/tmp/gdb-8.1/gdb/expprint.c

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/* Print in infix form a struct expression.

   Copyright (C) 1986-2018 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 "block.h"
#include "objfiles.h"
#include "valprint.h"

#include <ctype.h>

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;
  const 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_TYPE:
      (*pos) += 2;
      type_print (exp->elts[pc + 1].type, "", stream, 0);
      return;

    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_no_prettyformat_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_FLOAT:
      {
    struct value_print_options opts;

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

    case OP_VAR_VALUE:
      {
    const 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_VAR_MSYM_VALUE:
      {
    (*pos) += 3;
    fputs_filtered (MSYMBOL_PRINT_NAME (exp->elts[pc + 2].msymbol), stream);
      }
      return;

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

    case OP_VAR_ENTRY_VALUE:
      {
    (*pos) += 2;
    fprintf_filtered (stream, "%s@entry",
              SYMBOL_PRINT_NAME (exp->elts[pc + 1].symbol));
      }
      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,
             (gdb_byte *) &exp->elts[pc + 2].string, nargs,
             NULL, 0, &opts);
      }
      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,
             (gdb_byte *) &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 = (char *) 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 = (char *) 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,
               (gdb_byte *) 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 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:
      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_CAST_TYPE:
      if ((int) prec > (int) PREC_PREFIX)
    fputs_filtered ("(", stream);
      fputs_filtered ("(", stream);
      print_subexp (exp, pos, stream, PREC_PREFIX);
      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);
      print_subexp (exp, pos, stream, PREC_PREFIX);
      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_no_prettyformat_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_TYPE:
      if ((int) prec > (int) PREC_PREFIX)
    fputs_filtered ("(", stream);
      fputs_filtered ("{", stream);
      print_subexp (exp, pos, stream, PREC_PREFIX);
      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:
      {
    type_instance_flags flags
      = (type_instance_flag_value) longest_to_int (exp->elts[pc + 1].longconst);
    LONGEST count = exp->elts[pc + 2].longconst;

    /* The FLAGS.  */
    (*pos)++;
    /* The COUNT.  */
    (*pos)++;
    fputs_unfiltered ("TypeInstance(", 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);

    if (flags & TYPE_INSTANCE_FLAG_CONST)
      fputs_unfiltered (",const", stream);
    if (flags & TYPE_INSTANCE_FLAG_VOLATILE)
      fputs_unfiltered (",volatile", stream);

    fputs_unfiltered (")", stream);
    return;
      }

    case OP_RANGE:
      {
    enum range_type range_type;

    range_type = (enum range_type)
      longest_to_int (exp->elts[pc + 1].longconst);
    *pos += 2;

    fputs_filtered ("RANGE(", stream);
    if (range_type == HIGH_BOUND_DEFAULT
        || range_type == NONE_BOUND_DEFAULT)
      print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
    fputs_filtered ("..", stream);
    if (range_type == LOW_BOUND_DEFAULT
        || range_type == NONE_BOUND_DEFAULT)
      print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
    fputs_filtered (")", 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.  */
const 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 int dump_subexp_body (struct expression *exp, struct ui_file *, int);

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

const 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).  */

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

    xsnprintf (buf, sizeof (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,
             const char *note)
{
  int elt;
  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);

      const char *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:
      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_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_FLOAT:
      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 ");
      print_floating (exp->elts[elt + 1].floatconst,
              exp->elts[elt].type, stream);
      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_VAR_MSYM_VALUE:
      fprintf_filtered (stream, "Objfile @");
      gdb_print_host_address (exp->elts[elt].objfile, stream);
      fprintf_filtered (stream, ", msymbol @");
      gdb_print_host_address (exp->elts[elt + 1].msymbol, stream);
      fprintf_filtered (stream, " (%s)",
            MSYMBOL_PRINT_NAME (exp->elts[elt + 1].msymbol));
      elt += 3;
      break;
    case OP_VAR_ENTRY_VALUE:
      fprintf_filtered (stream, "Entry value of symbol @");
      gdb_print_host_address (exp->elts[elt].symbol, stream);
      fprintf_filtered (stream, " (%s)",
            SYMBOL_PRINT_NAME (exp->elts[elt].symbol));
      elt += 2;
      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_DYNAMIC_CAST:
    case UNOP_REINTERPRET_CAST:
    case UNOP_CAST_TYPE:
    case UNOP_MEMVAL_TYPE:
      fprintf_filtered (stream, " (");
      elt = dump_subexp (exp, stream, elt);
      fprintf_filtered (stream, ")");
      elt = dump_subexp (exp, stream, elt);
      break;
    case UNOP_MEMVAL:
    case UNOP_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 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 OP_TYPEOF:
    case OP_DECLTYPE:
      fprintf_filtered (stream, "Typeof (");
      elt = dump_subexp (exp, stream, elt);
      fprintf_filtered (stream, ")");
      break;
    case OP_TYPEID:
      fprintf_filtered (stream, "typeid (");
      elt = dump_subexp (exp, stream, elt);
      fprintf_filtered (stream, ")");
      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 OP_FUNC_STATIC_VAR:
      {
    int len = longest_to_int (exp->elts[elt].longconst);
    const char *var_name = &exp->elts[elt + 1].string;
    fprintf_filtered (stream, "Field name: `%.*s'", len, var_name);
    elt += 3 + BYTES_TO_EXP_ELEM (len + 1);
      }
      break;

    case TYPE_INSTANCE:
      {
    type_instance_flags flags
      = (type_instance_flag_value) longest_to_int (exp->elts[elt++].longconst);
    LONGEST 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);
      }

    fprintf_filtered (stream, " Flags: %s (", hex_string (flags));
    bool space = false;
    auto print_one = [&] (const char *mod)
      {
        if (space)
          fputs_filtered (" ", stream);
        space = true;
        fprintf_filtered (stream, "%s", mod);
      };
    if (flags & TYPE_INSTANCE_FLAG_CONST)
      print_one ("const");
    if (flags & TYPE_INSTANCE_FLAG_VOLATILE)
      print_one ("volatile");
    fprintf_filtered (stream, ")");

    /* Ending LEN and ending TYPE_INSTANCE.  */
    elt += 2;
    elt = dump_subexp (exp, stream, elt);
      }
      break;
    case OP_STRING:
      {
    LONGEST len = exp->elts[elt].longconst;
    LONGEST type = exp->elts[elt + 1].longconst;

    fprintf_filtered (stream, "Language-specific string type: %s",
              plongest (type));

    /* Skip length.  */
    elt += 1;

    /* Skip string content. */
    elt += BYTES_TO_EXP_ELEM (len);

    /* Skip length and ending OP_STRING. */
    elt += 2;
      }
      break;
    case OP_RANGE:
      {
    enum range_type range_type;

    range_type = (enum range_type)
      longest_to_int (exp->elts[elt].longconst);
    elt += 2;

    switch (range_type)
      {
      case BOTH_BOUND_DEFAULT:
        fputs_filtered ("Range '..'", stream);
        break;
      case LOW_BOUND_DEFAULT:
        fputs_filtered ("Range '..EXP'", stream);
        break;
      case HIGH_BOUND_DEFAULT:
        fputs_filtered ("Range 'EXP..'", stream);
        break;
      case NONE_BOUND_DEFAULT:
        fputs_filtered ("Range 'EXP..EXP'", stream);
        break;
      default:
        fputs_filtered ("Invalid Range!", stream);
        break;
      }

    if (range_type == HIGH_BOUND_DEFAULT
        || range_type == NONE_BOUND_DEFAULT)
      elt = dump_subexp (exp, stream, elt);
    if (range_type == LOW_BOUND_DEFAULT
        || range_type == NONE_BOUND_DEFAULT)
      elt = dump_subexp (exp, stream, elt);
      }
      break;

    default:
    case OP_NULL:
    case MULTI_SUBSCRIPT:
    case OP_F77_UNDETERMINED_ARGLIST:
    case OP_COMPLEX:
    case OP_BOOL:
    case OP_M2_STRING:
    case OP_THIS:
    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);
  print_expression (exp, 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);
}