gcc/go/go-lang.c

   1 /* go-lang.c -- Go frontend gcc interface.
   2    Copyright (C) 2009-2016 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
  41 /* Language-dependent contents of a type.  */
  42
  43 struct GTY(()) lang_type
  44 {
  45   char dummy;
  46 };
  47
  48 /* Language-dependent contents of a decl.  */
  49
  50 struct GTY(()) lang_decl
  51 {
  52   char dummy;
  53 };
  54
  55 /* Language-dependent contents of an identifier.  This must include a
  56    tree_identifier.  */
  57
  58 struct GTY(()) lang_identifier
  59 {
  60   struct tree_identifier common;
  61 };
  62
  63 /* The resulting tree type.  */
  64
  65 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
  66            chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
  67 lang_tree_node
  68 {
  69   union tree_node GTY((tag ("0"),
  70                        desc ("tree_node_structure (&%h)"))) generic;
  71   struct lang_identifier GTY((tag ("1"))) identifier;
  72 };
  73
  74 /* We don't use language_function.  */
  75
  76 struct GTY(()) language_function
  77 {
  78   int dummy;
  79 };
  80
  81 /* Option information we need to pass to go_create_gogo.  */
  82
  83 static const char *go_pkgpath = NULL;
  84 static const char *go_prefix = NULL;
  85 static const char *go_relative_import_path = NULL;
  86
  87 /* Language hooks.  */
  88
  89 static bool
  90 go_langhook_init (void)
  91 {
  92   build_common_tree_nodes (false);
  93
  94   /* I don't know why this has to be done explicitly.  */
  95   void_list_node = build_tree_list (NULL_TREE, void_type_node);
  96
  97   /* We must create the gogo IR after calling build_common_tree_nodes
  98      (because Gogo::define_builtin_function_trees refers indirectly
  99      to, e.g., unsigned_char_type_node) but before calling
 100      build_common_builtin_nodes (because it calls, indirectly,
 101      go_type_for_size).  */
 102   go_create_gogo (INT_TYPE_SIZE, POINTER_SIZE, go_pkgpath, go_prefix,
 103                   go_relative_import_path, go_check_divide_zero,
 104                   go_check_divide_overflow);
 105
 106   build_common_builtin_nodes ();
 107
 108   /* The default precision for floating point numbers.  This is used
 109      for floating point constants with abstract type.  This may
 110      eventually be controllable by a command line option.  */
 111   mpfr_set_default_prec (256);
 112
 113   /* Go uses exceptions.  */
 114   using_eh_for_cleanups ();
 115
 116   return true;
 117 }
 118
 119 /* The option mask.  */
 120
 121 static unsigned int
 122 go_langhook_option_lang_mask (void)
 123 {
 124   return CL_Go;
 125 }
 126
 127 /* Initialize the options structure.  */
 128
 129 static void
 130 go_langhook_init_options_struct (struct gcc_options *opts)
 131 {
 132   /* Go says that signed overflow is precisely defined.  */
 133   opts->x_flag_wrapv = 1;
 134
 135   /* We default to using strict aliasing, since Go pointers are safe.
 136      This is turned off for code that imports the "unsafe" package,
 137      because using unsafe.pointer violates C style aliasing
 138      requirements.  */
 139   opts->x_flag_strict_aliasing = 1;
 140
 141   /* Default to avoiding range issues for complex multiply and
 142      divide.  */
 143   opts->x_flag_complex_method = 2;
 144
 145   /* The builtin math functions should not set errno.  */
 146   opts->x_flag_errno_math = 0;
 147   opts->frontend_set_flag_errno_math = true;
 148
 149   /* Exceptions are used to handle recovering from panics.  */
 150   opts->x_flag_exceptions = 1;
 151   opts->x_flag_non_call_exceptions = 1;
 152
 153   /* We need to keep pointers live for the garbage collector.  */
 154   opts->x_flag_keep_gc_roots_live = 1;
 155
 156   /* Go programs expect runtime.Callers to work, and that uses
 157      libbacktrace that uses debug info.  Set the debug info level to 1
 158      by default.  In post_options we will set the debug type if the
 159      debug info level was not set back to 0 on the command line.  */
 160   opts->x_debug_info_level = DINFO_LEVEL_TERSE;
 161 }
 162
 163 /* Infrastructure for a vector of char * pointers.  */
 164
 165 typedef const char *go_char_p;
 166
 167 /* The list of directories to search after all the Go specific
 168    directories have been searched.  */
 169
 170 static vec<go_char_p> go_search_dirs;
 171
 172 /* Handle Go specific options.  Return 0 if we didn't do anything.  */
 173
 174 static bool
 175 go_langhook_handle_option (
 176     size_t scode,
 177     const char *arg,
 178     int value ATTRIBUTE_UNUSED,
 179     int kind ATTRIBUTE_UNUSED,
 180     location_t loc ATTRIBUTE_UNUSED,
 181     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
 182 {
 183   enum opt_code code = (enum opt_code) scode;
 184   bool ret = true;
 185
 186   switch (code)
 187     {
 188     case OPT_I:
 189       go_add_search_path (arg);
 190       break;
 191
 192     case OPT_L:
 193       /* A -L option is assumed to come from the compiler driver.
 194          This is a system directory.  We search the following
 195          directories, if they exist, before this one:
 196            dir/go/VERSION
 197            dir/go/VERSION/MACHINE
 198          This is like include/c++.  */
 199       {
 200         static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 201         size_t len;
 202         char *p;
 203         struct stat st;
 204
 205         len = strlen (arg);
 206         p = XALLOCAVEC (char,
 207                         (len + sizeof "go" + sizeof DEFAULT_TARGET_VERSION
 208                          + sizeof DEFAULT_TARGET_MACHINE + 3));
 209         strcpy (p, arg);
 210         if (len > 0 && !IS_DIR_SEPARATOR (p[len - 1]))
 211           strcat (p, dir_separator_str);
 212         strcat (p, "go");
 213         strcat (p, dir_separator_str);
 214         strcat (p, DEFAULT_TARGET_VERSION);
 215         if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 216           {
 217             go_add_search_path (p);
 218             strcat (p, dir_separator_str);
 219             strcat (p, DEFAULT_TARGET_MACHINE);
 220             if (stat (p, &st) == 0 && S_ISDIR (st.st_mode))
 221               go_add_search_path (p);
 222           }
 223
 224         /* Search ARG too, but only after we've searched to Go
 225            specific directories for all -L arguments.  */
 226         go_search_dirs.safe_push (arg);
 227       }
 228       break;
 229
 230     case OPT_fgo_dump_:
 231       ret = go_enable_dump (arg) ? true : false;
 232       break;
 233
 234     case OPT_fgo_optimize_:
 235       ret = go_enable_optimize (arg) ? true : false;
 236       break;
 237
 238     case OPT_fgo_pkgpath_:
 239       go_pkgpath = arg;
 240       break;
 241
 242     case OPT_fgo_prefix_:
 243       go_prefix = arg;
 244       break;
 245
 246     case OPT_fgo_relative_import_path_:
 247       go_relative_import_path = arg;
 248       break;
 249
 250     default:
 251       /* Just return 1 to indicate that the option is valid.  */
 252       break;
 253     }
 254
 255   return ret;
 256 }
 257
 258 /* Run after parsing options.  */
 259
 260 static bool
 261 go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
 262 {
 263   unsigned int ix;
 264   const char *dir;
 265
 266   gcc_assert (num_in_fnames > 0);
 267
 268   FOR_EACH_VEC_ELT (go_search_dirs, ix, dir)
 269     go_add_search_path (dir);
 270   go_search_dirs.release ();
 271
 272   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
 273     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 274
 275   /* Tail call optimizations can confuse uses of runtime.Callers.  */
 276   if (!global_options_set.x_flag_optimize_sibling_calls)
 277     global_options.x_flag_optimize_sibling_calls = 0;
 278
 279   /* If the debug info level is still 1, as set in init_options, make
 280      sure that some debugging type is selected.  */
 281   if (global_options.x_debug_info_level == DINFO_LEVEL_TERSE
 282       && global_options.x_write_symbols == NO_DEBUG)
 283     global_options.x_write_symbols = PREFERRED_DEBUGGING_TYPE;
 284
 285   /* We turn on stack splitting if we can.  */
 286   if (!global_options_set.x_flag_split_stack
 287       && targetm_common.supports_split_stack (false, &global_options))
 288     global_options.x_flag_split_stack = 1;
 289
 290   /* Returning false means that the backend should be used.  */
 291   return false;
 292 }
 293
 294 static void
 295 go_langhook_parse_file (void)
 296 {
 297   go_parse_input_files (in_fnames, num_in_fnames, flag_syntax_only,
 298                         go_require_return_statement);
 299
 300   /* Final processing of globals and early debug info generation.  */
 301   go_write_globals ();
 302 }
 303
 304 static tree
 305 go_langhook_type_for_size (unsigned int bits, int unsignedp)
 306 {
 307   tree type;
 308   if (unsignedp)
 309     {
 310       if (bits == INT_TYPE_SIZE)
 311         type = unsigned_type_node;
 312       else if (bits == CHAR_TYPE_SIZE)
 313         type = unsigned_char_type_node;
 314       else if (bits == SHORT_TYPE_SIZE)
 315         type = short_unsigned_type_node;
 316       else if (bits == LONG_TYPE_SIZE)
 317         type = long_unsigned_type_node;
 318       else if (bits == LONG_LONG_TYPE_SIZE)
 319         type = long_long_unsigned_type_node;
 320       else
 321         type = make_unsigned_type(bits);
 322     }
 323   else
 324     {
 325       if (bits == INT_TYPE_SIZE)
 326         type = integer_type_node;
 327       else if (bits == CHAR_TYPE_SIZE)
 328         type = signed_char_type_node;
 329       else if (bits == SHORT_TYPE_SIZE)
 330         type = short_integer_type_node;
 331       else if (bits == LONG_TYPE_SIZE)
 332         type = long_integer_type_node;
 333       else if (bits == LONG_LONG_TYPE_SIZE)
 334         type = long_long_integer_type_node;
 335       else
 336         type = make_signed_type(bits);
 337     }
 338   return type;
 339 }
 340
 341 static tree
 342 go_langhook_type_for_mode (machine_mode mode, int unsignedp)
 343 {
 344   tree type;
 345   /* Go has no vector types.  Build them here.  FIXME: It does not
 346      make sense for the middle-end to ask the frontend for a type
 347      which the frontend does not support.  However, at least for now
 348      it is required.  See PR 46805.  */
 349   if (VECTOR_MODE_P (mode))
 350     {
 351       tree inner;
 352
 353       inner = go_langhook_type_for_mode (GET_MODE_INNER (mode), unsignedp);
 354       if (inner != NULL_TREE)
 355         return build_vector_type_for_mode (inner, mode);
 356       return NULL_TREE;
 357     }
 358
 359   // FIXME: This static_cast should be in machmode.h.
 360   enum mode_class mc = static_cast<enum mode_class>(GET_MODE_CLASS(mode));
 361   if (mc == MODE_INT)
 362     return go_langhook_type_for_size(GET_MODE_BITSIZE(mode), unsignedp);
 363   else if (mc == MODE_FLOAT)
 364     {
 365       switch (GET_MODE_BITSIZE (mode))
 366         {
 367         case 32:
 368           return float_type_node;
 369         case 64:
 370           return double_type_node;
 371         default:
 372           // We have to check for long double in order to support
 373           // i386 excess precision.
 374           if (mode == TYPE_MODE(long_double_type_node))
 375             return long_double_type_node;
 376         }
 377     }
 378   else if (mc == MODE_COMPLEX_FLOAT)
 379     {
 380       switch (GET_MODE_BITSIZE (mode))
 381         {
 382         case 64:
 383           return complex_float_type_node;
 384         case 128:
 385           return complex_double_type_node;
 386         default:
 387           // We have to check for long double in order to support
 388           // i386 excess precision.
 389           if (mode == TYPE_MODE(complex_long_double_type_node))
 390             return complex_long_double_type_node;
 391         }
 392     }
 393
 394 #if HOST_BITS_PER_WIDE_INT >= 64
 395   /* The middle-end and some backends rely on TImode being supported
 396      for 64-bit HWI.  */
 397   if (mode == TImode)
 398     {
 399       type = build_nonstandard_integer_type (GET_MODE_BITSIZE (TImode),
 400                                              unsignedp);
 401       if (type && TYPE_MODE (type) == TImode)
 402         return type;
 403     }
 404 #endif
 405   return NULL_TREE;
 406 }
 407
 408 /* Record a builtin function.  We just ignore builtin functions.  */
 409
 410 static tree
 411 go_langhook_builtin_function (tree decl)
 412 {
 413   return decl;
 414 }
 415
 416 /* Return true if we are in the global binding level.  */
 417
 418 static bool
 419 go_langhook_global_bindings_p (void)
 420 {
 421   return current_function_decl == NULL_TREE;
 422 }
 423
 424 /* Push a declaration into the current binding level.  We can't
 425    usefully implement this since we don't want to convert from tree
 426    back to one of our internal data structures.  I think the only way
 427    this is used is to record a decl which is to be returned by
 428    getdecls, and we could implement it for that purpose if
 429    necessary.  */
 430
 431 static tree
 432 go_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
 433 {
 434   gcc_unreachable ();
 435 }
 436
 437 /* This hook is used to get the current list of declarations as trees.
 438    We don't support that; instead we use the write_globals hook.  This
 439    can't simply crash because it is called by -gstabs.  */
 440
 441 static tree
 442 go_langhook_getdecls (void)
 443 {
 444   return NULL;
 445 }
 446
 447 /* Go specific gimplification.  We need to gimplify
 448    CALL_EXPR_STATIC_CHAIN, because the gimplifier doesn't handle
 449    it.  */
 450
 451 static int
 452 go_langhook_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 453 {
 454   if (TREE_CODE (*expr_p) == CALL_EXPR
 455       && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
 456     gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
 457                    is_gimple_val, fb_rvalue);
 458   return GS_UNHANDLED;
 459 }
 460
 461 /* Return a decl for the exception personality function.  The function
 462    itself is implemented in libgo/runtime/go-unwind.c.  */
 463
 464 static tree
 465 go_langhook_eh_personality (void)
 466 {
 467   static tree personality_decl;
 468   if (personality_decl == NULL_TREE)
 469     {
 470       personality_decl = build_personality_function ("gccgo");
 471       go_preserve_from_gc (personality_decl);
 472     }
 473   return personality_decl;
 474 }
 475
 476 /* Functions called directly by the generic backend.  */
 477
 478 tree
 479 convert (tree type, tree expr)
 480 {
 481   if (type == error_mark_node
 482       || expr == error_mark_node
 483       || TREE_TYPE (expr) == error_mark_node)
 484     return error_mark_node;
 485
 486   if (type == TREE_TYPE (expr))
 487     return expr;
 488
 489   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
 490     return fold_convert (type, expr);
 491
 492   switch (TREE_CODE (type))
 493     {
 494     case VOID_TYPE:
 495     case BOOLEAN_TYPE:
 496       return fold_convert (type, expr);
 497     case INTEGER_TYPE:
 498       return fold (convert_to_integer (type, expr));
 499     case POINTER_TYPE:
 500       return fold (convert_to_pointer (type, expr));
 501     case REAL_TYPE:
 502       return fold (convert_to_real (type, expr));
 503     case COMPLEX_TYPE:
 504       return fold (convert_to_complex (type, expr));
 505     default:
 506       break;
 507     }
 508
 509   gcc_unreachable ();
 510 }
 511
 512 /* FIXME: This is a hack to preserve trees that we create from the
 513    garbage collector.  */
 514
 515 static GTY(()) tree go_gc_root;
 516
 517 void
 518 go_preserve_from_gc (tree t)
 519 {
 520   go_gc_root = tree_cons (NULL_TREE, t, go_gc_root);
 521 }
 522
 523 /* Convert an identifier for use in an error message.  */
 524
 525 const char *
 526 go_localize_identifier (const char *ident)
 527 {
 528   return identifier_to_locale (ident);
 529 }
 530
 531 #undef LANG_HOOKS_NAME
 532 #undef LANG_HOOKS_INIT
 533 #undef LANG_HOOKS_OPTION_LANG_MASK
 534 #undef LANG_HOOKS_INIT_OPTIONS_STRUCT
 535 #undef LANG_HOOKS_HANDLE_OPTION
 536 #undef LANG_HOOKS_POST_OPTIONS
 537 #undef LANG_HOOKS_PARSE_FILE
 538 #undef LANG_HOOKS_TYPE_FOR_MODE
 539 #undef LANG_HOOKS_TYPE_FOR_SIZE
 540 #undef LANG_HOOKS_BUILTIN_FUNCTION
 541 #undef LANG_HOOKS_GLOBAL_BINDINGS_P
 542 #undef LANG_HOOKS_PUSHDECL
 543 #undef LANG_HOOKS_GETDECLS
 544 #undef LANG_HOOKS_GIMPLIFY_EXPR
 545 #undef LANG_HOOKS_EH_PERSONALITY
 546
 547 #define LANG_HOOKS_NAME                 "GNU Go"
 548 #define LANG_HOOKS_INIT                 go_langhook_init
 549 #define LANG_HOOKS_OPTION_LANG_MASK     go_langhook_option_lang_mask
 550 #define LANG_HOOKS_INIT_OPTIONS_STRUCT  go_langhook_init_options_struct
 551 #define LANG_HOOKS_HANDLE_OPTION        go_langhook_handle_option
 552 #define LANG_HOOKS_POST_OPTIONS         go_langhook_post_options
 553 #define LANG_HOOKS_PARSE_FILE           go_langhook_parse_file
 554 #define LANG_HOOKS_TYPE_FOR_MODE        go_langhook_type_for_mode
 555 #define LANG_HOOKS_TYPE_FOR_SIZE        go_langhook_type_for_size
 556 #define LANG_HOOKS_BUILTIN_FUNCTION     go_langhook_builtin_function
 557 #define LANG_HOOKS_GLOBAL_BINDINGS_P    go_langhook_global_bindings_p
 558 #define LANG_HOOKS_PUSHDECL             go_langhook_pushdecl
 559 #define LANG_HOOKS_GETDECLS             go_langhook_getdecls
 560 #define LANG_HOOKS_GIMPLIFY_EXPR        go_langhook_gimplify_expr
 561 #define LANG_HOOKS_EH_PERSONALITY       go_langhook_eh_personality
 562
 563 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 564
 565 #include "gt-go-go-lang.h"
 566 #include "gtype-go.h"