c-valprint.c   [plain text]

/* Support for printing C values for GDB, the GNU debugger.
   Copyright 1986, 1988, 1989, 1991-1997, 2000
   Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "value.h"
#include "demangle.h"
#include "valprint.h"
#include "language.h"
#include "c-lang.h"


/* Print data of type TYPE located at VALADDR (within GDB), which came from
   the inferior at address ADDRESS, onto stdio stream STREAM according to
   FORMAT (a letter or 0 for natural format).  The data at VALADDR is in
   target byte order.

   If the data are a string pointer, returns the number of string characters
   printed.

   If DEREF_REF is nonzero, then dereference references, otherwise just print
   them like pointers.

   The PRETTY parameter controls prettyprinting.  */

int
c_val_print (struct type *type, char *valaddr, int embedded_offset,
	     CORE_ADDR address, struct ui_file *stream, int format,
	     int deref_ref, int recurse, enum val_prettyprint pretty)
{
  register unsigned int i = 0;	/* Number of characters printed */
  unsigned len;
  struct type *elttype;
  unsigned eltlen;
  LONGEST val;
  CORE_ADDR addr;

  CHECK_TYPEDEF (type);
  switch (TYPE_CODE (type))
    {
    case TYPE_CODE_ARRAY:
      elttype = check_typedef (TYPE_TARGET_TYPE (type));
      if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > 0)
	{
	  eltlen = TYPE_LENGTH (elttype);
	  len = TYPE_LENGTH (type) / eltlen;
	  if (prettyprint_arrays)
	    {
	      print_spaces_filtered (2 + 2 * recurse, stream);
	    }
	  /* For an array of chars, print with string syntax.  */
	  if (eltlen == 1 &&
	      ((TYPE_CODE (elttype) == TYPE_CODE_INT)
	       || ((current_language->la_language == language_m2)
		   && (TYPE_CODE (elttype) == TYPE_CODE_CHAR)))
	      && (format == 0 || format == 's'))
	    {
	      /* If requested, look for the first null char and only print
	         elements up to it.  */
	      if (stop_print_at_null)
		{
		  unsigned int temp_len;

		  /* Look for a NULL char. */
		  for (temp_len = 0;
		       (valaddr + embedded_offset)[temp_len]
		       && temp_len < len && temp_len < print_max;
		       temp_len++);
		  len = temp_len;
		}

	      LA_PRINT_STRING (stream, valaddr + embedded_offset, len, eltlen, 0);
	      i = len;
	    }
	  else
	    {
	      fprintf_filtered (stream, "{");
	      /* If this is a virtual function table, print the 0th
	         entry specially, and the rest of the members normally.  */
	      if (cp_is_vtbl_ptr_type (elttype))
		{
		  i = 1;
		  fprintf_filtered (stream, "%d vtable entries", len - 1);
		}
	      else
		{
		  i = 0;
		}
	      val_print_array_elements (type, valaddr + embedded_offset, address, stream,
				     format, deref_ref, recurse, pretty, i);
	      fprintf_filtered (stream, "}");
	    }
	  break;
	}
      /* Array of unspecified length: treat like pointer to first elt.  */
      addr = address;
      goto print_unpacked_pointer;

    case TYPE_CODE_PTR:
      if (format && format != 's')
	{
	  print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
	  break;
	}
      if (vtblprint && cp_is_vtbl_ptr_type (type))
	{
	  /* Print the unmangled name if desired.  */
	  /* Print vtable entry - we only get here if we ARE using
	     -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
	  CORE_ADDR addr
	    = extract_typed_address (valaddr + embedded_offset, type);
	  print_address_demangle (addr, stream, demangle);
	  break;
	}
      elttype = check_typedef (TYPE_TARGET_TYPE (type));
      if (TYPE_CODE (elttype) == TYPE_CODE_METHOD)
	{
	  cp_print_class_method (valaddr + embedded_offset, type, stream);
	}
      else if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
	{
	  cp_print_class_member (valaddr + embedded_offset,
				 TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (type)),
				 stream, "&");
	}
      else
	{
	  addr = unpack_pointer (type, valaddr + embedded_offset);
	print_unpacked_pointer:
	  elttype = check_typedef (TYPE_TARGET_TYPE (type));

	  if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
	    {
	      /* Try to print what function it points to.  */
	      print_address_demangle (addr, stream, demangle);
	      /* Return value is irrelevant except for string pointers.  */
	      return (0);
	    }

	  if (addressprint && format != 's')
	    {
	      print_address_numeric (addr, 1, stream);
	    }

	  /* For a pointer to char or unsigned char, also print the string
	     pointed to, unless pointer is null.  */
	  /* FIXME: need to handle wchar_t here... */

	  if (TYPE_LENGTH (elttype) == 1
	      && TYPE_CODE (elttype) == TYPE_CODE_INT
	      && (format == 0 || format == 's')
	      && addr != 0)
	    {
	      i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
	    }
	  else if (cp_is_vtbl_member (type))
	    {
	      /* print vtbl's nicely */
	      CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);

	      struct minimal_symbol *msymbol =
	      lookup_minimal_symbol_by_pc (vt_address);
	      if ((msymbol != NULL) &&
		  (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
		{
		  fputs_filtered (" <", stream);
		  fputs_filtered (SYMBOL_SOURCE_NAME (msymbol), stream);
		  fputs_filtered (">", stream);
		}
	      if (vt_address && vtblprint)
		{
		  value_ptr vt_val;
		  struct symbol *wsym = (struct symbol *) NULL;
		  struct type *wtype;
		  struct symtab *s;
		  struct block *block = (struct block *) NULL;
		  int is_this_fld;

		  if (msymbol != NULL)
		    wsym = lookup_symbol (SYMBOL_NAME (msymbol), block,
					  VAR_NAMESPACE, &is_this_fld, &s);

		  if (wsym)
		    {
		      wtype = SYMBOL_TYPE (wsym);
		    }
		  else
		    {
		      wtype = TYPE_TARGET_TYPE (type);
		    }
		  vt_val = value_at (wtype, vt_address, NULL);
		  val_print (VALUE_TYPE (vt_val), VALUE_CONTENTS (vt_val), 0,
			     VALUE_ADDRESS (vt_val), stream, format,
			     deref_ref, recurse + 1, pretty);
		  if (pretty)
		    {
		      fprintf_filtered (stream, "\n");
		      print_spaces_filtered (2 + 2 * recurse, stream);
		    }
		}
	    }

	  /* Return number of characters printed, including the terminating
	     '\0' if we reached the end.  val_print_string takes care including
	     the terminating '\0' if necessary.  */
	  return i;
	}
      break;

    case TYPE_CODE_MEMBER:
      error ("not implemented: member type in c_val_print");
      break;

    case TYPE_CODE_REF:
      elttype = check_typedef (TYPE_TARGET_TYPE (type));
      if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
	{
	  cp_print_class_member (valaddr + embedded_offset,
				 TYPE_DOMAIN_TYPE (elttype),
				 stream, "");
	  break;
	}
      if (addressprint)
	{
	  CORE_ADDR addr
	    = extract_typed_address (valaddr + embedded_offset, type);
	  fprintf_filtered (stream, "@");
	  print_address_numeric (addr, 1, stream);
	  if (deref_ref)
	    fputs_filtered (": ", stream);
	}
      /* De-reference the reference.  */
      if (deref_ref)
	{
	  if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
	    {
	      value_ptr deref_val =
	      value_at
	      (TYPE_TARGET_TYPE (type),
	       unpack_pointer (lookup_pointer_type (builtin_type_void),
			       valaddr + embedded_offset),
	       NULL);
	      val_print (VALUE_TYPE (deref_val),
			 VALUE_CONTENTS (deref_val),
			 0,
			 VALUE_ADDRESS (deref_val),
			 stream,
			 format,
			 deref_ref,
			 recurse,
			 pretty);
	    }
	  else
	    fputs_filtered ("???", stream);
	}
      break;

    case TYPE_CODE_UNION:
      if (recurse && !unionprint)
	{
	  fprintf_filtered (stream, "{...}");
	  break;
	}
      /* Fall through.  */
    case TYPE_CODE_STRUCT:
      if (vtblprint && cp_is_vtbl_ptr_type (type))
	{
	  /* Print the unmangled name if desired.  */
	  /* Print vtable entry - we only get here if NOT using
	     -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
	  int offset = (embedded_offset +
			TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
	  struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
	  CORE_ADDR addr
	    = extract_typed_address (valaddr + offset, field_type);

	  print_address_demangle (addr, stream, demangle);
	}
      else
	cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
			       recurse, pretty, NULL, 0);
      break;

    case TYPE_CODE_ENUM:
      if (format)
	{
	  print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
	  break;
	}
      len = TYPE_NFIELDS (type);
      val = unpack_long (type, valaddr + embedded_offset);
      for (i = 0; i < len; i++)
	{
	  QUIT;
	  if ((int) val == TYPE_FIELD_BITPOS (type, i))
	    break;
	}
      if (i < len)
	{
	  fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
	}
      else
	{
	  print_longest (stream, 'd', 0, val);
	}
      break;

    case TYPE_CODE_FUNC:
      if (format)
	{
	  print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
	  break;
	}
      /* FIXME, we should consider, at least for ANSI C language, eliminating
         the distinction made between FUNCs and POINTERs to FUNCs.  */
      fprintf_filtered (stream, "{");
      type_print (type, "", stream, -1);
      fprintf_filtered (stream, "} ");
      /* Try to print what function it points to, and its address.  */
      print_address_demangle (address, stream, demangle);
      break;

    case TYPE_CODE_BOOL:
      format = format ? format : output_format;
      if (format)
	print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
      else
	{
	  val = unpack_long (type, valaddr + embedded_offset);
	  if (val == 0)
	    fputs_filtered ("false", stream);
	  else if (val == 1)
	    fputs_filtered ("true", stream);
	  else
	    print_longest (stream, 'd', 0, val);
	}
      break;

    case TYPE_CODE_RANGE:
      /* FIXME: create_range_type does not set the unsigned bit in a
         range type (I think it probably should copy it from the target
         type), so we won't print values which are too large to
         fit in a signed integer correctly.  */
      /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
         print with the target type, though, because the size of our type
         and the target type might differ).  */
      /* FALLTHROUGH */

    case TYPE_CODE_INT:
      format = format ? format : output_format;
      if (format)
	{
	  print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
	}
      else
	{
	  val_print_type_code_int (type, valaddr + embedded_offset, stream);
	  /* C and C++ has no single byte int type, char is used instead.
	     Since we don't know whether the value is really intended to
	     be used as an integer or a character, print the character
	     equivalent as well. */
	  if (TYPE_LENGTH (type) == 1)
	    {
	      fputs_filtered (" ", stream);
	      LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
			     stream);
	    }
	}
      break;

    case TYPE_CODE_CHAR:
      format = format ? format : output_format;
      if (format)
	{
	  print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
	}
      else
	{
	  val = unpack_long (type, valaddr + embedded_offset);
	  if (TYPE_UNSIGNED (type))
	    fprintf_filtered (stream, "%u", (unsigned int) val);
	  else
	    fprintf_filtered (stream, "%d", (int) val);
	  fputs_filtered (" ", stream);
	  LA_PRINT_CHAR ((unsigned char) val, stream);
	}
      break;

    case TYPE_CODE_FLT:
      if (format)
	{
	  print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
	}
      else
	{
	  print_floating (valaddr + embedded_offset, type, stream);
	}
      break;

    case TYPE_CODE_METHOD:
      cp_print_class_method (valaddr + embedded_offset, lookup_pointer_type (type), stream);
      break;

    case TYPE_CODE_VOID:
      fprintf_filtered (stream, "void");
      break;

    case TYPE_CODE_ERROR:
      fprintf_filtered (stream, "<unknown type>");
      break;

    case TYPE_CODE_UNDEF:
      /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
         dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
         and no complete type for struct foo in that file.  */
      fprintf_filtered (stream, "<incomplete type>");
      break;

    default:
      error ("Invalid C/C++ type code %d in symbol table.", TYPE_CODE (type));
    }
  gdb_flush (stream);
  return (0);
}

int
c_value_print (value_ptr val, struct ui_file *stream, int format,
	       enum val_prettyprint pretty)
{
  struct type *type = VALUE_TYPE (val);
  struct type *real_type;
  int full, top, using_enc;

  /* If it is a pointer, indicate what it points to.

     Print type also if it is a reference.

     C++: if it is a member pointer, we will take care
     of that when we print it.  */
  if (TYPE_CODE (type) == TYPE_CODE_PTR ||
      TYPE_CODE (type) == TYPE_CODE_REF)
    {
      /* Hack:  remove (char *) for char strings.  Their
         type is indicated by the quoted string anyway. */
      if (TYPE_CODE (type) == TYPE_CODE_PTR &&
	  TYPE_NAME (type) == NULL &&
	  TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL &&
	  STREQ (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char"))
	{
	  /* Print nothing */
	}
      else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
	{

	  if (TYPE_CODE(type) == TYPE_CODE_REF)
	    {
	      /* Copy value, change to pointer, so we don't get an
	       * error about a non-pointer type in value_rtti_target_type
	       */
	      value_ptr temparg;
	      temparg=value_copy(val);
	      VALUE_TYPE (temparg) = lookup_pointer_type(TYPE_TARGET_TYPE(type));
	      val=temparg;
	    }
	  /* Pointer to class, check real type of object */
	  fprintf_filtered (stream, "(");
          real_type = value_rtti_target_type (val, &full, &top, &using_enc);
          if (real_type)
	    {
	      /* RTTI entry found */
              if (TYPE_CODE (type) == TYPE_CODE_PTR)
                {
                  /* create a pointer type pointing to the real type */
                  type = lookup_pointer_type (real_type);
                }
              else
                {
                  /* create a reference type referencing the real type */
                  type = lookup_reference_type (real_type);
                }
	      /* JYG: Need to adjust pointer value. */
              val->aligner.contents[0] -= top;

              /* Note: When we look up RTTI entries, we don't get any 
                 information on const or volatile attributes */
            }
          type_print (type, "", stream, -1);
	  fprintf_filtered (stream, ") ");
	}
      else
	{
	  /* normal case */
	  fprintf_filtered (stream, "(");
	  type_print (type, "", stream, -1);
	  fprintf_filtered (stream, ") ");
	}
    }
  if (objectprint && (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_CLASS))
    {
      /* Attempt to determine real type of object */
      real_type = value_rtti_type (val, &full, &top, &using_enc);
      if (real_type)
	{
	  /* We have RTTI information, so use it */
	  val = value_full_object (val, real_type, full, top, using_enc);
	  fprintf_filtered (stream, "(%s%s) ",
			    TYPE_NAME (real_type),
			    full ? "" : " [incomplete object]");
	  /* Print out object: enclosing type is same as real_type if full */
	  return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
			 VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
          /* Note: When we look up RTTI entries, we don't get any information on
             const or volatile attributes */
	}
      else if (type != VALUE_ENCLOSING_TYPE (val))
	{
	  /* No RTTI information, so let's do our best */
	  fprintf_filtered (stream, "(%s ?) ",
			    TYPE_NAME (VALUE_ENCLOSING_TYPE (val)));
	  return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
			 VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
	}
      /* Otherwise, we end up at the return outside this "if" */
    }

  return val_print (type, VALUE_CONTENTS_ALL (val), VALUE_EMBEDDED_OFFSET (val),
		    VALUE_ADDRESS (val),
		    stream, format, 1, 0, pretty);
}