gdb/macrocmd.c

   1 /* C preprocessor macro expansion commands for GDB.
   2    Copyright (C) 2002-2014 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-utils.h"
  26 #include "command.h"
  27 #include "gdbcmd.h"
  28 #include <string.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 (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 (char *exp, int from_tty)
  58 {
  59   struct macro_scope *ms = NULL;
  60   char *expanded = NULL;
  61   struct cleanup *cleanup_chain = make_cleanup (free_current_contents, &ms);
  62
  63   make_cleanup (free_current_contents, &expanded);
  64
  65   /* You know, when the user doesn't specify any expression, it would be
  66      really cool if this defaulted to the last expression evaluated.
  67      Then it would be easy to ask, "Hey, what did I just evaluate?"  But
  68      at the moment, the `print' commands don't save the last expression
  69      evaluated, just its value.  */
  70   if (! exp || ! *exp)
  71     error (_("You must follow the `macro expand' command with the"
  72            " expression you\n"
  73            "want to expand."));
  74
  75   ms = default_macro_scope ();
  76   if (ms)
  77     {
  78       expanded = macro_expand (exp, standard_macro_lookup, ms);
  79       fputs_filtered ("expands to: ", gdb_stdout);
  80       fputs_filtered (expanded, gdb_stdout);
  81       fputs_filtered ("\n", gdb_stdout);
  82     }
  83   else
  84     macro_inform_no_debuginfo ();
  85
  86   do_cleanups (cleanup_chain);
  87   return;
  88 }
  89
  90
  91 static void
  92 macro_expand_once_command (char *exp, int from_tty)
  93 {
  94   struct macro_scope *ms = NULL;
  95   char *expanded = NULL;
  96   struct cleanup *cleanup_chain = make_cleanup (free_current_contents, &ms);
  97   make_cleanup (free_current_contents, &expanded);
  98
  99   /* You know, when the user doesn't specify any expression, it would be
 100      really cool if this defaulted to the last expression evaluated.
 101      And it should set the once-expanded text as the new `last
 102      expression'.  That way, you could just hit return over and over and
 103      see the expression expanded one level at a time.  */
 104   if (! exp || ! *exp)
 105     error (_("You must follow the `macro expand-once' command with"
 106            " the expression\n"
 107            "you want to expand."));
 108
 109   ms = default_macro_scope ();
 110   if (ms)
 111     {
 112       expanded = macro_expand_once (exp, standard_macro_lookup, ms);
 113       fputs_filtered ("expands to: ", gdb_stdout);
 114       fputs_filtered (expanded, gdb_stdout);
 115       fputs_filtered ("\n", gdb_stdout);
 116     }
 117   else
 118     macro_inform_no_debuginfo ();
 119
 120   do_cleanups (cleanup_chain);
 121   return;
 122 }
 123
 124 /*  Outputs the include path of a macro starting at FILE and LINE to STREAM.
 125
 126     Care should be taken that this function does not cause any lookups into
 127     the splay tree so that it can be safely used while iterating.  */
 128 static void
 129 show_pp_source_pos (struct ui_file *stream,
 130                     struct macro_source_file *file,
 131                     int line)
 132 {
 133   char *fullname;
 134
 135   fullname = macro_source_fullname (file);
 136   fprintf_filtered (stream, "%s:%d\n", fullname, line);
 137   xfree (fullname);
 138
 139   while (file->included_by)
 140     {
 141       fullname = macro_source_fullname (file->included_by);
 142       fprintf_filtered (gdb_stdout, "  included at %s:%d\n", fullname,
 143                         file->included_at_line);
 144       xfree (fullname);
 145       file = file->included_by;
 146     }
 147 }
 148
 149 /* Outputs a macro for human consumption, detailing the include path
 150    and macro definition.  NAME is the name of the macro.
 151    D the definition.  FILE the start of the include path, and LINE the
 152    line number in FILE.
 153
 154    Care should be taken that this function does not cause any lookups into
 155    the splay tree so that it can be safely used while iterating.  */
 156 static void
 157 print_macro_definition (const char *name,
 158                         const struct macro_definition *d,
 159                         struct macro_source_file *file,
 160                         int line)
 161 {
 162   fprintf_filtered (gdb_stdout, "Defined at ");
 163   show_pp_source_pos (gdb_stdout, file, line);
 164
 165   if (line != 0)
 166     fprintf_filtered (gdb_stdout, "#define %s", name);
 167   else
 168     fprintf_filtered (gdb_stdout, "-D%s", name);
 169
 170   if (d->kind == macro_function_like)
 171     {
 172       int i;
 173
 174       fputs_filtered ("(", gdb_stdout);
 175       for (i = 0; i < d->argc; i++)
 176         {
 177           fputs_filtered (d->argv[i], gdb_stdout);
 178           if (i + 1 < d->argc)
 179             fputs_filtered (", ", gdb_stdout);
 180         }
 181       fputs_filtered (")", gdb_stdout);
 182     }
 183
 184   if (line != 0)
 185     fprintf_filtered (gdb_stdout, " %s\n", d->replacement);
 186   else
 187     fprintf_filtered (gdb_stdout, "=%s\n", d->replacement);
 188 }
 189
 190 /* A callback function for usage with macro_for_each and friends.
 191    If USER_DATA is null all macros will be printed.
 192    Otherwise USER_DATA is considered to be a string, printing
 193    only macros who's NAME matches USER_DATA.  Other arguments are
 194    routed to print_macro_definition.  */
 195 static void
 196 print_macro_callback (const char *name, const struct macro_definition *macro,
 197                    struct macro_source_file *source, int line,
 198                    void *user_data)
 199 {
 200   if (! user_data || strcmp (user_data, name) == 0)
 201     print_macro_definition (name, macro, source, line);
 202 }
 203
 204 /* The implementation of the `info macro' command.  */
 205 static void
 206 info_macro_command (char *args, int from_tty)
 207 {
 208   struct macro_scope *ms = NULL;
 209   struct cleanup *cleanup_chain;
 210   char *name;
 211   int show_all_macros_named = 0;
 212   char *arg_start = args;
 213   int processing_args = 1;
 214
 215   while (processing_args
 216          && arg_start && *arg_start == '-' && *arg_start != '\0')
 217     {
 218       char *p = skip_to_space (arg_start);
 219
 220       if (strncmp (arg_start, "-a", p - arg_start) == 0
 221           || strncmp (arg_start, "-all", p - arg_start) == 0)
 222         show_all_macros_named = 1;
 223       else if (strncmp (arg_start, "--", p - arg_start) == 0)
 224           /* Our macro support seems rather C specific but this would
 225              seem necessary for languages allowing - in macro names.
 226              e.g. Scheme's (defmacro ->foo () "bar\n")  */
 227         processing_args = 0;
 228       else
 229         {
 230           /* Relies on modified 'args' not making it in to history */
 231           *p = '\0';
 232           error (_("Unrecognized option '%s' to info macro command.  "
 233                    "Try \"help info macro\"."), arg_start);
 234         }
 235
 236         arg_start = skip_spaces (p);
 237     }
 238
 239   name = arg_start;
 240
 241   if (! name || ! *name)
 242     error (_("You must follow the `info macro' command with the name"
 243              " of the macro\n"
 244              "whose definition you want to see."));
 245
 246   ms = default_macro_scope ();
 247   cleanup_chain = make_cleanup (free_current_contents, &ms);
 248
 249   if (! ms)
 250     macro_inform_no_debuginfo ();
 251   else if (show_all_macros_named)
 252     macro_for_each (ms->file->table, print_macro_callback, name);
 253   else
 254     {
 255       struct macro_definition *d;
 256
 257       d = macro_lookup_definition (ms->file, ms->line, name);
 258       if (d)
 259         {
 260           int line;
 261           struct macro_source_file *file
 262             = macro_definition_location (ms->file, ms->line, name, &line);
 263
 264           print_macro_definition (name, d, file, line);
 265         }
 266       else
 267         {
 268           fprintf_filtered (gdb_stdout,
 269                             "The symbol `%s' has no definition as a C/C++"
 270                             " preprocessor macro\n"
 271                             "at ", name);
 272           show_pp_source_pos (gdb_stdout, ms->file, ms->line);
 273         }
 274     }
 275
 276   do_cleanups (cleanup_chain);
 277 }
 278
 279 /* Implementation of the "info macros" command. */
 280 static void
 281 info_macros_command (char *args, int from_tty)
 282 {
 283   struct macro_scope *ms = NULL;
 284   struct cleanup *cleanup_chain = make_cleanup (free_current_contents, &ms);
 285
 286   if (args == NULL)
 287     ms = default_macro_scope ();
 288   else
 289     {
 290       struct symtabs_and_lines sals =
 291         decode_line_with_current_source (args, 0);
 292
 293       if (sals.nelts)
 294         ms = sal_macro_scope (sals.sals[0]);
 295     }
 296
 297   if (! ms || ! ms->file || ! ms->file->table)
 298     macro_inform_no_debuginfo ();
 299   else
 300     macro_for_each_in_scope (ms->file, ms->line, print_macro_callback, NULL);
 301
 302   do_cleanups (cleanup_chain);
 303 }
 304
 305 \f
 306 /* User-defined macros.  */
 307
 308 static void
 309 skip_ws (char **expp)
 310 {
 311   while (macro_is_whitespace (**expp))
 312     ++*expp;
 313 }
 314
 315 /* Try to find the bounds of an identifier.  If an identifier is
 316    found, returns a newly allocated string; otherwise returns NULL.
 317    EXPP is a pointer to an input string; it is updated to point to the
 318    text following the identifier.  If IS_PARAMETER is true, this
 319    function will also allow "..." forms as used in varargs macro
 320    parameters.  */
 321
 322 static char *
 323 extract_identifier (char **expp, int is_parameter)
 324 {
 325   char *result;
 326   char *p = *expp;
 327   unsigned int len;
 328
 329   if (is_parameter && !strncmp (p, "...", 3))
 330     {
 331       /* Ok.  */
 332     }
 333   else
 334     {
 335       if (! *p || ! macro_is_identifier_nondigit (*p))
 336         return NULL;
 337       for (++p;
 338            *p && (macro_is_identifier_nondigit (*p) || macro_is_digit (*p));
 339            ++p)
 340         ;
 341     }
 342
 343   if (is_parameter && !strncmp (p, "...", 3))
 344     p += 3;
 345
 346   len = p - *expp;
 347   result = (char *) xmalloc (len + 1);
 348   memcpy (result, *expp, len);
 349   result[len] = '\0';
 350   *expp += len;
 351   return result;
 352 }
 353
 354 /* Helper function to clean up a temporarily-constructed macro object.
 355    This assumes that the contents were all allocated with xmalloc.  */
 356 static void
 357 free_macro_definition_ptr (void *ptr)
 358 {
 359   int i;
 360   struct macro_definition *loc = (struct macro_definition *) ptr;
 361
 362   for (i = 0; i < loc->argc; ++i)
 363     xfree ((char *) loc->argv[i]);
 364   xfree ((char *) loc->argv);
 365   /* Note that the 'replacement' field is not allocated.  */
 366 }
 367
 368 static void
 369 macro_define_command (char *exp, int from_tty)
 370 {
 371   struct macro_definition new_macro;
 372   char *name = NULL;
 373   struct cleanup *cleanup_chain;
 374
 375   if (!exp)
 376     error (_("usage: macro define NAME[(ARGUMENT-LIST)] [REPLACEMENT-LIST]"));
 377
 378   cleanup_chain = make_cleanup (free_macro_definition_ptr, &new_macro);
 379   make_cleanup (free_current_contents, &name);
 380
 381   memset (&new_macro, 0, sizeof (struct macro_definition));
 382
 383   skip_ws (&exp);
 384   name = extract_identifier (&exp, 0);
 385   if (! name)
 386     error (_("Invalid macro name."));
 387   if (*exp == '(')
 388     {
 389       /* Function-like macro.  */
 390       int alloced = 5;
 391       char **argv = (char **) xmalloc (alloced * sizeof (char *));
 392
 393       new_macro.kind = macro_function_like;
 394       new_macro.argc = 0;
 395       new_macro.argv = (const char * const *) argv;
 396
 397       /* Skip the '(' and whitespace.  */
 398       ++exp;
 399       skip_ws (&exp);
 400
 401       while (*exp != ')')
 402         {
 403           int i;
 404
 405           if (new_macro.argc == alloced)
 406             {
 407               alloced *= 2;
 408               argv = (char **) xrealloc (argv, alloced * sizeof (char *));
 409               /* Must update new_macro as well...  */
 410               new_macro.argv = (const char * const *) argv;
 411             }
 412           argv[new_macro.argc] = extract_identifier (&exp, 1);
 413           if (! argv[new_macro.argc])
 414             error (_("Macro is missing an argument."));
 415           ++new_macro.argc;
 416
 417           for (i = new_macro.argc - 2; i >= 0; --i)
 418             {
 419               if (! strcmp (argv[i], argv[new_macro.argc - 1]))
 420                 error (_("Two macro arguments with identical names."));
 421             }
 422
 423           skip_ws (&exp);
 424           if (*exp == ',')
 425             {
 426               ++exp;
 427               skip_ws (&exp);
 428             }
 429           else if (*exp != ')')
 430             error (_("',' or ')' expected at end of macro arguments."));
 431         }
 432       /* Skip the closing paren.  */
 433       ++exp;
 434       skip_ws (&exp);
 435
 436       macro_define_function (macro_main (macro_user_macros), -1, name,
 437                              new_macro.argc, (const char **) new_macro.argv,
 438                              exp);
 439     }
 440   else
 441     {
 442       skip_ws (&exp);
 443       macro_define_object (macro_main (macro_user_macros), -1, name, exp);
 444     }
 445
 446   do_cleanups (cleanup_chain);
 447 }
 448
 449
 450 static void
 451 macro_undef_command (char *exp, int from_tty)
 452 {
 453   char *name;
 454
 455   if (!exp)
 456     error (_("usage: macro undef NAME"));
 457
 458   skip_ws (&exp);
 459   name = extract_identifier (&exp, 0);
 460   if (! name)
 461     error (_("Invalid macro name."));
 462   macro_undef (macro_main (macro_user_macros), -1, name);
 463   xfree (name);
 464 }
 465
 466
 467 static void
 468 print_one_macro (const char *name, const struct macro_definition *macro,
 469                  struct macro_source_file *source, int line,
 470                  void *ignore)
 471 {
 472   fprintf_filtered (gdb_stdout, "macro define %s", name);
 473   if (macro->kind == macro_function_like)
 474     {
 475       int i;
 476
 477       fprintf_filtered (gdb_stdout, "(");
 478       for (i = 0; i < macro->argc; ++i)
 479         fprintf_filtered (gdb_stdout, "%s%s", (i > 0) ? ", " : "",
 480                           macro->argv[i]);
 481       fprintf_filtered (gdb_stdout, ")");
 482     }
 483   fprintf_filtered (gdb_stdout, " %s\n", macro->replacement);
 484 }
 485
 486
 487 static void
 488 macro_list_command (char *exp, int from_tty)
 489 {
 490   macro_for_each (macro_user_macros, print_one_macro, NULL);
 491 }
 492
 493 \f
 494 /* Initializing the `macrocmd' module.  */
 495
 496 extern initialize_file_ftype _initialize_macrocmd; /* -Wmissing-prototypes */
 497
 498 void
 499 _initialize_macrocmd (void)
 500 {
 501   /* We introduce a new command prefix, `macro', under which we'll put
 502      the various commands for working with preprocessor macros.  */
 503   add_prefix_cmd ("macro", class_info, macro_command,
 504                   _("Prefix for commands dealing with C preprocessor macros."),
 505                   &macrolist, "macro ", 0, &cmdlist);
 506
 507   add_cmd ("expand", no_class, macro_expand_command, _("\
 508 Fully expand any C/C++ preprocessor macro invocations in EXPRESSION.\n\
 509 Show the expanded expression."),
 510            &macrolist);
 511   add_alias_cmd ("exp", "expand", no_class, 1, &macrolist);
 512   add_cmd ("expand-once", no_class, macro_expand_once_command, _("\
 513 Expand C/C++ preprocessor macro invocations appearing directly in EXPRESSION.\n\
 514 Show the expanded expression.\n\
 515 \n\
 516 This command differs from `macro expand' in that it only expands macro\n\
 517 invocations that appear directly in EXPRESSION; if expanding a macro\n\
 518 introduces further macro invocations, those are left unexpanded.\n\
 519 \n\
 520 `macro expand-once' helps you see how a particular macro expands,\n\
 521 whereas `macro expand' shows you how all the macros involved in an\n\
 522 expression work together to yield a pre-processed expression."),
 523            &macrolist);
 524   add_alias_cmd ("exp1", "expand-once", no_class, 1, &macrolist);
 525
 526   add_cmd ("macro", no_class, info_macro_command,
 527            _("Show the definition of MACRO, and it's source location.\n\
 528 Usage: info macro [-a|-all] [--] MACRO\n\
 529 Options: \n\
 530   -a, --all    Output all definitions of MACRO in the current compilation\
 531  unit.\n\
 532   --           Specify the end of arguments and the beginning of the MACRO."),
 533
 534            &infolist);
 535
 536   add_cmd ("macros", no_class, info_macros_command,
 537            _("Show the definitions of all macros at LINESPEC, or the current \
 538 source location.\n\
 539 Usage: info macros [LINESPEC]"),
 540            &infolist);
 541
 542   add_cmd ("define", no_class, macro_define_command, _("\
 543 Define a new C/C++ preprocessor macro.\n\
 544 The GDB command `macro define DEFINITION' is equivalent to placing a\n\
 545 preprocessor directive of the form `#define DEFINITION' such that the\n\
 546 definition is visible in all the inferior's source files.\n\
 547 For example:\n\
 548   (gdb) macro define PI (3.1415926)\n\
 549   (gdb) macro define MIN(x,y) ((x) < (y) ? (x) : (y))"),
 550            &macrolist);
 551
 552   add_cmd ("undef", no_class, macro_undef_command, _("\
 553 Remove the definition of the C/C++ preprocessor macro with the given name."),
 554            &macrolist);
 555
 556   add_cmd ("list", no_class, macro_list_command,
 557            _("List all the macros defined using the `macro define' command."),
 558            &macrolist);
 559 }