gdb/macrocmd.c

   1 /* C preprocessor macro expansion commands for GDB.
   2    Copyright (C) 2002-2024 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 "macrotab.h"
  22 #include "macroexp.h"
  23 #include "macroscope.h"
  24 #include "cli/cli-style.h"
  25 #include "cli/cli-utils.h"
  26 #include "command.h"
  27 #include "cli/cli-cmds.h"
  28 #include "linespec.h"
  29 #include "ui-out.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, return it; otherwise return an empty string.
 275
 276    EXPP is a pointer to an input string; it is updated to point to the
 277    text following the identifier.  If IS_PARAMETER is true, this
 278    function will also allow "..." forms as used in varargs macro
 279    parameters.  */
 280
 281 static std::string
 282 extract_identifier (const char **expp, int is_parameter)
 283 {
 284   const char *p = *expp;
 285
 286   if (is_parameter && startswith (p, "..."))
 287     {
 288       /* Ok.  */
 289     }
 290   else
 291     {
 292       if (! *p || ! macro_is_identifier_nondigit (*p))
 293         return {};
 294
 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   std::string result (*expp, p);
 305   *expp = p;
 306
 307   return result;
 308 }
 309
 310 static void
 311 macro_define_command (const char *exp, int from_tty)
 312 {
 313   if (!exp)
 314     error (_("usage: macro define NAME[(ARGUMENT-LIST)] [REPLACEMENT-LIST]"));
 315
 316   skip_ws (&exp);
 317
 318   std::string name = extract_identifier (&exp, 0);
 319   if (name.empty ())
 320     error (_("Invalid macro name."));
 321
 322   if (*exp == '(')
 323     {
 324       /* Function-like macro.  */
 325       std::vector<std::string> argv;
 326
 327       /* Skip the '(' and whitespace.  */
 328       ++exp;
 329       skip_ws (&exp);
 330
 331       while (*exp != ')')
 332         {
 333           argv.emplace_back (extract_identifier (&exp, 1));
 334           if (argv.back ().empty ())
 335             error (_("Macro is missing an argument."));
 336
 337           for (const auto &other_arg : argv)
 338             {
 339               if (&other_arg != &argv.back () && other_arg == argv.back ())
 340                 error (_("Two macro arguments with identical names."));
 341             }
 342
 343           skip_ws (&exp);
 344           if (*exp == ',')
 345             {
 346               ++exp;
 347               skip_ws (&exp);
 348             }
 349           else if (*exp != ')')
 350             error (_("',' or ')' expected at end of macro arguments."));
 351         }
 352
 353       /* Skip the closing paren.  */
 354       ++exp;
 355       skip_ws (&exp);
 356
 357       macro_define_function (macro_main (macro_user_macros), -1, name.c_str (),
 358                              argv, exp);
 359     }
 360   else
 361     {
 362       skip_ws (&exp);
 363       macro_define_object (macro_main (macro_user_macros), -1, name.c_str (),
 364                            exp);
 365     }
 366 }
 367
 368
 369 static void
 370 macro_undef_command (const char *exp, int from_tty)
 371 {
 372   if (!exp)
 373     error (_("usage: macro undef NAME"));
 374
 375   skip_ws (&exp);
 376
 377   std::string name = extract_identifier (&exp, 0);
 378   if (name.empty ())
 379     error (_("Invalid macro name."));
 380
 381   macro_undef (macro_main (macro_user_macros), -1, name.c_str ());
 382 }
 383
 384
 385 static void
 386 print_one_macro (const char *name, const struct macro_definition *macro,
 387                  struct macro_source_file *source, int line)
 388 {
 389   gdb_printf ("macro define %s", name);
 390   if (macro->kind == macro_function_like)
 391     {
 392       int i;
 393
 394       gdb_printf ("(");
 395       for (i = 0; i < macro->argc; ++i)
 396         gdb_printf ("%s%s", (i > 0) ? ", " : "",
 397                          macro->argv[i]);
 398       gdb_printf (")");
 399     }
 400   gdb_printf (" %s\n", macro->replacement);
 401 }
 402
 403
 404 static void
 405 macro_list_command (const char *exp, int from_tty)
 406 {
 407   macro_for_each (macro_user_macros, print_one_macro);
 408 }
 409
 410 /* Initializing the `macrocmd' module.  */
 411
 412 void _initialize_macrocmd ();
 413 void
 414 _initialize_macrocmd ()
 415 {
 416   /* We introduce a new command prefix, `macro', under which we'll put
 417      the various commands for working with preprocessor macros.  */
 418   add_basic_prefix_cmd ("macro", class_info,
 419                         _("Prefix for commands dealing with C preprocessor macros."),
 420                         &macrolist, 0, &cmdlist);
 421
 422   cmd_list_element *macro_expand_cmd
 423     = add_cmd ("expand", no_class, macro_expand_command, _("\
 424 Fully expand any C/C++ preprocessor macro invocations in EXPRESSION.\n\
 425 Show the expanded expression."),
 426                &macrolist);
 427   add_alias_cmd ("exp", macro_expand_cmd, no_class, 1, &macrolist);
 428
 429   cmd_list_element *macro_expand_once_cmd
 430     = add_cmd ("expand-once", no_class, macro_expand_once_command, _("\
 431 Expand C/C++ preprocessor macro invocations appearing directly in EXPRESSION.\n\
 432 Show the expanded expression.\n\
 433 \n\
 434 This command differs from `macro expand' in that it only expands macro\n\
 435 invocations that appear directly in EXPRESSION; if expanding a macro\n\
 436 introduces further macro invocations, those are left unexpanded.\n\
 437 \n\
 438 `macro expand-once' helps you see how a particular macro expands,\n\
 439 whereas `macro expand' shows you how all the macros involved in an\n\
 440 expression work together to yield a pre-processed expression."),
 441                &macrolist);
 442   add_alias_cmd ("exp1", macro_expand_once_cmd, no_class, 1, &macrolist);
 443
 444   add_info ("macro", info_macro_command,
 445             _("Show the definition of MACRO, and it's source location.\n\
 446 Usage: info macro [-a|-all] [--] MACRO\n\
 447 Options:\n\
 448   -a, --all    Output all definitions of MACRO in the current compilation\
 449  unit.\n\
 450   --           Specify the end of arguments and the beginning of the MACRO."));
 451
 452   add_info ("macros", info_macros_command,
 453             _("Show the definitions of all macros at LINESPEC, or the current \
 454 source location.\n\
 455 Usage: info macros [LINESPEC]"));
 456
 457   add_cmd ("define", no_class, macro_define_command, _("\
 458 Define a new C/C++ preprocessor macro.\n\
 459 The GDB command `macro define DEFINITION' is equivalent to placing a\n\
 460 preprocessor directive of the form `#define DEFINITION' such that the\n\
 461 definition is visible in all the inferior's source files.\n\
 462 For example:\n\
 463   (gdb) macro define PI (3.1415926)\n\
 464   (gdb) macro define MIN(x,y) ((x) < (y) ? (x) : (y))"),
 465            &macrolist);
 466
 467   add_cmd ("undef", no_class, macro_undef_command, _("\
 468 Remove the definition of the C/C++ preprocessor macro with the given name."),
 469            &macrolist);
 470
 471   add_cmd ("list", no_class, macro_list_command,
 472            _("List all the macros defined using the `macro define' command."),
 473            &macrolist);
 474 }