gcc/go/go-lang.cc

   1 /* go-lang.cc -- Go frontend gcc interface.
   2    Copyright (C) 2009-2024 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_OS
  43 #define TARGET_AIX_OS 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 static const char *go_importcfg = NULL;
  94
  95 /* Language hooks.  */
  96
  97 static bool
  98 go_langhook_init (void)
  99 {
 100   build_common_tree_nodes (false);
 101
 102   /* We must create the gogo IR after calling build_common_tree_nodes
 103      (because Gogo::define_builtin_function_trees refers indirectly
 104      to, e.g., unsigned_char_type_node) but before calling
 105      build_common_builtin_nodes (because it calls, indirectly,
 106      go_type_for_size).  */
 107   struct go_create_gogo_args args;
 108   args.int_type_size = INT_TYPE_SIZE;
 109   args.pointer_size = POINTER_SIZE;
 110   args.pkgpath = go_pkgpath;
 111   args.prefix = go_prefix;
 112   args.relative_import_path = go_relative_import_path;
 113   args.c_header = go_c_header;
 114   args.embedcfg = go_embedcfg;
 115   args.importcfg = go_importcfg;
 116   args.check_divide_by_zero = go_check_divide_zero;
 117   args.check_divide_overflow = go_check_divide_overflow;
 118   args.compiling_runtime = go_compiling_runtime;
 119   args.debug_escape_level = go_debug_escape_level;
 120   args.debug_escape_hash = go_debug_escape_hash;
 121   args.nil_check_size_threshold = TARGET_AIX_OS ? -1 : 4096;
 122   args.debug_optimization = go_debug_optimization;
 123   args.need_eqtype = TARGET_AIX_OS ? true : false;
 124   args.linemap = go_get_linemap();
 125   args.backend = go_get_backend();
 126   go_create_gogo (&args);
 127
 128   build_common_builtin_nodes ();
 129
 130   /* The default precision for floating point numbers.  This is used
 131      for floating point constants with abstract type.  This may
 132      eventually be controllable by a command line option.  */
 133   mpfr_set_default_prec (256);
 134
 135   /* If necessary, override GCC's choice of minimum and maximum
 136      exponents.  This should only affect GCC middle-end
 137      compilation-time, not correctness.  */
 138   mpfr_exp_t exp = mpfr_get_emax ();
 139   if (exp < (1 << 16) - 1)
 140     mpfr_set_emax ((1 << 16) - 1);
 141   exp = mpfr_get_emin ();
 142   if (exp > - ((1 << 16) - 1))
 143     mpfr_set_emin (- ((1 << 16) - 1));
 144
 145   /* Go uses exceptions.  */
 146   using_eh_for_cleanups ();
 147
 148   return true;
 149 }
 150
 151 /* The option mask.  */
 152
 153 static unsigned int
 154 go_langhook_option_lang_mask (void)
 155 {
 156   return CL_Go;
 157 }
 158
 159 /* Initialize the options structure.  */
 160
 161 static void
 162 go_langhook_init_options_struct (struct gcc_options *opts)
 163 {
 164   /* Go says that signed overflow is precisely defined.  */
 165   opts->x_flag_wrapv = 1;
 166
 167   /* We default to using strict aliasing, since Go pointers are safe.
 168      This is turned off for code that imports the "unsafe" package,
 169      because using unsafe.pointer violates C style aliasing
 170      requirements.  */
 171   opts->x_flag_strict_aliasing = 1;
 172
 173   /* Default to avoiding range issues for complex multiply and
 174      divide.  */
 175   opts->x_flag_complex_method = 2;
 176   opts->x_flag_default_complex_method = opts->x_flag_complex_method;
 177
 178   /* The builtin math functions should not set errno.  */
 179   opts->x_flag_errno_math = 0;
 180   opts->frontend_set_flag_errno_math = true;
 181
 182   /* Exceptions are used to handle recovering from panics.  */
 183   opts->x_flag_exceptions = 1;
 184   opts->x_flag_non_call_exceptions = 1;
 185
 186   /* We need to keep pointers live for the garbage collector.  */
 187   opts->x_flag_keep_gc_roots_live = 1;
 188
 189   /* Go programs expect runtime.Callers to work, and that uses
 190      libbacktrace that uses debug info.  Set the debug info level to 1
 191      by default.  In post_options we will set the debug type if the
 192      debug info level was not set back to 0 on the command line.  */
 193   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 194 }
 195
 196 /* Infrastructure for a vector of char * pointers.  */
 197
 198 typedef const char *go_char_p;
 199
 200 /* The list of directories to search after all the Go specific
 201    directories have been searched.  */
 202
 203 static vec<go_char_p> go_search_dirs;
 204
 205 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 206
 207 static bool
 208 go_langhook_handle_option (
 209     size_t scode,
 210     const char *arg,
 211     HOST_WIDE_INT value,
 212     int kind ATTRIBUTE_UNUSED,
 213     location_t loc ATTRIBUTE_UNUSED,
 214     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 215 {
 216   enum opt_code code = (enum opt_code) scode;
 217   bool ret = true;
 218
 219   switch (code)
 220     {
 221     case OPT_I:
 222       go_add_search_path (arg);
 223       break;
 224
 225     case OPT_L:
 226       /* A -L option is assumed to come from the compiler driver.
 227          This is a system directory.  We search the following
 228          directories, if they exist, before this one:
 229            dir/go/VERSION
 230            dir/go/VERSION/MACHINE
 231          This is like include/c++.  */
 232       {
 233         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 234         size_t len;
 235         char *p;
 236         struct stat st;
 237
 238         len = strlen (arg);
 239         p = XALLOCAVEC (char,
 240                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 241                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 242         strcpy (p, arg);
 243         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 244           strcat (p, dir_separator_str);
 245         strcat (p, "go");
 246         strcat (p, dir_separator_str);
 247         strcat (p, DEFAULT_TARGET_VERSION);
 248         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 249           {
 250             go_add_search_path (p);
 251             strcat (p, dir_separator_str);
 252             strcat (p, DEFAULT_TARGET_MACHINE);
 253             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 254               go_add_search_path (p);
 255           }
 256
 257         /* Search ARG too, but only after we've searched to Go
 258            specific directories for all -L arguments.  */
 259         go_search_dirs.safe_push (arg);
 260       }
 261       break;
 262
 263     case OPT_fgo_dump_:
 264       ret = go_enable_dump (arg) ? true : false;
 265       break;
 266
 267     case OPT_fgo_optimize_:
 268       ret = go_enable_optimize (arg, value) ? true : false;
 269       break;
 270
 271     case OPT_fgo_pkgpath_:
 272       go_pkgpath = arg;
 273       break;
 274
 275     case OPT_fgo_prefix_:
 276       go_prefix = arg;
 277       break;
 278
 279     case OPT_fgo_relative_import_path_:
 280       go_relative_import_path = arg;
 281       break;
 282
 283     case OPT_fgo_c_header_:
 284       go_c_header = arg;
 285       break;
 286
 287     case OPT_fgo_embedcfg_:
 288       go_embedcfg = arg;
 289       break;
 290
 291     case OPT_fgo_importcfg_:
 292       go_importcfg = arg;
 293       break;
 294
 295     default:
 296       /* Just return 1 to indicate that the option is valid.  */
 297       break;
 298     }
 299
 300   return ret;
 301 }
 302
 303 /* Run after parsing options.  */
 304
 305 static bool
 306 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 307 {
 308   unsigned int ix;
 309   const char *dir;
 310
 311   gcc_assert (num_in_fnames > 0);
 312
 313   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 314     go_add_search_path (dir);
 315   go_search_dirs.release ();
 316
 317   if (flag_excess_precision == EXCESS_PRECISION_DEFAULT)
 318     flag_excess_precision = EXCESS_PRECISION_STANDARD;
 319
 320   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 321   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 322                        flag_optimize_sibling_calls, 0);
 323
 324   /* Partial inlining can confuses uses of runtime.Callers.
 325      See https://gcc.gnu.org/PR91663.  */
 326   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 327                        flag_partial_inlining, 0);
 328
 329   /* Go programs expect runtime.Callers to give the right answers,
 330      which means that we can't combine functions even if they look the
 331      same.  */
 332   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 333                        flag_ipa_icf_functions, 0);
 334
 335   /* If the debug info level is still 1, as set in init_options, make
 336      sure that some debugging type is selected.  */
 337   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 338       && global_options.x_write_symbols == NO_DEBUG)
 339     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 340
 341   /* We turn on stack splitting if we can.  */
 342   if (targetm_common.supports_split_stack (false, &global_options))
 343     SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 344                          flag_split_stack, 1);
 345
 346   /* If stack splitting is turned on, and the user did not explicitly
 347      request function partitioning, turn off partitioning, as it
 348      confuses the linker when trying to handle partitioned split-stack
 349      code that calls a non-split-stack function.  */
 350   if (global_options.x_flag_split_stack
 351       && global_options.x_flag_reorder_blocks_and_partition)
 352     SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 353                          flag_reorder_blocks_and_partition, 0);
 354
 355   /* Returning false means that the backend should be used.  */
 356   return false;
 357 }
 358
 359 static void
 360 go_langhook_parse_file (void)
 361 {
 362   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 363                         go_require_return_statement);
 364
 365   /* Final processing of globals and early debug info generation.  */
 366   go_write_globals ();
 367 }
 368
 369 static tree
 370 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 371 {
 372   tree type;
 373   if (unsignedp)
 374     {
 375       if (bits == INT_TYPE_SIZE)
 376         type = unsigned_type_node;
 377       else if (bits == CHAR_TYPE_SIZE)
 378         type = unsigned_char_type_node;
 379       else if (bits == SHORT_TYPE_SIZE)
 380         type = short_unsigned_type_node;
 381       else if (bits == LONG_TYPE_SIZE)
 382         type = long_unsigned_type_node;
 383       else if (bits == LONG_LONG_TYPE_SIZE)
 384         type = long_long_unsigned_type_node;
 385       else
 386         type = make_unsigned_type(bits);
 387     }
 388   else
 389     {
 390       if (bits == INT_TYPE_SIZE)
 391         type = integer_type_node;
 392       else if (bits == CHAR_TYPE_SIZE)
 393         type = signed_char_type_node;
 394       else if (bits == SHORT_TYPE_SIZE)
 395         type = short_integer_type_node;
 396       else if (bits == LONG_TYPE_SIZE)
 397         type = long_integer_type_node;
 398       else if (bits == LONG_LONG_TYPE_SIZE)
 399         type = long_long_integer_type_node;
 400       else
 401         type = make_signed_type(bits);
 402     }
 403   return type;
 404 }
 405
 406 static tree
 407 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 408 {
 409   tree type;
 410   /* Go has no vector types.  Build them here.  FIXME: It does not
 411      make sense for the middle-end to ask the frontend for a type
 412      which the frontend does not support.  However, at least for now
 413      it is required.  See PR 46805.  */
 414   if (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL
 415       && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 416     {
 417       unsigned int elem_bits = vector_element_size (GET_MODE_PRECISION (mode),
 418                                                     GET_MODE_NUNITS (mode));
 419       tree bool_type = build_nonstandard_boolean_type (elem_bits);
 420       return build_vector_type_for_mode (bool_type, mode);
 421     }
 422   else if (VECTOR_MODE_P (mode)
 423            && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 424     {
 425       tree inner;
 426
 427       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 428       if (inner != NULL_TREE)
 429         return build_vector_type_for_mode (inner, mode);
 430       return NULL_TREE;
 431     }
 432
 433   scalar_int_mode imode;
 434   scalar_float_mode fmode;
 435   complex_mode cmode;
 436   if (is_int_mode (mode, &imode))
 437     return go_langhook_type_for_size (GET_MODE_BITSIZE (imode), unsignedp);
 438   else if (is_float_mode (mode, &fmode))
 439     {
 440       switch (GET_MODE_BITSIZE (fmode))
 441         {
 442         case 32:
 443           return float_type_node;
 444         case 64:
 445           return double_type_node;
 446         default:
 447           // We have to check for long double in order to support
 448           // i386 excess precision.
 449           if (fmode == TYPE_MODE(long_double_type_node))
 450             return long_double_type_node;
 451         }
 452     }
 453   else if (is_complex_float_mode (mode, &cmode))
 454     {
 455       switch (GET_MODE_BITSIZE (cmode))
 456         {
 457         case 64:
 458           return complex_float_type_node;
 459         case 128:
 460           return complex_double_type_node;
 461         default:
 462           // We have to check for long double in order to support
 463           // i386 excess precision.
 464           if (cmode == TYPE_MODE(complex_long_double_type_node))
 465             return complex_long_double_type_node;
 466         }
 467     }
 468
 469 #if HOST_BITS_PER_WIDE_INT >= 64
 470   /* The middle-end and some backends rely on TImode being supported
 471      for 64-bit HWI.  */
 472   if (mode == TImode)
 473     {
 474       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 475                                              unsignedp);
 476       if (type && TYPE_MODE (type) == TImode)
 477         return type;
 478     }
 479 #endif
 480   return NULL_TREE;
 481 }
 482
 483 /* Record a builtin function.  We just ignore builtin functions.  */
 484
 485 static tree
 486 go_langhook_builtin_function (tree decl)
 487 {
 488   return decl;
 489 }
 490
 491 /* Return true if we are in the global binding level.  */
 492
 493 static bool
 494 go_langhook_global_bindings_p (void)
 495 {
 496   return current_function_decl == NULL_TREE;
 497 }
 498
 499 /* Push a declaration into the current binding level.  We can't
 500    usefully implement this since we don't want to convert from tree
 501    back to one of our internal data structures.  I think the only way
 502    this is used is to record a decl which is to be returned by
 503    getdecls, and we could implement it for that purpose if
 504    necessary.  */
 505
 506 static tree
 507 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 508 {
 509   gcc_unreachable ();
 510 }
 511
 512 /* This hook is used to get the current list of declarations as trees.
 513    We don't support that; instead we use the write_globals hook.  */
 514
 515 static tree
 516 go_langhook_getdecls (void)
 517 {
 518   return NULL;
 519 }
 520
 521 /* Go specific gimplification.  We need to gimplify
 522    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 523    it.  */
 524
 525 static int
 526 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 527 {
 528   if (TREE_CODE (*expr_p) == CALL_EXPR
 529       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 530     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 531                    is_gimple_val, fb_rvalue);
 532   return GS_UNHANDLED;
 533 }
 534
 535 /* Return a decl for the exception personality function.  The function
 536    itself is implemented in libgo/runtime/go-unwind.c.  */
 537
 538 static tree
 539 go_langhook_eh_personality (void)
 540 {
 541   static tree personality_decl;
 542   if (personality_decl == NULL_TREE)
 543     {
 544       personality_decl = build_personality_function ("gccgo");
 545       go_preserve_from_gc (personality_decl);
 546     }
 547   return personality_decl;
 548 }
 549
 550 /* Get a value for the SARIF v2.1.0 "artifact.sourceLanguage" property,
 551    based on the list in SARIF v2.1.0 Appendix J.  */
 552
 553 static const char *
 554 go_get_sarif_source_language (const char *)
 555 {
 556   return "go";
 557 }
 558
 559 /* Functions called directly by the generic backend.  */
 560
 561 tree
 562 convert (tree type, tree expr)
 563 {
 564   if (type == error_mark_node
 565       || expr == error_mark_node
 566       || TREE_TYPE (expr) == error_mark_node)
 567     return error_mark_node;
 568
 569   if (type == TREE_TYPE (expr))
 570     return expr;
 571
 572   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 573     return fold_convert (type, expr);
 574
 575   switch (TREE_CODE (type))
 576     {
 577     case VOID_TYPE:
 578     case BOOLEAN_TYPE:
 579       return fold_convert (type, expr);
 580     case INTEGER_TYPE:
 581       return fold (convert_to_integer (type, expr));
 582     case POINTER_TYPE:
 583       return fold (convert_to_pointer (type, expr));
 584     case REAL_TYPE:
 585       return fold (convert_to_real (type, expr));
 586     case COMPLEX_TYPE:
 587       return fold (convert_to_complex (type, expr));
 588     default:
 589       break;
 590     }
 591
 592   gcc_unreachable ();
 593 }
 594
 595 /* FIXME: This is a hack to preserve trees that we create from the
 596    garbage collector.  */
 597
 598 static GTY(()) tree go_gc_root;
 599
 600 void
 601 go_preserve_from_gc (tree t)
 602 {
 603   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 604 }
 605
 606 /* Convert an identifier for use in an error message.  */
 607
 608 const char *
 609 go_localize_identifier (const char *ident)
 610 {
 611   return identifier_to_locale (ident);
 612 }
 613
 614 #undef LANG_HOOKS_NAME
 615 #undef LANG_HOOKS_INIT
 616 #undef LANG_HOOKS_OPTION_LANG_MASK
 617 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 618 #undef LANG_HOOKS_HANDLE_OPTION
 619 #undef LANG_HOOKS_POST_OPTIONS
 620 #undef LANG_HOOKS_PARSE_FILE
 621 #undef LANG_HOOKS_TYPE_FOR_MODE
 622 #undef LANG_HOOKS_TYPE_FOR_SIZE
 623 #undef LANG_HOOKS_BUILTIN_FUNCTION
 624 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 625 #undef LANG_HOOKS_PUSHDECL
 626 #undef LANG_HOOKS_GETDECLS
 627 #undef LANG_HOOKS_GIMPLIFY_EXPR
 628 #undef LANG_HOOKS_EH_PERSONALITY
 629 #undef LANG_HOOKS_GET_SARIF_SOURCE_LANGUAGE
 630
 631 #define LANG_HOOKS_NAME                 "GNU Go"
 632 #define LANG_HOOKS_INIT                 go_langhook_init
 633 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 634 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 635 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 636 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 637 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 638 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 639 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 640 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 641 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 642 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 643 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 644 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 645 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 646 #define LANG_HOOKS_GET_SARIF_SOURCE_LANGUAGE go_get_sarif_source_language
 647
 648 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 649
 650 #include "gt-go-go-lang.h"
 651 #include "gtype-go.h"