[deliverable/binutils-gdb.git] / gdb / expprint.c

/* Print in infix form a struct expression.

   Copyright (C) 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   1998, 1999, 2000, 2003, 2007, 2008, 2009, 2010, 2011
   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "expression.h"
#include "value.h"
#include "language.h"
#include "parser-defs.h"
#include "user-regs.h"		/* For user_reg_map_regnum_to_name.  */
#include "target.h"
#include "gdb_string.h"
#include "block.h"
#include "objfiles.h"
#include "gdb_assert.h"
#include "valprint.h"

#ifdef HAVE_CTYPE_H
#include <ctype.h>
#endif

void
print_expression (struct expression *exp, struct ui_file *stream)
{
  int pc = 0;

  print_subexp (exp, &pc, stream, PREC_NULL);
}

/* Print the subexpression of EXP that starts in position POS, on STREAM.
   PREC is the precedence of the surrounding operator;
   if the precedence of the main operator of this subexpression is less,
   parentheses are needed here.  */

void
print_subexp (struct expression *exp, int *pos,
	      struct ui_file *stream, enum precedence prec)
{
  exp->language_defn->la_exp_desc->print_subexp (exp, pos, stream, prec);
}

/* Standard implementation of print_subexp for use in language_defn
   vectors.  */
void
print_subexp_standard (struct expression *exp, int *pos,
		       struct ui_file *stream, enum precedence prec)
{
  unsigned tem;
  const struct op_print *op_print_tab;
  int pc;
  unsigned nargs;
  char *op_str;
  int assign_modify = 0;
  enum exp_opcode opcode;
  enum precedence myprec = PREC_NULL;
  /* Set to 1 for a right-associative operator.  */
  int assoc = 0;
  struct value *val;
  char *tempstr = NULL;

  op_print_tab = exp->language_defn->la_op_print_tab;
  pc = (*pos)++;
  opcode = exp->elts[pc].opcode;
  switch (opcode)
    {
      /* Common ops */

    case OP_SCOPE:
      myprec = PREC_PREFIX;
      assoc = 0;
      fputs_filtered (type_name_no_tag (exp->elts[pc + 1].type), stream);
      fputs_filtered ("::", stream);
      nargs = longest_to_int (exp->elts[pc + 2].longconst);
      (*pos) += 4 + BYTES_TO_EXP_ELEM (nargs + 1);
      fputs_filtered (&exp->elts[pc + 3].string, stream);
      return;

    case OP_LONG:
      {
	struct value_print_options opts;

	get_raw_print_options (&opts);
	(*pos) += 3;
	value_print (value_from_longest (exp->elts[pc + 1].type,
					 exp->elts[pc + 2].longconst),
		     stream, &opts);
      }
      return;

    case OP_DOUBLE:
      {
	struct value_print_options opts;

	get_raw_print_options (&opts);
	(*pos) += 3;
	value_print (value_from_double (exp->elts[pc + 1].type,
					exp->elts[pc + 2].doubleconst),
		     stream, &opts);
      }
      return;

    case OP_VAR_VALUE:
      {
	struct block *b;

	(*pos) += 3;
	b = exp->elts[pc + 1].block;
	if (b != NULL
	    && BLOCK_FUNCTION (b) != NULL
	    && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)) != NULL)
	  {
	    fputs_filtered (SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)), stream);
	    fputs_filtered ("::", stream);
	  }
	fputs_filtered (SYMBOL_PRINT_NAME (exp->elts[pc + 2].symbol), stream);
      }
      return;

    case OP_LAST:
      (*pos) += 2;
      fprintf_filtered (stream, "$%d",
			longest_to_int (exp->elts[pc + 1].longconst));
      return;

    case OP_REGISTER:
      {
	const char *name = &exp->elts[pc + 2].string;

	(*pos) += 3 + BYTES_TO_EXP_ELEM (exp->elts[pc + 1].longconst + 1);
	fprintf_filtered (stream, "$%s", name);
	return;
      }

    case OP_BOOL:
      (*pos) += 2;
      fprintf_filtered (stream, "%s",
			longest_to_int (exp->elts[pc + 1].longconst)
			? "TRUE" : "FALSE");
      return;

    case OP_INTERNALVAR:
      (*pos) += 2;
      fprintf_filtered (stream, "$%s",
			internalvar_name (exp->elts[pc + 1].internalvar));
      return;

    case OP_FUNCALL:
      (*pos) += 2;
      nargs = longest_to_int (exp->elts[pc + 1].longconst);
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered (" (", stream);
      for (tem = 0; tem < nargs; tem++)
	{
	  if (tem != 0)
	    fputs_filtered (", ", stream);
	  print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
	}
      fputs_filtered (")", stream);
      return;

    case OP_NAME:
      nargs = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (nargs + 1);
      fputs_filtered (&exp->elts[pc + 2].string, stream);
      return;

    case OP_STRING:
      {
	struct value_print_options opts;

	nargs = longest_to_int (exp->elts[pc + 1].longconst);
	(*pos) += 3 + BYTES_TO_EXP_ELEM (nargs + 1);
	/* LA_PRINT_STRING will print using the current repeat count threshold.
	   If necessary, we can temporarily set it to zero, or pass it as an
	   additional parameter to LA_PRINT_STRING.  -fnf */
	get_user_print_options (&opts);
	LA_PRINT_STRING (stream, builtin_type (exp->gdbarch)->builtin_char,
			 &exp->elts[pc + 2].string, nargs, NULL, 0, &opts);
      }
      return;

    case OP_BITSTRING:
      nargs = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos)
	+= 3 + BYTES_TO_EXP_ELEM ((nargs + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT);
      fprintf_unfiltered (stream, "B'<unimplemented>'");
      return;

    case OP_OBJC_NSSTRING:	/* Objective-C Foundation Class
				   NSString constant.  */
      {
	struct value_print_options opts;

	nargs = longest_to_int (exp->elts[pc + 1].longconst);
	(*pos) += 3 + BYTES_TO_EXP_ELEM (nargs + 1);
	fputs_filtered ("@\"", stream);
	get_user_print_options (&opts);
	LA_PRINT_STRING (stream, builtin_type (exp->gdbarch)->builtin_char,
			 &exp->elts[pc + 2].string, nargs, NULL, 0, &opts);
	fputs_filtered ("\"", stream);
      }
      return;

    case OP_OBJC_MSGCALL:
      {			/* Objective C message (method) call.  */
	char *selector;

	(*pos) += 3;
	nargs = longest_to_int (exp->elts[pc + 2].longconst);
	fprintf_unfiltered (stream, "[");
	print_subexp (exp, pos, stream, PREC_SUFFIX);
	if (0 == target_read_string (exp->elts[pc + 1].longconst,
				     &selector, 1024, NULL))
	  {
	    error (_("bad selector"));
	    return;
	  }
	if (nargs)
	  {
	    char *s, *nextS;

	    s = alloca (strlen (selector) + 1);
	    strcpy (s, selector);
	    for (tem = 0; tem < nargs; tem++)
	      {
		nextS = strchr (s, ':');
		gdb_assert (nextS);	/* Make sure we found ':'.  */
		*nextS = '\0';
		fprintf_unfiltered (stream, " %s: ", s);
		s = nextS + 1;
		print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
	      }
	  }
	else
	  {
	    fprintf_unfiltered (stream, " %s", selector);
	  }
	fprintf_unfiltered (stream, "]");
	/* "selector" was malloc'd by target_read_string.  Free it.  */
	xfree (selector);
	return;
      }

    case OP_ARRAY:
      (*pos) += 3;
      nargs = longest_to_int (exp->elts[pc + 2].longconst);
      nargs -= longest_to_int (exp->elts[pc + 1].longconst);
      nargs++;
      tem = 0;
      if (exp->elts[pc + 4].opcode == OP_LONG
	  && exp->elts[pc + 5].type
	     == builtin_type (exp->gdbarch)->builtin_char
	  && exp->language_defn->la_language == language_c)
	{
	  /* Attempt to print C character arrays using string syntax.
	     Walk through the args, picking up one character from each
	     of the OP_LONG expression elements.  If any array element
	     does not match our expection of what we should find for
	     a simple string, revert back to array printing.  Note that
	     the last expression element is an explicit null terminator
	     byte, which doesn't get printed.  */
	  tempstr = alloca (nargs);
	  pc += 4;
	  while (tem < nargs)
	    {
	      if (exp->elts[pc].opcode != OP_LONG
		  || exp->elts[pc + 1].type
		     != builtin_type (exp->gdbarch)->builtin_char)
		{
		  /* Not a simple array of char, use regular array
		     printing.  */
		  tem = 0;
		  break;
		}
	      else
		{
		  tempstr[tem++] =
		    longest_to_int (exp->elts[pc + 2].longconst);
		  pc += 4;
		}
	    }
	}
      if (tem > 0)
	{
	  struct value_print_options opts;

	  get_user_print_options (&opts);
	  LA_PRINT_STRING (stream, builtin_type (exp->gdbarch)->builtin_char,
			   tempstr, nargs - 1, NULL, 0, &opts);
	  (*pos) = pc;
	}
      else
	{
	  fputs_filtered (" {", stream);
	  for (tem = 0; tem < nargs; tem++)
	    {
	      if (tem != 0)
		{
		  fputs_filtered (", ", stream);
		}
	      print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
	    }
	  fputs_filtered ("}", stream);
	}
      return;

    case OP_LABELED:
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      /* Gcc support both these syntaxes.  Unsure which is preferred.  */
#if 1
      fputs_filtered (&exp->elts[pc + 2].string, stream);
      fputs_filtered (": ", stream);
#else
      fputs_filtered (".", stream);
      fputs_filtered (&exp->elts[pc + 2].string, stream);
      fputs_filtered ("=", stream);
#endif
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      return;

    case TERNOP_COND:
      if ((int) prec > (int) PREC_COMMA)
	fputs_filtered ("(", stream);
      /* Print the subexpressions, forcing parentheses
         around any binary operations within them.
         This is more parentheses than are strictly necessary,
         but it looks clearer.  */
      print_subexp (exp, pos, stream, PREC_HYPER);
      fputs_filtered (" ? ", stream);
      print_subexp (exp, pos, stream, PREC_HYPER);
      fputs_filtered (" : ", stream);
      print_subexp (exp, pos, stream, PREC_HYPER);
      if ((int) prec > (int) PREC_COMMA)
	fputs_filtered (")", stream);
      return;

    case TERNOP_SLICE:
    case TERNOP_SLICE_COUNT:
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered ("(", stream);
      print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
      fputs_filtered (opcode == TERNOP_SLICE ? " : " : " UP ", stream);
      print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
      fputs_filtered (")", stream);
      return;

    case STRUCTOP_STRUCT:
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered (".", stream);
      fputs_filtered (&exp->elts[pc + 2].string, stream);
      return;

      /* Will not occur for Modula-2.  */
    case STRUCTOP_PTR:
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered ("->", stream);
      fputs_filtered (&exp->elts[pc + 2].string, stream);
      return;

    case STRUCTOP_MEMBER:
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered (".*", stream);
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      return;

    case STRUCTOP_MPTR:
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered ("->*", stream);
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      return;

    case BINOP_SUBSCRIPT:
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered ("[", stream);
      print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
      fputs_filtered ("]", stream);
      return;

    case UNOP_POSTINCREMENT:
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered ("++", stream);
      return;

    case UNOP_POSTDECREMENT:
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fputs_filtered ("--", stream);
      return;

    case UNOP_CAST:
      (*pos) += 2;
      if ((int) prec > (int) PREC_PREFIX)
	fputs_filtered ("(", stream);
      fputs_filtered ("(", stream);
      type_print (exp->elts[pc + 1].type, "", stream, 0);
      fputs_filtered (") ", stream);
      print_subexp (exp, pos, stream, PREC_PREFIX);
      if ((int) prec > (int) PREC_PREFIX)
	fputs_filtered (")", stream);
      return;

    case UNOP_DYNAMIC_CAST:
    case UNOP_REINTERPRET_CAST:
      fputs_filtered (opcode == UNOP_DYNAMIC_CAST ? "dynamic_cast"
		      : "reinterpret_cast", stream);
      fputs_filtered ("<", stream);
      (*pos) += 2;
      type_print (exp->elts[pc + 1].type, "", stream, 0);
      fputs_filtered ("> (", stream);
      print_subexp (exp, pos, stream, PREC_PREFIX);
      fputs_filtered (")", stream);
      return;

    case UNOP_MEMVAL:
      (*pos) += 2;
      if ((int) prec > (int) PREC_PREFIX)
	fputs_filtered ("(", stream);
      if (TYPE_CODE (exp->elts[pc + 1].type) == TYPE_CODE_FUNC
	  && exp->elts[pc + 3].opcode == OP_LONG)
	{
	  struct value_print_options opts;

	  /* We have a minimal symbol fn, probably.  It's encoded
	     as a UNOP_MEMVAL (function-type) of an OP_LONG (int, address).
	     Swallow the OP_LONG (including both its opcodes); ignore
	     its type; print the value in the type of the MEMVAL.  */
	  (*pos) += 4;
	  val = value_at_lazy (exp->elts[pc + 1].type,
			       (CORE_ADDR) exp->elts[pc + 5].longconst);
	  get_raw_print_options (&opts);
	  value_print (val, stream, &opts);
	}
      else
	{
	  fputs_filtered ("{", stream);
	  type_print (exp->elts[pc + 1].type, "", stream, 0);
	  fputs_filtered ("} ", stream);
	  print_subexp (exp, pos, stream, PREC_PREFIX);
	}
      if ((int) prec > (int) PREC_PREFIX)
	fputs_filtered (")", stream);
      return;

    case UNOP_MEMVAL_TLS:
      (*pos) += 3;
      if ((int) prec > (int) PREC_PREFIX)
	fputs_filtered ("(", stream);
      fputs_filtered ("{", stream);
      type_print (exp->elts[pc + 2].type, "", stream, 0);
      fputs_filtered ("} ", stream);
      print_subexp (exp, pos, stream, PREC_PREFIX);
      if ((int) prec > (int) PREC_PREFIX)
	fputs_filtered (")", stream);
      return;

    case BINOP_ASSIGN_MODIFY:
      opcode = exp->elts[pc + 1].opcode;
      (*pos) += 2;
      myprec = PREC_ASSIGN;
      assoc = 1;
      assign_modify = 1;
      op_str = "???";
      for (tem = 0; op_print_tab[tem].opcode != OP_NULL; tem++)
	if (op_print_tab[tem].opcode == opcode)
	  {
	    op_str = op_print_tab[tem].string;
	    break;
	  }
      if (op_print_tab[tem].opcode != opcode)
	/* Not found; don't try to keep going because we don't know how
	   to interpret further elements.  */
	error (_("Invalid expression"));
      break;

      /* C++ ops */

    case OP_THIS:
      ++(*pos);
      if (exp->language_defn->la_name_of_this)
	fputs_filtered (exp->language_defn->la_name_of_this, stream);
      else
	fprintf_filtered (stream, _("<language %s has no 'this'>"),
			  exp->language_defn->la_name);
      return;

      /* Modula-2 ops */

    case MULTI_SUBSCRIPT:
      (*pos) += 2;
      nargs = longest_to_int (exp->elts[pc + 1].longconst);
      print_subexp (exp, pos, stream, PREC_SUFFIX);
      fprintf_unfiltered (stream, " [");
      for (tem = 0; tem < nargs; tem++)
	{
	  if (tem != 0)
	    fprintf_unfiltered (stream, ", ");
	  print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
	}
      fprintf_unfiltered (stream, "]");
      return;

    case BINOP_VAL:
      (*pos) += 2;
      fprintf_unfiltered (stream, "VAL(");
      type_print (exp->elts[pc + 1].type, "", stream, 0);
      fprintf_unfiltered (stream, ",");
      print_subexp (exp, pos, stream, PREC_PREFIX);
      fprintf_unfiltered (stream, ")");
      return;

    case TYPE_INSTANCE:
      {
	LONGEST count = exp->elts[pc + 1].longconst;

	/* The COUNT.  */
	(*pos)++;
	fputs_unfiltered ("TypesInstance(", stream);
	while (count-- > 0)
	  {
	    type_print (exp->elts[(*pos)++].type, "", stream, 0);
	    if (count > 0)
	      fputs_unfiltered (",", stream);
	  }
	fputs_unfiltered (",", stream);
	/* Ending COUNT and ending TYPE_INSTANCE.  */
	(*pos) += 2;
	print_subexp (exp, pos, stream, PREC_PREFIX);
	fputs_unfiltered (")", stream);
	return;
      }

      /* Default ops */

    default:
      op_str = "???";
      for (tem = 0; op_print_tab[tem].opcode != OP_NULL; tem++)
	if (op_print_tab[tem].opcode == opcode)
	  {
	    op_str = op_print_tab[tem].string;
	    myprec = op_print_tab[tem].precedence;
	    assoc = op_print_tab[tem].right_assoc;
	    break;
	  }
      if (op_print_tab[tem].opcode != opcode)
	/* Not found; don't try to keep going because we don't know how
	   to interpret further elements.  For example, this happens
	   if opcode is OP_TYPE.  */
	error (_("Invalid expression"));
    }

  /* Note that PREC_BUILTIN will always emit parentheses.  */
  if ((int) myprec < (int) prec)
    fputs_filtered ("(", stream);
  if ((int) opcode > (int) BINOP_END)
    {
      if (assoc)
	{
	  /* Unary postfix operator.  */
	  print_subexp (exp, pos, stream, PREC_SUFFIX);
	  fputs_filtered (op_str, stream);
	}
      else
	{
	  /* Unary prefix operator.  */
	  fputs_filtered (op_str, stream);
	  if (myprec == PREC_BUILTIN_FUNCTION)
	    fputs_filtered ("(", stream);
	  print_subexp (exp, pos, stream, PREC_PREFIX);
	  if (myprec == PREC_BUILTIN_FUNCTION)
	    fputs_filtered (")", stream);
	}
    }
  else
    {
      /* Binary operator.  */
      /* Print left operand.
         If operator is right-associative,
         increment precedence for this operand.  */
      print_subexp (exp, pos, stream,
		    (enum precedence) ((int) myprec + assoc));
      /* Print the operator itself.  */
      if (assign_modify)
	fprintf_filtered (stream, " %s= ", op_str);
      else if (op_str[0] == ',')
	fprintf_filtered (stream, "%s ", op_str);
      else
	fprintf_filtered (stream, " %s ", op_str);
      /* Print right operand.
         If operator is left-associative,
         increment precedence for this operand.  */
      print_subexp (exp, pos, stream,
		    (enum precedence) ((int) myprec + !assoc));
    }

  if ((int) myprec < (int) prec)
    fputs_filtered (")", stream);
}

/* Return the operator corresponding to opcode OP as
   a string.   NULL indicates that the opcode was not found in the
   current language table.  */
char *
op_string (enum exp_opcode op)
{
  int tem;
  const struct op_print *op_print_tab;

  op_print_tab = current_language->la_op_print_tab;
  for (tem = 0; op_print_tab[tem].opcode != OP_NULL; tem++)
    if (op_print_tab[tem].opcode == op)
      return op_print_tab[tem].string;
  return NULL;
}

/* Support for dumping the raw data from expressions in a human readable
   form.  */

static char *op_name (struct expression *, enum exp_opcode);
static int dump_subexp_body (struct expression *exp, struct ui_file *, int);

/* Name for OPCODE, when it appears in expression EXP.  */

static char *
op_name (struct expression *exp, enum exp_opcode opcode)
{
  return exp->language_defn->la_exp_desc->op_name (opcode);
}

/* Default name for the standard operator OPCODE (i.e., one defined in
   the definition of enum exp_opcode).  */

char *
op_name_standard (enum exp_opcode opcode)
{
  switch (opcode)
    {
    default:
      {
	static char buf[30];

	sprintf (buf, "<unknown %d>", opcode);
	return buf;
      }
#define OP(name)	\
    case name:		\
      return #name ;
#include "std-operator.def"
#undef OP
    }
}

/* Print a raw dump of expression EXP to STREAM.
   NOTE, if non-NULL, is printed as extra explanatory text.  */

void
dump_raw_expression (struct expression *exp, struct ui_file *stream,
		     char *note)
{
  int elt;
  char *opcode_name;
  char *eltscan;
  int eltsize;

  fprintf_filtered (stream, "Dump of expression @ ");
  gdb_print_host_address (exp, stream);
  if (note)
    fprintf_filtered (stream, ", %s:", note);
  fprintf_filtered (stream, "\n\tLanguage %s, %d elements, %ld bytes each.\n",
		    exp->language_defn->la_name, exp->nelts,
		    (long) sizeof (union exp_element));
  fprintf_filtered (stream, "\t%5s  %20s  %16s  %s\n", "Index", "Opcode",
		    "Hex Value", "String Value");
  for (elt = 0; elt < exp->nelts; elt++)
    {
      fprintf_filtered (stream, "\t%5d  ", elt);
      opcode_name = op_name (exp, exp->elts[elt].opcode);

      fprintf_filtered (stream, "%20s  ", opcode_name);
      print_longest (stream, 'd', 0, exp->elts[elt].longconst);
      fprintf_filtered (stream, "  ");

      for (eltscan = (char *) &exp->elts[elt],
	   eltsize = sizeof (union exp_element);
	   eltsize-- > 0;
	   eltscan++)
	{
	  fprintf_filtered (stream, "%c",
			    isprint (*eltscan) ? (*eltscan & 0xFF) : '.');
	}
      fprintf_filtered (stream, "\n");
    }
}

/* Dump the subexpression of prefix expression EXP whose operator is at
   position ELT onto STREAM.  Returns the position of the next 
   subexpression in EXP.  */

int
dump_subexp (struct expression *exp, struct ui_file *stream, int elt)
{
  static int indent = 0;
  int i;

  fprintf_filtered (stream, "\n");
  fprintf_filtered (stream, "\t%5d  ", elt);

  for (i = 1; i <= indent; i++)
    fprintf_filtered (stream, " ");
  indent += 2;

  fprintf_filtered (stream, "%-20s  ", op_name (exp, exp->elts[elt].opcode));

  elt = dump_subexp_body (exp, stream, elt);

  indent -= 2;

  return elt;
}

/* Dump the operands of prefix expression EXP whose opcode is at
   position ELT onto STREAM.  Returns the position of the next 
   subexpression in EXP.  */

static int
dump_subexp_body (struct expression *exp, struct ui_file *stream, int elt)
{
  return exp->language_defn->la_exp_desc->dump_subexp_body (exp, stream, elt);
}

/* Default value for subexp_body in exp_descriptor vector.  */

int
dump_subexp_body_standard (struct expression *exp, 
			   struct ui_file *stream, int elt)
{
  int opcode = exp->elts[elt++].opcode;

  switch (opcode)
    {
    case TERNOP_COND:
    case TERNOP_SLICE:
    case TERNOP_SLICE_COUNT:
      elt = dump_subexp (exp, stream, elt);
      /* FALL THROUGH */
    case BINOP_ADD:
    case BINOP_SUB:
    case BINOP_MUL:
    case BINOP_DIV:
    case BINOP_REM:
    case BINOP_MOD:
    case BINOP_LSH:
    case BINOP_RSH:
    case BINOP_LOGICAL_AND:
    case BINOP_LOGICAL_OR:
    case BINOP_BITWISE_AND:
    case BINOP_BITWISE_IOR:
    case BINOP_BITWISE_XOR:
    case BINOP_EQUAL:
    case BINOP_NOTEQUAL:
    case BINOP_LESS:
    case BINOP_GTR:
    case BINOP_LEQ:
    case BINOP_GEQ:
    case BINOP_REPEAT:
    case BINOP_ASSIGN:
    case BINOP_COMMA:
    case BINOP_SUBSCRIPT:
    case BINOP_EXP:
    case BINOP_MIN:
    case BINOP_MAX:
    case BINOP_INTDIV:
    case BINOP_ASSIGN_MODIFY:
    case BINOP_VAL:
    case BINOP_CONCAT:
    case BINOP_IN:
    case BINOP_RANGE:
    case BINOP_END:
    case STRUCTOP_MEMBER:
    case STRUCTOP_MPTR:
      elt = dump_subexp (exp, stream, elt);
      /* FALL THROUGH */
    case UNOP_NEG:
    case UNOP_LOGICAL_NOT:
    case UNOP_COMPLEMENT:
    case UNOP_IND:
    case UNOP_ADDR:
    case UNOP_PREINCREMENT:
    case UNOP_POSTINCREMENT:
    case UNOP_PREDECREMENT:
    case UNOP_POSTDECREMENT:
    case UNOP_SIZEOF:
    case UNOP_PLUS:
    case UNOP_CAP:
    case UNOP_CHR:
    case UNOP_ORD:
    case UNOP_ABS:
    case UNOP_FLOAT:
    case UNOP_HIGH:
    case UNOP_MAX:
    case UNOP_MIN:
    case UNOP_ODD:
    case UNOP_TRUNC:
      elt = dump_subexp (exp, stream, elt);
      break;
    case OP_LONG:
      fprintf_filtered (stream, "Type @");
      gdb_print_host_address (exp->elts[elt].type, stream);
      fprintf_filtered (stream, " (");
      type_print (exp->elts[elt].type, NULL, stream, 0);
      fprintf_filtered (stream, "), value %ld (0x%lx)",
			(long) exp->elts[elt + 1].longconst,
			(long) exp->elts[elt + 1].longconst);
      elt += 3;
      break;
    case OP_DOUBLE:
      fprintf_filtered (stream, "Type @");
      gdb_print_host_address (exp->elts[elt].type, stream);
      fprintf_filtered (stream, " (");
      type_print (exp->elts[elt].type, NULL, stream, 0);
      fprintf_filtered (stream, "), value %g",
			(double) exp->elts[elt + 1].doubleconst);
      elt += 3;
      break;
    case OP_VAR_VALUE:
      fprintf_filtered (stream, "Block @");
      gdb_print_host_address (exp->elts[elt].block, stream);
      fprintf_filtered (stream, ", symbol @");
      gdb_print_host_address (exp->elts[elt + 1].symbol, stream);
      fprintf_filtered (stream, " (%s)",
			SYMBOL_PRINT_NAME (exp->elts[elt + 1].symbol));
      elt += 3;
      break;
    case OP_LAST:
      fprintf_filtered (stream, "History element %ld",
			(long) exp->elts[elt].longconst);
      elt += 2;
      break;
    case OP_REGISTER:
      fprintf_filtered (stream, "Register $%s", &exp->elts[elt + 1].string);
      elt += 3 + BYTES_TO_EXP_ELEM (exp->elts[elt].longconst + 1);
      break;
    case OP_INTERNALVAR:
      fprintf_filtered (stream, "Internal var @");
      gdb_print_host_address (exp->elts[elt].internalvar, stream);
      fprintf_filtered (stream, " (%s)",
			internalvar_name (exp->elts[elt].internalvar));
      elt += 2;
      break;
    case OP_FUNCALL:
      {
	int i, nargs;

	nargs = longest_to_int (exp->elts[elt].longconst);

	fprintf_filtered (stream, "Number of args: %d", nargs);
	elt += 2;

	for (i = 1; i <= nargs + 1; i++)
	  elt = dump_subexp (exp, stream, elt);
      }
      break;
    case OP_ARRAY:
      {
	int lower, upper;
	int i;

	lower = longest_to_int (exp->elts[elt].longconst);
	upper = longest_to_int (exp->elts[elt + 1].longconst);

	fprintf_filtered (stream, "Bounds [%d:%d]", lower, upper);
	elt += 3;

	for (i = 1; i <= upper - lower + 1; i++)
	  elt = dump_subexp (exp, stream, elt);
      }
      break;
    case UNOP_MEMVAL:
    case UNOP_CAST:
    case UNOP_DYNAMIC_CAST:
    case UNOP_REINTERPRET_CAST:
      fprintf_filtered (stream, "Type @");
      gdb_print_host_address (exp->elts[elt].type, stream);
      fprintf_filtered (stream, " (");
      type_print (exp->elts[elt].type, NULL, stream, 0);
      fprintf_filtered (stream, ")");
      elt = dump_subexp (exp, stream, elt + 2);
      break;
    case UNOP_MEMVAL_TLS:
      fprintf_filtered (stream, "TLS type @");
      gdb_print_host_address (exp->elts[elt + 1].type, stream);
      fprintf_filtered (stream, " (__thread /* \"%s\" */ ",
                        (exp->elts[elt].objfile == NULL ? "(null)"
			 : exp->elts[elt].objfile->name));
      type_print (exp->elts[elt + 1].type, NULL, stream, 0);
      fprintf_filtered (stream, ")");
      elt = dump_subexp (exp, stream, elt + 3);
      break;
    case OP_TYPE:
      fprintf_filtered (stream, "Type @");
      gdb_print_host_address (exp->elts[elt].type, stream);
      fprintf_filtered (stream, " (");
      type_print (exp->elts[elt].type, NULL, stream, 0);
      fprintf_filtered (stream, ")");
      elt += 2;
      break;
    case STRUCTOP_STRUCT:
    case STRUCTOP_PTR:
      {
	char *elem_name;
	int len;

	len = longest_to_int (exp->elts[elt].longconst);
	elem_name = &exp->elts[elt + 1].string;

	fprintf_filtered (stream, "Element name: `%.*s'", len, elem_name);
	elt = dump_subexp (exp, stream, elt + 3 + BYTES_TO_EXP_ELEM (len + 1));
      }
      break;
    case OP_SCOPE:
      {
	char *elem_name;
	int len;

	fprintf_filtered (stream, "Type @");
	gdb_print_host_address (exp->elts[elt].type, stream);
	fprintf_filtered (stream, " (");
	type_print (exp->elts[elt].type, NULL, stream, 0);
	fprintf_filtered (stream, ") ");

	len = longest_to_int (exp->elts[elt + 1].longconst);
	elem_name = &exp->elts[elt + 2].string;

	fprintf_filtered (stream, "Field name: `%.*s'", len, elem_name);
	elt += 4 + BYTES_TO_EXP_ELEM (len + 1);
      }
      break;
    case TYPE_INSTANCE:
      {
	char *elem_name;
	LONGEST len;

	len = exp->elts[elt++].longconst;
	fprintf_filtered (stream, "%s TypeInstance: ", plongest (len));
	while (len-- > 0)
	  {
	    fprintf_filtered (stream, "Type @");
	    gdb_print_host_address (exp->elts[elt].type, stream);
	    fprintf_filtered (stream, " (");
	    type_print (exp->elts[elt].type, NULL, stream, 0);
	    fprintf_filtered (stream, ")");
	    elt++;
	    if (len > 0)
	      fputs_filtered (", ", stream);
	  }
	/* Ending LEN and ending TYPE_INSTANCE.  */
	elt += 2;
	elt = dump_subexp (exp, stream, elt);
      }
      break;
    default:
    case OP_NULL:
    case MULTI_SUBSCRIPT:
    case OP_F77_UNDETERMINED_ARGLIST:
    case OP_COMPLEX:
    case OP_STRING:
    case OP_BITSTRING:
    case OP_BOOL:
    case OP_M2_STRING:
    case OP_THIS:
    case OP_LABELED:
    case OP_NAME:
      fprintf_filtered (stream, "Unknown format");
    }

  return elt;
}

void
dump_prefix_expression (struct expression *exp, struct ui_file *stream)
{
  int elt;

  fprintf_filtered (stream, "Dump of expression @ ");
  gdb_print_host_address (exp, stream);
  fputs_filtered (", after conversion to prefix form:\nExpression: `", stream);
  if (exp->elts[0].opcode != OP_TYPE)
    print_expression (exp, stream);
  else
    fputs_filtered ("Type printing not yet supported....", stream);
  fprintf_filtered (stream, "'\n\tLanguage %s, %d elements, %ld bytes each.\n",
		    exp->language_defn->la_name, exp->nelts,
		    (long) sizeof (union exp_element));
  fputs_filtered ("\n", stream);

  for (elt = 0; elt < exp->nelts;)
    elt = dump_subexp (exp, stream, elt);
  fputs_filtered ("\n", stream);
}