636 lines
14 KiB
C
636 lines
14 KiB
C
/* Parse expressions for GDB.
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Copyright (C) 1986, 1989, 1990, 1991 Free Software Foundation, Inc.
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Modified from expread.y by the Department of Computer Science at the
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State University of New York at Buffalo, 1991.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* Parse an expression from text in a string,
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and return the result as a struct expression pointer.
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That structure contains arithmetic operations in reverse polish,
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with constants represented by operations that are followed by special data.
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See expression.h for the details of the format.
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What is important here is that it can be built up sequentially
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during the process of parsing; the lower levels of the tree always
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come first in the result. */
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#include <stdio.h>
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#include "defs.h"
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#include "symtab.h"
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#include "gdbtypes.h"
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#include "frame.h"
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#include "expression.h"
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#include "value.h"
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#include "command.h"
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#include "language.h"
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#include "parser-defs.h"
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static void
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prefixify_expression PARAMS ((struct expression *));
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static int
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length_of_subexp PARAMS ((struct expression *, int));
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static void
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prefixify_subexp PARAMS ((struct expression *, struct expression *, int, int));
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/* Assign machine-independent names to certain registers
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(unless overridden by the REGISTER_NAMES table) */
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struct std_regs std_regs[] = {
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#ifdef PC_REGNUM
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{ "pc", PC_REGNUM },
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#endif
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#ifdef FP_REGNUM
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{ "fp", FP_REGNUM },
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#endif
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#ifdef SP_REGNUM
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{ "sp", SP_REGNUM },
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#endif
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#ifdef PS_REGNUM
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{ "ps", PS_REGNUM },
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#endif
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};
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unsigned num_std_regs = (sizeof std_regs / sizeof std_regs[0]);
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/* Begin counting arguments for a function call,
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saving the data about any containing call. */
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void
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start_arglist ()
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{
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register struct funcall *new = (struct funcall *) xmalloc (sizeof (struct funcall));
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new->next = funcall_chain;
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new->arglist_len = arglist_len;
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arglist_len = 0;
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funcall_chain = new;
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}
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/* Return the number of arguments in a function call just terminated,
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and restore the data for the containing function call. */
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int
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end_arglist ()
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{
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register int val = arglist_len;
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register struct funcall *call = funcall_chain;
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funcall_chain = call->next;
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arglist_len = call->arglist_len;
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free (call);
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return val;
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}
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/* Free everything in the funcall chain.
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Used when there is an error inside parsing. */
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void
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free_funcalls ()
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{
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register struct funcall *call, *next;
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for (call = funcall_chain; call; call = next)
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{
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next = call->next;
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free (call);
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}
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}
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/* This page contains the functions for adding data to the struct expression
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being constructed. */
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/* Add one element to the end of the expression. */
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/* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
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a register through here */
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void
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write_exp_elt (expelt)
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union exp_element expelt;
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{
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if (expout_ptr >= expout_size)
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{
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expout_size *= 2;
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expout = (struct expression *) xrealloc ((char *) expout,
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sizeof (struct expression)
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+ expout_size * sizeof (union exp_element));
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}
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expout->elts[expout_ptr++] = expelt;
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}
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void
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write_exp_elt_opcode (expelt)
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enum exp_opcode expelt;
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{
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union exp_element tmp;
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tmp.opcode = expelt;
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write_exp_elt (tmp);
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}
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void
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write_exp_elt_sym (expelt)
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struct symbol *expelt;
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{
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union exp_element tmp;
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tmp.symbol = expelt;
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write_exp_elt (tmp);
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}
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void
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write_exp_elt_longcst (expelt)
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LONGEST expelt;
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{
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union exp_element tmp;
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tmp.longconst = expelt;
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write_exp_elt (tmp);
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}
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void
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write_exp_elt_dblcst (expelt)
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double expelt;
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{
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union exp_element tmp;
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tmp.doubleconst = expelt;
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write_exp_elt (tmp);
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}
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void
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write_exp_elt_type (expelt)
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struct type *expelt;
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{
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union exp_element tmp;
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tmp.type = expelt;
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write_exp_elt (tmp);
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}
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void
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write_exp_elt_intern (expelt)
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struct internalvar *expelt;
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{
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union exp_element tmp;
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tmp.internalvar = expelt;
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write_exp_elt (tmp);
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}
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/* Add a string constant to the end of the expression.
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Follow it by its length in bytes, as a separate exp_element. */
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void
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write_exp_string (str)
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struct stoken str;
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{
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register int len = str.length;
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register int lenelt
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= (len + sizeof (union exp_element)) / sizeof (union exp_element);
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expout_ptr += lenelt;
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if (expout_ptr >= expout_size)
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{
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expout_size = max (expout_size * 2, expout_ptr + 10);
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expout = (struct expression *)
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xrealloc ((char *) expout, (sizeof (struct expression)
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+ (expout_size * sizeof (union exp_element))));
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}
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bcopy (str.ptr, (char *) &expout->elts[expout_ptr - lenelt], len);
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((char *) &expout->elts[expout_ptr - lenelt])[len] = 0;
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write_exp_elt_longcst ((LONGEST) len);
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}
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/* Return a null-terminated temporary copy of the name
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of a string token. */
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char *
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copy_name (token)
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struct stoken token;
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{
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bcopy (token.ptr, namecopy, token.length);
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namecopy[token.length] = 0;
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return namecopy;
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}
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/* Reverse an expression from suffix form (in which it is constructed)
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to prefix form (in which we can conveniently print or execute it). */
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static void
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prefixify_expression (expr)
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register struct expression *expr;
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{
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register int len = sizeof (struct expression) +
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expr->nelts * sizeof (union exp_element);
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register struct expression *temp;
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register int inpos = expr->nelts, outpos = 0;
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temp = (struct expression *) alloca (len);
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/* Copy the original expression into temp. */
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bcopy (expr, temp, len);
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prefixify_subexp (temp, expr, inpos, outpos);
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}
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/* Return the number of exp_elements in the subexpression of EXPR
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whose last exp_element is at index ENDPOS - 1 in EXPR. */
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static int
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length_of_subexp (expr, endpos)
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register struct expression *expr;
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register int endpos;
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{
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register int oplen = 1;
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register int args = 0;
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register int i;
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if (endpos < 0)
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error ("?error in length_of_subexp");
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i = (int) expr->elts[endpos - 1].opcode;
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switch (i)
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{
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/* C++ */
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case OP_SCOPE:
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oplen = 4 + ((expr->elts[endpos - 2].longconst
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+ sizeof (union exp_element))
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/ sizeof (union exp_element));
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break;
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case OP_LONG:
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case OP_DOUBLE:
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oplen = 4;
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break;
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case OP_TYPE:
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case OP_BOOL:
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case OP_VAR_VALUE:
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case OP_LAST:
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case OP_REGISTER:
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case OP_INTERNALVAR:
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oplen = 3;
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break;
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case OP_FUNCALL:
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oplen = 3;
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args = 1 + expr->elts[endpos - 2].longconst;
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break;
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case UNOP_MAX:
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case UNOP_MIN:
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oplen = 3;
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args = 0;
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break;
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case BINOP_VAL:
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case UNOP_CAST:
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case UNOP_MEMVAL:
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oplen = 3;
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args = 1;
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break;
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case UNOP_ABS:
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case UNOP_CAP:
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case UNOP_CHR:
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case UNOP_FLOAT:
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case UNOP_HIGH:
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case UNOP_ODD:
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case UNOP_ORD:
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case UNOP_TRUNC:
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oplen = 1;
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args = 1;
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break;
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case STRUCTOP_STRUCT:
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case STRUCTOP_PTR:
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args = 1;
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case OP_M2_STRING:
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case OP_STRING:
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oplen = 3 + ((expr->elts[endpos - 2].longconst
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+ sizeof (union exp_element))
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/ sizeof (union exp_element));
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break;
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case TERNOP_COND:
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args = 3;
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break;
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/* Modula-2 */
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case BINOP_MULTI_SUBSCRIPT:
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oplen=3;
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args = 1 + expr->elts[endpos- 2].longconst;
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break;
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case BINOP_ASSIGN_MODIFY:
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oplen = 3;
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args = 2;
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break;
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/* C++ */
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case OP_THIS:
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oplen = 2;
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break;
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default:
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args = 1 + (i < (int) BINOP_END);
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}
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while (args > 0)
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{
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oplen += length_of_subexp (expr, endpos - oplen);
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args--;
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}
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return oplen;
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}
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/* Copy the subexpression ending just before index INEND in INEXPR
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into OUTEXPR, starting at index OUTBEG.
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In the process, convert it from suffix to prefix form. */
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static void
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prefixify_subexp (inexpr, outexpr, inend, outbeg)
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register struct expression *inexpr;
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struct expression *outexpr;
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register int inend;
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int outbeg;
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{
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register int oplen = 1;
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register int args = 0;
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register int i;
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int *arglens;
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enum exp_opcode opcode;
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/* Compute how long the last operation is (in OPLEN),
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and also how many preceding subexpressions serve as
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arguments for it (in ARGS). */
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opcode = inexpr->elts[inend - 1].opcode;
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switch (opcode)
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{
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/* C++ */
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case OP_SCOPE:
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oplen = 4 + ((inexpr->elts[inend - 2].longconst
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+ sizeof (union exp_element))
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/ sizeof (union exp_element));
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break;
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case OP_LONG:
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case OP_DOUBLE:
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oplen = 4;
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break;
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case OP_TYPE:
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case OP_BOOL:
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case OP_VAR_VALUE:
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case OP_LAST:
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case OP_REGISTER:
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case OP_INTERNALVAR:
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oplen = 3;
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break;
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case OP_FUNCALL:
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oplen = 3;
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args = 1 + inexpr->elts[inend - 2].longconst;
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break;
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case UNOP_MIN:
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case UNOP_MAX:
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oplen = 3;
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args = 0;
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break;
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case UNOP_CAST:
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case UNOP_MEMVAL:
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oplen = 3;
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args = 1;
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break;
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case UNOP_ABS:
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case UNOP_CAP:
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case UNOP_CHR:
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case UNOP_FLOAT:
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case UNOP_HIGH:
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case UNOP_ODD:
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case UNOP_ORD:
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case UNOP_TRUNC:
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oplen=1;
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args=1;
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break;
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case STRUCTOP_STRUCT:
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case STRUCTOP_PTR:
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args = 1;
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case OP_M2_STRING:
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case OP_STRING:
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oplen = 3 + ((inexpr->elts[inend - 2].longconst
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+ sizeof (union exp_element))
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/ sizeof (union exp_element));
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break;
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case TERNOP_COND:
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args = 3;
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break;
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case BINOP_ASSIGN_MODIFY:
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oplen = 3;
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args = 2;
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break;
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/* Modula-2 */
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case BINOP_MULTI_SUBSCRIPT:
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oplen=3;
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args = 1 + inexpr->elts[inend - 2].longconst;
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break;
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/* C++ */
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case OP_THIS:
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oplen = 2;
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break;
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default:
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args = 1 + ((int) opcode < (int) BINOP_END);
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}
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/* Copy the final operator itself, from the end of the input
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to the beginning of the output. */
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inend -= oplen;
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bcopy (&inexpr->elts[inend], &outexpr->elts[outbeg],
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oplen * sizeof (union exp_element));
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outbeg += oplen;
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/* Find the lengths of the arg subexpressions. */
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arglens = (int *) alloca (args * sizeof (int));
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for (i = args - 1; i >= 0; i--)
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{
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oplen = length_of_subexp (inexpr, inend);
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arglens[i] = oplen;
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inend -= oplen;
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}
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/* Now copy each subexpression, preserving the order of
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the subexpressions, but prefixifying each one.
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In this loop, inend starts at the beginning of
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the expression this level is working on
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and marches forward over the arguments.
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outbeg does similarly in the output. */
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for (i = 0; i < args; i++)
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{
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oplen = arglens[i];
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inend += oplen;
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prefixify_subexp (inexpr, outexpr, inend, outbeg);
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outbeg += oplen;
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}
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}
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/* This page contains the two entry points to this file. */
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/* Read an expression from the string *STRINGPTR points to,
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parse it, and return a pointer to a struct expression that we malloc.
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Use block BLOCK as the lexical context for variable names;
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if BLOCK is zero, use the block of the selected stack frame.
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Meanwhile, advance *STRINGPTR to point after the expression,
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at the first nonwhite character that is not part of the expression
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(possibly a null character).
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If COMMA is nonzero, stop if a comma is reached. */
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struct expression *
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parse_exp_1 (stringptr, block, comma)
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char **stringptr;
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struct block *block;
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int comma;
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{
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struct cleanup *old_chain;
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lexptr = *stringptr;
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paren_depth = 0;
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type_stack_depth = 0;
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comma_terminates = comma;
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if (lexptr == 0 || *lexptr == 0)
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error_no_arg ("expression to compute");
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old_chain = make_cleanup (free_funcalls, 0);
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funcall_chain = 0;
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expression_context_block = block ? block : get_selected_block ();
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namecopy = (char *) alloca (strlen (lexptr) + 1);
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expout_size = 10;
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expout_ptr = 0;
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expout = (struct expression *)
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xmalloc (sizeof (struct expression)
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+ expout_size * sizeof (union exp_element));
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expout->language_defn = current_language;
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make_cleanup (free_current_contents, &expout);
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if (current_language->la_parser ())
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current_language->la_error (NULL);
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discard_cleanups (old_chain);
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expout->nelts = expout_ptr;
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expout = (struct expression *)
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xrealloc ((char *) expout,
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sizeof (struct expression)
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+ expout_ptr * sizeof (union exp_element));
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prefixify_expression (expout);
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*stringptr = lexptr;
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return expout;
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}
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/* Parse STRING as an expression, and complain if this fails
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to use up all of the contents of STRING. */
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struct expression *
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parse_expression (string)
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char *string;
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{
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register struct expression *exp;
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exp = parse_exp_1 (&string, 0, 0);
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if (*string)
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error ("Junk after end of expression.");
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return exp;
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}
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void
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push_type (tp)
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enum type_pieces tp;
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{
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if (type_stack_depth == type_stack_size)
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{
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type_stack_size *= 2;
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type_stack = (union type_stack_elt *)
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xrealloc ((char *) type_stack, type_stack_size * sizeof (*type_stack));
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}
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type_stack[type_stack_depth++].piece = tp;
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||
}
|
||
|
||
void
|
||
push_type_int (n)
|
||
int n;
|
||
{
|
||
if (type_stack_depth == type_stack_size)
|
||
{
|
||
type_stack_size *= 2;
|
||
type_stack = (union type_stack_elt *)
|
||
xrealloc ((char *) type_stack, type_stack_size * sizeof (*type_stack));
|
||
}
|
||
type_stack[type_stack_depth++].int_val = n;
|
||
}
|
||
|
||
enum type_pieces
|
||
pop_type ()
|
||
{
|
||
if (type_stack_depth)
|
||
return type_stack[--type_stack_depth].piece;
|
||
return tp_end;
|
||
}
|
||
|
||
int
|
||
pop_type_int ()
|
||
{
|
||
if (type_stack_depth)
|
||
return type_stack[--type_stack_depth].int_val;
|
||
/* "Can't happen". */
|
||
return 0;
|
||
}
|
||
|
||
void
|
||
_initialize_parse ()
|
||
{
|
||
type_stack_size = 80;
|
||
type_stack_depth = 0;
|
||
type_stack = (union type_stack_elt *)
|
||
xmalloc (type_stack_size * sizeof (*type_stack));
|
||
}
|