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