gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2015 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 "ansidecl.h"
  23 #include "coretypes.h"
  24 #include "opts.h"
  25 #include "hash-set.h"
  26 #include "machmode.h"
  27 #include "vec.h"
  28 #include "double-int.h"
  29 #include "input.h"
  30 #include "alias.h"
  31 #include "symtab.h"
  32 #include "options.h"
  33 #include "wide-int.h"
  34 #include "inchash.h"
  35 #include "tree.h"
  36 #include "fold-const.h"
  37 #include "tm.h"
  38 #include "hard-reg-set.h"
  39 #include "input.h"
  40 #include "function.h"
  41 #include "gimple-expr.h"
  42 #include "gimplify.h"
  43 #include "stor-layout.h"
  44 #include "toplev.h"
  45 #include "debug.h"
  46 #include "options.h"
  47 #include "flags.h"
  48 #include "convert.h"
  49 #include "diagnostic.h"
  50 #include "langhooks.h"
  51 #include "langhooks-def.h"
  52 #include "target.h"
  53 #include "common/common-target.h"
  54
  55 #include <mpfr.h>
  56
  57 #include "go-c.h"
  58
  59 /* Language-dependent contents of a type.  */
  60
  61 struct GTY(()) lang_type
  62 {
  63   char dummy;
  64 };
  65
  66 /* Language-dependent contents of a decl.  */
  67
  68 struct GTY(()) lang_decl
  69 {
  70   char dummy;
  71 };
  72
  73 /* Language-dependent contents of an identifier.  This must include a
  74    tree_identifier.  */
  75
  76 struct GTY(()) lang_identifier
  77 {
  78   struct tree_identifier common;
  79 };
  80
  81 /* The resulting tree type.  */
  82
  83 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
  84            chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
  85 lang_tree_node
  86 {
  87   union tree_node GTY((tag ("0"),
  88                        desc ("tree_node_structure (&%h)"))) generic;
  89   struct lang_identifier GTY((tag ("1"))) identifier;
  90 };
  91
  92 /* We don't use language_function.  */
  93
  94 struct GTY(()) language_function
  95 {
  96   int dummy;
  97 };
  98
  99 /* Option information we need to pass to go_create_gogo.  */
 100
 101 static const char *go_pkgpath = NULL;
 102 static const char *go_prefix = NULL;
 103 static const char *go_relative_import_path = NULL;
 104
 105 /* Language hooks.  */
 106
 107 static bool
 108 go_langhook_init (void)
 109 {
 110   build_common_tree_nodes (false, false);
 111
 112   /* I don't know why this has to be done explicitly.  */
 113   void_list_node = build_tree_list (NULL_TREE, void_type_node);
 114
 115   /* We must create the gogo IR after calling build_common_tree_nodes
 116      (because Gogo::define_builtin_function_trees refers indirectly
 117      to, e.g., unsigned_char_type_node) but before calling
 118      build_common_builtin_nodes (because it calls, indirectly,
 119      go_type_for_size).  */
 120   go_create_gogo (INT_TYPE_SIZE, POINTER_SIZE, go_pkgpath, go_prefix,
 121                   go_relative_import_path, go_check_divide_zero,
 122                   go_check_divide_overflow);
 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   /* We turn on stack splitting if we can.  */
 168   if (targetm_common.supports_split_stack (false, opts))
 169     opts->x_flag_split_stack = 1;
 170
 171   /* Exceptions are used to handle recovering from panics.  */
 172   opts->x_flag_exceptions = 1;
 173   opts->x_flag_non_call_exceptions = 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 ATTRIBUTE_UNUSED,
 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) ? 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     default:
 270       /* Just return 1 to indicate that the option is valid.  */
 271       break;
 272     }
 273
 274   return ret;
 275 }
 276
 277 /* Run after parsing options.  */
 278
 279 static bool
 280 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 281 {
 282   unsigned int ix;
 283   const char *dir;
 284
 285   gcc_assert (num_in_fnames > 0);
 286
 287   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 288     go_add_search_path (dir);
 289   go_search_dirs.release ();
 290
 291   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
 292     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 293
 294   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 295   if (!global_options_set.x_flag_optimize_sibling_calls)
 296     global_options.x_flag_optimize_sibling_calls = 0;
 297
 298   /* If the debug info level is still 1, as set in init_options, make
 299      sure that some debugging type is selected.  */
 300   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 301       && global_options.x_write_symbols == NO_DEBUG)
 302     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 303
 304   /* Returning false means that the backend should be used.  */
 305   return false;
 306 }
 307
 308 static void
 309 go_langhook_parse_file (void)
 310 {
 311   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 312                         go_require_return_statement);
 313 }
 314
 315 static tree
 316 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 317 {
 318   tree type;
 319   if (unsignedp)
 320     {
 321       if (bits == INT_TYPE_SIZE)
 322         type = unsigned_type_node;
 323       else if (bits == CHAR_TYPE_SIZE)
 324         type = unsigned_char_type_node;
 325       else if (bits == SHORT_TYPE_SIZE)
 326         type = short_unsigned_type_node;
 327       else if (bits == LONG_TYPE_SIZE)
 328         type = long_unsigned_type_node;
 329       else if (bits == LONG_LONG_TYPE_SIZE)
 330         type = long_long_unsigned_type_node;
 331       else
 332         type = make_unsigned_type(bits);
 333     }
 334   else
 335     {
 336       if (bits == INT_TYPE_SIZE)
 337         type = integer_type_node;
 338       else if (bits == CHAR_TYPE_SIZE)
 339         type = signed_char_type_node;
 340       else if (bits == SHORT_TYPE_SIZE)
 341         type = short_integer_type_node;
 342       else if (bits == LONG_TYPE_SIZE)
 343         type = long_integer_type_node;
 344       else if (bits == LONG_LONG_TYPE_SIZE)
 345         type = long_long_integer_type_node;
 346       else
 347         type = make_signed_type(bits);
 348     }
 349   return type;
 350 }
 351
 352 static tree
 353 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 354 {
 355   tree type;
 356   /* Go has no vector types.  Build them here.  FIXME: It does not
 357      make sense for the middle-end to ask the frontend for a type
 358      which the frontend does not support.  However, at least for now
 359      it is required.  See PR 46805.  */
 360   if (VECTOR_MODE_P (mode))
 361     {
 362       tree inner;
 363
 364       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 365       if (inner != NULL_TREE)
 366         return build_vector_type_for_mode (inner, mode);
 367       return NULL_TREE;
 368     }
 369
 370   // FIXME: This static_cast should be in machmode.h.
 371   enum mode_class mc = static_cast<enum mode_class>(GET_MODE_CLASS(mode));
 372   if (mc == MODE_INT)
 373     return go_langhook_type_for_size(GET_MODE_BITSIZE(mode), unsignedp);
 374   else if (mc == MODE_FLOAT)
 375     {
 376       switch (GET_MODE_BITSIZE (mode))
 377         {
 378         case 32:
 379           return float_type_node;
 380         case 64:
 381           return double_type_node;
 382         default:
 383           // We have to check for long double in order to support
 384           // i386 excess precision.
 385           if (mode == TYPE_MODE(long_double_type_node))
 386             return long_double_type_node;
 387         }
 388     }
 389   else if (mc == MODE_COMPLEX_FLOAT)
 390     {
 391       switch (GET_MODE_BITSIZE (mode))
 392         {
 393         case 64:
 394           return complex_float_type_node;
 395         case 128:
 396           return complex_double_type_node;
 397         default:
 398           // We have to check for long double in order to support
 399           // i386 excess precision.
 400           if (mode == TYPE_MODE(complex_long_double_type_node))
 401             return complex_long_double_type_node;
 402         }
 403     }
 404
 405 #if HOST_BITS_PER_WIDE_INT >= 64
 406   /* The middle-end and some backends rely on TImode being supported
 407      for 64-bit HWI.  */
 408   if (mode == TImode)
 409     {
 410       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 411                                              unsignedp);
 412       if (type && TYPE_MODE (type) == TImode)
 413         return type;
 414     }
 415 #endif
 416   return NULL_TREE;
 417 }
 418
 419 /* Record a builtin function.  We just ignore builtin functions.  */
 420
 421 static tree
 422 go_langhook_builtin_function (tree decl)
 423 {
 424   return decl;
 425 }
 426
 427 /* Return true if we are in the global binding level.  */
 428
 429 static bool
 430 go_langhook_global_bindings_p (void)
 431 {
 432   return current_function_decl == NULL_TREE;
 433 }
 434
 435 /* Push a declaration into the current binding level.  We can't
 436    usefully implement this since we don't want to convert from tree
 437    back to one of our internal data structures.  I think the only way
 438    this is used is to record a decl which is to be returned by
 439    getdecls, and we could implement it for that purpose if
 440    necessary.  */
 441
 442 static tree
 443 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 444 {
 445   gcc_unreachable ();
 446 }
 447
 448 /* This hook is used to get the current list of declarations as trees.
 449    We don't support that; instead we use the write_globals hook.  This
 450    can't simply crash because it is called by -gstabs.  */
 451
 452 static tree
 453 go_langhook_getdecls (void)
 454 {
 455   return NULL;
 456 }
 457
 458 /* Write out globals.  */
 459
 460 static void
 461 go_langhook_write_globals (void)
 462 {
 463   go_write_globals ();
 464 }
 465
 466 /* Go specific gimplification.  We need to gimplify
 467    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 468    it.  */
 469
 470 static int
 471 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 472 {
 473   if (TREE_CODE (*expr_p) == CALL_EXPR
 474       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 475     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 476                    is_gimple_val, fb_rvalue);
 477   return GS_UNHANDLED;
 478 }
 479
 480 /* Return a decl for the exception personality function.  The function
 481    itself is implemented in libgo/runtime/go-unwind.c.  */
 482
 483 static tree
 484 go_langhook_eh_personality (void)
 485 {
 486   static tree personality_decl;
 487   if (personality_decl == NULL_TREE)
 488     {
 489       personality_decl = build_personality_function ("gccgo");
 490       go_preserve_from_gc (personality_decl);
 491     }
 492   return personality_decl;
 493 }
 494
 495 /* Functions called directly by the generic backend.  */
 496
 497 tree
 498 convert (tree type, tree expr)
 499 {
 500   if (type == error_mark_node
 501       || expr == error_mark_node
 502       || TREE_TYPE (expr) == error_mark_node)
 503     return error_mark_node;
 504
 505   if (type == TREE_TYPE (expr))
 506     return expr;
 507
 508   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 509     return fold_convert (type, expr);
 510
 511   switch (TREE_CODE (type))
 512     {
 513     case VOID_TYPE:
 514     case BOOLEAN_TYPE:
 515       return fold_convert (type, expr);
 516     case INTEGER_TYPE:
 517       return fold (convert_to_integer (type, expr));
 518     case POINTER_TYPE:
 519       return fold (convert_to_pointer (type, expr));
 520     case REAL_TYPE:
 521       return fold (convert_to_real (type, expr));
 522     case COMPLEX_TYPE:
 523       return fold (convert_to_complex (type, expr));
 524     default:
 525       break;
 526     }
 527
 528   gcc_unreachable ();
 529 }
 530
 531 /* FIXME: This is a hack to preserve trees that we create from the
 532    garbage collector.  */
 533
 534 static GTY(()) tree go_gc_root;
 535
 536 void
 537 go_preserve_from_gc (tree t)
 538 {
 539   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 540 }
 541
 542 /* Convert an identifier for use in an error message.  */
 543
 544 const char *
 545 go_localize_identifier (const char *ident)
 546 {
 547   return identifier_to_locale (ident);
 548 }
 549
 550 #undef LANG_HOOKS_NAME
 551 #undef LANG_HOOKS_INIT
 552 #undef LANG_HOOKS_OPTION_LANG_MASK
 553 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 554 #undef LANG_HOOKS_HANDLE_OPTION
 555 #undef LANG_HOOKS_POST_OPTIONS
 556 #undef LANG_HOOKS_PARSE_FILE
 557 #undef LANG_HOOKS_TYPE_FOR_MODE
 558 #undef LANG_HOOKS_TYPE_FOR_SIZE
 559 #undef LANG_HOOKS_BUILTIN_FUNCTION
 560 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 561 #undef LANG_HOOKS_PUSHDECL
 562 #undef LANG_HOOKS_GETDECLS
 563 #undef LANG_HOOKS_WRITE_GLOBALS
 564 #undef LANG_HOOKS_GIMPLIFY_EXPR
 565 #undef LANG_HOOKS_EH_PERSONALITY
 566
 567 #define LANG_HOOKS_NAME                 "GNU Go"
 568 #define LANG_HOOKS_INIT                 go_langhook_init
 569 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 570 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 571 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 572 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 573 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 574 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 575 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 576 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 577 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 578 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 579 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 580 #define LANG_HOOKS_WRITE_GLOBALS        go_langhook_write_globals
 581 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 582 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 583
 584 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 585
 586 #include "gt-go-go-lang.h"
 587 #include "gtype-go.h"