gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2019 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.linemap = go_get_linemap();
 123   args.backend = go_get_backend();
 124   go_create_gogo (&args);
 125
 126   build_common_builtin_nodes ();
 127
 128   /* The default precision for floating point numbers.  This is used
 129      for floating point constants with abstract type.  This may
 130      eventually be controllable by a command line option.  */
 131   mpfr_set_default_prec (256);
 132
 133   /* Go uses exceptions.  */
 134   using_eh_for_cleanups ();
 135
 136   return true;
 137 }
 138
 139 /* The option mask.  */
 140
 141 static unsigned int
 142 go_langhook_option_lang_mask (void)
 143 {
 144   return CL_Go;
 145 }
 146
 147 /* Initialize the options structure.  */
 148
 149 static void
 150 go_langhook_init_options_struct (struct gcc_options *opts)
 151 {
 152   /* Go says that signed overflow is precisely defined.  */
 153   opts->x_flag_wrapv = 1;
 154
 155   /* We default to using strict aliasing, since Go pointers are safe.
 156      This is turned off for code that imports the "unsafe" package,
 157      because using unsafe.pointer violates C style aliasing
 158      requirements.  */
 159   opts->x_flag_strict_aliasing = 1;
 160
 161   /* Default to avoiding range issues for complex multiply and
 162      divide.  */
 163   opts->x_flag_complex_method = 2;
 164
 165   /* The builtin math functions should not set errno.  */
 166   opts->x_flag_errno_math = 0;
 167   opts->frontend_set_flag_errno_math = true;
 168
 169   /* Exceptions are used to handle recovering from panics.  */
 170   opts->x_flag_exceptions = 1;
 171   opts->x_flag_non_call_exceptions = 1;
 172
 173   /* We need to keep pointers live for the garbage collector.  */
 174   opts->x_flag_keep_gc_roots_live = 1;
 175
 176   /* Go programs expect runtime.Callers to work, and that uses
 177      libbacktrace that uses debug info.  Set the debug info level to 1
 178      by default.  In post_options we will set the debug type if the
 179      debug info level was not set back to 0 on the command line.  */
 180   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 181 }
 182
 183 /* Infrastructure for a vector of char * pointers.  */
 184
 185 typedef const char *go_char_p;
 186
 187 /* The list of directories to search after all the Go specific
 188    directories have been searched.  */
 189
 190 static vec<go_char_p> go_search_dirs;
 191
 192 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 193
 194 static bool
 195 go_langhook_handle_option (
 196     size_t scode,
 197     const char *arg,
 198     HOST_WIDE_INT value,
 199     int kind ATTRIBUTE_UNUSED,
 200     location_t loc ATTRIBUTE_UNUSED,
 201     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 202 {
 203   enum opt_code code = (enum opt_code) scode;
 204   bool ret = true;
 205
 206   switch (code)
 207     {
 208     case OPT_I:
 209       go_add_search_path (arg);
 210       break;
 211
 212     case OPT_L:
 213       /* A -L option is assumed to come from the compiler driver.
 214          This is a system directory.  We search the following
 215          directories, if they exist, before this one:
 216            dir/go/VERSION
 217            dir/go/VERSION/MACHINE
 218          This is like include/c++.  */
 219       {
 220         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 221         size_t len;
 222         char *p;
 223         struct stat st;
 224
 225         len = strlen (arg);
 226         p = XALLOCAVEC (char,
 227                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 228                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 229         strcpy (p, arg);
 230         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 231           strcat (p, dir_separator_str);
 232         strcat (p, "go");
 233         strcat (p, dir_separator_str);
 234         strcat (p, DEFAULT_TARGET_VERSION);
 235         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 236           {
 237             go_add_search_path (p);
 238             strcat (p, dir_separator_str);
 239             strcat (p, DEFAULT_TARGET_MACHINE);
 240             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 241               go_add_search_path (p);
 242           }
 243
 244         /* Search ARG too, but only after we've searched to Go
 245            specific directories for all -L arguments.  */
 246         go_search_dirs.safe_push (arg);
 247       }
 248       break;
 249
 250     case OPT_fgo_dump_:
 251       ret = go_enable_dump (arg) ? true : false;
 252       break;
 253
 254     case OPT_fgo_optimize_:
 255       ret = go_enable_optimize (arg, value) ? true : false;
 256       break;
 257
 258     case OPT_fgo_pkgpath_:
 259       go_pkgpath = arg;
 260       break;
 261
 262     case OPT_fgo_prefix_:
 263       go_prefix = arg;
 264       break;
 265
 266     case OPT_fgo_relative_import_path_:
 267       go_relative_import_path = arg;
 268       break;
 269
 270     case OPT_fgo_c_header_:
 271       go_c_header = arg;
 272       break;
 273
 274     default:
 275       /* Just return 1 to indicate that the option is valid.  */
 276       break;
 277     }
 278
 279   return ret;
 280 }
 281
 282 /* Run after parsing options.  */
 283
 284 static bool
 285 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 286 {
 287   unsigned int ix;
 288   const char *dir;
 289
 290   gcc_assert (num_in_fnames > 0);
 291
 292   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 293     go_add_search_path (dir);
 294   go_search_dirs.release ();
 295
 296   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
 297     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 298
 299   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 300   if (!global_options_set.x_flag_optimize_sibling_calls)
 301     global_options.x_flag_optimize_sibling_calls = 0;
 302
 303   /* If the debug info level is still 1, as set in init_options, make
 304      sure that some debugging type is selected.  */
 305   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 306       && global_options.x_write_symbols == NO_DEBUG)
 307     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 308
 309   /* We turn on stack splitting if we can.  */
 310   if (!global_options_set.x_flag_split_stack
 311       && targetm_common.supports_split_stack (false, &global_options))
 312     global_options.x_flag_split_stack = 1;
 313
 314   /* If stack splitting is turned on, and the user did not explicitly
 315      request function partitioning, turn off partitioning, as it
 316      confuses the linker when trying to handle partitioned split-stack
 317      code that calls a non-split-stack function.  */
 318   if (global_options.x_flag_split_stack
 319       && global_options.x_flag_reorder_blocks_and_partition
 320       && !global_options_set.x_flag_reorder_blocks_and_partition)
 321     global_options.x_flag_reorder_blocks_and_partition = 0;
 322
 323   /* Returning false means that the backend should be used.  */
 324   return false;
 325 }
 326
 327 static void
 328 go_langhook_parse_file (void)
 329 {
 330   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 331                         go_require_return_statement);
 332
 333   /* Final processing of globals and early debug info generation.  */
 334   go_write_globals ();
 335 }
 336
 337 static tree
 338 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 339 {
 340   tree type;
 341   if (unsignedp)
 342     {
 343       if (bits == INT_TYPE_SIZE)
 344         type = unsigned_type_node;
 345       else if (bits == CHAR_TYPE_SIZE)
 346         type = unsigned_char_type_node;
 347       else if (bits == SHORT_TYPE_SIZE)
 348         type = short_unsigned_type_node;
 349       else if (bits == LONG_TYPE_SIZE)
 350         type = long_unsigned_type_node;
 351       else if (bits == LONG_LONG_TYPE_SIZE)
 352         type = long_long_unsigned_type_node;
 353       else
 354         type = make_unsigned_type(bits);
 355     }
 356   else
 357     {
 358       if (bits == INT_TYPE_SIZE)
 359         type = integer_type_node;
 360       else if (bits == CHAR_TYPE_SIZE)
 361         type = signed_char_type_node;
 362       else if (bits == SHORT_TYPE_SIZE)
 363         type = short_integer_type_node;
 364       else if (bits == LONG_TYPE_SIZE)
 365         type = long_integer_type_node;
 366       else if (bits == LONG_LONG_TYPE_SIZE)
 367         type = long_long_integer_type_node;
 368       else
 369         type = make_signed_type(bits);
 370     }
 371   return type;
 372 }
 373
 374 static tree
 375 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 376 {
 377   tree type;
 378   /* Go has no vector types.  Build them here.  FIXME: It does not
 379      make sense for the middle-end to ask the frontend for a type
 380      which the frontend does not support.  However, at least for now
 381      it is required.  See PR 46805.  */
 382   if (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL
 383       && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 384     {
 385       unsigned int elem_bits = vector_element_size (GET_MODE_BITSIZE (mode),
 386                                                     GET_MODE_NUNITS (mode));
 387       tree bool_type = build_nonstandard_boolean_type (elem_bits);
 388       return build_vector_type_for_mode (bool_type, mode);
 389     }
 390   else if (VECTOR_MODE_P (mode)
 391            && valid_vector_subparts_p (GET_MODE_NUNITS (mode)))
 392     {
 393       tree inner;
 394
 395       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 396       if (inner != NULL_TREE)
 397         return build_vector_type_for_mode (inner, mode);
 398       return NULL_TREE;
 399     }
 400
 401   scalar_int_mode imode;
 402   scalar_float_mode fmode;
 403   complex_mode cmode;
 404   if (is_int_mode (mode, &imode))
 405     return go_langhook_type_for_size (GET_MODE_BITSIZE (imode), unsignedp);
 406   else if (is_float_mode (mode, &fmode))
 407     {
 408       switch (GET_MODE_BITSIZE (fmode))
 409         {
 410         case 32:
 411           return float_type_node;
 412         case 64:
 413           return double_type_node;
 414         default:
 415           // We have to check for long double in order to support
 416           // i386 excess precision.
 417           if (fmode == TYPE_MODE(long_double_type_node))
 418             return long_double_type_node;
 419         }
 420     }
 421   else if (is_complex_float_mode (mode, &cmode))
 422     {
 423       switch (GET_MODE_BITSIZE (cmode))
 424         {
 425         case 64:
 426           return complex_float_type_node;
 427         case 128:
 428           return complex_double_type_node;
 429         default:
 430           // We have to check for long double in order to support
 431           // i386 excess precision.
 432           if (cmode == TYPE_MODE(complex_long_double_type_node))
 433             return complex_long_double_type_node;
 434         }
 435     }
 436
 437 #if HOST_BITS_PER_WIDE_INT >= 64
 438   /* The middle-end and some backends rely on TImode being supported
 439      for 64-bit HWI.  */
 440   if (mode == TImode)
 441     {
 442       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 443                                              unsignedp);
 444       if (type && TYPE_MODE (type) == TImode)
 445         return type;
 446     }
 447 #endif
 448   return NULL_TREE;
 449 }
 450
 451 /* Record a builtin function.  We just ignore builtin functions.  */
 452
 453 static tree
 454 go_langhook_builtin_function (tree decl)
 455 {
 456   return decl;
 457 }
 458
 459 /* Return true if we are in the global binding level.  */
 460
 461 static bool
 462 go_langhook_global_bindings_p (void)
 463 {
 464   return current_function_decl == NULL_TREE;
 465 }
 466
 467 /* Push a declaration into the current binding level.  We can't
 468    usefully implement this since we don't want to convert from tree
 469    back to one of our internal data structures.  I think the only way
 470    this is used is to record a decl which is to be returned by
 471    getdecls, and we could implement it for that purpose if
 472    necessary.  */
 473
 474 static tree
 475 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 476 {
 477   gcc_unreachable ();
 478 }
 479
 480 /* This hook is used to get the current list of declarations as trees.
 481    We don't support that; instead we use the write_globals hook.  This
 482    can't simply crash because it is called by -gstabs.  */
 483
 484 static tree
 485 go_langhook_getdecls (void)
 486 {
 487   return NULL;
 488 }
 489
 490 /* Go specific gimplification.  We need to gimplify
 491    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 492    it.  */
 493
 494 static int
 495 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 496 {
 497   if (TREE_CODE (*expr_p) == CALL_EXPR
 498       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 499     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 500                    is_gimple_val, fb_rvalue);
 501   return GS_UNHANDLED;
 502 }
 503
 504 /* Return a decl for the exception personality function.  The function
 505    itself is implemented in libgo/runtime/go-unwind.c.  */
 506
 507 static tree
 508 go_langhook_eh_personality (void)
 509 {
 510   static tree personality_decl;
 511   if (personality_decl == NULL_TREE)
 512     {
 513       personality_decl = build_personality_function ("gccgo");
 514       go_preserve_from_gc (personality_decl);
 515     }
 516   return personality_decl;
 517 }
 518
 519 /* Functions called directly by the generic backend.  */
 520
 521 tree
 522 convert (tree type, tree expr)
 523 {
 524   if (type == error_mark_node
 525       || expr == error_mark_node
 526       || TREE_TYPE (expr) == error_mark_node)
 527     return error_mark_node;
 528
 529   if (type == TREE_TYPE (expr))
 530     return expr;
 531
 532   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 533     return fold_convert (type, expr);
 534
 535   switch (TREE_CODE (type))
 536     {
 537     case VOID_TYPE:
 538     case BOOLEAN_TYPE:
 539       return fold_convert (type, expr);
 540     case INTEGER_TYPE:
 541       return fold (convert_to_integer (type, expr));
 542     case POINTER_TYPE:
 543       return fold (convert_to_pointer (type, expr));
 544     case REAL_TYPE:
 545       return fold (convert_to_real (type, expr));
 546     case COMPLEX_TYPE:
 547       return fold (convert_to_complex (type, expr));
 548     default:
 549       break;
 550     }
 551
 552   gcc_unreachable ();
 553 }
 554
 555 /* FIXME: This is a hack to preserve trees that we create from the
 556    garbage collector.  */
 557
 558 static GTY(()) tree go_gc_root;
 559
 560 void
 561 go_preserve_from_gc (tree t)
 562 {
 563   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 564 }
 565
 566 /* Convert an identifier for use in an error message.  */
 567
 568 const char *
 569 go_localize_identifier (const char *ident)
 570 {
 571   return identifier_to_locale (ident);
 572 }
 573
 574 #undef LANG_HOOKS_NAME
 575 #undef LANG_HOOKS_INIT
 576 #undef LANG_HOOKS_OPTION_LANG_MASK
 577 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 578 #undef LANG_HOOKS_HANDLE_OPTION
 579 #undef LANG_HOOKS_POST_OPTIONS
 580 #undef LANG_HOOKS_PARSE_FILE
 581 #undef LANG_HOOKS_TYPE_FOR_MODE
 582 #undef LANG_HOOKS_TYPE_FOR_SIZE
 583 #undef LANG_HOOKS_BUILTIN_FUNCTION
 584 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 585 #undef LANG_HOOKS_PUSHDECL
 586 #undef LANG_HOOKS_GETDECLS
 587 #undef LANG_HOOKS_GIMPLIFY_EXPR
 588 #undef LANG_HOOKS_EH_PERSONALITY
 589
 590 #define LANG_HOOKS_NAME                 "GNU Go"
 591 #define LANG_HOOKS_INIT                 go_langhook_init
 592 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 593 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 594 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 595 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 596 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 597 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 598 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 599 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 600 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 601 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 602 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 603 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 604 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 605
 606 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 607
 608 #include "gt-go-go-lang.h"
 609 #include "gtype-go.h"