gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2018 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.linemap = go_get_linemap();
 122   args.backend = go_get_backend();
 123   go_create_gogo (&args);
 124
 125   build_common_builtin_nodes ();
 126
 127   /* The default precision for floating point numbers.  This is used
 128      for floating point constants with abstract type.  This may
 129      eventually be controllable by a command line option.  */
 130   mpfr_set_default_prec (256);
 131
 132   /* Go uses exceptions.  */
 133   using_eh_for_cleanups ();
 134
 135   return true;
 136 }
 137
 138 /* The option mask.  */
 139
 140 static unsigned int
 141 go_langhook_option_lang_mask (void)
 142 {
 143   return CL_Go;
 144 }
 145
 146 /* Initialize the options structure.  */
 147
 148 static void
 149 go_langhook_init_options_struct (struct gcc_options *opts)
 150 {
 151   /* Go says that signed overflow is precisely defined.  */
 152   opts->x_flag_wrapv = 1;
 153
 154   /* We default to using strict aliasing, since Go pointers are safe.
 155      This is turned off for code that imports the "unsafe" package,
 156      because using unsafe.pointer violates C style aliasing
 157      requirements.  */
 158   opts->x_flag_strict_aliasing = 1;
 159
 160   /* Default to avoiding range issues for complex multiply and
 161      divide.  */
 162   opts->x_flag_complex_method = 2;
 163
 164   /* The builtin math functions should not set errno.  */
 165   opts->x_flag_errno_math = 0;
 166   opts->frontend_set_flag_errno_math = true;
 167
 168   /* Exceptions are used to handle recovering from panics.  */
 169   opts->x_flag_exceptions = 1;
 170   opts->x_flag_non_call_exceptions = 1;
 171
 172   /* We need to keep pointers live for the garbage collector.  */
 173   opts->x_flag_keep_gc_roots_live = 1;
 174
 175   /* Go programs expect runtime.Callers to work, and that uses
 176      libbacktrace that uses debug info.  Set the debug info level to 1
 177      by default.  In post_options we will set the debug type if the
 178      debug info level was not set back to 0 on the command line.  */
 179   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 180 }
 181
 182 /* Infrastructure for a vector of char * pointers.  */
 183
 184 typedef const char *go_char_p;
 185
 186 /* The list of directories to search after all the Go specific
 187    directories have been searched.  */
 188
 189 static vec<go_char_p> go_search_dirs;
 190
 191 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 192
 193 static bool
 194 go_langhook_handle_option (
 195     size_t scode,
 196     const char *arg,
 197     int value,
 198     int kind ATTRIBUTE_UNUSED,
 199     location_t loc ATTRIBUTE_UNUSED,
 200     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 201 {
 202   enum opt_code code = (enum opt_code) scode;
 203   bool ret = true;
 204
 205   switch (code)
 206     {
 207     case OPT_I:
 208       go_add_search_path (arg);
 209       break;
 210
 211     case OPT_L:
 212       /* A -L option is assumed to come from the compiler driver.
 213          This is a system directory.  We search the following
 214          directories, if they exist, before this one:
 215            dir/go/VERSION
 216            dir/go/VERSION/MACHINE
 217          This is like include/c++.  */
 218       {
 219         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 220         size_t len;
 221         char *p;
 222         struct stat st;
 223
 224         len = strlen (arg);
 225         p = XALLOCAVEC (char,
 226                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 227                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 228         strcpy (p, arg);
 229         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 230           strcat (p, dir_separator_str);
 231         strcat (p, "go");
 232         strcat (p, dir_separator_str);
 233         strcat (p, DEFAULT_TARGET_VERSION);
 234         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 235           {
 236             go_add_search_path (p);
 237             strcat (p, dir_separator_str);
 238             strcat (p, DEFAULT_TARGET_MACHINE);
 239             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 240               go_add_search_path (p);
 241           }
 242
 243         /* Search ARG too, but only after we've searched to Go
 244            specific directories for all -L arguments.  */
 245         go_search_dirs.safe_push (arg);
 246       }
 247       break;
 248
 249     case OPT_fgo_dump_:
 250       ret = go_enable_dump (arg) ? true : false;
 251       break;
 252
 253     case OPT_fgo_optimize_:
 254       ret = go_enable_optimize (arg, value) ? true : false;
 255       break;
 256
 257     case OPT_fgo_pkgpath_:
 258       go_pkgpath = arg;
 259       break;
 260
 261     case OPT_fgo_prefix_:
 262       go_prefix = arg;
 263       break;
 264
 265     case OPT_fgo_relative_import_path_:
 266       go_relative_import_path = arg;
 267       break;
 268
 269     case OPT_fgo_c_header_:
 270       go_c_header = arg;
 271       break;
 272
 273     default:
 274       /* Just return 1 to indicate that the option is valid.  */
 275       break;
 276     }
 277
 278   return ret;
 279 }
 280
 281 /* Run after parsing options.  */
 282
 283 static bool
 284 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 285 {
 286   unsigned int ix;
 287   const char *dir;
 288
 289   gcc_assert (num_in_fnames > 0);
 290
 291   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 292     go_add_search_path (dir);
 293   go_search_dirs.release ();
 294
 295   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
 296     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 297
 298   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 299   if (!global_options_set.x_flag_optimize_sibling_calls)
 300     global_options.x_flag_optimize_sibling_calls = 0;
 301
 302   /* If the debug info level is still 1, as set in init_options, make
 303      sure that some debugging type is selected.  */
 304   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 305       && global_options.x_write_symbols == NO_DEBUG)
 306     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 307
 308   /* We turn on stack splitting if we can.  */
 309   if (!global_options_set.x_flag_split_stack
 310       && targetm_common.supports_split_stack (false, &global_options))
 311     global_options.x_flag_split_stack = 1;
 312
 313   /* If stack splitting is turned on, and the user did not explicitly
 314      request function partitioning, turn off partitioning, as it
 315      confuses the linker when trying to handle partitioned split-stack
 316      code that calls a non-split-stack function.  */
 317   if (global_options.x_flag_split_stack
 318       && global_options.x_flag_reorder_blocks_and_partition
 319       && !global_options_set.x_flag_reorder_blocks_and_partition)
 320     global_options.x_flag_reorder_blocks_and_partition = 0;
 321
 322   /* Returning false means that the backend should be used.  */
 323   return false;
 324 }
 325
 326 static void
 327 go_langhook_parse_file (void)
 328 {
 329   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 330                         go_require_return_statement);
 331
 332   /* Final processing of globals and early debug info generation.  */
 333   go_write_globals ();
 334 }
 335
 336 static tree
 337 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 338 {
 339   tree type;
 340   if (unsignedp)
 341     {
 342       if (bits == INT_TYPE_SIZE)
 343         type = unsigned_type_node;
 344       else if (bits == CHAR_TYPE_SIZE)
 345         type = unsigned_char_type_node;
 346       else if (bits == SHORT_TYPE_SIZE)
 347         type = short_unsigned_type_node;
 348       else if (bits == LONG_TYPE_SIZE)
 349         type = long_unsigned_type_node;
 350       else if (bits == LONG_LONG_TYPE_SIZE)
 351         type = long_long_unsigned_type_node;
 352       else
 353         type = make_unsigned_type(bits);
 354     }
 355   else
 356     {
 357       if (bits == INT_TYPE_SIZE)
 358         type = integer_type_node;
 359       else if (bits == CHAR_TYPE_SIZE)
 360         type = signed_char_type_node;
 361       else if (bits == SHORT_TYPE_SIZE)
 362         type = short_integer_type_node;
 363       else if (bits == LONG_TYPE_SIZE)
 364         type = long_integer_type_node;
 365       else if (bits == LONG_LONG_TYPE_SIZE)
 366         type = long_long_integer_type_node;
 367       else
 368         type = make_signed_type(bits);
 369     }
 370   return type;
 371 }
 372
 373 static tree
 374 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 375 {
 376   tree type;
 377   /* Go has no vector types.  Build them here.  FIXME: It does not
 378      make sense for the middle-end to ask the frontend for a type
 379      which the frontend does not support.  However, at least for now
 380      it is required.  See PR 46805.  */
 381   if (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL
 382       && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 383     {
 384       unsigned int elem_bits = vector_element_size (GET_MODE_BITSIZE (mode),
 385                                                     GET_MODE_NUNITS (mode));
 386       tree bool_type = build_nonstandard_boolean_type (elem_bits);
 387       return build_vector_type_for_mode (bool_type, mode);
 388     }
 389   else if (VECTOR_MODE_P (mode)
 390            && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 391     {
 392       tree inner;
 393
 394       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 395       if (inner != NULL_TREE)
 396         return build_vector_type_for_mode (inner, mode);
 397       return NULL_TREE;
 398     }
 399
 400   scalar_int_mode imode;
 401   scalar_float_mode fmode;
 402   complex_mode cmode;
 403   if (is_int_mode (mode, &imode))
 404     return go_langhook_type_for_size (GET_MODE_BITSIZE (imode), unsignedp);
 405   else if (is_float_mode (mode, &fmode))
 406     {
 407       switch (GET_MODE_BITSIZE (fmode))
 408         {
 409         case 32:
 410           return float_type_node;
 411         case 64:
 412           return double_type_node;
 413         default:
 414           // We have to check for long double in order to support
 415           // i386 excess precision.
 416           if (fmode == TYPE_MODE(long_double_type_node))
 417             return long_double_type_node;
 418         }
 419     }
 420   else if (is_complex_float_mode (mode, &cmode))
 421     {
 422       switch (GET_MODE_BITSIZE (cmode))
 423         {
 424         case 64:
 425           return complex_float_type_node;
 426         case 128:
 427           return complex_double_type_node;
 428         default:
 429           // We have to check for long double in order to support
 430           // i386 excess precision.
 431           if (cmode == TYPE_MODE(complex_long_double_type_node))
 432             return complex_long_double_type_node;
 433         }
 434     }
 435
 436 #if HOST_BITS_PER_WIDE_INT >= 64
 437   /* The middle-end and some backends rely on TImode being supported
 438      for 64-bit HWI.  */
 439   if (mode == TImode)
 440     {
 441       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 442                                              unsignedp);
 443       if (type && TYPE_MODE (type) == TImode)
 444         return type;
 445     }
 446 #endif
 447   return NULL_TREE;
 448 }
 449
 450 /* Record a builtin function.  We just ignore builtin functions.  */
 451
 452 static tree
 453 go_langhook_builtin_function (tree decl)
 454 {
 455   return decl;
 456 }
 457
 458 /* Return true if we are in the global binding level.  */
 459
 460 static bool
 461 go_langhook_global_bindings_p (void)
 462 {
 463   return current_function_decl == NULL_TREE;
 464 }
 465
 466 /* Push a declaration into the current binding level.  We can't
 467    usefully implement this since we don't want to convert from tree
 468    back to one of our internal data structures.  I think the only way
 469    this is used is to record a decl which is to be returned by
 470    getdecls, and we could implement it for that purpose if
 471    necessary.  */
 472
 473 static tree
 474 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 475 {
 476   gcc_unreachable ();
 477 }
 478
 479 /* This hook is used to get the current list of declarations as trees.
 480    We don't support that; instead we use the write_globals hook.  This
 481    can't simply crash because it is called by -gstabs.  */
 482
 483 static tree
 484 go_langhook_getdecls (void)
 485 {
 486   return NULL;
 487 }
 488
 489 /* Go specific gimplification.  We need to gimplify
 490    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 491    it.  */
 492
 493 static int
 494 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 495 {
 496   if (TREE_CODE (*expr_p) == CALL_EXPR
 497       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 498     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 499                    is_gimple_val, fb_rvalue);
 500   return GS_UNHANDLED;
 501 }
 502
 503 /* Return a decl for the exception personality function.  The function
 504    itself is implemented in libgo/runtime/go-unwind.c.  */
 505
 506 static tree
 507 go_langhook_eh_personality (void)
 508 {
 509   static tree personality_decl;
 510   if (personality_decl == NULL_TREE)
 511     {
 512       personality_decl = build_personality_function ("gccgo");
 513       go_preserve_from_gc (personality_decl);
 514     }
 515   return personality_decl;
 516 }
 517
 518 /* Functions called directly by the generic backend.  */
 519
 520 tree
 521 convert (tree type, tree expr)
 522 {
 523   if (type == error_mark_node
 524       || expr == error_mark_node
 525       || TREE_TYPE (expr) == error_mark_node)
 526     return error_mark_node;
 527
 528   if (type == TREE_TYPE (expr))
 529     return expr;
 530
 531   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 532     return fold_convert (type, expr);
 533
 534   switch (TREE_CODE (type))
 535     {
 536     case VOID_TYPE:
 537     case BOOLEAN_TYPE:
 538       return fold_convert (type, expr);
 539     case INTEGER_TYPE:
 540       return fold (convert_to_integer (type, expr));
 541     case POINTER_TYPE:
 542       return fold (convert_to_pointer (type, expr));
 543     case REAL_TYPE:
 544       return fold (convert_to_real (type, expr));
 545     case COMPLEX_TYPE:
 546       return fold (convert_to_complex (type, expr));
 547     default:
 548       break;
 549     }
 550
 551   gcc_unreachable ();
 552 }
 553
 554 /* FIXME: This is a hack to preserve trees that we create from the
 555    garbage collector.  */
 556
 557 static GTY(()) tree go_gc_root;
 558
 559 void
 560 go_preserve_from_gc (tree t)
 561 {
 562   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 563 }
 564
 565 /* Convert an identifier for use in an error message.  */
 566
 567 const char *
 568 go_localize_identifier (const char *ident)
 569 {
 570   return identifier_to_locale (ident);
 571 }
 572
 573 #undef LANG_HOOKS_NAME
 574 #undef LANG_HOOKS_INIT
 575 #undef LANG_HOOKS_OPTION_LANG_MASK
 576 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 577 #undef LANG_HOOKS_HANDLE_OPTION
 578 #undef LANG_HOOKS_POST_OPTIONS
 579 #undef LANG_HOOKS_PARSE_FILE
 580 #undef LANG_HOOKS_TYPE_FOR_MODE
 581 #undef LANG_HOOKS_TYPE_FOR_SIZE
 582 #undef LANG_HOOKS_BUILTIN_FUNCTION
 583 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 584 #undef LANG_HOOKS_PUSHDECL
 585 #undef LANG_HOOKS_GETDECLS
 586 #undef LANG_HOOKS_GIMPLIFY_EXPR
 587 #undef LANG_HOOKS_EH_PERSONALITY
 588
 589 #define LANG_HOOKS_NAME                 "GNU Go"
 590 #define LANG_HOOKS_INIT                 go_langhook_init
 591 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 592 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 593 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 594 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 595 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 596 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 597 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 598 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 599 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 600 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 601 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 602 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 603 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 604
 605 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 606
 607 #include "gt-go-go-lang.h"
 608 #include "gtype-go.h"