gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2020 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
  93 /* Language hooks.  */
  94
  95 static bool
  96 go_langhook_init (void)
  97 {
  98   build_common_tree_nodes (false);
  99
 100   /* I don't know why this has to be done explicitly.  */
 101   void_list_node = build_tree_list (NULL_TREE, void_type_node);
 102
 103   /* We must create the gogo IR after calling build_common_tree_nodes
 104      (because Gogo::define_builtin_function_trees refers indirectly
 105      to, e.g., unsigned_char_type_node) but before calling
 106      build_common_builtin_nodes (because it calls, indirectly,
 107      go_type_for_size).  */
 108   struct go_create_gogo_args args;
 109   args.int_type_size = INT_TYPE_SIZE;
 110   args.pointer_size = POINTER_SIZE;
 111   args.pkgpath = go_pkgpath;
 112   args.prefix = go_prefix;
 113   args.relative_import_path = go_relative_import_path;
 114   args.c_header = go_c_header;
 115   args.check_divide_by_zero = go_check_divide_zero;
 116   args.check_divide_overflow = go_check_divide_overflow;
 117   args.compiling_runtime = go_compiling_runtime;
 118   args.debug_escape_level = go_debug_escape_level;
 119   args.debug_escape_hash = go_debug_escape_hash;
 120   args.nil_check_size_threshold = TARGET_AIX ? -1 : 4096;
 121   args.debug_optimization = go_debug_optimization;
 122   args.need_eqtype = TARGET_AIX ? true : false;
 123   args.linemap = go_get_linemap();
 124   args.backend = go_get_backend();
 125   go_create_gogo (&args);
 126
 127   build_common_builtin_nodes ();
 128
 129   /* The default precision for floating point numbers.  This is used
 130      for floating point constants with abstract type.  This may
 131      eventually be controllable by a command line option.  */
 132   mpfr_set_default_prec (256);
 133
 134   /* Go uses exceptions.  */
 135   using_eh_for_cleanups ();
 136
 137   return true;
 138 }
 139
 140 /* The option mask.  */
 141
 142 static unsigned int
 143 go_langhook_option_lang_mask (void)
 144 {
 145   return CL_Go;
 146 }
 147
 148 /* Initialize the options structure.  */
 149
 150 static void
 151 go_langhook_init_options_struct (struct gcc_options *opts)
 152 {
 153   /* Go says that signed overflow is precisely defined.  */
 154   opts->x_flag_wrapv = 1;
 155
 156   /* We default to using strict aliasing, since Go pointers are safe.
 157      This is turned off for code that imports the "unsafe" package,
 158      because using unsafe.pointer violates C style aliasing
 159      requirements.  */
 160   opts->x_flag_strict_aliasing = 1;
 161
 162   /* Default to avoiding range issues for complex multiply and
 163      divide.  */
 164   opts->x_flag_complex_method = 2;
 165
 166   /* The builtin math functions should not set errno.  */
 167   opts->x_flag_errno_math = 0;
 168   opts->frontend_set_flag_errno_math = true;
 169
 170   /* Exceptions are used to handle recovering from panics.  */
 171   opts->x_flag_exceptions = 1;
 172   opts->x_flag_non_call_exceptions = 1;
 173
 174   /* We need to keep pointers live for the garbage collector.  */
 175   opts->x_flag_keep_gc_roots_live = 1;
 176
 177   /* Go programs expect runtime.Callers to work, and that uses
 178      libbacktrace that uses debug info.  Set the debug info level to 1
 179      by default.  In post_options we will set the debug type if the
 180      debug info level was not set back to 0 on the command line.  */
 181   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 182 }
 183
 184 /* Infrastructure for a vector of char * pointers.  */
 185
 186 typedef const char *go_char_p;
 187
 188 /* The list of directories to search after all the Go specific
 189    directories have been searched.  */
 190
 191 static vec<go_char_p> go_search_dirs;
 192
 193 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 194
 195 static bool
 196 go_langhook_handle_option (
 197     size_t scode,
 198     const char *arg,
 199     HOST_WIDE_INT value,
 200     int kind ATTRIBUTE_UNUSED,
 201     location_t loc ATTRIBUTE_UNUSED,
 202     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 203 {
 204   enum opt_code code = (enum opt_code) scode;
 205   bool ret = true;
 206
 207   switch (code)
 208     {
 209     case OPT_I:
 210       go_add_search_path (arg);
 211       break;
 212
 213     case OPT_L:
 214       /* A -L option is assumed to come from the compiler driver.
 215          This is a system directory.  We search the following
 216          directories, if they exist, before this one:
 217            dir/go/VERSION
 218            dir/go/VERSION/MACHINE
 219          This is like include/c++.  */
 220       {
 221         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 222         size_t len;
 223         char *p;
 224         struct stat st;
 225
 226         len = strlen (arg);
 227         p = XALLOCAVEC (char,
 228                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 229                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 230         strcpy (p, arg);
 231         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 232           strcat (p, dir_separator_str);
 233         strcat (p, "go");
 234         strcat (p, dir_separator_str);
 235         strcat (p, DEFAULT_TARGET_VERSION);
 236         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 237           {
 238             go_add_search_path (p);
 239             strcat (p, dir_separator_str);
 240             strcat (p, DEFAULT_TARGET_MACHINE);
 241             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 242               go_add_search_path (p);
 243           }
 244
 245         /* Search ARG too, but only after we've searched to Go
 246            specific directories for all -L arguments.  */
 247         go_search_dirs.safe_push (arg);
 248       }
 249       break;
 250
 251     case OPT_fgo_dump_:
 252       ret = go_enable_dump (arg) ? true : false;
 253       break;
 254
 255     case OPT_fgo_optimize_:
 256       ret = go_enable_optimize (arg, value) ? true : false;
 257       break;
 258
 259     case OPT_fgo_pkgpath_:
 260       go_pkgpath = arg;
 261       break;
 262
 263     case OPT_fgo_prefix_:
 264       go_prefix = arg;
 265       break;
 266
 267     case OPT_fgo_relative_import_path_:
 268       go_relative_import_path = arg;
 269       break;
 270
 271     case OPT_fgo_c_header_:
 272       go_c_header = arg;
 273       break;
 274
 275     default:
 276       /* Just return 1 to indicate that the option is valid.  */
 277       break;
 278     }
 279
 280   return ret;
 281 }
 282
 283 /* Run after parsing options.  */
 284
 285 static bool
 286 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 287 {
 288   unsigned int ix;
 289   const char *dir;
 290
 291   gcc_assert (num_in_fnames > 0);
 292
 293   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 294     go_add_search_path (dir);
 295   go_search_dirs.release ();
 296
 297   if (flag_excess_precision == EXCESS_PRECISION_DEFAULT)
 298     flag_excess_precision = EXCESS_PRECISION_STANDARD;
 299
 300   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 301   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 302                        flag_optimize_sibling_calls, 0);
 303
 304   /* Partial inlining can confuses uses of runtime.Callers.
 305      See https://gcc.gnu.org/PR91663.  */
 306   SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 307                        flag_partial_inlining, 0);
 308
 309   /* If the debug info level is still 1, as set in init_options, make
 310      sure that some debugging type is selected.  */
 311   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 312       && global_options.x_write_symbols == NO_DEBUG)
 313     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 314
 315   /* We turn on stack splitting if we can.  */
 316   if (targetm_common.supports_split_stack (false, &global_options))
 317     SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 318                          flag_split_stack, 1);
 319
 320   /* If stack splitting is turned on, and the user did not explicitly
 321      request function partitioning, turn off partitioning, as it
 322      confuses the linker when trying to handle partitioned split-stack
 323      code that calls a non-split-stack function.  */
 324   if (global_options.x_flag_split_stack
 325       && global_options.x_flag_reorder_blocks_and_partition)
 326     SET_OPTION_IF_UNSET (&global_options, &global_options_set,
 327                          flag_reorder_blocks_and_partition, 0);
 328
 329   /* Returning false means that the backend should be used.  */
 330   return false;
 331 }
 332
 333 static void
 334 go_langhook_parse_file (void)
 335 {
 336   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 337                         go_require_return_statement);
 338
 339   /* Final processing of globals and early debug info generation.  */
 340   go_write_globals ();
 341 }
 342
 343 static tree
 344 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 345 {
 346   tree type;
 347   if (unsignedp)
 348     {
 349       if (bits == INT_TYPE_SIZE)
 350         type = unsigned_type_node;
 351       else if (bits == CHAR_TYPE_SIZE)
 352         type = unsigned_char_type_node;
 353       else if (bits == SHORT_TYPE_SIZE)
 354         type = short_unsigned_type_node;
 355       else if (bits == LONG_TYPE_SIZE)
 356         type = long_unsigned_type_node;
 357       else if (bits == LONG_LONG_TYPE_SIZE)
 358         type = long_long_unsigned_type_node;
 359       else
 360         type = make_unsigned_type(bits);
 361     }
 362   else
 363     {
 364       if (bits == INT_TYPE_SIZE)
 365         type = integer_type_node;
 366       else if (bits == CHAR_TYPE_SIZE)
 367         type = signed_char_type_node;
 368       else if (bits == SHORT_TYPE_SIZE)
 369         type = short_integer_type_node;
 370       else if (bits == LONG_TYPE_SIZE)
 371         type = long_integer_type_node;
 372       else if (bits == LONG_LONG_TYPE_SIZE)
 373         type = long_long_integer_type_node;
 374       else
 375         type = make_signed_type(bits);
 376     }
 377   return type;
 378 }
 379
 380 static tree
 381 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 382 {
 383   tree type;
 384   /* Go has no vector types.  Build them here.  FIXME: It does not
 385      make sense for the middle-end to ask the frontend for a type
 386      which the frontend does not support.  However, at least for now
 387      it is required.  See PR 46805.  */
 388   if (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL
 389       && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 390     {
 391       unsigned int elem_bits = vector_element_size (GET_MODE_BITSIZE (mode),
 392                                                     GET_MODE_NUNITS (mode));
 393       tree bool_type = build_nonstandard_boolean_type (elem_bits);
 394       return build_vector_type_for_mode (bool_type, mode);
 395     }
 396   else if (VECTOR_MODE_P (mode)
 397            && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 398     {
 399       tree inner;
 400
 401       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 402       if (inner != NULL_TREE)
 403         return build_vector_type_for_mode (inner, mode);
 404       return NULL_TREE;
 405     }
 406
 407   scalar_int_mode imode;
 408   scalar_float_mode fmode;
 409   complex_mode cmode;
 410   if (is_int_mode (mode, &imode))
 411     return go_langhook_type_for_size (GET_MODE_BITSIZE (imode), unsignedp);
 412   else if (is_float_mode (mode, &fmode))
 413     {
 414       switch (GET_MODE_BITSIZE (fmode))
 415         {
 416         case 32:
 417           return float_type_node;
 418         case 64:
 419           return double_type_node;
 420         default:
 421           // We have to check for long double in order to support
 422           // i386 excess precision.
 423           if (fmode == TYPE_MODE(long_double_type_node))
 424             return long_double_type_node;
 425         }
 426     }
 427   else if (is_complex_float_mode (mode, &cmode))
 428     {
 429       switch (GET_MODE_BITSIZE (cmode))
 430         {
 431         case 64:
 432           return complex_float_type_node;
 433         case 128:
 434           return complex_double_type_node;
 435         default:
 436           // We have to check for long double in order to support
 437           // i386 excess precision.
 438           if (cmode == TYPE_MODE(complex_long_double_type_node))
 439             return complex_long_double_type_node;
 440         }
 441     }
 442
 443 #if HOST_BITS_PER_WIDE_INT >= 64
 444   /* The middle-end and some backends rely on TImode being supported
 445      for 64-bit HWI.  */
 446   if (mode == TImode)
 447     {
 448       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 449                                              unsignedp);
 450       if (type && TYPE_MODE (type) == TImode)
 451         return type;
 452     }
 453 #endif
 454   return NULL_TREE;
 455 }
 456
 457 /* Record a builtin function.  We just ignore builtin functions.  */
 458
 459 static tree
 460 go_langhook_builtin_function (tree decl)
 461 {
 462   return decl;
 463 }
 464
 465 /* Return true if we are in the global binding level.  */
 466
 467 static bool
 468 go_langhook_global_bindings_p (void)
 469 {
 470   return current_function_decl == NULL_TREE;
 471 }
 472
 473 /* Push a declaration into the current binding level.  We can't
 474    usefully implement this since we don't want to convert from tree
 475    back to one of our internal data structures.  I think the only way
 476    this is used is to record a decl which is to be returned by
 477    getdecls, and we could implement it for that purpose if
 478    necessary.  */
 479
 480 static tree
 481 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 482 {
 483   gcc_unreachable ();
 484 }
 485
 486 /* This hook is used to get the current list of declarations as trees.
 487    We don't support that; instead we use the write_globals hook.  This
 488    can't simply crash because it is called by -gstabs.  */
 489
 490 static tree
 491 go_langhook_getdecls (void)
 492 {
 493   return NULL;
 494 }
 495
 496 /* Go specific gimplification.  We need to gimplify
 497    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 498    it.  */
 499
 500 static int
 501 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 502 {
 503   if (TREE_CODE (*expr_p) == CALL_EXPR
 504       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 505     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 506                    is_gimple_val, fb_rvalue);
 507   return GS_UNHANDLED;
 508 }
 509
 510 /* Return a decl for the exception personality function.  The function
 511    itself is implemented in libgo/runtime/go-unwind.c.  */
 512
 513 static tree
 514 go_langhook_eh_personality (void)
 515 {
 516   static tree personality_decl;
 517   if (personality_decl == NULL_TREE)
 518     {
 519       personality_decl = build_personality_function ("gccgo");
 520       go_preserve_from_gc (personality_decl);
 521     }
 522   return personality_decl;
 523 }
 524
 525 /* Functions called directly by the generic backend.  */
 526
 527 tree
 528 convert (tree type, tree expr)
 529 {
 530   if (type == error_mark_node
 531       || expr == error_mark_node
 532       || TREE_TYPE (expr) == error_mark_node)
 533     return error_mark_node;
 534
 535   if (type == TREE_TYPE (expr))
 536     return expr;
 537
 538   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 539     return fold_convert (type, expr);
 540
 541   switch (TREE_CODE (type))
 542     {
 543     case VOID_TYPE:
 544     case BOOLEAN_TYPE:
 545       return fold_convert (type, expr);
 546     case INTEGER_TYPE:
 547       return fold (convert_to_integer (type, expr));
 548     case POINTER_TYPE:
 549       return fold (convert_to_pointer (type, expr));
 550     case REAL_TYPE:
 551       return fold (convert_to_real (type, expr));
 552     case COMPLEX_TYPE:
 553       return fold (convert_to_complex (type, expr));
 554     default:
 555       break;
 556     }
 557
 558   gcc_unreachable ();
 559 }
 560
 561 /* FIXME: This is a hack to preserve trees that we create from the
 562    garbage collector.  */
 563
 564 static GTY(()) tree go_gc_root;
 565
 566 void
 567 go_preserve_from_gc (tree t)
 568 {
 569   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 570 }
 571
 572 /* Convert an identifier for use in an error message.  */
 573
 574 const char *
 575 go_localize_identifier (const char *ident)
 576 {
 577   return identifier_to_locale (ident);
 578 }
 579
 580 #undef LANG_HOOKS_NAME
 581 #undef LANG_HOOKS_INIT
 582 #undef LANG_HOOKS_OPTION_LANG_MASK
 583 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 584 #undef LANG_HOOKS_HANDLE_OPTION
 585 #undef LANG_HOOKS_POST_OPTIONS
 586 #undef LANG_HOOKS_PARSE_FILE
 587 #undef LANG_HOOKS_TYPE_FOR_MODE
 588 #undef LANG_HOOKS_TYPE_FOR_SIZE
 589 #undef LANG_HOOKS_BUILTIN_FUNCTION
 590 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 591 #undef LANG_HOOKS_PUSHDECL
 592 #undef LANG_HOOKS_GETDECLS
 593 #undef LANG_HOOKS_GIMPLIFY_EXPR
 594 #undef LANG_HOOKS_EH_PERSONALITY
 595
 596 #define LANG_HOOKS_NAME                 "GNU Go"
 597 #define LANG_HOOKS_INIT                 go_langhook_init
 598 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 599 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 600 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 601 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 602 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 603 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 604 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 605 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 606 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 607 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 608 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 609 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 610 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 611
 612 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 613
 614 #include "gt-go-go-lang.h"
 615 #include "gtype-go.h"