gdb/macrocmd.c

   1 /* C preprocessor macro expansion commands for GDB.
   2    Copyright (C) 2002-2020 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 static void
  37 macro_command (const char *arg, int from_tty)
  38 {
  39   printf_unfiltered
  40     ("\"macro\" must be followed by the name of a macro command.\n");
  41   help_list (macrolist, "macro ", all_commands, gdb_stdout);
  42 }
  43
  44
  45 \f
  46 /* Macro expansion commands.  */
  47
  48
  49 /* Prints an informational message regarding the lack of macro information.  */
  50 static void
  51 macro_inform_no_debuginfo (void)
  52 {
  53   puts_filtered ("GDB has no preprocessor macro information for that code.\n");
  54 }
  55
  56 static void
  57 macro_expand_command (const char *exp, int from_tty)
  58 {
  59   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
  60   gdb::unique_xmalloc_ptr<char> expanded;
  61
  62   /* You know, when the user doesn't specify any expression, it would be
  63      really cool if this defaulted to the last expression evaluated.
  64      Then it would be easy to ask, "Hey, what did I just evaluate?"  But
  65      at the moment, the `print' commands don't save the last expression
  66      evaluated, just its value.  */
  67   if (! exp || ! *exp)
  68     error (_("You must follow the `macro expand' command with the"
  69            " expression you\n"
  70            "want to expand."));
  71
  72   ms = default_macro_scope ();
  73   if (ms)
  74     {
  75       expanded = macro_expand (exp, standard_macro_lookup, ms.get ());
  76       fputs_filtered ("expands to: ", gdb_stdout);
  77       fputs_filtered (expanded.get (), gdb_stdout);
  78       fputs_filtered ("\n", gdb_stdout);
  79     }
  80   else
  81     macro_inform_no_debuginfo ();
  82 }
  83
  84
  85 static void
  86 macro_expand_once_command (const char *exp, int from_tty)
  87 {
  88   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
  89   gdb::unique_xmalloc_ptr<char> expanded;
  90
  91   /* You know, when the user doesn't specify any expression, it would be
  92      really cool if this defaulted to the last expression evaluated.
  93      And it should set the once-expanded text as the new `last
  94      expression'.  That way, you could just hit return over and over and
  95      see the expression expanded one level at a time.  */
  96   if (! exp || ! *exp)
  97     error (_("You must follow the `macro expand-once' command with"
  98            " the expression\n"
  99            "you want to expand."));
 100
 101   ms = default_macro_scope ();
 102   if (ms)
 103     {
 104       expanded = macro_expand_once (exp, standard_macro_lookup, ms.get ());
 105       fputs_filtered ("expands to: ", gdb_stdout);
 106       fputs_filtered (expanded.get (), gdb_stdout);
 107       fputs_filtered ("\n", gdb_stdout);
 108     }
 109   else
 110     macro_inform_no_debuginfo ();
 111 }
 112
 113 /*  Outputs the include path of a macro starting at FILE and LINE to STREAM.
 114
 115     Care should be taken that this function does not cause any lookups into
 116     the splay tree so that it can be safely used while iterating.  */
 117 static void
 118 show_pp_source_pos (struct ui_file *stream,
 119                     struct macro_source_file *file,
 120                     int line)
 121 {
 122   std::string fullname = macro_source_fullname (file);
 123   fprintf_filtered (stream, "%ps:%d\n",
 124                     styled_string (file_name_style.style (),
 125                                    fullname.c_str ()),
 126                     line);
 127
 128   while (file->included_by)
 129     {
 130       fullname = macro_source_fullname (file->included_by);
 131       fputs_filtered (_("  included at "), stream);
 132       fputs_styled (fullname.c_str (), file_name_style.style (), stream);
 133       fprintf_filtered (stream, ":%d\n", file->included_at_line);
 134       file = file->included_by;
 135     }
 136 }
 137
 138 /* Outputs a macro for human consumption, detailing the include path
 139    and macro definition.  NAME is the name of the macro.
 140    D the definition.  FILE the start of the include path, and LINE the
 141    line number in FILE.
 142
 143    Care should be taken that this function does not cause any lookups into
 144    the splay tree so that it can be safely used while iterating.  */
 145 static void
 146 print_macro_definition (const char *name,
 147                         const struct macro_definition *d,
 148                         struct macro_source_file *file,
 149                         int line)
 150 {
 151   fprintf_filtered (gdb_stdout, "Defined at ");
 152   show_pp_source_pos (gdb_stdout, file, line);
 153
 154   if (line != 0)
 155     fprintf_filtered (gdb_stdout, "#define %s", name);
 156   else
 157     fprintf_filtered (gdb_stdout, "-D%s", name);
 158
 159   if (d->kind == macro_function_like)
 160     {
 161       int i;
 162
 163       fputs_filtered ("(", gdb_stdout);
 164       for (i = 0; i < d->argc; i++)
 165         {
 166           fputs_filtered (d->argv[i], gdb_stdout);
 167           if (i + 1 < d->argc)
 168             fputs_filtered (", ", gdb_stdout);
 169         }
 170       fputs_filtered (")", gdb_stdout);
 171     }
 172
 173   if (line != 0)
 174     fprintf_filtered (gdb_stdout, " %s\n", d->replacement);
 175   else
 176     fprintf_filtered (gdb_stdout, "=%s\n", d->replacement);
 177 }
 178
 179 /* The implementation of the `info macro' command.  */
 180 static void
 181 info_macro_command (const char *args, int from_tty)
 182 {
 183   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 184   const char *name;
 185   int show_all_macros_named = 0;
 186   const char *arg_start = args;
 187   int processing_args = 1;
 188
 189   while (processing_args
 190          && arg_start && *arg_start == '-' && *arg_start != '\0')
 191     {
 192       const char *p = skip_to_space (arg_start);
 193
 194       if (strncmp (arg_start, "-a", p - arg_start) == 0
 195           || strncmp (arg_start, "-all", p - arg_start) == 0)
 196         show_all_macros_named = 1;
 197       else if (strncmp (arg_start, "--", p - arg_start) == 0)
 198           /* Our macro support seems rather C specific but this would
 199              seem necessary for languages allowing - in macro names.
 200              e.g. Scheme's (defmacro ->foo () "bar\n")  */
 201         processing_args = 0;
 202       else
 203         report_unrecognized_option_error ("info macro", arg_start);
 204
 205       arg_start = skip_spaces (p);
 206     }
 207
 208   name = arg_start;
 209
 210   if (! name || ! *name)
 211     error (_("You must follow the `info macro' command with the name"
 212              " of the macro\n"
 213              "whose definition you want to see."));
 214
 215   ms = default_macro_scope ();
 216
 217   if (! ms)
 218     macro_inform_no_debuginfo ();
 219   else if (show_all_macros_named)
 220     macro_for_each (ms->file->table, [&] (const char *macro_name,
 221                                           const macro_definition *macro,
 222                                           macro_source_file *source,
 223                                           int line)
 224       {
 225         if (strcmp (name, macro_name) == 0)
 226           print_macro_definition (name, macro, source, line);
 227       });
 228   else
 229     {
 230       struct macro_definition *d;
 231
 232       d = macro_lookup_definition (ms->file, ms->line, name);
 233       if (d)
 234         {
 235           int line;
 236           struct macro_source_file *file
 237             = macro_definition_location (ms->file, ms->line, name, &line);
 238
 239           print_macro_definition (name, d, file, line);
 240         }
 241       else
 242         {
 243           fprintf_filtered (gdb_stdout,
 244                             "The symbol `%s' has no definition as a C/C++"
 245                             " preprocessor macro\n"
 246                             "at ", name);
 247           show_pp_source_pos (gdb_stdout, ms->file, ms->line);
 248         }
 249     }
 250 }
 251
 252 /* Implementation of the "info macros" command. */
 253 static void
 254 info_macros_command (const char *args, int from_tty)
 255 {
 256   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 257
 258   if (args == NULL)
 259     ms = default_macro_scope ();
 260   else
 261     {
 262       std::vector<symtab_and_line> sals
 263         = decode_line_with_current_source (args, 0);
 264
 265       if (!sals.empty ())
 266         ms = sal_macro_scope (sals[0]);
 267     }
 268
 269   if (! ms || ! ms->file || ! ms->file->table)
 270     macro_inform_no_debuginfo ();
 271   else
 272     macro_for_each_in_scope (ms->file, ms->line, print_macro_definition);
 273 }
 274
 275 \f
 276 /* User-defined macros.  */
 277
 278 static void
 279 skip_ws (const char **expp)
 280 {
 281   while (macro_is_whitespace (**expp))
 282     ++*expp;
 283 }
 284
 285 /* Try to find the bounds of an identifier.  If an identifier is
 286    found, returns a newly allocated string; otherwise returns NULL.
 287    EXPP is a pointer to an input string; it is updated to point to the
 288    text following the identifier.  If IS_PARAMETER is true, this
 289    function will also allow "..." forms as used in varargs macro
 290    parameters.  */
 291
 292 static gdb::unique_xmalloc_ptr<char>
 293 extract_identifier (const char **expp, int is_parameter)
 294 {
 295   char *result;
 296   const char *p = *expp;
 297   unsigned int len;
 298
 299   if (is_parameter && startswith (p, "..."))
 300     {
 301       /* Ok.  */
 302     }
 303   else
 304     {
 305       if (! *p || ! macro_is_identifier_nondigit (*p))
 306         return NULL;
 307       for (++p;
 308            *p && (macro_is_identifier_nondigit (*p) || macro_is_digit (*p));
 309            ++p)
 310         ;
 311     }
 312
 313   if (is_parameter && startswith (p, "..."))
 314     p += 3;
 315
 316   len = p - *expp;
 317   result = (char *) xmalloc (len + 1);
 318   memcpy (result, *expp, len);
 319   result[len] = '\0';
 320   *expp += len;
 321   return gdb::unique_xmalloc_ptr<char> (result);
 322 }
 323
 324 struct temporary_macro_definition : public macro_definition
 325 {
 326   temporary_macro_definition ()
 327   {
 328     table = nullptr;
 329     kind = macro_object_like;
 330     argc = 0;
 331     argv = nullptr;
 332     replacement = nullptr;
 333   }
 334
 335   ~temporary_macro_definition ()
 336   {
 337     int i;
 338
 339     for (i = 0; i < argc; ++i)
 340       xfree ((char *) argv[i]);
 341     xfree ((char *) argv);
 342     /* Note that the 'replacement' field is not allocated.  */
 343   }
 344 };
 345
 346 static void
 347 macro_define_command (const char *exp, int from_tty)
 348 {
 349   temporary_macro_definition new_macro;
 350
 351   if (!exp)
 352     error (_("usage: macro define NAME[(ARGUMENT-LIST)] [REPLACEMENT-LIST]"));
 353
 354   skip_ws (&exp);
 355   gdb::unique_xmalloc_ptr<char> name = extract_identifier (&exp, 0);
 356   if (name == NULL)
 357     error (_("Invalid macro name."));
 358   if (*exp == '(')
 359     {
 360       /* Function-like macro.  */
 361       int alloced = 5;
 362       char **argv = XNEWVEC (char *, alloced);
 363
 364       new_macro.kind = macro_function_like;
 365       new_macro.argc = 0;
 366       new_macro.argv = (const char * const *) argv;
 367
 368       /* Skip the '(' and whitespace.  */
 369       ++exp;
 370       skip_ws (&exp);
 371
 372       while (*exp != ')')
 373         {
 374           int i;
 375
 376           if (new_macro.argc == alloced)
 377             {
 378               alloced *= 2;
 379               argv = (char **) xrealloc (argv, alloced * sizeof (char *));
 380               /* Must update new_macro as well...  */
 381               new_macro.argv = (const char * const *) argv;
 382             }
 383           argv[new_macro.argc] = extract_identifier (&exp, 1).release ();
 384           if (! argv[new_macro.argc])
 385             error (_("Macro is missing an argument."));
 386           ++new_macro.argc;
 387
 388           for (i = new_macro.argc - 2; i >= 0; --i)
 389             {
 390               if (! strcmp (argv[i], argv[new_macro.argc - 1]))
 391                 error (_("Two macro arguments with identical names."));
 392             }
 393
 394           skip_ws (&exp);
 395           if (*exp == ',')
 396             {
 397               ++exp;
 398               skip_ws (&exp);
 399             }
 400           else if (*exp != ')')
 401             error (_("',' or ')' expected at end of macro arguments."));
 402         }
 403       /* Skip the closing paren.  */
 404       ++exp;
 405       skip_ws (&exp);
 406
 407       macro_define_function (macro_main (macro_user_macros), -1, name.get (),
 408                              new_macro.argc, (const char **) new_macro.argv,
 409                              exp);
 410     }
 411   else
 412     {
 413       skip_ws (&exp);
 414       macro_define_object (macro_main (macro_user_macros), -1, name.get (),
 415                            exp);
 416     }
 417 }
 418
 419
 420 static void
 421 macro_undef_command (const char *exp, int from_tty)
 422 {
 423   if (!exp)
 424     error (_("usage: macro undef NAME"));
 425
 426   skip_ws (&exp);
 427   gdb::unique_xmalloc_ptr<char> name = extract_identifier (&exp, 0);
 428   if (name == nullptr)
 429     error (_("Invalid macro name."));
 430   macro_undef (macro_main (macro_user_macros), -1, name.get ());
 431 }
 432
 433
 434 static void
 435 print_one_macro (const char *name, const struct macro_definition *macro,
 436                  struct macro_source_file *source, int line)
 437 {
 438   fprintf_filtered (gdb_stdout, "macro define %s", name);
 439   if (macro->kind == macro_function_like)
 440     {
 441       int i;
 442
 443       fprintf_filtered (gdb_stdout, "(");
 444       for (i = 0; i < macro->argc; ++i)
 445         fprintf_filtered (gdb_stdout, "%s%s", (i > 0) ? ", " : "",
 446                           macro->argv[i]);
 447       fprintf_filtered (gdb_stdout, ")");
 448     }
 449   fprintf_filtered (gdb_stdout, " %s\n", macro->replacement);
 450 }
 451
 452
 453 static void
 454 macro_list_command (const char *exp, int from_tty)
 455 {
 456   macro_for_each (macro_user_macros, print_one_macro);
 457 }
 458
 459 /* Initializing the `macrocmd' module.  */
 460
 461 void
 462 _initialize_macrocmd (void)
 463 {
 464   /* We introduce a new command prefix, `macro', under which we'll put
 465      the various commands for working with preprocessor macros.  */
 466   add_prefix_cmd ("macro", class_info, macro_command,
 467                   _("Prefix for commands dealing with C preprocessor macros."),
 468                   &macrolist, "macro ", 0, &cmdlist);
 469
 470   add_cmd ("expand", no_class, macro_expand_command, _("\
 471 Fully expand any C/C++ preprocessor macro invocations in EXPRESSION.\n\
 472 Show the expanded expression."),
 473            &macrolist);
 474   add_alias_cmd ("exp", "expand", no_class, 1, &macrolist);
 475   add_cmd ("expand-once", no_class, macro_expand_once_command, _("\
 476 Expand C/C++ preprocessor macro invocations appearing directly in EXPRESSION.\n\
 477 Show the expanded expression.\n\
 478 \n\
 479 This command differs from `macro expand' in that it only expands macro\n\
 480 invocations that appear directly in EXPRESSION; if expanding a macro\n\
 481 introduces further macro invocations, those are left unexpanded.\n\
 482 \n\
 483 `macro expand-once' helps you see how a particular macro expands,\n\
 484 whereas `macro expand' shows you how all the macros involved in an\n\
 485 expression work together to yield a pre-processed expression."),
 486            &macrolist);
 487   add_alias_cmd ("exp1", "expand-once", no_class, 1, &macrolist);
 488
 489   add_info ("macro", info_macro_command,
 490             _("Show the definition of MACRO, and it's source location.\n\
 491 Usage: info macro [-a|-all] [--] MACRO\n\
 492 Options: \n\
 493   -a, --all    Output all definitions of MACRO in the current compilation\
 494  unit.\n\
 495   --           Specify the end of arguments and the beginning of the MACRO."));
 496
 497   add_info ("macros", info_macros_command,
 498             _("Show the definitions of all macros at LINESPEC, or the current \
 499 source location.\n\
 500 Usage: info macros [LINESPEC]"));
 501
 502   add_cmd ("define", no_class, macro_define_command, _("\
 503 Define a new C/C++ preprocessor macro.\n\
 504 The GDB command `macro define DEFINITION' is equivalent to placing a\n\
 505 preprocessor directive of the form `#define DEFINITION' such that the\n\
 506 definition is visible in all the inferior's source files.\n\
 507 For example:\n\
 508   (gdb) macro define PI (3.1415926)\n\
 509   (gdb) macro define MIN(x,y) ((x) < (y) ? (x) : (y))"),
 510            &macrolist);
 511
 512   add_cmd ("undef", no_class, macro_undef_command, _("\
 513 Remove the definition of the C/C++ preprocessor macro with the given name."),
 514            &macrolist);
 515
 516   add_cmd ("list", no_class, macro_list_command,
 517            _("List all the macros defined using the `macro define' command."),
 518            &macrolist);
 519 }