gdb/macrocmd.c

   1 /* C preprocessor macro expansion commands for GDB.
   2    Copyright (C) 2002-2022 Free Software Foundation, Inc.
   3    Contributed by Red Hat, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #include "defs.h"
  22 #include "macrotab.h"
  23 #include "macroexp.h"
  24 #include "macroscope.h"
  25 #include "cli/cli-style.h"
  26 #include "cli/cli-utils.h"
  27 #include "command.h"
  28 #include "gdbcmd.h"
  29 #include "linespec.h"
  30
  31 \f
  32 /* The `macro' prefix command.  */
  33
  34 static struct cmd_list_element *macrolist;
  35
  36 \f
  37 /* Macro expansion commands.  */
  38
  39
  40 /* Prints an informational message regarding the lack of macro information.  */
  41 static void
  42 macro_inform_no_debuginfo (void)
  43 {
  44   gdb_puts ("GDB has no preprocessor macro information for that code.\n");
  45 }
  46
  47 static void
  48 macro_expand_command (const char *exp, int from_tty)
  49 {
  50   /* You know, when the user doesn't specify any expression, it would be
  51      really cool if this defaulted to the last expression evaluated.
  52      Then it would be easy to ask, "Hey, what did I just evaluate?"  But
  53      at the moment, the `print' commands don't save the last expression
  54      evaluated, just its value.  */
  55   if (! exp || ! *exp)
  56     error (_("You must follow the `macro expand' command with the"
  57            " expression you\n"
  58            "want to expand."));
  59
  60   gdb::unique_xmalloc_ptr<macro_scope> ms = default_macro_scope ();
  61
  62   if (ms != nullptr)
  63     {
  64       gdb::unique_xmalloc_ptr<char> expanded = macro_expand (exp, *ms);
  65
  66       gdb_puts ("expands to: ");
  67       gdb_puts (expanded.get ());
  68       gdb_puts ("\n");
  69     }
  70   else
  71     macro_inform_no_debuginfo ();
  72 }
  73
  74
  75 static void
  76 macro_expand_once_command (const char *exp, int from_tty)
  77 {
  78   /* You know, when the user doesn't specify any expression, it would be
  79      really cool if this defaulted to the last expression evaluated.
  80      And it should set the once-expanded text as the new `last
  81      expression'.  That way, you could just hit return over and over and
  82      see the expression expanded one level at a time.  */
  83   if (! exp || ! *exp)
  84     error (_("You must follow the `macro expand-once' command with"
  85            " the expression\n"
  86            "you want to expand."));
  87
  88   gdb::unique_xmalloc_ptr<macro_scope> ms = default_macro_scope ();
  89
  90   if (ms != nullptr)
  91     {
  92       gdb::unique_xmalloc_ptr<char> expanded = macro_expand_once (exp, *ms);
  93
  94       gdb_puts ("expands to: ");
  95       gdb_puts (expanded.get ());
  96       gdb_puts ("\n");
  97     }
  98   else
  99     macro_inform_no_debuginfo ();
 100 }
 101
 102 /*  Outputs the include path of a macro starting at FILE and LINE to STREAM.
 103
 104     Care should be taken that this function does not cause any lookups into
 105     the splay tree so that it can be safely used while iterating.  */
 106 static void
 107 show_pp_source_pos (struct ui_file *stream,
 108                     struct macro_source_file *file,
 109                     int line)
 110 {
 111   std::string fullname = macro_source_fullname (file);
 112   gdb_printf (stream, "%ps:%d\n",
 113               styled_string (file_name_style.style (),
 114                              fullname.c_str ()),
 115               line);
 116
 117   while (file->included_by)
 118     {
 119       fullname = macro_source_fullname (file->included_by);
 120       gdb_puts (_("  included at "), stream);
 121       fputs_styled (fullname.c_str (), file_name_style.style (), stream);
 122       gdb_printf (stream, ":%d\n", file->included_at_line);
 123       file = file->included_by;
 124     }
 125 }
 126
 127 /* Outputs a macro for human consumption, detailing the include path
 128    and macro definition.  NAME is the name of the macro.
 129    D the definition.  FILE the start of the include path, and LINE the
 130    line number in FILE.
 131
 132    Care should be taken that this function does not cause any lookups into
 133    the splay tree so that it can be safely used while iterating.  */
 134 static void
 135 print_macro_definition (const char *name,
 136                         const struct macro_definition *d,
 137                         struct macro_source_file *file,
 138                         int line)
 139 {
 140   gdb_printf ("Defined at ");
 141   show_pp_source_pos (gdb_stdout, file, line);
 142
 143   if (line != 0)
 144     gdb_printf ("#define %s", name);
 145   else
 146     gdb_printf ("-D%s", name);
 147
 148   if (d->kind == macro_function_like)
 149     {
 150       int i;
 151
 152       gdb_puts ("(");
 153       for (i = 0; i < d->argc; i++)
 154         {
 155           gdb_puts (d->argv[i]);
 156           if (i + 1 < d->argc)
 157             gdb_puts (", ");
 158         }
 159       gdb_puts (")");
 160     }
 161
 162   if (line != 0)
 163     gdb_printf (" %s\n", d->replacement);
 164   else
 165     gdb_printf ("=%s\n", d->replacement);
 166 }
 167
 168 /* The implementation of the `info macro' command.  */
 169 static void
 170 info_macro_command (const char *args, int from_tty)
 171 {
 172   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 173   const char *name;
 174   int show_all_macros_named = 0;
 175   const char *arg_start = args;
 176   int processing_args = 1;
 177
 178   while (processing_args
 179          && arg_start && *arg_start == '-' && *arg_start != '\0')
 180     {
 181       const char *p = skip_to_space (arg_start);
 182
 183       if (strncmp (arg_start, "-a", p - arg_start) == 0
 184           || strncmp (arg_start, "-all", p - arg_start) == 0)
 185         show_all_macros_named = 1;
 186       else if (strncmp (arg_start, "--", p - arg_start) == 0)
 187           /* Our macro support seems rather C specific but this would
 188              seem necessary for languages allowing - in macro names.
 189              e.g. Scheme's (defmacro ->foo () "bar\n")  */
 190         processing_args = 0;
 191       else
 192         report_unrecognized_option_error ("info macro", arg_start);
 193
 194       arg_start = skip_spaces (p);
 195     }
 196
 197   name = arg_start;
 198
 199   if (! name || ! *name)
 200     error (_("You must follow the `info macro' command with the name"
 201              " of the macro\n"
 202              "whose definition you want to see."));
 203
 204   ms = default_macro_scope ();
 205
 206   if (! ms)
 207     macro_inform_no_debuginfo ();
 208   else if (show_all_macros_named)
 209     macro_for_each (ms->file->table, [&] (const char *macro_name,
 210                                           const macro_definition *macro,
 211                                           macro_source_file *source,
 212                                           int line)
 213       {
 214         if (strcmp (name, macro_name) == 0)
 215           print_macro_definition (name, macro, source, line);
 216       });
 217   else
 218     {
 219       struct macro_definition *d;
 220
 221       d = macro_lookup_definition (ms->file, ms->line, name);
 222       if (d)
 223         {
 224           int line;
 225           struct macro_source_file *file
 226             = macro_definition_location (ms->file, ms->line, name, &line);
 227
 228           print_macro_definition (name, d, file, line);
 229         }
 230       else
 231         {
 232           gdb_printf ("The symbol `%s' has no definition as a C/C++"
 233                       " preprocessor macro\n"
 234                       "at ", name);
 235           show_pp_source_pos (gdb_stdout, ms->file, ms->line);
 236         }
 237     }
 238 }
 239
 240 /* Implementation of the "info macros" command. */
 241 static void
 242 info_macros_command (const char *args, int from_tty)
 243 {
 244   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 245
 246   if (args == NULL)
 247     ms = default_macro_scope ();
 248   else
 249     {
 250       std::vector<symtab_and_line> sals
 251         = decode_line_with_current_source (args, 0);
 252
 253       if (!sals.empty ())
 254         ms = sal_macro_scope (sals[0]);
 255     }
 256
 257   if (! ms || ! ms->file || ! ms->file->table)
 258     macro_inform_no_debuginfo ();
 259   else
 260     macro_for_each_in_scope (ms->file, ms->line, print_macro_definition);
 261 }
 262
 263 \f
 264 /* User-defined macros.  */
 265
 266 static void
 267 skip_ws (const char **expp)
 268 {
 269   while (macro_is_whitespace (**expp))
 270     ++*expp;
 271 }
 272
 273 /* Try to find the bounds of an identifier.  If an identifier is
 274    found, returns a newly allocated string; otherwise returns NULL.
 275    EXPP is a pointer to an input string; it is updated to point to the
 276    text following the identifier.  If IS_PARAMETER is true, this
 277    function will also allow "..." forms as used in varargs macro
 278    parameters.  */
 279
 280 static gdb::unique_xmalloc_ptr<char>
 281 extract_identifier (const char **expp, int is_parameter)
 282 {
 283   char *result;
 284   const char *p = *expp;
 285   unsigned int len;
 286
 287   if (is_parameter && startswith (p, "..."))
 288     {
 289       /* Ok.  */
 290     }
 291   else
 292     {
 293       if (! *p || ! macro_is_identifier_nondigit (*p))
 294         return NULL;
 295       for (++p;
 296            *p && (macro_is_identifier_nondigit (*p) || macro_is_digit (*p));
 297            ++p)
 298         ;
 299     }
 300
 301   if (is_parameter && startswith (p, "..."))
 302     p += 3;
 303
 304   len = p - *expp;
 305   result = (char *) xmalloc (len + 1);
 306   memcpy (result, *expp, len);
 307   result[len] = '\0';
 308   *expp += len;
 309   return gdb::unique_xmalloc_ptr<char> (result);
 310 }
 311
 312 struct temporary_macro_definition : public macro_definition
 313 {
 314   temporary_macro_definition ()
 315   {
 316     table = nullptr;
 317     kind = macro_object_like;
 318     argc = 0;
 319     argv = nullptr;
 320     replacement = nullptr;
 321   }
 322
 323   ~temporary_macro_definition ()
 324   {
 325     int i;
 326
 327     for (i = 0; i < argc; ++i)
 328       xfree ((char *) argv[i]);
 329     xfree ((char *) argv);
 330     /* Note that the 'replacement' field is not allocated.  */
 331   }
 332 };
 333
 334 static void
 335 macro_define_command (const char *exp, int from_tty)
 336 {
 337   temporary_macro_definition new_macro;
 338
 339   if (!exp)
 340     error (_("usage: macro define NAME[(ARGUMENT-LIST)] [REPLACEMENT-LIST]"));
 341
 342   skip_ws (&exp);
 343   gdb::unique_xmalloc_ptr<char> name = extract_identifier (&exp, 0);
 344   if (name == NULL)
 345     error (_("Invalid macro name."));
 346   if (*exp == '(')
 347     {
 348       /* Function-like macro.  */
 349       int alloced = 5;
 350       char **argv = XNEWVEC (char *, alloced);
 351
 352       new_macro.kind = macro_function_like;
 353       new_macro.argc = 0;
 354       new_macro.argv = (const char * const *) argv;
 355
 356       /* Skip the '(' and whitespace.  */
 357       ++exp;
 358       skip_ws (&exp);
 359
 360       while (*exp != ')')
 361         {
 362           int i;
 363
 364           if (new_macro.argc == alloced)
 365             {
 366               alloced *= 2;
 367               argv = (char **) xrealloc (argv, alloced * sizeof (char *));
 368               /* Must update new_macro as well...  */
 369               new_macro.argv = (const char * const *) argv;
 370             }
 371           argv[new_macro.argc] = extract_identifier (&exp, 1).release ();
 372           if (! argv[new_macro.argc])
 373             error (_("Macro is missing an argument."));
 374           ++new_macro.argc;
 375
 376           for (i = new_macro.argc - 2; i >= 0; --i)
 377             {
 378               if (! strcmp (argv[i], argv[new_macro.argc - 1]))
 379                 error (_("Two macro arguments with identical names."));
 380             }
 381
 382           skip_ws (&exp);
 383           if (*exp == ',')
 384             {
 385               ++exp;
 386               skip_ws (&exp);
 387             }
 388           else if (*exp != ')')
 389             error (_("',' or ')' expected at end of macro arguments."));
 390         }
 391       /* Skip the closing paren.  */
 392       ++exp;
 393       skip_ws (&exp);
 394
 395       macro_define_function (macro_main (macro_user_macros), -1, name.get (),
 396                              new_macro.argc, (const char **) new_macro.argv,
 397                              exp);
 398     }
 399   else
 400     {
 401       skip_ws (&exp);
 402       macro_define_object (macro_main (macro_user_macros), -1, name.get (),
 403                            exp);
 404     }
 405 }
 406
 407
 408 static void
 409 macro_undef_command (const char *exp, int from_tty)
 410 {
 411   if (!exp)
 412     error (_("usage: macro undef NAME"));
 413
 414   skip_ws (&exp);
 415   gdb::unique_xmalloc_ptr<char> name = extract_identifier (&exp, 0);
 416   if (name == nullptr)
 417     error (_("Invalid macro name."));
 418   macro_undef (macro_main (macro_user_macros), -1, name.get ());
 419 }
 420
 421
 422 static void
 423 print_one_macro (const char *name, const struct macro_definition *macro,
 424                  struct macro_source_file *source, int line)
 425 {
 426   gdb_printf ("macro define %s", name);
 427   if (macro->kind == macro_function_like)
 428     {
 429       int i;
 430
 431       gdb_printf ("(");
 432       for (i = 0; i < macro->argc; ++i)
 433         gdb_printf ("%s%s", (i > 0) ? ", " : "",
 434                          macro->argv[i]);
 435       gdb_printf (")");
 436     }
 437   gdb_printf (" %s\n", macro->replacement);
 438 }
 439
 440
 441 static void
 442 macro_list_command (const char *exp, int from_tty)
 443 {
 444   macro_for_each (macro_user_macros, print_one_macro);
 445 }
 446
 447 /* Initializing the `macrocmd' module.  */
 448
 449 void _initialize_macrocmd ();
 450 void
 451 _initialize_macrocmd ()
 452 {
 453   /* We introduce a new command prefix, `macro', under which we'll put
 454      the various commands for working with preprocessor macros.  */
 455   add_basic_prefix_cmd ("macro", class_info,
 456                         _("Prefix for commands dealing with C preprocessor macros."),
 457                         &macrolist, 0, &cmdlist);
 458
 459   cmd_list_element *macro_expand_cmd
 460     = add_cmd ("expand", no_class, macro_expand_command, _("\
 461 Fully expand any C/C++ preprocessor macro invocations in EXPRESSION.\n\
 462 Show the expanded expression."),
 463                &macrolist);
 464   add_alias_cmd ("exp", macro_expand_cmd, no_class, 1, &macrolist);
 465
 466   cmd_list_element *macro_expand_once_cmd
 467     = add_cmd ("expand-once", no_class, macro_expand_once_command, _("\
 468 Expand C/C++ preprocessor macro invocations appearing directly in EXPRESSION.\n\
 469 Show the expanded expression.\n\
 470 \n\
 471 This command differs from `macro expand' in that it only expands macro\n\
 472 invocations that appear directly in EXPRESSION; if expanding a macro\n\
 473 introduces further macro invocations, those are left unexpanded.\n\
 474 \n\
 475 `macro expand-once' helps you see how a particular macro expands,\n\
 476 whereas `macro expand' shows you how all the macros involved in an\n\
 477 expression work together to yield a pre-processed expression."),
 478                &macrolist);
 479   add_alias_cmd ("exp1", macro_expand_once_cmd, no_class, 1, &macrolist);
 480
 481   add_info ("macro", info_macro_command,
 482             _("Show the definition of MACRO, and it's source location.\n\
 483 Usage: info macro [-a|-all] [--] MACRO\n\
 484 Options: \n\
 485   -a, --all    Output all definitions of MACRO in the current compilation\
 486  unit.\n\
 487   --           Specify the end of arguments and the beginning of the MACRO."));
 488
 489   add_info ("macros", info_macros_command,
 490             _("Show the definitions of all macros at LINESPEC, or the current \
 491 source location.\n\
 492 Usage: info macros [LINESPEC]"));
 493
 494   add_cmd ("define", no_class, macro_define_command, _("\
 495 Define a new C/C++ preprocessor macro.\n\
 496 The GDB command `macro define DEFINITION' is equivalent to placing a\n\
 497 preprocessor directive of the form `#define DEFINITION' such that the\n\
 498 definition is visible in all the inferior's source files.\n\
 499 For example:\n\
 500   (gdb) macro define PI (3.1415926)\n\
 501   (gdb) macro define MIN(x,y) ((x) < (y) ? (x) : (y))"),
 502            &macrolist);
 503
 504   add_cmd ("undef", no_class, macro_undef_command, _("\
 505 Remove the definition of the C/C++ preprocessor macro with the given name."),
 506            &macrolist);
 507
 508   add_cmd ("list", no_class, macro_list_command,
 509            _("List all the macros defined using the `macro define' command."),
 510            &macrolist);
 511 }