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