gdb/macrocmd.c

   1 /* C preprocessor macro expansion commands for GDB.
   2    Copyright (C) 2002-2019 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 "linespec.h"
  29
  30 \f
  31 /* The `macro' prefix command.  */
  32
  33 static struct cmd_list_element *macrolist;
  34
  35 static void
  36 macro_command (const char *arg, int from_tty)
  37 {
  38   printf_unfiltered
  39     ("\"macro\" must be followed by the name of a macro command.\n");
  40   help_list (macrolist, "macro ", all_commands, gdb_stdout);
  41 }
  42
  43
  44 \f
  45 /* Macro expansion commands.  */
  46
  47
  48 /* Prints an informational message regarding the lack of macro information.  */
  49 static void
  50 macro_inform_no_debuginfo (void)
  51 {
  52   puts_filtered ("GDB has no preprocessor macro information for that code.\n");
  53 }
  54
  55 static void
  56 macro_expand_command (const char *exp, int from_tty)
  57 {
  58   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
  59   gdb::unique_xmalloc_ptr<char> expanded;
  60
  61   /* You know, when the user doesn't specify any expression, it would be
  62      really cool if this defaulted to the last expression evaluated.
  63      Then it would be easy to ask, "Hey, what did I just evaluate?"  But
  64      at the moment, the `print' commands don't save the last expression
  65      evaluated, just its value.  */
  66   if (! exp || ! *exp)
  67     error (_("You must follow the `macro expand' command with the"
  68            " expression you\n"
  69            "want to expand."));
  70
  71   ms = default_macro_scope ();
  72   if (ms)
  73     {
  74       expanded = macro_expand (exp, standard_macro_lookup, ms.get ());
  75       fputs_filtered ("expands to: ", gdb_stdout);
  76       fputs_filtered (expanded.get (), gdb_stdout);
  77       fputs_filtered ("\n", gdb_stdout);
  78     }
  79   else
  80     macro_inform_no_debuginfo ();
  81 }
  82
  83
  84 static void
  85 macro_expand_once_command (const char *exp, int from_tty)
  86 {
  87   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
  88   gdb::unique_xmalloc_ptr<char> expanded;
  89
  90   /* You know, when the user doesn't specify any expression, it would be
  91      really cool if this defaulted to the last expression evaluated.
  92      And it should set the once-expanded text as the new `last
  93      expression'.  That way, you could just hit return over and over and
  94      see the expression expanded one level at a time.  */
  95   if (! exp || ! *exp)
  96     error (_("You must follow the `macro expand-once' command with"
  97            " the expression\n"
  98            "you want to expand."));
  99
 100   ms = default_macro_scope ();
 101   if (ms)
 102     {
 103       expanded = macro_expand_once (exp, standard_macro_lookup, ms.get ());
 104       fputs_filtered ("expands to: ", gdb_stdout);
 105       fputs_filtered (expanded.get (), gdb_stdout);
 106       fputs_filtered ("\n", gdb_stdout);
 107     }
 108   else
 109     macro_inform_no_debuginfo ();
 110 }
 111
 112 /*  Outputs the include path of a macro starting at FILE and LINE to STREAM.
 113
 114     Care should be taken that this function does not cause any lookups into
 115     the splay tree so that it can be safely used while iterating.  */
 116 static void
 117 show_pp_source_pos (struct ui_file *stream,
 118                     struct macro_source_file *file,
 119                     int line)
 120 {
 121   char *fullname;
 122
 123   fullname = macro_source_fullname (file);
 124   fprintf_filtered (stream, "%s:%d\n", fullname, line);
 125   xfree (fullname);
 126
 127   while (file->included_by)
 128     {
 129       fullname = macro_source_fullname (file->included_by);
 130       fprintf_filtered (gdb_stdout, "  included at %s:%d\n", fullname,
 131                         file->included_at_line);
 132       xfree (fullname);
 133       file = file->included_by;
 134     }
 135 }
 136
 137 /* Outputs a macro for human consumption, detailing the include path
 138    and macro definition.  NAME is the name of the macro.
 139    D the definition.  FILE the start of the include path, and LINE the
 140    line number in FILE.
 141
 142    Care should be taken that this function does not cause any lookups into
 143    the splay tree so that it can be safely used while iterating.  */
 144 static void
 145 print_macro_definition (const char *name,
 146                         const struct macro_definition *d,
 147                         struct macro_source_file *file,
 148                         int line)
 149 {
 150   fprintf_filtered (gdb_stdout, "Defined at ");
 151   show_pp_source_pos (gdb_stdout, file, line);
 152
 153   if (line != 0)
 154     fprintf_filtered (gdb_stdout, "#define %s", name);
 155   else
 156     fprintf_filtered (gdb_stdout, "-D%s", name);
 157
 158   if (d->kind == macro_function_like)
 159     {
 160       int i;
 161
 162       fputs_filtered ("(", gdb_stdout);
 163       for (i = 0; i < d->argc; i++)
 164         {
 165           fputs_filtered (d->argv[i], gdb_stdout);
 166           if (i + 1 < d->argc)
 167             fputs_filtered (", ", gdb_stdout);
 168         }
 169       fputs_filtered (")", gdb_stdout);
 170     }
 171
 172   if (line != 0)
 173     fprintf_filtered (gdb_stdout, " %s\n", d->replacement);
 174   else
 175     fprintf_filtered (gdb_stdout, "=%s\n", d->replacement);
 176 }
 177
 178 /* The implementation of the `info macro' command.  */
 179 static void
 180 info_macro_command (const char *args, int from_tty)
 181 {
 182   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 183   const char *name;
 184   int show_all_macros_named = 0;
 185   const char *arg_start = args;
 186   int processing_args = 1;
 187
 188   while (processing_args
 189          && arg_start && *arg_start == '-' && *arg_start != '\0')
 190     {
 191       const char *p = skip_to_space (arg_start);
 192
 193       if (strncmp (arg_start, "-a", p - arg_start) == 0
 194           || strncmp (arg_start, "-all", p - arg_start) == 0)
 195         show_all_macros_named = 1;
 196       else if (strncmp (arg_start, "--", p - arg_start) == 0)
 197           /* Our macro support seems rather C specific but this would
 198              seem necessary for languages allowing - in macro names.
 199              e.g. Scheme's (defmacro ->foo () "bar\n")  */
 200         processing_args = 0;
 201       else
 202         report_unrecognized_option_error ("info macro", arg_start);
 203
 204       arg_start = skip_spaces (p);
 205     }
 206
 207   name = arg_start;
 208
 209   if (! name || ! *name)
 210     error (_("You must follow the `info macro' command with the name"
 211              " of the macro\n"
 212              "whose definition you want to see."));
 213
 214   ms = default_macro_scope ();
 215
 216   if (! ms)
 217     macro_inform_no_debuginfo ();
 218   else if (show_all_macros_named)
 219     macro_for_each (ms->file->table, [&] (const char *macro_name,
 220                                           const macro_definition *macro,
 221                                           macro_source_file *source,
 222                                           int line)
 223       {
 224         if (strcmp (name, macro_name) == 0)
 225           print_macro_definition (name, macro, source, line);
 226       });
 227   else
 228     {
 229       struct macro_definition *d;
 230
 231       d = macro_lookup_definition (ms->file, ms->line, name);
 232       if (d)
 233         {
 234           int line;
 235           struct macro_source_file *file
 236             = macro_definition_location (ms->file, ms->line, name, &line);
 237
 238           print_macro_definition (name, d, file, line);
 239         }
 240       else
 241         {
 242           fprintf_filtered (gdb_stdout,
 243                             "The symbol `%s' has no definition as a C/C++"
 244                             " preprocessor macro\n"
 245                             "at ", name);
 246           show_pp_source_pos (gdb_stdout, ms->file, ms->line);
 247         }
 248     }
 249 }
 250
 251 /* Implementation of the "info macros" command. */
 252 static void
 253 info_macros_command (const char *args, int from_tty)
 254 {
 255   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 256
 257   if (args == NULL)
 258     ms = default_macro_scope ();
 259   else
 260     {
 261       std::vector<symtab_and_line> sals
 262         = decode_line_with_current_source (args, 0);
 263
 264       if (!sals.empty ())
 265         ms = sal_macro_scope (sals[0]);
 266     }
 267
 268   if (! ms || ! ms->file || ! ms->file->table)
 269     macro_inform_no_debuginfo ();
 270   else
 271     macro_for_each_in_scope (ms->file, ms->line, print_macro_definition);
 272 }
 273
 274 \f
 275 /* User-defined macros.  */
 276
 277 static void
 278 skip_ws (const char **expp)
 279 {
 280   while (macro_is_whitespace (**expp))
 281     ++*expp;
 282 }
 283
 284 /* Try to find the bounds of an identifier.  If an identifier is
 285    found, returns a newly allocated string; otherwise returns NULL.
 286    EXPP is a pointer to an input string; it is updated to point to the
 287    text following the identifier.  If IS_PARAMETER is true, this
 288    function will also allow "..." forms as used in varargs macro
 289    parameters.  */
 290
 291 static char *
 292 extract_identifier (const char **expp, int is_parameter)
 293 {
 294   char *result;
 295   const char *p = *expp;
 296   unsigned int len;
 297
 298   if (is_parameter && startswith (p, "..."))
 299     {
 300       /* Ok.  */
 301     }
 302   else
 303     {
 304       if (! *p || ! macro_is_identifier_nondigit (*p))
 305         return NULL;
 306       for (++p;
 307            *p && (macro_is_identifier_nondigit (*p) || macro_is_digit (*p));
 308            ++p)
 309         ;
 310     }
 311
 312   if (is_parameter && startswith (p, "..."))
 313     p += 3;
 314
 315   len = p - *expp;
 316   result = (char *) xmalloc (len + 1);
 317   memcpy (result, *expp, len);
 318   result[len] = '\0';
 319   *expp += len;
 320   return result;
 321 }
 322
 323 struct temporary_macro_definition : public macro_definition
 324 {
 325   temporary_macro_definition ()
 326   {
 327     table = nullptr;
 328     kind = macro_object_like;
 329     argc = 0;
 330     argv = nullptr;
 331     replacement = nullptr;
 332   }
 333
 334   ~temporary_macro_definition ()
 335   {
 336     int i;
 337
 338     for (i = 0; i < argc; ++i)
 339       xfree ((char *) argv[i]);
 340     xfree ((char *) argv);
 341     /* Note that the 'replacement' field is not allocated.  */
 342   }
 343 };
 344
 345 static void
 346 macro_define_command (const char *exp, int from_tty)
 347 {
 348   temporary_macro_definition new_macro;
 349   char *name = NULL;
 350
 351   if (!exp)
 352     error (_("usage: macro define NAME[(ARGUMENT-LIST)] [REPLACEMENT-LIST]"));
 353
 354   skip_ws (&exp);
 355   name = extract_identifier (&exp, 0);
 356   if (! name)
 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);
 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,
 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, exp);
 415     }
 416 }
 417
 418
 419 static void
 420 macro_undef_command (const char *exp, int from_tty)
 421 {
 422   char *name;
 423
 424   if (!exp)
 425     error (_("usage: macro undef NAME"));
 426
 427   skip_ws (&exp);
 428   name = extract_identifier (&exp, 0);
 429   if (! name)
 430     error (_("Invalid macro name."));
 431   macro_undef (macro_main (macro_user_macros), -1, name);
 432   xfree (name);
 433 }
 434
 435
 436 static void
 437 print_one_macro (const char *name, const struct macro_definition *macro,
 438                  struct macro_source_file *source, int line)
 439 {
 440   fprintf_filtered (gdb_stdout, "macro define %s", name);
 441   if (macro->kind == macro_function_like)
 442     {
 443       int i;
 444
 445       fprintf_filtered (gdb_stdout, "(");
 446       for (i = 0; i < macro->argc; ++i)
 447         fprintf_filtered (gdb_stdout, "%s%s", (i > 0) ? ", " : "",
 448                           macro->argv[i]);
 449       fprintf_filtered (gdb_stdout, ")");
 450     }
 451   fprintf_filtered (gdb_stdout, " %s\n", macro->replacement);
 452 }
 453
 454
 455 static void
 456 macro_list_command (const char *exp, int from_tty)
 457 {
 458   macro_for_each (macro_user_macros, print_one_macro);
 459 }
 460
 461 /* Initializing the `macrocmd' module.  */
 462
 463 void
 464 _initialize_macrocmd (void)
 465 {
 466   /* We introduce a new command prefix, `macro', under which we'll put
 467      the various commands for working with preprocessor macros.  */
 468   add_prefix_cmd ("macro", class_info, macro_command,
 469                   _("Prefix for commands dealing with C preprocessor macros."),
 470                   &macrolist, "macro ", 0, &cmdlist);
 471
 472   add_cmd ("expand", no_class, macro_expand_command, _("\
 473 Fully expand any C/C++ preprocessor macro invocations in EXPRESSION.\n\
 474 Show the expanded expression."),
 475            &macrolist);
 476   add_alias_cmd ("exp", "expand", no_class, 1, &macrolist);
 477   add_cmd ("expand-once", no_class, macro_expand_once_command, _("\
 478 Expand C/C++ preprocessor macro invocations appearing directly in EXPRESSION.\n\
 479 Show the expanded expression.\n\
 480 \n\
 481 This command differs from `macro expand' in that it only expands macro\n\
 482 invocations that appear directly in EXPRESSION; if expanding a macro\n\
 483 introduces further macro invocations, those are left unexpanded.\n\
 484 \n\
 485 `macro expand-once' helps you see how a particular macro expands,\n\
 486 whereas `macro expand' shows you how all the macros involved in an\n\
 487 expression work together to yield a pre-processed expression."),
 488            &macrolist);
 489   add_alias_cmd ("exp1", "expand-once", no_class, 1, &macrolist);
 490
 491   add_info ("macro", info_macro_command,
 492             _("Show the definition of MACRO, and it's source location.\n\
 493 Usage: info macro [-a|-all] [--] MACRO\n\
 494 Options: \n\
 495   -a, --all    Output all definitions of MACRO in the current compilation\
 496  unit.\n\
 497   --           Specify the end of arguments and the beginning of the MACRO."));
 498
 499   add_info ("macros", info_macros_command,
 500             _("Show the definitions of all macros at LINESPEC, or the current \
 501 source location.\n\
 502 Usage: info macros [LINESPEC]"));
 503
 504   add_cmd ("define", no_class, macro_define_command, _("\
 505 Define a new C/C++ preprocessor macro.\n\
 506 The GDB command `macro define DEFINITION' is equivalent to placing a\n\
 507 preprocessor directive of the form `#define DEFINITION' such that the\n\
 508 definition is visible in all the inferior's source files.\n\
 509 For example:\n\
 510   (gdb) macro define PI (3.1415926)\n\
 511   (gdb) macro define MIN(x,y) ((x) < (y) ? (x) : (y))"),
 512            &macrolist);
 513
 514   add_cmd ("undef", no_class, macro_undef_command, _("\
 515 Remove the definition of the C/C++ preprocessor macro with the given name."),
 516            &macrolist);
 517
 518   add_cmd ("list", no_class, macro_list_command,
 519            _("List all the macros defined using the `macro define' command."),
 520            &macrolist);
 521 }