xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/printcmd.c (revision cef8759bd76c1b621f8eab8faa6f208faabc2e15)
1 /* Print values for GNU debugger GDB.
2 
3    Copyright (C) 1986-2017 Free Software Foundation, 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 #include "defs.h"
21 #include "frame.h"
22 #include "symtab.h"
23 #include "gdbtypes.h"
24 #include "value.h"
25 #include "language.h"
26 #include "expression.h"
27 #include "gdbcore.h"
28 #include "gdbcmd.h"
29 #include "target.h"
30 #include "breakpoint.h"
31 #include "demangle.h"
32 #include "gdb-demangle.h"
33 #include "valprint.h"
34 #include "annotate.h"
35 #include "symfile.h"		/* for overlay functions */
36 #include "objfiles.h"		/* ditto */
37 #include "completer.h"		/* for completion functions */
38 #include "ui-out.h"
39 #include "block.h"
40 #include "disasm.h"
41 #include "dfp.h"
42 #include "observer.h"
43 #include "solist.h"
44 #include "parser-defs.h"
45 #include "charset.h"
46 #include "arch-utils.h"
47 #include "cli/cli-utils.h"
48 #include "cli/cli-script.h"
49 #include "format.h"
50 #include "source.h"
51 
52 #ifdef TUI
53 #include "tui/tui.h"		/* For tui_active et al.   */
54 #endif
55 
56 /* Last specified output format.  */
57 
58 static char last_format = 0;
59 
60 /* Last specified examination size.  'b', 'h', 'w' or `q'.  */
61 
62 static char last_size = 'w';
63 
64 /* Default address to examine next, and associated architecture.  */
65 
66 static struct gdbarch *next_gdbarch;
67 static CORE_ADDR next_address;
68 
69 /* Number of delay instructions following current disassembled insn.  */
70 
71 static int branch_delay_insns;
72 
73 /* Last address examined.  */
74 
75 static CORE_ADDR last_examine_address;
76 
77 /* Contents of last address examined.
78    This is not valid past the end of the `x' command!  */
79 
80 static struct value *last_examine_value;
81 
82 /* Largest offset between a symbolic value and an address, that will be
83    printed as `0x1234 <symbol+offset>'.  */
84 
85 static unsigned int max_symbolic_offset = UINT_MAX;
86 static void
87 show_max_symbolic_offset (struct ui_file *file, int from_tty,
88 			  struct cmd_list_element *c, const char *value)
89 {
90   fprintf_filtered (file,
91 		    _("The largest offset that will be "
92 		      "printed in <symbol+1234> form is %s.\n"),
93 		    value);
94 }
95 
96 /* Append the source filename and linenumber of the symbol when
97    printing a symbolic value as `<symbol at filename:linenum>' if set.  */
98 static int print_symbol_filename = 0;
99 static void
100 show_print_symbol_filename (struct ui_file *file, int from_tty,
101 			    struct cmd_list_element *c, const char *value)
102 {
103   fprintf_filtered (file, _("Printing of source filename and "
104 			    "line number with <symbol> is %s.\n"),
105 		    value);
106 }
107 
108 /* Number of auto-display expression currently being displayed.
109    So that we can disable it if we get a signal within it.
110    -1 when not doing one.  */
111 
112 static int current_display_number;
113 
114 struct display
115   {
116     /* Chain link to next auto-display item.  */
117     struct display *next;
118 
119     /* The expression as the user typed it.  */
120     char *exp_string;
121 
122     /* Expression to be evaluated and displayed.  */
123     expression_up exp;
124 
125     /* Item number of this auto-display item.  */
126     int number;
127 
128     /* Display format specified.  */
129     struct format_data format;
130 
131     /* Program space associated with `block'.  */
132     struct program_space *pspace;
133 
134     /* Innermost block required by this expression when evaluated.  */
135     const struct block *block;
136 
137     /* Status of this display (enabled or disabled).  */
138     int enabled_p;
139   };
140 
141 /* Chain of expressions whose values should be displayed
142    automatically each time the program stops.  */
143 
144 static struct display *display_chain;
145 
146 static int display_number;
147 
148 /* Walk the following statement or block through all displays.
149    ALL_DISPLAYS_SAFE does so even if the statement deletes the current
150    display.  */
151 
152 #define ALL_DISPLAYS(B)				\
153   for (B = display_chain; B; B = B->next)
154 
155 #define ALL_DISPLAYS_SAFE(B,TMP)		\
156   for (B = display_chain;			\
157        B ? (TMP = B->next, 1): 0;		\
158        B = TMP)
159 
160 /* Prototypes for exported functions.  */
161 
162 void _initialize_printcmd (void);
163 
164 /* Prototypes for local functions.  */
165 
166 static void do_one_display (struct display *);
167 
168 
169 /* Decode a format specification.  *STRING_PTR should point to it.
170    OFORMAT and OSIZE are used as defaults for the format and size
171    if none are given in the format specification.
172    If OSIZE is zero, then the size field of the returned value
173    should be set only if a size is explicitly specified by the
174    user.
175    The structure returned describes all the data
176    found in the specification.  In addition, *STRING_PTR is advanced
177    past the specification and past all whitespace following it.  */
178 
179 static struct format_data
180 decode_format (const char **string_ptr, int oformat, int osize)
181 {
182   struct format_data val;
183   const char *p = *string_ptr;
184 
185   val.format = '?';
186   val.size = '?';
187   val.count = 1;
188   val.raw = 0;
189 
190   if (*p == '-')
191     {
192       val.count = -1;
193       p++;
194     }
195   if (*p >= '0' && *p <= '9')
196     val.count *= atoi (p);
197   while (*p >= '0' && *p <= '9')
198     p++;
199 
200   /* Now process size or format letters that follow.  */
201 
202   while (1)
203     {
204       if (*p == 'b' || *p == 'h' || *p == 'w' || *p == 'g')
205 	val.size = *p++;
206       else if (*p == 'r')
207 	{
208 	  val.raw = 1;
209 	  p++;
210 	}
211       else if (*p >= 'a' && *p <= 'z')
212 	val.format = *p++;
213       else
214 	break;
215     }
216 
217   while (*p == ' ' || *p == '\t')
218     p++;
219   *string_ptr = p;
220 
221   /* Set defaults for format and size if not specified.  */
222   if (val.format == '?')
223     {
224       if (val.size == '?')
225 	{
226 	  /* Neither has been specified.  */
227 	  val.format = oformat;
228 	  val.size = osize;
229 	}
230       else
231 	/* If a size is specified, any format makes a reasonable
232 	   default except 'i'.  */
233 	val.format = oformat == 'i' ? 'x' : oformat;
234     }
235   else if (val.size == '?')
236     switch (val.format)
237       {
238       case 'a':
239 	/* Pick the appropriate size for an address.  This is deferred
240 	   until do_examine when we know the actual architecture to use.
241 	   A special size value of 'a' is used to indicate this case.  */
242 	val.size = osize ? 'a' : osize;
243 	break;
244       case 'f':
245 	/* Floating point has to be word or giantword.  */
246 	if (osize == 'w' || osize == 'g')
247 	  val.size = osize;
248 	else
249 	  /* Default it to giantword if the last used size is not
250 	     appropriate.  */
251 	  val.size = osize ? 'g' : osize;
252 	break;
253       case 'c':
254 	/* Characters default to one byte.  */
255 	val.size = osize ? 'b' : osize;
256 	break;
257       case 's':
258 	/* Display strings with byte size chars unless explicitly
259 	   specified.  */
260 	val.size = '\0';
261 	break;
262 
263       default:
264 	/* The default is the size most recently specified.  */
265 	val.size = osize;
266       }
267 
268   return val;
269 }
270 
271 /* Print value VAL on stream according to OPTIONS.
272    Do not end with a newline.
273    SIZE is the letter for the size of datum being printed.
274    This is used to pad hex numbers so they line up.  SIZE is 0
275    for print / output and set for examine.  */
276 
277 static void
278 print_formatted (struct value *val, int size,
279 		 const struct value_print_options *options,
280 		 struct ui_file *stream)
281 {
282   struct type *type = check_typedef (value_type (val));
283   int len = TYPE_LENGTH (type);
284 
285   if (VALUE_LVAL (val) == lval_memory)
286     next_address = value_address (val) + len;
287 
288   if (size)
289     {
290       switch (options->format)
291 	{
292 	case 's':
293 	  {
294 	    struct type *elttype = value_type (val);
295 
296 	    next_address = (value_address (val)
297 			    + val_print_string (elttype, NULL,
298 						value_address (val), -1,
299 						stream, options) * len);
300 	  }
301 	  return;
302 
303 	case 'i':
304 	  /* We often wrap here if there are long symbolic names.  */
305 	  wrap_here ("    ");
306 	  next_address = (value_address (val)
307 			  + gdb_print_insn (get_type_arch (type),
308 					    value_address (val), stream,
309 					    &branch_delay_insns));
310 	  return;
311 	}
312     }
313 
314   if (options->format == 0 || options->format == 's'
315       || TYPE_CODE (type) == TYPE_CODE_REF
316       || TYPE_CODE (type) == TYPE_CODE_ARRAY
317       || TYPE_CODE (type) == TYPE_CODE_STRING
318       || TYPE_CODE (type) == TYPE_CODE_STRUCT
319       || TYPE_CODE (type) == TYPE_CODE_UNION
320       || TYPE_CODE (type) == TYPE_CODE_NAMESPACE)
321     value_print (val, stream, options);
322   else
323     /* User specified format, so don't look to the type to tell us
324        what to do.  */
325     val_print_scalar_formatted (type,
326 				value_embedded_offset (val),
327 				val,
328 				options, size, stream);
329 }
330 
331 /* Return builtin floating point type of same length as TYPE.
332    If no such type is found, return TYPE itself.  */
333 static struct type *
334 float_type_from_length (struct type *type)
335 {
336   struct gdbarch *gdbarch = get_type_arch (type);
337   const struct builtin_type *builtin = builtin_type (gdbarch);
338 
339   if (TYPE_LENGTH (type) == TYPE_LENGTH (builtin->builtin_float))
340     type = builtin->builtin_float;
341   else if (TYPE_LENGTH (type) == TYPE_LENGTH (builtin->builtin_double))
342     type = builtin->builtin_double;
343   else if (TYPE_LENGTH (type) == TYPE_LENGTH (builtin->builtin_long_double))
344     type = builtin->builtin_long_double;
345 
346   return type;
347 }
348 
349 /* Print a scalar of data of type TYPE, pointed to in GDB by VALADDR,
350    according to OPTIONS and SIZE on STREAM.  Formats s and i are not
351    supported at this level.  */
352 
353 void
354 print_scalar_formatted (const gdb_byte *valaddr, struct type *type,
355 			const struct value_print_options *options,
356 			int size, struct ui_file *stream)
357 {
358   struct gdbarch *gdbarch = get_type_arch (type);
359   LONGEST val_long = 0;
360   unsigned int len = TYPE_LENGTH (type);
361   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
362 
363   /* String printing should go through val_print_scalar_formatted.  */
364   gdb_assert (options->format != 's');
365 
366   if (len > sizeof(LONGEST)
367       && (TYPE_CODE (type) == TYPE_CODE_INT
368 	  || TYPE_CODE (type) == TYPE_CODE_ENUM))
369     {
370       switch (options->format)
371 	{
372 	case 'o':
373 	  print_octal_chars (stream, valaddr, len, byte_order);
374 	  return;
375 	case 'u':
376 	case 'd':
377 	  print_decimal_chars (stream, valaddr, len, byte_order);
378 	  return;
379 	case 't':
380 	  print_binary_chars (stream, valaddr, len, byte_order);
381 	  return;
382 	case 'x':
383 	  print_hex_chars (stream, valaddr, len, byte_order);
384 	  return;
385 	case 'c':
386 	  print_char_chars (stream, type, valaddr, len, byte_order);
387 	  return;
388 	default:
389 	  break;
390 	};
391     }
392 
393   if (options->format != 'f')
394     val_long = unpack_long (type, valaddr);
395 
396   /* If the value is a pointer, and pointers and addresses are not the
397      same, then at this point, the value's length (in target bytes) is
398      gdbarch_addr_bit/TARGET_CHAR_BIT, not TYPE_LENGTH (type).  */
399   if (TYPE_CODE (type) == TYPE_CODE_PTR)
400     len = gdbarch_addr_bit (gdbarch) / TARGET_CHAR_BIT;
401 
402   /* If we are printing it as unsigned, truncate it in case it is actually
403      a negative signed value (e.g. "print/u (short)-1" should print 65535
404      (if shorts are 16 bits) instead of 4294967295).  */
405   if (options->format != 'd' || TYPE_UNSIGNED (type))
406     {
407       if (len < sizeof (LONGEST))
408 	val_long &= ((LONGEST) 1 << HOST_CHAR_BIT * len) - 1;
409     }
410 
411   switch (options->format)
412     {
413     case 'x':
414       if (!size)
415 	{
416 	  /* No size specified, like in print.  Print varying # of digits.  */
417 	  print_longest (stream, 'x', 1, val_long);
418 	}
419       else
420 	switch (size)
421 	  {
422 	  case 'b':
423 	  case 'h':
424 	  case 'w':
425 	  case 'g':
426 	    print_longest (stream, size, 1, val_long);
427 	    break;
428 	  default:
429 	    error (_("Undefined output size \"%c\"."), size);
430 	  }
431       break;
432 
433     case 'd':
434       print_longest (stream, 'd', 1, val_long);
435       break;
436 
437     case 'u':
438       print_longest (stream, 'u', 0, val_long);
439       break;
440 
441     case 'o':
442       if (val_long)
443 	print_longest (stream, 'o', 1, val_long);
444       else
445 	fprintf_filtered (stream, "0");
446       break;
447 
448     case 'a':
449       {
450 	CORE_ADDR addr = unpack_pointer (type, valaddr);
451 
452 	print_address (gdbarch, addr, stream);
453       }
454       break;
455 
456     case 'c':
457       {
458 	struct value_print_options opts = *options;
459 
460 	opts.format = 0;
461 	if (TYPE_UNSIGNED (type))
462 	  type = builtin_type (gdbarch)->builtin_true_unsigned_char;
463  	else
464 	  type = builtin_type (gdbarch)->builtin_true_char;
465 
466 	value_print (value_from_longest (type, val_long), stream, &opts);
467       }
468       break;
469 
470     case 'f':
471       type = float_type_from_length (type);
472       print_floating (valaddr, type, stream);
473       break;
474 
475     case 0:
476       internal_error (__FILE__, __LINE__,
477 		      _("failed internal consistency check"));
478 
479     case 't':
480       /* Binary; 't' stands for "two".  */
481       {
482 	char bits[8 * (sizeof val_long) + 1];
483 	char buf[8 * (sizeof val_long) + 32];
484 	char *cp = bits;
485 	int width;
486 
487 	if (!size)
488 	  width = 8 * (sizeof val_long);
489 	else
490 	  switch (size)
491 	    {
492 	    case 'b':
493 	      width = 8;
494 	      break;
495 	    case 'h':
496 	      width = 16;
497 	      break;
498 	    case 'w':
499 	      width = 32;
500 	      break;
501 	    case 'g':
502 	      width = 64;
503 	      break;
504 	    default:
505 	      error (_("Undefined output size \"%c\"."), size);
506 	    }
507 
508 	bits[width] = '\0';
509 	while (width-- > 0)
510 	  {
511 	    bits[width] = (val_long & 1) ? '1' : '0';
512 	    val_long >>= 1;
513 	  }
514 	if (!size)
515 	  {
516 	    while (*cp && *cp == '0')
517 	      cp++;
518 	    if (*cp == '\0')
519 	      cp--;
520 	  }
521 	strncpy (buf, cp, sizeof (bits));
522 	fputs_filtered (buf, stream);
523       }
524       break;
525 
526     case 'z':
527       print_hex_chars (stream, valaddr, len, byte_order);
528       break;
529 
530     default:
531       error (_("Undefined output format \"%c\"."), options->format);
532     }
533 }
534 
535 /* Specify default address for `x' command.
536    The `info lines' command uses this.  */
537 
538 void
539 set_next_address (struct gdbarch *gdbarch, CORE_ADDR addr)
540 {
541   struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
542 
543   next_gdbarch = gdbarch;
544   next_address = addr;
545 
546   /* Make address available to the user as $_.  */
547   set_internalvar (lookup_internalvar ("_"),
548 		   value_from_pointer (ptr_type, addr));
549 }
550 
551 /* Optionally print address ADDR symbolically as <SYMBOL+OFFSET> on STREAM,
552    after LEADIN.  Print nothing if no symbolic name is found nearby.
553    Optionally also print source file and line number, if available.
554    DO_DEMANGLE controls whether to print a symbol in its native "raw" form,
555    or to interpret it as a possible C++ name and convert it back to source
556    form.  However note that DO_DEMANGLE can be overridden by the specific
557    settings of the demangle and asm_demangle variables.  Returns
558    non-zero if anything was printed; zero otherwise.  */
559 
560 int
561 print_address_symbolic (struct gdbarch *gdbarch, CORE_ADDR addr,
562 			struct ui_file *stream,
563 			int do_demangle, const char *leadin)
564 {
565   char *name = NULL;
566   char *filename = NULL;
567   int unmapped = 0;
568   int offset = 0;
569   int line = 0;
570 
571   /* Throw away both name and filename.  */
572   struct cleanup *cleanup_chain = make_cleanup (free_current_contents, &name);
573   make_cleanup (free_current_contents, &filename);
574 
575   if (build_address_symbolic (gdbarch, addr, do_demangle, &name, &offset,
576 			      &filename, &line, &unmapped))
577     {
578       do_cleanups (cleanup_chain);
579       return 0;
580     }
581 
582   fputs_filtered (leadin, stream);
583   if (unmapped)
584     fputs_filtered ("<*", stream);
585   else
586     fputs_filtered ("<", stream);
587   fputs_filtered (name, stream);
588   if (offset != 0)
589     fprintf_filtered (stream, "+%u", (unsigned int) offset);
590 
591   /* Append source filename and line number if desired.  Give specific
592      line # of this addr, if we have it; else line # of the nearest symbol.  */
593   if (print_symbol_filename && filename != NULL)
594     {
595       if (line != -1)
596 	fprintf_filtered (stream, " at %s:%d", filename, line);
597       else
598 	fprintf_filtered (stream, " in %s", filename);
599     }
600   if (unmapped)
601     fputs_filtered ("*>", stream);
602   else
603     fputs_filtered (">", stream);
604 
605   do_cleanups (cleanup_chain);
606   return 1;
607 }
608 
609 /* Given an address ADDR return all the elements needed to print the
610    address in a symbolic form.  NAME can be mangled or not depending
611    on DO_DEMANGLE (and also on the asm_demangle global variable,
612    manipulated via ''set print asm-demangle'').  Return 0 in case of
613    success, when all the info in the OUT paramters is valid.  Return 1
614    otherwise.  */
615 int
616 build_address_symbolic (struct gdbarch *gdbarch,
617 			CORE_ADDR addr,  /* IN */
618 			int do_demangle, /* IN */
619 			char **name,     /* OUT */
620 			int *offset,     /* OUT */
621 			char **filename, /* OUT */
622 			int *line,       /* OUT */
623 			int *unmapped)   /* OUT */
624 {
625   struct bound_minimal_symbol msymbol;
626   struct symbol *symbol;
627   CORE_ADDR name_location = 0;
628   struct obj_section *section = NULL;
629   const char *name_temp = "";
630 
631   /* Let's say it is mapped (not unmapped).  */
632   *unmapped = 0;
633 
634   /* Determine if the address is in an overlay, and whether it is
635      mapped.  */
636   if (overlay_debugging)
637     {
638       section = find_pc_overlay (addr);
639       if (pc_in_unmapped_range (addr, section))
640 	{
641 	  *unmapped = 1;
642 	  addr = overlay_mapped_address (addr, section);
643 	}
644     }
645 
646   /* First try to find the address in the symbol table, then
647      in the minsyms.  Take the closest one.  */
648 
649   /* This is defective in the sense that it only finds text symbols.  So
650      really this is kind of pointless--we should make sure that the
651      minimal symbols have everything we need (by changing that we could
652      save some memory, but for many debug format--ELF/DWARF or
653      anything/stabs--it would be inconvenient to eliminate those minimal
654      symbols anyway).  */
655   msymbol = lookup_minimal_symbol_by_pc_section (addr, section);
656   symbol = find_pc_sect_function (addr, section);
657 
658   if (symbol)
659     {
660       /* If this is a function (i.e. a code address), strip out any
661 	 non-address bits.  For instance, display a pointer to the
662 	 first instruction of a Thumb function as <function>; the
663 	 second instruction will be <function+2>, even though the
664 	 pointer is <function+3>.  This matches the ISA behavior.  */
665       addr = gdbarch_addr_bits_remove (gdbarch, addr);
666 
667       name_location = BLOCK_START (SYMBOL_BLOCK_VALUE (symbol));
668       if (do_demangle || asm_demangle)
669 	name_temp = SYMBOL_PRINT_NAME (symbol);
670       else
671 	name_temp = SYMBOL_LINKAGE_NAME (symbol);
672     }
673 
674   if (msymbol.minsym != NULL
675       && MSYMBOL_HAS_SIZE (msymbol.minsym)
676       && MSYMBOL_SIZE (msymbol.minsym) == 0
677       && MSYMBOL_TYPE (msymbol.minsym) != mst_text
678       && MSYMBOL_TYPE (msymbol.minsym) != mst_text_gnu_ifunc
679       && MSYMBOL_TYPE (msymbol.minsym) != mst_file_text)
680     msymbol.minsym = NULL;
681 
682   if (msymbol.minsym != NULL)
683     {
684       if (BMSYMBOL_VALUE_ADDRESS (msymbol) > name_location || symbol == NULL)
685 	{
686 	  /* If this is a function (i.e. a code address), strip out any
687 	     non-address bits.  For instance, display a pointer to the
688 	     first instruction of a Thumb function as <function>; the
689 	     second instruction will be <function+2>, even though the
690 	     pointer is <function+3>.  This matches the ISA behavior.  */
691 	  if (MSYMBOL_TYPE (msymbol.minsym) == mst_text
692 	      || MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc
693 	      || MSYMBOL_TYPE (msymbol.minsym) == mst_file_text
694 	      || MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
695 	    addr = gdbarch_addr_bits_remove (gdbarch, addr);
696 
697 	  /* The msymbol is closer to the address than the symbol;
698 	     use the msymbol instead.  */
699 	  symbol = 0;
700 	  name_location = BMSYMBOL_VALUE_ADDRESS (msymbol);
701 	  if (do_demangle || asm_demangle)
702 	    name_temp = MSYMBOL_PRINT_NAME (msymbol.minsym);
703 	  else
704 	    name_temp = MSYMBOL_LINKAGE_NAME (msymbol.minsym);
705 	}
706     }
707   if (symbol == NULL && msymbol.minsym == NULL)
708     return 1;
709 
710   /* If the nearest symbol is too far away, don't print anything symbolic.  */
711 
712   /* For when CORE_ADDR is larger than unsigned int, we do math in
713      CORE_ADDR.  But when we detect unsigned wraparound in the
714      CORE_ADDR math, we ignore this test and print the offset,
715      because addr+max_symbolic_offset has wrapped through the end
716      of the address space back to the beginning, giving bogus comparison.  */
717   if (addr > name_location + max_symbolic_offset
718       && name_location + max_symbolic_offset > name_location)
719     return 1;
720 
721   *offset = addr - name_location;
722 
723   *name = xstrdup (name_temp);
724 
725   if (print_symbol_filename)
726     {
727       struct symtab_and_line sal;
728 
729       sal = find_pc_sect_line (addr, section, 0);
730 
731       if (sal.symtab)
732 	{
733 	  *filename = xstrdup (symtab_to_filename_for_display (sal.symtab));
734 	  *line = sal.line;
735 	}
736     }
737   return 0;
738 }
739 
740 
741 /* Print address ADDR symbolically on STREAM.
742    First print it as a number.  Then perhaps print
743    <SYMBOL + OFFSET> after the number.  */
744 
745 void
746 print_address (struct gdbarch *gdbarch,
747 	       CORE_ADDR addr, struct ui_file *stream)
748 {
749   fputs_filtered (paddress (gdbarch, addr), stream);
750   print_address_symbolic (gdbarch, addr, stream, asm_demangle, " ");
751 }
752 
753 /* Return a prefix for instruction address:
754    "=> " for current instruction, else "   ".  */
755 
756 const char *
757 pc_prefix (CORE_ADDR addr)
758 {
759   if (has_stack_frames ())
760     {
761       struct frame_info *frame;
762       CORE_ADDR pc;
763 
764       frame = get_selected_frame (NULL);
765       if (get_frame_pc_if_available (frame, &pc) && pc == addr)
766 	return "=> ";
767     }
768   return "   ";
769 }
770 
771 /* Print address ADDR symbolically on STREAM.  Parameter DEMANGLE
772    controls whether to print the symbolic name "raw" or demangled.
773    Return non-zero if anything was printed; zero otherwise.  */
774 
775 int
776 print_address_demangle (const struct value_print_options *opts,
777 			struct gdbarch *gdbarch, CORE_ADDR addr,
778 			struct ui_file *stream, int do_demangle)
779 {
780   if (opts->addressprint)
781     {
782       fputs_filtered (paddress (gdbarch, addr), stream);
783       print_address_symbolic (gdbarch, addr, stream, do_demangle, " ");
784     }
785   else
786     {
787       return print_address_symbolic (gdbarch, addr, stream, do_demangle, "");
788     }
789   return 1;
790 }
791 
792 
793 /* Find the address of the instruction that is INST_COUNT instructions before
794    the instruction at ADDR.
795    Since some architectures have variable-length instructions, we can't just
796    simply subtract INST_COUNT * INSN_LEN from ADDR.  Instead, we use line
797    number information to locate the nearest known instruction boundary,
798    and disassemble forward from there.  If we go out of the symbol range
799    during disassembling, we return the lowest address we've got so far and
800    set the number of instructions read to INST_READ.  */
801 
802 static CORE_ADDR
803 find_instruction_backward (struct gdbarch *gdbarch, CORE_ADDR addr,
804                            int inst_count, int *inst_read)
805 {
806   /* The vector PCS is used to store instruction addresses within
807      a pc range.  */
808   CORE_ADDR loop_start, loop_end, p;
809   std::vector<CORE_ADDR> pcs;
810   struct symtab_and_line sal;
811 
812   *inst_read = 0;
813   loop_start = loop_end = addr;
814 
815   /* In each iteration of the outer loop, we get a pc range that ends before
816      LOOP_START, then we count and store every instruction address of the range
817      iterated in the loop.
818      If the number of instructions counted reaches INST_COUNT, return the
819      stored address that is located INST_COUNT instructions back from ADDR.
820      If INST_COUNT is not reached, we subtract the number of counted
821      instructions from INST_COUNT, and go to the next iteration.  */
822   do
823     {
824       pcs.clear ();
825       sal = find_pc_sect_line (loop_start, NULL, 1);
826       if (sal.line <= 0)
827         {
828           /* We reach here when line info is not available.  In this case,
829              we print a message and just exit the loop.  The return value
830              is calculated after the loop.  */
831           printf_filtered (_("No line number information available "
832                              "for address "));
833           wrap_here ("  ");
834           print_address (gdbarch, loop_start - 1, gdb_stdout);
835           printf_filtered ("\n");
836           break;
837         }
838 
839       loop_end = loop_start;
840       loop_start = sal.pc;
841 
842       /* This loop pushes instruction addresses in the range from
843          LOOP_START to LOOP_END.  */
844       for (p = loop_start; p < loop_end;)
845         {
846 	  pcs.push_back (p);
847           p += gdb_insn_length (gdbarch, p);
848         }
849 
850       inst_count -= pcs.size ();
851       *inst_read += pcs.size ();
852     }
853   while (inst_count > 0);
854 
855   /* After the loop, the vector PCS has instruction addresses of the last
856      source line we processed, and INST_COUNT has a negative value.
857      We return the address at the index of -INST_COUNT in the vector for
858      the reason below.
859      Let's assume the following instruction addresses and run 'x/-4i 0x400e'.
860        Line X of File
861           0x4000
862           0x4001
863           0x4005
864        Line Y of File
865           0x4009
866           0x400c
867        => 0x400e
868           0x4011
869      find_instruction_backward is called with INST_COUNT = 4 and expected to
870      return 0x4001.  When we reach here, INST_COUNT is set to -1 because
871      it was subtracted by 2 (from Line Y) and 3 (from Line X).  The value
872      4001 is located at the index 1 of the last iterated line (= Line X),
873      which is simply calculated by -INST_COUNT.
874      The case when the length of PCS is 0 means that we reached an area for
875      which line info is not available.  In such case, we return LOOP_START,
876      which was the lowest instruction address that had line info.  */
877   p = pcs.size () > 0 ? pcs[-inst_count] : loop_start;
878 
879   /* INST_READ includes all instruction addresses in a pc range.  Need to
880      exclude the beginning part up to the address we're returning.  That
881      is, exclude {0x4000} in the example above.  */
882   if (inst_count < 0)
883     *inst_read += inst_count;
884 
885   return p;
886 }
887 
888 /* Backward read LEN bytes of target memory from address MEMADDR + LEN,
889    placing the results in GDB's memory from MYADDR + LEN.  Returns
890    a count of the bytes actually read.  */
891 
892 static int
893 read_memory_backward (struct gdbarch *gdbarch,
894                       CORE_ADDR memaddr, gdb_byte *myaddr, int len)
895 {
896   int errcode;
897   int nread;      /* Number of bytes actually read.  */
898 
899   /* First try a complete read.  */
900   errcode = target_read_memory (memaddr, myaddr, len);
901   if (errcode == 0)
902     {
903       /* Got it all.  */
904       nread = len;
905     }
906   else
907     {
908       /* Loop, reading one byte at a time until we get as much as we can.  */
909       memaddr += len;
910       myaddr += len;
911       for (nread = 0; nread < len; ++nread)
912         {
913           errcode = target_read_memory (--memaddr, --myaddr, 1);
914           if (errcode != 0)
915             {
916               /* The read was unsuccessful, so exit the loop.  */
917               printf_filtered (_("Cannot access memory at address %s\n"),
918                                paddress (gdbarch, memaddr));
919               break;
920             }
921         }
922     }
923   return nread;
924 }
925 
926 /* Returns true if X (which is LEN bytes wide) is the number zero.  */
927 
928 static int
929 integer_is_zero (const gdb_byte *x, int len)
930 {
931   int i = 0;
932 
933   while (i < len && x[i] == 0)
934     ++i;
935   return (i == len);
936 }
937 
938 /* Find the start address of a string in which ADDR is included.
939    Basically we search for '\0' and return the next address,
940    but if OPTIONS->PRINT_MAX is smaller than the length of a string,
941    we stop searching and return the address to print characters as many as
942    PRINT_MAX from the string.  */
943 
944 static CORE_ADDR
945 find_string_backward (struct gdbarch *gdbarch,
946                       CORE_ADDR addr, int count, int char_size,
947                       const struct value_print_options *options,
948                       int *strings_counted)
949 {
950   const int chunk_size = 0x20;
951   gdb_byte *buffer = NULL;
952   struct cleanup *cleanup = NULL;
953   int read_error = 0;
954   int chars_read = 0;
955   int chars_to_read = chunk_size;
956   int chars_counted = 0;
957   int count_original = count;
958   CORE_ADDR string_start_addr = addr;
959 
960   gdb_assert (char_size == 1 || char_size == 2 || char_size == 4);
961   buffer = (gdb_byte *) xmalloc (chars_to_read * char_size);
962   cleanup = make_cleanup (xfree, buffer);
963   while (count > 0 && read_error == 0)
964     {
965       int i;
966 
967       addr -= chars_to_read * char_size;
968       chars_read = read_memory_backward (gdbarch, addr, buffer,
969                                          chars_to_read * char_size);
970       chars_read /= char_size;
971       read_error = (chars_read == chars_to_read) ? 0 : 1;
972       /* Searching for '\0' from the end of buffer in backward direction.  */
973       for (i = 0; i < chars_read && count > 0 ; ++i, ++chars_counted)
974         {
975           int offset = (chars_to_read - i - 1) * char_size;
976 
977           if (integer_is_zero (buffer + offset, char_size)
978               || chars_counted == options->print_max)
979             {
980               /* Found '\0' or reached print_max.  As OFFSET is the offset to
981                  '\0', we add CHAR_SIZE to return the start address of
982                  a string.  */
983               --count;
984               string_start_addr = addr + offset + char_size;
985               chars_counted = 0;
986             }
987         }
988     }
989 
990   /* Update STRINGS_COUNTED with the actual number of loaded strings.  */
991   *strings_counted = count_original - count;
992 
993   if (read_error != 0)
994     {
995       /* In error case, STRING_START_ADDR is pointing to the string that
996          was last successfully loaded.  Rewind the partially loaded string.  */
997       string_start_addr -= chars_counted * char_size;
998     }
999 
1000   do_cleanups (cleanup);
1001   return string_start_addr;
1002 }
1003 
1004 /* Examine data at address ADDR in format FMT.
1005    Fetch it from memory and print on gdb_stdout.  */
1006 
1007 static void
1008 do_examine (struct format_data fmt, struct gdbarch *gdbarch, CORE_ADDR addr)
1009 {
1010   char format = 0;
1011   char size;
1012   int count = 1;
1013   struct type *val_type = NULL;
1014   int i;
1015   int maxelts;
1016   struct value_print_options opts;
1017   int need_to_update_next_address = 0;
1018   CORE_ADDR addr_rewound = 0;
1019 
1020   format = fmt.format;
1021   size = fmt.size;
1022   count = fmt.count;
1023   next_gdbarch = gdbarch;
1024   next_address = addr;
1025 
1026   /* Instruction format implies fetch single bytes
1027      regardless of the specified size.
1028      The case of strings is handled in decode_format, only explicit
1029      size operator are not changed to 'b'.  */
1030   if (format == 'i')
1031     size = 'b';
1032 
1033   if (size == 'a')
1034     {
1035       /* Pick the appropriate size for an address.  */
1036       if (gdbarch_ptr_bit (next_gdbarch) == 64)
1037 	size = 'g';
1038       else if (gdbarch_ptr_bit (next_gdbarch) == 32)
1039 	size = 'w';
1040       else if (gdbarch_ptr_bit (next_gdbarch) == 16)
1041 	size = 'h';
1042       else
1043 	/* Bad value for gdbarch_ptr_bit.  */
1044 	internal_error (__FILE__, __LINE__,
1045 			_("failed internal consistency check"));
1046     }
1047 
1048   if (size == 'b')
1049     val_type = builtin_type (next_gdbarch)->builtin_int8;
1050   else if (size == 'h')
1051     val_type = builtin_type (next_gdbarch)->builtin_int16;
1052   else if (size == 'w')
1053     val_type = builtin_type (next_gdbarch)->builtin_int32;
1054   else if (size == 'g')
1055     val_type = builtin_type (next_gdbarch)->builtin_int64;
1056 
1057   if (format == 's')
1058     {
1059       struct type *char_type = NULL;
1060 
1061       /* Search for "char16_t"  or "char32_t" types or fall back to 8-bit char
1062 	 if type is not found.  */
1063       if (size == 'h')
1064 	char_type = builtin_type (next_gdbarch)->builtin_char16;
1065       else if (size == 'w')
1066 	char_type = builtin_type (next_gdbarch)->builtin_char32;
1067       if (char_type)
1068         val_type = char_type;
1069       else
1070         {
1071 	  if (size != '\0' && size != 'b')
1072 	    warning (_("Unable to display strings with "
1073 		       "size '%c', using 'b' instead."), size);
1074 	  size = 'b';
1075 	  val_type = builtin_type (next_gdbarch)->builtin_int8;
1076         }
1077     }
1078 
1079   maxelts = 8;
1080   if (size == 'w')
1081     maxelts = 4;
1082   if (size == 'g')
1083     maxelts = 2;
1084   if (format == 's' || format == 'i')
1085     maxelts = 1;
1086 
1087   get_formatted_print_options (&opts, format);
1088 
1089   if (count < 0)
1090     {
1091       /* This is the negative repeat count case.
1092          We rewind the address based on the given repeat count and format,
1093          then examine memory from there in forward direction.  */
1094 
1095       count = -count;
1096       if (format == 'i')
1097         {
1098           next_address = find_instruction_backward (gdbarch, addr, count,
1099                                                     &count);
1100         }
1101       else if (format == 's')
1102         {
1103           next_address = find_string_backward (gdbarch, addr, count,
1104                                                TYPE_LENGTH (val_type),
1105                                                &opts, &count);
1106         }
1107       else
1108         {
1109           next_address = addr - count * TYPE_LENGTH (val_type);
1110         }
1111 
1112       /* The following call to print_formatted updates next_address in every
1113          iteration.  In backward case, we store the start address here
1114          and update next_address with it before exiting the function.  */
1115       addr_rewound = (format == 's'
1116                       ? next_address - TYPE_LENGTH (val_type)
1117                       : next_address);
1118       need_to_update_next_address = 1;
1119     }
1120 
1121   /* Print as many objects as specified in COUNT, at most maxelts per line,
1122      with the address of the next one at the start of each line.  */
1123 
1124   while (count > 0)
1125     {
1126       QUIT;
1127       if (format == 'i')
1128 	fputs_filtered (pc_prefix (next_address), gdb_stdout);
1129       print_address (next_gdbarch, next_address, gdb_stdout);
1130       printf_filtered (":");
1131       for (i = maxelts;
1132 	   i > 0 && count > 0;
1133 	   i--, count--)
1134 	{
1135 	  printf_filtered ("\t");
1136 	  /* Note that print_formatted sets next_address for the next
1137 	     object.  */
1138 	  last_examine_address = next_address;
1139 
1140 	  if (last_examine_value)
1141 	    value_free (last_examine_value);
1142 
1143 	  /* The value to be displayed is not fetched greedily.
1144 	     Instead, to avoid the possibility of a fetched value not
1145 	     being used, its retrieval is delayed until the print code
1146 	     uses it.  When examining an instruction stream, the
1147 	     disassembler will perform its own memory fetch using just
1148 	     the address stored in LAST_EXAMINE_VALUE.  FIXME: Should
1149 	     the disassembler be modified so that LAST_EXAMINE_VALUE
1150 	     is left with the byte sequence from the last complete
1151 	     instruction fetched from memory?  */
1152 	  last_examine_value = value_at_lazy (val_type, next_address);
1153 
1154 	  if (last_examine_value)
1155 	    release_value (last_examine_value);
1156 
1157 	  print_formatted (last_examine_value, size, &opts, gdb_stdout);
1158 
1159 	  /* Display any branch delay slots following the final insn.  */
1160 	  if (format == 'i' && count == 1)
1161 	    count += branch_delay_insns;
1162 	}
1163       printf_filtered ("\n");
1164       gdb_flush (gdb_stdout);
1165     }
1166 
1167   if (need_to_update_next_address)
1168     next_address = addr_rewound;
1169 }
1170 
1171 static void
1172 validate_format (struct format_data fmt, const char *cmdname)
1173 {
1174   if (fmt.size != 0)
1175     error (_("Size letters are meaningless in \"%s\" command."), cmdname);
1176   if (fmt.count != 1)
1177     error (_("Item count other than 1 is meaningless in \"%s\" command."),
1178 	   cmdname);
1179   if (fmt.format == 'i')
1180     error (_("Format letter \"%c\" is meaningless in \"%s\" command."),
1181 	   fmt.format, cmdname);
1182 }
1183 
1184 /* Parse print command format string into *FMTP and update *EXPP.
1185    CMDNAME should name the current command.  */
1186 
1187 void
1188 print_command_parse_format (const char **expp, const char *cmdname,
1189 			    struct format_data *fmtp)
1190 {
1191   const char *exp = *expp;
1192 
1193   if (exp && *exp == '/')
1194     {
1195       exp++;
1196       *fmtp = decode_format (&exp, last_format, 0);
1197       validate_format (*fmtp, cmdname);
1198       last_format = fmtp->format;
1199     }
1200   else
1201     {
1202       fmtp->count = 1;
1203       fmtp->format = 0;
1204       fmtp->size = 0;
1205       fmtp->raw = 0;
1206     }
1207 
1208   *expp = exp;
1209 }
1210 
1211 /* Print VAL to console according to *FMTP, including recording it to
1212    the history.  */
1213 
1214 void
1215 print_value (struct value *val, const struct format_data *fmtp)
1216 {
1217   struct value_print_options opts;
1218   int histindex = record_latest_value (val);
1219 
1220   annotate_value_history_begin (histindex, value_type (val));
1221 
1222   printf_filtered ("$%d = ", histindex);
1223 
1224   annotate_value_history_value ();
1225 
1226   get_formatted_print_options (&opts, fmtp->format);
1227   opts.raw = fmtp->raw;
1228 
1229   print_formatted (val, fmtp->size, &opts, gdb_stdout);
1230   printf_filtered ("\n");
1231 
1232   annotate_value_history_end ();
1233 }
1234 
1235 /* Evaluate string EXP as an expression in the current language and
1236    print the resulting value.  EXP may contain a format specifier as the
1237    first argument ("/x myvar" for example, to print myvar in hex).  */
1238 
1239 static void
1240 print_command_1 (const char *exp, int voidprint)
1241 {
1242   struct value *val;
1243   struct format_data fmt;
1244 
1245   print_command_parse_format (&exp, "print", &fmt);
1246 
1247   if (exp && *exp)
1248     {
1249       expression_up expr = parse_expression (exp);
1250       val = evaluate_expression (expr.get ());
1251     }
1252   else
1253     val = access_value_history (0);
1254 
1255   if (voidprint || (val && value_type (val) &&
1256 		    TYPE_CODE (value_type (val)) != TYPE_CODE_VOID))
1257     print_value (val, &fmt);
1258 }
1259 
1260 static void
1261 print_command (char *exp, int from_tty)
1262 {
1263   print_command_1 (exp, 1);
1264 }
1265 
1266 /* Same as print, except it doesn't print void results.  */
1267 static void
1268 call_command (char *exp, int from_tty)
1269 {
1270   print_command_1 (exp, 0);
1271 }
1272 
1273 /* Implementation of the "output" command.  */
1274 
1275 static void
1276 output_command (char *exp, int from_tty)
1277 {
1278   output_command_const (exp, from_tty);
1279 }
1280 
1281 /* Like output_command, but takes a const string as argument.  */
1282 
1283 void
1284 output_command_const (const char *exp, int from_tty)
1285 {
1286   char format = 0;
1287   struct value *val;
1288   struct format_data fmt;
1289   struct value_print_options opts;
1290 
1291   fmt.size = 0;
1292   fmt.raw = 0;
1293 
1294   if (exp && *exp == '/')
1295     {
1296       exp++;
1297       fmt = decode_format (&exp, 0, 0);
1298       validate_format (fmt, "output");
1299       format = fmt.format;
1300     }
1301 
1302   expression_up expr = parse_expression (exp);
1303 
1304   val = evaluate_expression (expr.get ());
1305 
1306   annotate_value_begin (value_type (val));
1307 
1308   get_formatted_print_options (&opts, format);
1309   opts.raw = fmt.raw;
1310   print_formatted (val, fmt.size, &opts, gdb_stdout);
1311 
1312   annotate_value_end ();
1313 
1314   wrap_here ("");
1315   gdb_flush (gdb_stdout);
1316 }
1317 
1318 static void
1319 set_command (char *exp, int from_tty)
1320 {
1321   expression_up expr = parse_expression (exp);
1322 
1323   if (expr->nelts >= 1)
1324     switch (expr->elts[0].opcode)
1325       {
1326       case UNOP_PREINCREMENT:
1327       case UNOP_POSTINCREMENT:
1328       case UNOP_PREDECREMENT:
1329       case UNOP_POSTDECREMENT:
1330       case BINOP_ASSIGN:
1331       case BINOP_ASSIGN_MODIFY:
1332       case BINOP_COMMA:
1333 	break;
1334       default:
1335 	warning
1336 	  (_("Expression is not an assignment (and might have no effect)"));
1337       }
1338 
1339   evaluate_expression (expr.get ());
1340 }
1341 
1342 static void
1343 sym_info (char *arg, int from_tty)
1344 {
1345   struct minimal_symbol *msymbol;
1346   struct objfile *objfile;
1347   struct obj_section *osect;
1348   CORE_ADDR addr, sect_addr;
1349   int matches = 0;
1350   unsigned int offset;
1351 
1352   if (!arg)
1353     error_no_arg (_("address"));
1354 
1355   addr = parse_and_eval_address (arg);
1356   ALL_OBJSECTIONS (objfile, osect)
1357   {
1358     /* Only process each object file once, even if there's a separate
1359        debug file.  */
1360     if (objfile->separate_debug_objfile_backlink)
1361       continue;
1362 
1363     sect_addr = overlay_mapped_address (addr, osect);
1364 
1365     if (obj_section_addr (osect) <= sect_addr
1366 	&& sect_addr < obj_section_endaddr (osect)
1367 	&& (msymbol
1368 	    = lookup_minimal_symbol_by_pc_section (sect_addr, osect).minsym))
1369       {
1370 	const char *obj_name, *mapped, *sec_name, *msym_name;
1371 	char *loc_string;
1372 	struct cleanup *old_chain;
1373 
1374 	matches = 1;
1375 	offset = sect_addr - MSYMBOL_VALUE_ADDRESS (objfile, msymbol);
1376 	mapped = section_is_mapped (osect) ? _("mapped") : _("unmapped");
1377 	sec_name = osect->the_bfd_section->name;
1378 	msym_name = MSYMBOL_PRINT_NAME (msymbol);
1379 
1380 	/* Don't print the offset if it is zero.
1381 	   We assume there's no need to handle i18n of "sym + offset".  */
1382 	if (offset)
1383 	  loc_string = xstrprintf ("%s + %u", msym_name, offset);
1384 	else
1385 	  loc_string = xstrprintf ("%s", msym_name);
1386 
1387 	/* Use a cleanup to free loc_string in case the user quits
1388 	   a pagination request inside printf_filtered.  */
1389 	old_chain = make_cleanup (xfree, loc_string);
1390 
1391 	gdb_assert (osect->objfile && objfile_name (osect->objfile));
1392 	obj_name = objfile_name (osect->objfile);
1393 
1394 	if (MULTI_OBJFILE_P ())
1395 	  if (pc_in_unmapped_range (addr, osect))
1396 	    if (section_is_overlay (osect))
1397 	      printf_filtered (_("%s in load address range of "
1398 				 "%s overlay section %s of %s\n"),
1399 			       loc_string, mapped, sec_name, obj_name);
1400 	    else
1401 	      printf_filtered (_("%s in load address range of "
1402 				 "section %s of %s\n"),
1403 			       loc_string, sec_name, obj_name);
1404 	  else
1405 	    if (section_is_overlay (osect))
1406 	      printf_filtered (_("%s in %s overlay section %s of %s\n"),
1407 			       loc_string, mapped, sec_name, obj_name);
1408 	    else
1409 	      printf_filtered (_("%s in section %s of %s\n"),
1410 			       loc_string, sec_name, obj_name);
1411 	else
1412 	  if (pc_in_unmapped_range (addr, osect))
1413 	    if (section_is_overlay (osect))
1414 	      printf_filtered (_("%s in load address range of %s overlay "
1415 				 "section %s\n"),
1416 			       loc_string, mapped, sec_name);
1417 	    else
1418 	      printf_filtered (_("%s in load address range of section %s\n"),
1419 			       loc_string, sec_name);
1420 	  else
1421 	    if (section_is_overlay (osect))
1422 	      printf_filtered (_("%s in %s overlay section %s\n"),
1423 			       loc_string, mapped, sec_name);
1424 	    else
1425 	      printf_filtered (_("%s in section %s\n"),
1426 			       loc_string, sec_name);
1427 
1428 	do_cleanups (old_chain);
1429       }
1430   }
1431   if (matches == 0)
1432     printf_filtered (_("No symbol matches %s.\n"), arg);
1433 }
1434 
1435 static void
1436 address_info (char *exp, int from_tty)
1437 {
1438   struct gdbarch *gdbarch;
1439   int regno;
1440   struct symbol *sym;
1441   struct bound_minimal_symbol msymbol;
1442   long val;
1443   struct obj_section *section;
1444   CORE_ADDR load_addr, context_pc = 0;
1445   struct field_of_this_result is_a_field_of_this;
1446 
1447   if (exp == 0)
1448     error (_("Argument required."));
1449 
1450   sym = lookup_symbol (exp, get_selected_block (&context_pc), VAR_DOMAIN,
1451 		       &is_a_field_of_this).symbol;
1452   if (sym == NULL)
1453     {
1454       if (is_a_field_of_this.type != NULL)
1455 	{
1456 	  printf_filtered ("Symbol \"");
1457 	  fprintf_symbol_filtered (gdb_stdout, exp,
1458 				   current_language->la_language, DMGL_ANSI);
1459 	  printf_filtered ("\" is a field of the local class variable ");
1460 	  if (current_language->la_language == language_objc)
1461 	    printf_filtered ("`self'\n");	/* ObjC equivalent of "this" */
1462 	  else
1463 	    printf_filtered ("`this'\n");
1464 	  return;
1465 	}
1466 
1467       msymbol = lookup_bound_minimal_symbol (exp);
1468 
1469       if (msymbol.minsym != NULL)
1470 	{
1471 	  struct objfile *objfile = msymbol.objfile;
1472 
1473 	  gdbarch = get_objfile_arch (objfile);
1474 	  load_addr = BMSYMBOL_VALUE_ADDRESS (msymbol);
1475 
1476 	  printf_filtered ("Symbol \"");
1477 	  fprintf_symbol_filtered (gdb_stdout, exp,
1478 				   current_language->la_language, DMGL_ANSI);
1479 	  printf_filtered ("\" is at ");
1480 	  fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1481 	  printf_filtered (" in a file compiled without debugging");
1482 	  section = MSYMBOL_OBJ_SECTION (objfile, msymbol.minsym);
1483 	  if (section_is_overlay (section))
1484 	    {
1485 	      load_addr = overlay_unmapped_address (load_addr, section);
1486 	      printf_filtered (",\n -- loaded at ");
1487 	      fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1488 	      printf_filtered (" in overlay section %s",
1489 			       section->the_bfd_section->name);
1490 	    }
1491 	  printf_filtered (".\n");
1492 	}
1493       else
1494 	error (_("No symbol \"%s\" in current context."), exp);
1495       return;
1496     }
1497 
1498   printf_filtered ("Symbol \"");
1499   fprintf_symbol_filtered (gdb_stdout, SYMBOL_PRINT_NAME (sym),
1500 			   current_language->la_language, DMGL_ANSI);
1501   printf_filtered ("\" is ");
1502   val = SYMBOL_VALUE (sym);
1503   if (SYMBOL_OBJFILE_OWNED (sym))
1504     section = SYMBOL_OBJ_SECTION (symbol_objfile (sym), sym);
1505   else
1506     section = NULL;
1507   gdbarch = symbol_arch (sym);
1508 
1509   if (SYMBOL_COMPUTED_OPS (sym) != NULL)
1510     {
1511       SYMBOL_COMPUTED_OPS (sym)->describe_location (sym, context_pc,
1512 						    gdb_stdout);
1513       printf_filtered (".\n");
1514       return;
1515     }
1516 
1517   switch (SYMBOL_CLASS (sym))
1518     {
1519     case LOC_CONST:
1520     case LOC_CONST_BYTES:
1521       printf_filtered ("constant");
1522       break;
1523 
1524     case LOC_LABEL:
1525       printf_filtered ("a label at address ");
1526       load_addr = SYMBOL_VALUE_ADDRESS (sym);
1527       fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1528       if (section_is_overlay (section))
1529 	{
1530 	  load_addr = overlay_unmapped_address (load_addr, section);
1531 	  printf_filtered (",\n -- loaded at ");
1532 	  fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1533 	  printf_filtered (" in overlay section %s",
1534 			   section->the_bfd_section->name);
1535 	}
1536       break;
1537 
1538     case LOC_COMPUTED:
1539       gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method"));
1540 
1541     case LOC_REGISTER:
1542       /* GDBARCH is the architecture associated with the objfile the symbol
1543 	 is defined in; the target architecture may be different, and may
1544 	 provide additional registers.  However, we do not know the target
1545 	 architecture at this point.  We assume the objfile architecture
1546 	 will contain all the standard registers that occur in debug info
1547 	 in that objfile.  */
1548       regno = SYMBOL_REGISTER_OPS (sym)->register_number (sym, gdbarch);
1549 
1550       if (SYMBOL_IS_ARGUMENT (sym))
1551 	printf_filtered (_("an argument in register %s"),
1552 			 gdbarch_register_name (gdbarch, regno));
1553       else
1554 	printf_filtered (_("a variable in register %s"),
1555 			 gdbarch_register_name (gdbarch, regno));
1556       break;
1557 
1558     case LOC_STATIC:
1559       printf_filtered (_("static storage at address "));
1560       load_addr = SYMBOL_VALUE_ADDRESS (sym);
1561       fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1562       if (section_is_overlay (section))
1563 	{
1564 	  load_addr = overlay_unmapped_address (load_addr, section);
1565 	  printf_filtered (_(",\n -- loaded at "));
1566 	  fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1567 	  printf_filtered (_(" in overlay section %s"),
1568 			   section->the_bfd_section->name);
1569 	}
1570       break;
1571 
1572     case LOC_REGPARM_ADDR:
1573       /* Note comment at LOC_REGISTER.  */
1574       regno = SYMBOL_REGISTER_OPS (sym)->register_number (sym, gdbarch);
1575       printf_filtered (_("address of an argument in register %s"),
1576 		       gdbarch_register_name (gdbarch, regno));
1577       break;
1578 
1579     case LOC_ARG:
1580       printf_filtered (_("an argument at offset %ld"), val);
1581       break;
1582 
1583     case LOC_LOCAL:
1584       printf_filtered (_("a local variable at frame offset %ld"), val);
1585       break;
1586 
1587     case LOC_REF_ARG:
1588       printf_filtered (_("a reference argument at offset %ld"), val);
1589       break;
1590 
1591     case LOC_TYPEDEF:
1592       printf_filtered (_("a typedef"));
1593       break;
1594 
1595     case LOC_BLOCK:
1596       printf_filtered (_("a function at address "));
1597       load_addr = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
1598       fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1599       if (section_is_overlay (section))
1600 	{
1601 	  load_addr = overlay_unmapped_address (load_addr, section);
1602 	  printf_filtered (_(",\n -- loaded at "));
1603 	  fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1604 	  printf_filtered (_(" in overlay section %s"),
1605 			   section->the_bfd_section->name);
1606 	}
1607       break;
1608 
1609     case LOC_UNRESOLVED:
1610       {
1611 	struct bound_minimal_symbol msym;
1612 
1613 	msym = lookup_minimal_symbol_and_objfile (SYMBOL_LINKAGE_NAME (sym));
1614 	if (msym.minsym == NULL)
1615 	  printf_filtered ("unresolved");
1616 	else
1617 	  {
1618 	    section = MSYMBOL_OBJ_SECTION (msym.objfile, msym.minsym);
1619 
1620 	    if (section
1621 		&& (section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0)
1622 	      {
1623 		load_addr = MSYMBOL_VALUE_RAW_ADDRESS (msym.minsym);
1624 		printf_filtered (_("a thread-local variable at offset %s "
1625 				   "in the thread-local storage for `%s'"),
1626 				 paddress (gdbarch, load_addr),
1627 				 objfile_name (section->objfile));
1628 	      }
1629 	    else
1630 	      {
1631 		load_addr = BMSYMBOL_VALUE_ADDRESS (msym);
1632 		printf_filtered (_("static storage at address "));
1633 		fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1634 		if (section_is_overlay (section))
1635 		  {
1636 		    load_addr = overlay_unmapped_address (load_addr, section);
1637 		    printf_filtered (_(",\n -- loaded at "));
1638 		    fputs_filtered (paddress (gdbarch, load_addr), gdb_stdout);
1639 		    printf_filtered (_(" in overlay section %s"),
1640 				     section->the_bfd_section->name);
1641 		  }
1642 	      }
1643 	  }
1644       }
1645       break;
1646 
1647     case LOC_OPTIMIZED_OUT:
1648       printf_filtered (_("optimized out"));
1649       break;
1650 
1651     default:
1652       printf_filtered (_("of unknown (botched) type"));
1653       break;
1654     }
1655   printf_filtered (".\n");
1656 }
1657 
1658 
1659 static void
1660 x_command (char *exp, int from_tty)
1661 {
1662   struct format_data fmt;
1663   struct cleanup *old_chain;
1664   struct value *val;
1665 
1666   fmt.format = last_format ? last_format : 'x';
1667   fmt.size = last_size;
1668   fmt.count = 1;
1669   fmt.raw = 0;
1670 
1671   if (exp && *exp == '/')
1672     {
1673       const char *tmp = exp + 1;
1674 
1675       fmt = decode_format (&tmp, last_format, last_size);
1676       exp = (char *) tmp;
1677     }
1678 
1679   /* If we have an expression, evaluate it and use it as the address.  */
1680 
1681   if (exp != 0 && *exp != 0)
1682     {
1683       expression_up expr = parse_expression (exp);
1684       /* Cause expression not to be there any more if this command is
1685          repeated with Newline.  But don't clobber a user-defined
1686          command's definition.  */
1687       if (from_tty)
1688 	*exp = 0;
1689       val = evaluate_expression (expr.get ());
1690       if (TYPE_IS_REFERENCE (value_type (val)))
1691 	val = coerce_ref (val);
1692       /* In rvalue contexts, such as this, functions are coerced into
1693          pointers to functions.  This makes "x/i main" work.  */
1694       if (/* last_format == 'i'  && */
1695 	  TYPE_CODE (value_type (val)) == TYPE_CODE_FUNC
1696 	   && VALUE_LVAL (val) == lval_memory)
1697 	next_address = value_address (val);
1698       else
1699 	next_address = value_as_address (val);
1700 
1701       next_gdbarch = expr->gdbarch;
1702     }
1703 
1704   if (!next_gdbarch)
1705     error_no_arg (_("starting display address"));
1706 
1707   do_examine (fmt, next_gdbarch, next_address);
1708 
1709   /* If the examine succeeds, we remember its size and format for next
1710      time.  Set last_size to 'b' for strings.  */
1711   if (fmt.format == 's')
1712     last_size = 'b';
1713   else
1714     last_size = fmt.size;
1715   last_format = fmt.format;
1716 
1717   /* Set a couple of internal variables if appropriate.  */
1718   if (last_examine_value)
1719     {
1720       /* Make last address examined available to the user as $_.  Use
1721          the correct pointer type.  */
1722       struct type *pointer_type
1723 	= lookup_pointer_type (value_type (last_examine_value));
1724       set_internalvar (lookup_internalvar ("_"),
1725 		       value_from_pointer (pointer_type,
1726 					   last_examine_address));
1727 
1728       /* Make contents of last address examined available to the user
1729 	 as $__.  If the last value has not been fetched from memory
1730 	 then don't fetch it now; instead mark it by voiding the $__
1731 	 variable.  */
1732       if (value_lazy (last_examine_value))
1733 	clear_internalvar (lookup_internalvar ("__"));
1734       else
1735 	set_internalvar (lookup_internalvar ("__"), last_examine_value);
1736     }
1737 }
1738 
1739 
1740 /* Add an expression to the auto-display chain.
1741    Specify the expression.  */
1742 
1743 static void
1744 display_command (char *arg, int from_tty)
1745 {
1746   struct format_data fmt;
1747   struct display *newobj;
1748   const char *exp = arg;
1749 
1750   if (exp == 0)
1751     {
1752       do_displays ();
1753       return;
1754     }
1755 
1756   if (*exp == '/')
1757     {
1758       exp++;
1759       fmt = decode_format (&exp, 0, 0);
1760       if (fmt.size && fmt.format == 0)
1761 	fmt.format = 'x';
1762       if (fmt.format == 'i' || fmt.format == 's')
1763 	fmt.size = 'b';
1764     }
1765   else
1766     {
1767       fmt.format = 0;
1768       fmt.size = 0;
1769       fmt.count = 0;
1770       fmt.raw = 0;
1771     }
1772 
1773   innermost_block = NULL;
1774   expression_up expr = parse_expression (exp);
1775 
1776   newobj = new display ();
1777 
1778   newobj->exp_string = xstrdup (exp);
1779   newobj->exp = std::move (expr);
1780   newobj->block = innermost_block;
1781   newobj->pspace = current_program_space;
1782   newobj->number = ++display_number;
1783   newobj->format = fmt;
1784   newobj->enabled_p = 1;
1785   newobj->next = NULL;
1786 
1787   if (display_chain == NULL)
1788     display_chain = newobj;
1789   else
1790     {
1791       struct display *last;
1792 
1793       for (last = display_chain; last->next != NULL; last = last->next)
1794 	;
1795       last->next = newobj;
1796     }
1797 
1798   if (from_tty)
1799     do_one_display (newobj);
1800 
1801   dont_repeat ();
1802 }
1803 
1804 static void
1805 free_display (struct display *d)
1806 {
1807   xfree (d->exp_string);
1808   delete d;
1809 }
1810 
1811 /* Clear out the display_chain.  Done when new symtabs are loaded,
1812    since this invalidates the types stored in many expressions.  */
1813 
1814 void
1815 clear_displays (void)
1816 {
1817   struct display *d;
1818 
1819   while ((d = display_chain) != NULL)
1820     {
1821       display_chain = d->next;
1822       free_display (d);
1823     }
1824 }
1825 
1826 /* Delete the auto-display DISPLAY.  */
1827 
1828 static void
1829 delete_display (struct display *display)
1830 {
1831   struct display *d;
1832 
1833   gdb_assert (display != NULL);
1834 
1835   if (display_chain == display)
1836     display_chain = display->next;
1837 
1838   ALL_DISPLAYS (d)
1839     if (d->next == display)
1840       {
1841 	d->next = display->next;
1842 	break;
1843       }
1844 
1845   free_display (display);
1846 }
1847 
1848 /* Call FUNCTION on each of the displays whose numbers are given in
1849    ARGS.  DATA is passed unmodified to FUNCTION.  */
1850 
1851 static void
1852 map_display_numbers (char *args,
1853 		     void (*function) (struct display *,
1854 				       void *),
1855 		     void *data)
1856 {
1857   int num;
1858 
1859   if (args == NULL)
1860     error_no_arg (_("one or more display numbers"));
1861 
1862   number_or_range_parser parser (args);
1863 
1864   while (!parser.finished ())
1865     {
1866       const char *p = parser.cur_tok ();
1867 
1868       num = parser.get_number ();
1869       if (num == 0)
1870 	warning (_("bad display number at or near '%s'"), p);
1871       else
1872 	{
1873 	  struct display *d, *tmp;
1874 
1875 	  ALL_DISPLAYS_SAFE (d, tmp)
1876 	    if (d->number == num)
1877 	      break;
1878 	  if (d == NULL)
1879 	    printf_unfiltered (_("No display number %d.\n"), num);
1880 	  else
1881 	    function (d, data);
1882 	}
1883     }
1884 }
1885 
1886 /* Callback for map_display_numbers, that deletes a display.  */
1887 
1888 static void
1889 do_delete_display (struct display *d, void *data)
1890 {
1891   delete_display (d);
1892 }
1893 
1894 /* "undisplay" command.  */
1895 
1896 static void
1897 undisplay_command (char *args, int from_tty)
1898 {
1899   if (args == NULL)
1900     {
1901       if (query (_("Delete all auto-display expressions? ")))
1902 	clear_displays ();
1903       dont_repeat ();
1904       return;
1905     }
1906 
1907   map_display_numbers (args, do_delete_display, NULL);
1908   dont_repeat ();
1909 }
1910 
1911 /* Display a single auto-display.
1912    Do nothing if the display cannot be printed in the current context,
1913    or if the display is disabled.  */
1914 
1915 static void
1916 do_one_display (struct display *d)
1917 {
1918   int within_current_scope;
1919 
1920   if (d->enabled_p == 0)
1921     return;
1922 
1923   /* The expression carries the architecture that was used at parse time.
1924      This is a problem if the expression depends on architecture features
1925      (e.g. register numbers), and the current architecture is now different.
1926      For example, a display statement like "display/i $pc" is expected to
1927      display the PC register of the current architecture, not the arch at
1928      the time the display command was given.  Therefore, we re-parse the
1929      expression if the current architecture has changed.  */
1930   if (d->exp != NULL && d->exp->gdbarch != get_current_arch ())
1931     {
1932       d->exp.reset ();
1933       d->block = NULL;
1934     }
1935 
1936   if (d->exp == NULL)
1937     {
1938 
1939       TRY
1940 	{
1941 	  innermost_block = NULL;
1942 	  d->exp = parse_expression (d->exp_string);
1943 	  d->block = innermost_block;
1944 	}
1945       CATCH (ex, RETURN_MASK_ALL)
1946 	{
1947 	  /* Can't re-parse the expression.  Disable this display item.  */
1948 	  d->enabled_p = 0;
1949 	  warning (_("Unable to display \"%s\": %s"),
1950 		   d->exp_string, ex.message);
1951 	  return;
1952 	}
1953       END_CATCH
1954     }
1955 
1956   if (d->block)
1957     {
1958       if (d->pspace == current_program_space)
1959 	within_current_scope = contained_in (get_selected_block (0), d->block);
1960       else
1961 	within_current_scope = 0;
1962     }
1963   else
1964     within_current_scope = 1;
1965   if (!within_current_scope)
1966     return;
1967 
1968   scoped_restore save_display_number
1969     = make_scoped_restore (&current_display_number, d->number);
1970 
1971   annotate_display_begin ();
1972   printf_filtered ("%d", d->number);
1973   annotate_display_number_end ();
1974   printf_filtered (": ");
1975   if (d->format.size)
1976     {
1977 
1978       annotate_display_format ();
1979 
1980       printf_filtered ("x/");
1981       if (d->format.count != 1)
1982 	printf_filtered ("%d", d->format.count);
1983       printf_filtered ("%c", d->format.format);
1984       if (d->format.format != 'i' && d->format.format != 's')
1985 	printf_filtered ("%c", d->format.size);
1986       printf_filtered (" ");
1987 
1988       annotate_display_expression ();
1989 
1990       puts_filtered (d->exp_string);
1991       annotate_display_expression_end ();
1992 
1993       if (d->format.count != 1 || d->format.format == 'i')
1994 	printf_filtered ("\n");
1995       else
1996 	printf_filtered ("  ");
1997 
1998       annotate_display_value ();
1999 
2000       TRY
2001         {
2002 	  struct value *val;
2003 	  CORE_ADDR addr;
2004 
2005 	  val = evaluate_expression (d->exp.get ());
2006 	  addr = value_as_address (val);
2007 	  if (d->format.format == 'i')
2008 	    addr = gdbarch_addr_bits_remove (d->exp->gdbarch, addr);
2009 	  do_examine (d->format, d->exp->gdbarch, addr);
2010 	}
2011       CATCH (ex, RETURN_MASK_ERROR)
2012 	{
2013 	  fprintf_filtered (gdb_stdout, _("<error: %s>\n"), ex.message);
2014 	}
2015       END_CATCH
2016     }
2017   else
2018     {
2019       struct value_print_options opts;
2020 
2021       annotate_display_format ();
2022 
2023       if (d->format.format)
2024 	printf_filtered ("/%c ", d->format.format);
2025 
2026       annotate_display_expression ();
2027 
2028       puts_filtered (d->exp_string);
2029       annotate_display_expression_end ();
2030 
2031       printf_filtered (" = ");
2032 
2033       annotate_display_expression ();
2034 
2035       get_formatted_print_options (&opts, d->format.format);
2036       opts.raw = d->format.raw;
2037 
2038       TRY
2039         {
2040 	  struct value *val;
2041 
2042 	  val = evaluate_expression (d->exp.get ());
2043 	  print_formatted (val, d->format.size, &opts, gdb_stdout);
2044 	}
2045       CATCH (ex, RETURN_MASK_ERROR)
2046 	{
2047 	  fprintf_filtered (gdb_stdout, _("<error: %s>"), ex.message);
2048 	}
2049       END_CATCH
2050 
2051       printf_filtered ("\n");
2052     }
2053 
2054   annotate_display_end ();
2055 
2056   gdb_flush (gdb_stdout);
2057 }
2058 
2059 /* Display all of the values on the auto-display chain which can be
2060    evaluated in the current scope.  */
2061 
2062 void
2063 do_displays (void)
2064 {
2065   struct display *d;
2066 
2067   for (d = display_chain; d; d = d->next)
2068     do_one_display (d);
2069 }
2070 
2071 /* Delete the auto-display which we were in the process of displaying.
2072    This is done when there is an error or a signal.  */
2073 
2074 void
2075 disable_display (int num)
2076 {
2077   struct display *d;
2078 
2079   for (d = display_chain; d; d = d->next)
2080     if (d->number == num)
2081       {
2082 	d->enabled_p = 0;
2083 	return;
2084       }
2085   printf_unfiltered (_("No display number %d.\n"), num);
2086 }
2087 
2088 void
2089 disable_current_display (void)
2090 {
2091   if (current_display_number >= 0)
2092     {
2093       disable_display (current_display_number);
2094       fprintf_unfiltered (gdb_stderr,
2095 			  _("Disabling display %d to "
2096 			    "avoid infinite recursion.\n"),
2097 			  current_display_number);
2098     }
2099   current_display_number = -1;
2100 }
2101 
2102 static void
2103 display_info (char *ignore, int from_tty)
2104 {
2105   struct display *d;
2106 
2107   if (!display_chain)
2108     printf_unfiltered (_("There are no auto-display expressions now.\n"));
2109   else
2110     printf_filtered (_("Auto-display expressions now in effect:\n\
2111 Num Enb Expression\n"));
2112 
2113   for (d = display_chain; d; d = d->next)
2114     {
2115       printf_filtered ("%d:   %c  ", d->number, "ny"[(int) d->enabled_p]);
2116       if (d->format.size)
2117 	printf_filtered ("/%d%c%c ", d->format.count, d->format.size,
2118 			 d->format.format);
2119       else if (d->format.format)
2120 	printf_filtered ("/%c ", d->format.format);
2121       puts_filtered (d->exp_string);
2122       if (d->block && !contained_in (get_selected_block (0), d->block))
2123 	printf_filtered (_(" (cannot be evaluated in the current context)"));
2124       printf_filtered ("\n");
2125       gdb_flush (gdb_stdout);
2126     }
2127 }
2128 
2129 /* Callback fo map_display_numbers, that enables or disables the
2130    passed in display D.  */
2131 
2132 static void
2133 do_enable_disable_display (struct display *d, void *data)
2134 {
2135   d->enabled_p = *(int *) data;
2136 }
2137 
2138 /* Implamentation of both the "disable display" and "enable display"
2139    commands.  ENABLE decides what to do.  */
2140 
2141 static void
2142 enable_disable_display_command (char *args, int from_tty, int enable)
2143 {
2144   if (args == NULL)
2145     {
2146       struct display *d;
2147 
2148       ALL_DISPLAYS (d)
2149 	d->enabled_p = enable;
2150       return;
2151     }
2152 
2153   map_display_numbers (args, do_enable_disable_display, &enable);
2154 }
2155 
2156 /* The "enable display" command.  */
2157 
2158 static void
2159 enable_display_command (char *args, int from_tty)
2160 {
2161   enable_disable_display_command (args, from_tty, 1);
2162 }
2163 
2164 /* The "disable display" command.  */
2165 
2166 static void
2167 disable_display_command (char *args, int from_tty)
2168 {
2169   enable_disable_display_command (args, from_tty, 0);
2170 }
2171 
2172 /* display_chain items point to blocks and expressions.  Some expressions in
2173    turn may point to symbols.
2174    Both symbols and blocks are obstack_alloc'd on objfile_stack, and are
2175    obstack_free'd when a shared library is unloaded.
2176    Clear pointers that are about to become dangling.
2177    Both .exp and .block fields will be restored next time we need to display
2178    an item by re-parsing .exp_string field in the new execution context.  */
2179 
2180 static void
2181 clear_dangling_display_expressions (struct objfile *objfile)
2182 {
2183   struct display *d;
2184   struct program_space *pspace;
2185 
2186   /* With no symbol file we cannot have a block or expression from it.  */
2187   if (objfile == NULL)
2188     return;
2189   pspace = objfile->pspace;
2190   if (objfile->separate_debug_objfile_backlink)
2191     {
2192       objfile = objfile->separate_debug_objfile_backlink;
2193       gdb_assert (objfile->pspace == pspace);
2194     }
2195 
2196   for (d = display_chain; d != NULL; d = d->next)
2197     {
2198       if (d->pspace != pspace)
2199 	continue;
2200 
2201       if (lookup_objfile_from_block (d->block) == objfile
2202 	  || (d->exp != NULL && exp_uses_objfile (d->exp.get (), objfile)))
2203       {
2204 	d->exp.reset ();
2205 	d->block = NULL;
2206       }
2207     }
2208 }
2209 
2210 
2211 /* Print the value in stack frame FRAME of a variable specified by a
2212    struct symbol.  NAME is the name to print; if NULL then VAR's print
2213    name will be used.  STREAM is the ui_file on which to print the
2214    value.  INDENT specifies the number of indent levels to print
2215    before printing the variable name.
2216 
2217    This function invalidates FRAME.  */
2218 
2219 void
2220 print_variable_and_value (const char *name, struct symbol *var,
2221 			  struct frame_info *frame,
2222 			  struct ui_file *stream, int indent)
2223 {
2224 
2225   if (!name)
2226     name = SYMBOL_PRINT_NAME (var);
2227 
2228   fprintf_filtered (stream, "%s%s = ", n_spaces (2 * indent), name);
2229   TRY
2230     {
2231       struct value *val;
2232       struct value_print_options opts;
2233 
2234       /* READ_VAR_VALUE needs a block in order to deal with non-local
2235 	 references (i.e. to handle nested functions).  In this context, we
2236 	 print variables that are local to this frame, so we can avoid passing
2237 	 a block to it.  */
2238       val = read_var_value (var, NULL, frame);
2239       get_user_print_options (&opts);
2240       opts.deref_ref = 1;
2241       common_val_print (val, stream, indent, &opts, current_language);
2242 
2243       /* common_val_print invalidates FRAME when a pretty printer calls inferior
2244 	 function.  */
2245       frame = NULL;
2246     }
2247   CATCH (except, RETURN_MASK_ERROR)
2248     {
2249       fprintf_filtered(stream, "<error reading variable %s (%s)>", name,
2250 		       except.message);
2251     }
2252   END_CATCH
2253 
2254   fprintf_filtered (stream, "\n");
2255 }
2256 
2257 /* Subroutine of ui_printf to simplify it.
2258    Print VALUE to STREAM using FORMAT.
2259    VALUE is a C-style string on the target.  */
2260 
2261 static void
2262 printf_c_string (struct ui_file *stream, const char *format,
2263 		 struct value *value)
2264 {
2265   gdb_byte *str;
2266   CORE_ADDR tem;
2267   int j;
2268 
2269   tem = value_as_address (value);
2270 
2271   /* This is a %s argument.  Find the length of the string.  */
2272   for (j = 0;; j++)
2273     {
2274       gdb_byte c;
2275 
2276       QUIT;
2277       read_memory (tem + j, &c, 1);
2278       if (c == 0)
2279 	break;
2280     }
2281 
2282   /* Copy the string contents into a string inside GDB.  */
2283   str = (gdb_byte *) alloca (j + 1);
2284   if (j != 0)
2285     read_memory (tem, str, j);
2286   str[j] = 0;
2287 
2288   fprintf_filtered (stream, format, (char *) str);
2289 }
2290 
2291 /* Subroutine of ui_printf to simplify it.
2292    Print VALUE to STREAM using FORMAT.
2293    VALUE is a wide C-style string on the target.  */
2294 
2295 static void
2296 printf_wide_c_string (struct ui_file *stream, const char *format,
2297 		      struct value *value)
2298 {
2299   gdb_byte *str;
2300   CORE_ADDR tem;
2301   int j;
2302   struct gdbarch *gdbarch = get_type_arch (value_type (value));
2303   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2304   struct type *wctype = lookup_typename (current_language, gdbarch,
2305 					 "wchar_t", NULL, 0);
2306   int wcwidth = TYPE_LENGTH (wctype);
2307   gdb_byte *buf = (gdb_byte *) alloca (wcwidth);
2308   struct obstack output;
2309   struct cleanup *inner_cleanup;
2310 
2311   tem = value_as_address (value);
2312 
2313   /* This is a %s argument.  Find the length of the string.  */
2314   for (j = 0;; j += wcwidth)
2315     {
2316       QUIT;
2317       read_memory (tem + j, buf, wcwidth);
2318       if (extract_unsigned_integer (buf, wcwidth, byte_order) == 0)
2319 	break;
2320     }
2321 
2322   /* Copy the string contents into a string inside GDB.  */
2323   str = (gdb_byte *) alloca (j + wcwidth);
2324   if (j != 0)
2325     read_memory (tem, str, j);
2326   memset (&str[j], 0, wcwidth);
2327 
2328   obstack_init (&output);
2329   inner_cleanup = make_cleanup_obstack_free (&output);
2330 
2331   convert_between_encodings (target_wide_charset (gdbarch),
2332 			     host_charset (),
2333 			     str, j, wcwidth,
2334 			     &output, translit_char);
2335   obstack_grow_str0 (&output, "");
2336 
2337   fprintf_filtered (stream, format, obstack_base (&output));
2338   do_cleanups (inner_cleanup);
2339 }
2340 
2341 /* Subroutine of ui_printf to simplify it.
2342    Print VALUE, a decimal floating point value, to STREAM using FORMAT.  */
2343 
2344 static void
2345 printf_decfloat (struct ui_file *stream, const char *format,
2346 		 struct value *value)
2347 {
2348   const gdb_byte *param_ptr = value_contents (value);
2349 
2350 #if defined (PRINTF_HAS_DECFLOAT)
2351   /* If we have native support for Decimal floating
2352      printing, handle it here.  */
2353   fprintf_filtered (stream, format, param_ptr);
2354 #else
2355   /* As a workaround until vasprintf has native support for DFP
2356      we convert the DFP values to string and print them using
2357      the %s format specifier.  */
2358   const char *p;
2359 
2360   /* Parameter data.  */
2361   struct type *param_type = value_type (value);
2362   struct gdbarch *gdbarch = get_type_arch (param_type);
2363   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2364 
2365   /* DFP output data.  */
2366   struct value *dfp_value = NULL;
2367   gdb_byte *dfp_ptr;
2368   int dfp_len = 16;
2369   gdb_byte dec[16];
2370   struct type *dfp_type = NULL;
2371   char decstr[MAX_DECIMAL_STRING];
2372 
2373   /* Points to the end of the string so that we can go back
2374      and check for DFP length modifiers.  */
2375   p = format + strlen (format);
2376 
2377   /* Look for the float/double format specifier.  */
2378   while (*p != 'f' && *p != 'e' && *p != 'E'
2379 	 && *p != 'g' && *p != 'G')
2380     p--;
2381 
2382   /* Search for the '%' char and extract the size and type of
2383      the output decimal value based on its modifiers
2384      (%Hf, %Df, %DDf).  */
2385   while (*--p != '%')
2386     {
2387       if (*p == 'H')
2388 	{
2389 	  dfp_len = 4;
2390 	  dfp_type = builtin_type (gdbarch)->builtin_decfloat;
2391 	}
2392       else if (*p == 'D' && *(p - 1) == 'D')
2393 	{
2394 	  dfp_len = 16;
2395 	  dfp_type = builtin_type (gdbarch)->builtin_declong;
2396 	  p--;
2397 	}
2398       else
2399 	{
2400 	  dfp_len = 8;
2401 	  dfp_type = builtin_type (gdbarch)->builtin_decdouble;
2402 	}
2403     }
2404 
2405   /* Conversion between different DFP types.  */
2406   if (TYPE_CODE (param_type) == TYPE_CODE_DECFLOAT)
2407     decimal_convert (param_ptr, TYPE_LENGTH (param_type),
2408 		     byte_order, dec, dfp_len, byte_order);
2409   else
2410     /* If this is a non-trivial conversion, just output 0.
2411        A correct converted value can be displayed by explicitly
2412        casting to a DFP type.  */
2413     decimal_from_string (dec, dfp_len, byte_order, "0");
2414 
2415   dfp_value = value_from_decfloat (dfp_type, dec);
2416 
2417   dfp_ptr = (gdb_byte *) value_contents (dfp_value);
2418 
2419   decimal_to_string (dfp_ptr, dfp_len, byte_order, decstr);
2420 
2421   /* Print the DFP value.  */
2422   fprintf_filtered (stream, "%s", decstr);
2423 #endif
2424 }
2425 
2426 /* Subroutine of ui_printf to simplify it.
2427    Print VALUE, a target pointer, to STREAM using FORMAT.  */
2428 
2429 static void
2430 printf_pointer (struct ui_file *stream, const char *format,
2431 		struct value *value)
2432 {
2433   /* We avoid the host's %p because pointers are too
2434      likely to be the wrong size.  The only interesting
2435      modifier for %p is a width; extract that, and then
2436      handle %p as glibc would: %#x or a literal "(nil)".  */
2437 
2438   const char *p;
2439   char *fmt, *fmt_p;
2440 #ifdef PRINTF_HAS_LONG_LONG
2441   long long val = value_as_long (value);
2442 #else
2443   long val = value_as_long (value);
2444 #endif
2445 
2446   fmt = (char *) alloca (strlen (format) + 5);
2447 
2448   /* Copy up to the leading %.  */
2449   p = format;
2450   fmt_p = fmt;
2451   while (*p)
2452     {
2453       int is_percent = (*p == '%');
2454 
2455       *fmt_p++ = *p++;
2456       if (is_percent)
2457 	{
2458 	  if (*p == '%')
2459 	    *fmt_p++ = *p++;
2460 	  else
2461 	    break;
2462 	}
2463     }
2464 
2465   if (val != 0)
2466     *fmt_p++ = '#';
2467 
2468   /* Copy any width.  */
2469   while (*p >= '0' && *p < '9')
2470     *fmt_p++ = *p++;
2471 
2472   gdb_assert (*p == 'p' && *(p + 1) == '\0');
2473   if (val != 0)
2474     {
2475 #ifdef PRINTF_HAS_LONG_LONG
2476       *fmt_p++ = 'l';
2477 #endif
2478       *fmt_p++ = 'l';
2479       *fmt_p++ = 'x';
2480       *fmt_p++ = '\0';
2481       fprintf_filtered (stream, fmt, val);
2482     }
2483   else
2484     {
2485       *fmt_p++ = 's';
2486       *fmt_p++ = '\0';
2487       fprintf_filtered (stream, fmt, "(nil)");
2488     }
2489 }
2490 
2491 /* printf "printf format string" ARG to STREAM.  */
2492 
2493 static void
2494 ui_printf (const char *arg, struct ui_file *stream)
2495 {
2496   struct format_piece *fpieces;
2497   const char *s = arg;
2498   struct value **val_args;
2499   int allocated_args = 20;
2500   struct cleanup *old_cleanups;
2501 
2502   val_args = XNEWVEC (struct value *, allocated_args);
2503   old_cleanups = make_cleanup (free_current_contents, &val_args);
2504 
2505   if (s == 0)
2506     error_no_arg (_("format-control string and values to print"));
2507 
2508   s = skip_spaces_const (s);
2509 
2510   /* A format string should follow, enveloped in double quotes.  */
2511   if (*s++ != '"')
2512     error (_("Bad format string, missing '\"'."));
2513 
2514   fpieces = parse_format_string (&s);
2515 
2516   make_cleanup (free_format_pieces_cleanup, &fpieces);
2517 
2518   if (*s++ != '"')
2519     error (_("Bad format string, non-terminated '\"'."));
2520 
2521   s = skip_spaces_const (s);
2522 
2523   if (*s != ',' && *s != 0)
2524     error (_("Invalid argument syntax"));
2525 
2526   if (*s == ',')
2527     s++;
2528   s = skip_spaces_const (s);
2529 
2530   {
2531     int nargs = 0;
2532     int nargs_wanted;
2533     int i, fr;
2534     char *current_substring;
2535 
2536     nargs_wanted = 0;
2537     for (fr = 0; fpieces[fr].string != NULL; fr++)
2538       if (fpieces[fr].argclass != literal_piece)
2539 	++nargs_wanted;
2540 
2541     /* Now, parse all arguments and evaluate them.
2542        Store the VALUEs in VAL_ARGS.  */
2543 
2544     while (*s != '\0')
2545       {
2546 	const char *s1;
2547 
2548 	if (nargs == allocated_args)
2549 	  val_args = (struct value **) xrealloc ((char *) val_args,
2550 						 (allocated_args *= 2)
2551 						 * sizeof (struct value *));
2552 	s1 = s;
2553 	val_args[nargs] = parse_to_comma_and_eval (&s1);
2554 
2555 	nargs++;
2556 	s = s1;
2557 	if (*s == ',')
2558 	  s++;
2559       }
2560 
2561     if (nargs != nargs_wanted)
2562       error (_("Wrong number of arguments for specified format-string"));
2563 
2564     /* Now actually print them.  */
2565     i = 0;
2566     for (fr = 0; fpieces[fr].string != NULL; fr++)
2567       {
2568 	current_substring = fpieces[fr].string;
2569 	switch (fpieces[fr].argclass)
2570 	  {
2571 	  case string_arg:
2572 	    printf_c_string (stream, current_substring, val_args[i]);
2573 	    break;
2574 	  case wide_string_arg:
2575 	    printf_wide_c_string (stream, current_substring, val_args[i]);
2576 	    break;
2577 	  case wide_char_arg:
2578 	    {
2579 	      struct gdbarch *gdbarch
2580 		= get_type_arch (value_type (val_args[i]));
2581 	      struct type *wctype = lookup_typename (current_language, gdbarch,
2582 						     "wchar_t", NULL, 0);
2583 	      struct type *valtype;
2584 	      struct obstack output;
2585 	      struct cleanup *inner_cleanup;
2586 	      const gdb_byte *bytes;
2587 
2588 	      valtype = value_type (val_args[i]);
2589 	      if (TYPE_LENGTH (valtype) != TYPE_LENGTH (wctype)
2590 		  || TYPE_CODE (valtype) != TYPE_CODE_INT)
2591 		error (_("expected wchar_t argument for %%lc"));
2592 
2593 	      bytes = value_contents (val_args[i]);
2594 
2595 	      obstack_init (&output);
2596 	      inner_cleanup = make_cleanup_obstack_free (&output);
2597 
2598 	      convert_between_encodings (target_wide_charset (gdbarch),
2599 					 host_charset (),
2600 					 bytes, TYPE_LENGTH (valtype),
2601 					 TYPE_LENGTH (valtype),
2602 					 &output, translit_char);
2603 	      obstack_grow_str0 (&output, "");
2604 
2605 	      fprintf_filtered (stream, current_substring,
2606                                 obstack_base (&output));
2607 	      do_cleanups (inner_cleanup);
2608 	    }
2609 	    break;
2610 	  case double_arg:
2611 	    {
2612 	      struct type *type = value_type (val_args[i]);
2613 	      DOUBLEST val;
2614 	      int inv;
2615 
2616 	      /* If format string wants a float, unchecked-convert the value
2617 		 to floating point of the same size.  */
2618 	      type = float_type_from_length (type);
2619 	      val = unpack_double (type, value_contents (val_args[i]), &inv);
2620 	      if (inv)
2621 		error (_("Invalid floating value found in program."));
2622 
2623               fprintf_filtered (stream, current_substring, (double) val);
2624 	      break;
2625 	    }
2626 	  case long_double_arg:
2627 #ifdef HAVE_LONG_DOUBLE
2628 	    {
2629 	      struct type *type = value_type (val_args[i]);
2630 	      DOUBLEST val;
2631 	      int inv;
2632 
2633 	      /* If format string wants a float, unchecked-convert the value
2634 		 to floating point of the same size.  */
2635 	      type = float_type_from_length (type);
2636 	      val = unpack_double (type, value_contents (val_args[i]), &inv);
2637 	      if (inv)
2638 		error (_("Invalid floating value found in program."));
2639 
2640 	      fprintf_filtered (stream, current_substring,
2641                                 (long double) val);
2642 	      break;
2643 	    }
2644 #else
2645 	    error (_("long double not supported in printf"));
2646 #endif
2647 	  case long_long_arg:
2648 #ifdef PRINTF_HAS_LONG_LONG
2649 	    {
2650 	      long long val = value_as_long (val_args[i]);
2651 
2652               fprintf_filtered (stream, current_substring, val);
2653 	      break;
2654 	    }
2655 #else
2656 	    error (_("long long not supported in printf"));
2657 #endif
2658 	  case int_arg:
2659 	    {
2660 	      int val = value_as_long (val_args[i]);
2661 
2662               fprintf_filtered (stream, current_substring, val);
2663 	      break;
2664 	    }
2665 	  case long_arg:
2666 	    {
2667 	      long val = value_as_long (val_args[i]);
2668 
2669               fprintf_filtered (stream, current_substring, val);
2670 	      break;
2671 	    }
2672 	  /* Handles decimal floating values.  */
2673 	  case decfloat_arg:
2674 	    printf_decfloat (stream, current_substring, val_args[i]);
2675 	    break;
2676 	  case ptr_arg:
2677 	    printf_pointer (stream, current_substring, val_args[i]);
2678 	    break;
2679 	  case literal_piece:
2680 	    /* Print a portion of the format string that has no
2681 	       directives.  Note that this will not include any
2682 	       ordinary %-specs, but it might include "%%".  That is
2683 	       why we use printf_filtered and not puts_filtered here.
2684 	       Also, we pass a dummy argument because some platforms
2685 	       have modified GCC to include -Wformat-security by
2686 	       default, which will warn here if there is no
2687 	       argument.  */
2688 	    fprintf_filtered (stream, current_substring, 0);
2689 	    break;
2690 	  default:
2691 	    internal_error (__FILE__, __LINE__,
2692 			    _("failed internal consistency check"));
2693 	  }
2694 	/* Maybe advance to the next argument.  */
2695 	if (fpieces[fr].argclass != literal_piece)
2696 	  ++i;
2697       }
2698   }
2699   do_cleanups (old_cleanups);
2700 }
2701 
2702 /* Implement the "printf" command.  */
2703 
2704 static void
2705 printf_command (char *arg, int from_tty)
2706 {
2707   ui_printf (arg, gdb_stdout);
2708   gdb_flush (gdb_stdout);
2709 }
2710 
2711 /* Implement the "eval" command.  */
2712 
2713 static void
2714 eval_command (char *arg, int from_tty)
2715 {
2716   string_file stb;
2717 
2718   ui_printf (arg, &stb);
2719 
2720   std::string expanded = insert_user_defined_cmd_args (stb.c_str ());
2721 
2722   execute_command (&expanded[0], from_tty);
2723 }
2724 
2725 void
2726 _initialize_printcmd (void)
2727 {
2728   struct cmd_list_element *c;
2729 
2730   current_display_number = -1;
2731 
2732   observer_attach_free_objfile (clear_dangling_display_expressions);
2733 
2734   add_info ("address", address_info,
2735 	    _("Describe where symbol SYM is stored."));
2736 
2737   add_info ("symbol", sym_info, _("\
2738 Describe what symbol is at location ADDR.\n\
2739 Only for symbols with fixed locations (global or static scope)."));
2740 
2741   add_com ("x", class_vars, x_command, _("\
2742 Examine memory: x/FMT ADDRESS.\n\
2743 ADDRESS is an expression for the memory address to examine.\n\
2744 FMT is a repeat count followed by a format letter and a size letter.\n\
2745 Format letters are o(octal), x(hex), d(decimal), u(unsigned decimal),\n\
2746   t(binary), f(float), a(address), i(instruction), c(char), s(string)\n\
2747   and z(hex, zero padded on the left).\n\
2748 Size letters are b(byte), h(halfword), w(word), g(giant, 8 bytes).\n\
2749 The specified number of objects of the specified size are printed\n\
2750 according to the format.  If a negative number is specified, memory is\n\
2751 examined backward from the address.\n\n\
2752 Defaults for format and size letters are those previously used.\n\
2753 Default count is 1.  Default address is following last thing printed\n\
2754 with this command or \"print\"."));
2755 
2756 #if 0
2757   add_com ("whereis", class_vars, whereis_command,
2758 	   _("Print line number and file of definition of variable."));
2759 #endif
2760 
2761   add_info ("display", display_info, _("\
2762 Expressions to display when program stops, with code numbers."));
2763 
2764   add_cmd ("undisplay", class_vars, undisplay_command, _("\
2765 Cancel some expressions to be displayed when program stops.\n\
2766 Arguments are the code numbers of the expressions to stop displaying.\n\
2767 No argument means cancel all automatic-display expressions.\n\
2768 \"delete display\" has the same effect as this command.\n\
2769 Do \"info display\" to see current list of code numbers."),
2770 	   &cmdlist);
2771 
2772   add_com ("display", class_vars, display_command, _("\
2773 Print value of expression EXP each time the program stops.\n\
2774 /FMT may be used before EXP as in the \"print\" command.\n\
2775 /FMT \"i\" or \"s\" or including a size-letter is allowed,\n\
2776 as in the \"x\" command, and then EXP is used to get the address to examine\n\
2777 and examining is done as in the \"x\" command.\n\n\
2778 With no argument, display all currently requested auto-display expressions.\n\
2779 Use \"undisplay\" to cancel display requests previously made."));
2780 
2781   add_cmd ("display", class_vars, enable_display_command, _("\
2782 Enable some expressions to be displayed when program stops.\n\
2783 Arguments are the code numbers of the expressions to resume displaying.\n\
2784 No argument means enable all automatic-display expressions.\n\
2785 Do \"info display\" to see current list of code numbers."), &enablelist);
2786 
2787   add_cmd ("display", class_vars, disable_display_command, _("\
2788 Disable some expressions to be displayed when program stops.\n\
2789 Arguments are the code numbers of the expressions to stop displaying.\n\
2790 No argument means disable all automatic-display expressions.\n\
2791 Do \"info display\" to see current list of code numbers."), &disablelist);
2792 
2793   add_cmd ("display", class_vars, undisplay_command, _("\
2794 Cancel some expressions to be displayed when program stops.\n\
2795 Arguments are the code numbers of the expressions to stop displaying.\n\
2796 No argument means cancel all automatic-display expressions.\n\
2797 Do \"info display\" to see current list of code numbers."), &deletelist);
2798 
2799   add_com ("printf", class_vars, printf_command, _("\
2800 printf \"printf format string\", arg1, arg2, arg3, ..., argn\n\
2801 This is useful for formatted output in user-defined commands."));
2802 
2803   add_com ("output", class_vars, output_command, _("\
2804 Like \"print\" but don't put in value history and don't print newline.\n\
2805 This is useful in user-defined commands."));
2806 
2807   add_prefix_cmd ("set", class_vars, set_command, _("\
2808 Evaluate expression EXP and assign result to variable VAR, using assignment\n\
2809 syntax appropriate for the current language (VAR = EXP or VAR := EXP for\n\
2810 example).  VAR may be a debugger \"convenience\" variable (names starting\n\
2811 with $), a register (a few standard names starting with $), or an actual\n\
2812 variable in the program being debugged.  EXP is any valid expression.\n\
2813 Use \"set variable\" for variables with names identical to set subcommands.\n\
2814 \n\
2815 With a subcommand, this command modifies parts of the gdb environment.\n\
2816 You can see these environment settings with the \"show\" command."),
2817 		  &setlist, "set ", 1, &cmdlist);
2818   if (dbx_commands)
2819     add_com ("assign", class_vars, set_command, _("\
2820 Evaluate expression EXP and assign result to variable VAR, using assignment\n\
2821 syntax appropriate for the current language (VAR = EXP or VAR := EXP for\n\
2822 example).  VAR may be a debugger \"convenience\" variable (names starting\n\
2823 with $), a register (a few standard names starting with $), or an actual\n\
2824 variable in the program being debugged.  EXP is any valid expression.\n\
2825 Use \"set variable\" for variables with names identical to set subcommands.\n\
2826 \nWith a subcommand, this command modifies parts of the gdb environment.\n\
2827 You can see these environment settings with the \"show\" command."));
2828 
2829   /* "call" is the same as "set", but handy for dbx users to call fns.  */
2830   c = add_com ("call", class_vars, call_command, _("\
2831 Call a function in the program.\n\
2832 The argument is the function name and arguments, in the notation of the\n\
2833 current working language.  The result is printed and saved in the value\n\
2834 history, if it is not void."));
2835   set_cmd_completer (c, expression_completer);
2836 
2837   add_cmd ("variable", class_vars, set_command, _("\
2838 Evaluate expression EXP and assign result to variable VAR, using assignment\n\
2839 syntax appropriate for the current language (VAR = EXP or VAR := EXP for\n\
2840 example).  VAR may be a debugger \"convenience\" variable (names starting\n\
2841 with $), a register (a few standard names starting with $), or an actual\n\
2842 variable in the program being debugged.  EXP is any valid expression.\n\
2843 This may usually be abbreviated to simply \"set\"."),
2844 	   &setlist);
2845 
2846   c = add_com ("print", class_vars, print_command, _("\
2847 Print value of expression EXP.\n\
2848 Variables accessible are those of the lexical environment of the selected\n\
2849 stack frame, plus all those whose scope is global or an entire file.\n\
2850 \n\
2851 $NUM gets previous value number NUM.  $ and $$ are the last two values.\n\
2852 $$NUM refers to NUM'th value back from the last one.\n\
2853 Names starting with $ refer to registers (with the values they would have\n\
2854 if the program were to return to the stack frame now selected, restoring\n\
2855 all registers saved by frames farther in) or else to debugger\n\
2856 \"convenience\" variables (any such name not a known register).\n\
2857 Use assignment expressions to give values to convenience variables.\n\
2858 \n\
2859 {TYPE}ADREXP refers to a datum of data type TYPE, located at address ADREXP.\n\
2860 @ is a binary operator for treating consecutive data objects\n\
2861 anywhere in memory as an array.  FOO@NUM gives an array whose first\n\
2862 element is FOO, whose second element is stored in the space following\n\
2863 where FOO is stored, etc.  FOO must be an expression whose value\n\
2864 resides in memory.\n\
2865 \n\
2866 EXP may be preceded with /FMT, where FMT is a format letter\n\
2867 but no count or size letter (see \"x\" command)."));
2868   set_cmd_completer (c, expression_completer);
2869   add_com_alias ("p", "print", class_vars, 1);
2870   add_com_alias ("inspect", "print", class_vars, 1);
2871 
2872   add_setshow_uinteger_cmd ("max-symbolic-offset", no_class,
2873 			    &max_symbolic_offset, _("\
2874 Set the largest offset that will be printed in <symbol+1234> form."), _("\
2875 Show the largest offset that will be printed in <symbol+1234> form."), _("\
2876 Tell GDB to only display the symbolic form of an address if the\n\
2877 offset between the closest earlier symbol and the address is less than\n\
2878 the specified maximum offset.  The default is \"unlimited\", which tells GDB\n\
2879 to always print the symbolic form of an address if any symbol precedes\n\
2880 it.  Zero is equivalent to \"unlimited\"."),
2881 			    NULL,
2882 			    show_max_symbolic_offset,
2883 			    &setprintlist, &showprintlist);
2884   add_setshow_boolean_cmd ("symbol-filename", no_class,
2885 			   &print_symbol_filename, _("\
2886 Set printing of source filename and line number with <symbol>."), _("\
2887 Show printing of source filename and line number with <symbol>."), NULL,
2888 			   NULL,
2889 			   show_print_symbol_filename,
2890 			   &setprintlist, &showprintlist);
2891 
2892   add_com ("eval", no_class, eval_command, _("\
2893 Convert \"printf format string\", arg1, arg2, arg3, ..., argn to\n\
2894 a command line, and call it."));
2895 }
2896