
 340     SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 341                          flag_split_stack, 1);
 342
 343   /* If stack splitting is turned on, and the user did not explicitly
 344      request function partitioning, turn off partitioning, as it
 345      confuses the linker when trying to handle partitioned split-stack
 346      code that calls a non-split-stack function.  */
 347   if (global_options.x_flag_split_stack
 348       && global_options.x_flag_reorder_blocks_and_partition)
 349     SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 350                          flag_reorder_blocks_and_partition, 0);
 351
 352   /* Returning false means that the backend should be used.  */
 353   return false;
 354 }
 355
 356 static void
 357 go_langhook_parse_file (void)
 358 {
 359   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 360                         go_require_return_statement);
 361
 362   /* Final processing of globals and early debug info generation.  */
 363   go_write_globals ();
 364 }
 365
 366 static tree
 367 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 368 {
 369   tree type;
 370   if (unsignedp)
 371     {
 372       if (bits == INT_TYPE_SIZE)
 373         type = unsigned_type_node;
 374       else if (bits == CHAR_TYPE_SIZE)
 375         type = unsigned_char_type_node;
 376       else if (bits == SHORT_TYPE_SIZE)
 377         type = short_unsigned_type_node;
 378       else if (bits == LONG_TYPE_SIZE)
 379         type = long_unsigned_type_node;
 380       else if (bits == LONG_LONG_TYPE_SIZE)
 381         type = long_long_unsigned_type_node;
 382       else
 383         type = make_unsigned_type(bits);
 384     }
 385   else
 386     {
 387       if (bits == INT_TYPE_SIZE)
 388         type = integer_type_node;
 389       else if (bits == CHAR_TYPE_SIZE)
 390         type = signed_char_type_node;
 391       else if (bits == SHORT_TYPE_SIZE)
 392         type = short_integer_type_node;
 393       else if (bits == LONG_TYPE_SIZE)
 394         type = long_integer_type_node;
 395       else if (bits == LONG_LONG_TYPE_SIZE)
 396         type = long_long_integer_type_node;
 397       else
 398         type = make_signed_type(bits);
 399     }
 400   return type;
 401 }
 402
 403 static tree
 404 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 405 {
 406   tree type;
 407   /* Go has no vector types.  Build them here.  FIXME: It does not
 408      make sense for the middle-end to ask the frontend for a type
 409      which the frontend does not support.  However, at least for now
 410      it is required.  See PR 46805.  */
 411   if (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL
 412       && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 413     {
 414       unsigned int elem_bits = vector_element_size (GET_MODE_BITSIZE (mode),
 415                                                     GET_MODE_NUNITS (mode));
 416       tree bool_type = build_nonstandard_boolean_type (elem_bits);
 417       return build_vector_type_for_mode (bool_type, mode);
 418     }
 419   else if (VECTOR_MODE_P (mode)
 420            && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 421     {
 422       tree inner;
 423
 424       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 425       if (inner != NULL_TREE)
 426         return build_vector_type_for_mode (inner, mode);
 427       return NULL_TREE;
 428     }
 429
 430   scalar_int_mode imode;
 431   scalar_float_mode fmode;
 432   complex_mode cmode;
 433   if (is_int_mode (mode, &imode))
 434     return go_langhook_type_for_size (GET_MODE_BITSIZE (imode), unsignedp);
 435   else if (is_float_mode (mode, &fmode))
 436     {
 437       switch (GET_MODE_BITSIZE (fmode))
 438         {
 439         case 32:
 440           return float_type_node;
 441         case 64:
 442           return double_type_node;
 443         default:
 444           // We have to check for long double in order to support
 445           // i386 excess precision.
 446           if (fmode == TYPE_MODE(long_double_type_node))
 447             return long_double_type_node;
 448         }
 449     }
 450   else if (is_complex_float_mode (mode, &cmode))
 451     {
 452       switch (GET_MODE_BITSIZE (cmode))
 453         {
 454         case 64:
 455           return complex_float_type_node;
 456         case 128:
 457           return complex_double_type_node;
 458         default:
 459           // We have to check for long double in order to support
 460           // i386 excess precision.
 461           if (cmode == TYPE_MODE(complex_long_double_type_node))
 462             return complex_long_double_type_node;
 463         }
 464     }
 465
 466 #if HOST_BITS_PER_WIDE_INT >= 64
 467   /* The middle-end and some backends rely on TImode being supported
 468      for 64-bit HWI.  */
 469   if (mode == TImode)
 470     {
 471       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 472                                              unsignedp);
 473       if (type && TYPE_MODE (type) == TImode)
 474         return type;
 475     }
 476 #endif
 477   return NULL_TREE;
 478 }
 479
 480 /* Record a builtin function.  We just ignore builtin functions.  */
 481
 482 static tree
 483 go_langhook_builtin_function (tree decl)
 484 {
 485   return decl;
 486 }
 487
 488 /* Return true if we are in the global binding level.  */
 489
 490 static bool
 491 go_langhook_global_bindings_p (void)
 492 {
 493   return current_function_decl == NULL_TREE;
 494 }
 495
 496 /* Push a declaration into the current binding level.  We can't
 497    usefully implement this since we don't want to convert from tree
 498    back to one of our internal data structures.  I think the only way
 499    this is used is to record a decl which is to be returned by
 500    getdecls, and we could implement it for that purpose if
 501    necessary.  */
 502
 503 static tree
 504 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 505 {
 506   gcc_unreachable ();
 507 }
 508
 509 /* This hook is used to get the current list of declarations as trees.
 510    We don't support that; instead we use the write_globals hook.  This
 511    can't simply crash because it is called by -gstabs.  */
 512
 513 static tree
 514 go_langhook_getdecls (void)
 515 {
 516   return NULL;
 517 }
 518
 519 /* Go specific gimplification.  We need to gimplify
 520    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 521    it.  */
 522
 523 static int
 524 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 525 {
 526   if (TREE_CODE (*expr_p) == CALL_EXPR
 527       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 528     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 529                    is_gimple_val, fb_rvalue);
 530   return GS_UNHANDLED;
 531 }
 532
 533 /* Return a decl for the exception personality function.  The function
 534    itself is implemented in libgo/runtime/go-unwind.c.  */
 535
 536 static tree
 537 go_langhook_eh_personality (void)
 538 {
 539   static tree personality_decl;
 540   if (personality_decl == NULL_TREE)
 541     {
 542       personality_decl = build_personality_function ("gccgo");
 543       go_preserve_from_gc (personality_decl);
 544     }
 545   return personality_decl;
 546 }
 547
 548 /* Get a value for the SARIF v2.1.0 "artifact.sourceLanguage" property,
 549    based on the list in SARIF v2.1.0 Appendix J.  */
 550
 551 static const char *
 552 go_get_sarif_source_language (const char *)
 553 {
 554   return "go";
 555 }
 556
 557 /* Functions called directly by the generic backend.  */
 558
 559 tree
 560 convert (tree type, tree expr)
 561 {
 562   if (type == error_mark_node
 563       || expr == error_mark_node
 564       || TREE_TYPE (expr) == error_mark_node)
 565     return error_mark_node;
 566
 567   if (type == TREE_TYPE (expr))
 568     return expr;
 569
 570   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 571     return fold_convert (type, expr);
 572
 573   switch (TREE_CODE (type))
 574     {
 575     case VOID_TYPE:
 576     case BOOLEAN_TYPE:
 577       return fold_convert (type, expr);
 578     case INTEGER_TYPE:
 579       return fold (convert_to_integer (type, expr));
 580     case POINTER_TYPE:
 581       return fold (convert_to_pointer (type, expr));
 582     case REAL_TYPE:
 583       return fold (convert_to_real (type, expr));
 584     case COMPLEX_TYPE:
 585       return fold (convert_to_complex (type, expr));
 586     default:
 587       break;
 588     }
 589
 590   gcc_unreachable ();
 591 }
 592
 593 /* FIXME: This is a hack to preserve trees that we create from the
 594    garbage collector.  */
 595
 596 static GTY(()) tree go_gc_root;
 597
 598 void
 599 go_preserve_from_gc (tree t)
 600 {
 601   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 602 }
 603
 604 /* Convert an identifier for use in an error message.  */
 605
 606 const char *
 607 go_localize_identifier (const char *ident)
 608 {
 609   return identifier_to_locale (ident);
 610 }
 611
 612 #undef LANG_HOOKS_NAME
 613 #undef LANG_HOOKS_INIT
 614 #undef LANG_HOOKS_OPTION_LANG_MASK
 615 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 616 #undef LANG_HOOKS_HANDLE_OPTION
 617 #undef LANG_HOOKS_POST_OPTIONS
 618 #undef LANG_HOOKS_PARSE_FILE
 619 #undef LANG_HOOKS_TYPE_FOR_MODE
 620 #undef LANG_HOOKS_TYPE_FOR_SIZE
 621 #undef LANG_HOOKS_BUILTIN_FUNCTION
 622 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 623 #undef LANG_HOOKS_PUSHDECL
 624 #undef LANG_HOOKS_GETDECLS
 625 #undef LANG_HOOKS_GIMPLIFY_EXPR
 626 #undef LANG_HOOKS_EH_PERSONALITY
 627 #undef LANG_HOOKS_GET_SARIF_SOURCE_LANGUAGE
 628
 629 #define LANG_HOOKS_NAME                 "GNU Go"
 630 #define LANG_HOOKS_INIT                 go_langhook_init
 631 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 632 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 633 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 634 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 635 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 636 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 637 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 638 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 639 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 640 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 641 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 642 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 643 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 644 #define LANG_HOOKS_GET_SARIF_SOURCE_LANGUAGE go_get_sarif_source_language
 645
 646 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 647
 648 #include "gt-go-go-lang.h"
 649 #include "gtype-go.h"