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/* Parse expressions for GDB.

   Copyright (C) 1986, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,

   1998, 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

   Modified from expread.y by the Department of Computer Science at the

   State University of New York at Buffalo, 1991.

   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/>.  */

/* Parse an expression from text in a string,

   and return the result as a  struct expression  pointer.

   That structure contains arithmetic operations in reverse polish,

   with constants represented by operations that are followed by special data.

   See expression.h for the details of the format.

   What is important here is that it can be built up sequentially

   during the process of parsing; the lower levels of the tree always

   come first in the result.  */

#include "defs.h"

#include <ctype.h>

#include "arch-utils.h"

#include "gdb_string.h"

#include "symtab.h"

#include "gdbtypes.h"

#include "frame.h"

#include "expression.h"

#include "value.h"

#include "command.h"

#include "language.h"

#include "f-lang.h"

#include "parser-defs.h"

#include "gdbcmd.h"

#include "symfile.h"            /* for overlay functions */

#include "inferior.h"

#include "doublest.h"

#include "gdb_assert.h"

#include "block.h"

#include "source.h"

#include "objfiles.h"

#include "exceptions.h"

#include "user-regs.h"

/* Standard set of definitions for printing, dumping, prefixifying,

 * and evaluating expressions.  */

const struct exp_descriptor exp_descriptor_standard =

  {

    print_subexp_standard,

    operator_length_standard,

    op_name_standard,

    dump_subexp_body_standard,

    evaluate_subexp_standard

  };

/* Global variables declared in parser-defs.h (and commented there).  */

struct expression *expout;

int expout_size;

int expout_ptr;

struct block *expression_context_block;

CORE_ADDR expression_context_pc;

struct block *innermost_block;

int arglist_len;

union type_stack_elt *type_stack;

int type_stack_depth, type_stack_size;

char *lexptr;

char *prev_lexptr;

int paren_depth;

int comma_terminates;

/* True if parsing an expression to find a field reference.  This is

   only used by completion.  */

int in_parse_field;

/* The index of the last struct expression directly before a '.' or

   '->'.  This is set when parsing and is only used when completing a

   field name.  It is -1 if no dereference operation was found.  */

static int expout_last_struct = -1;

/* A temporary buffer for identifiers, so we can null-terminate them.

   We allocate this with xrealloc.  parse_exp_1 used to allocate with

   alloca, using the size of the whole expression as a conservative

   estimate of the space needed.  However, macro expansion can

   introduce names longer than the original expression; there's no

   practical way to know beforehand how large that might be.  */

char *namecopy;

size_t namecopy_size;

static int expressiondebug = 0;

static void

show_expressiondebug (struct ui_file *file, int from_tty,

                      struct cmd_list_element *c, const char *value)

{

  fprintf_filtered (file, _("Expression debugging is %s.\n"), value);

}

/* Non-zero if an expression parser should set yydebug.  */

int parser_debug;

static void

show_parserdebug (struct ui_file *file, int from_tty,

                  struct cmd_list_element *c, const char *value)

{

  fprintf_filtered (file, _("Parser debugging is %s.\n"), value);

}

static void free_funcalls (void *ignore);

static int prefixify_expression (struct expression *);

static int prefixify_subexp (struct expression *, struct expression *, int,

                             int);

static struct expression *parse_exp_in_context (char **, struct block *, int,

                                                int, int *);

void _initialize_parse (void);

/* Data structure for saving values of arglist_len for function calls whose

   arguments contain other function calls.  */

struct funcall

  {

    struct funcall *next;

    int arglist_len;

  };

static struct funcall *funcall_chain;

/* Begin counting arguments for a function call,

   saving the data about any containing call.  */

void

start_arglist (void)

{

  struct funcall *new;

  new = (struct funcall *) xmalloc (sizeof (struct funcall));

  new->next = funcall_chain;

  new->arglist_len = arglist_len;

  arglist_len = 0;

  funcall_chain = new;

}

/* Return the number of arguments in a function call just terminated,

   and restore the data for the containing function call.  */

int

end_arglist (void)

{

  int val = arglist_len;

  struct funcall *call = funcall_chain;

  funcall_chain = call->next;

  arglist_len = call->arglist_len;

  xfree (call);

  return val;

}

/* Free everything in the funcall chain.

   Used when there is an error inside parsing.  */

static void

free_funcalls (void *ignore)

{

  struct funcall *call, *next;

  for (call = funcall_chain; call; call = next)

    {

      next = call->next;

      xfree (call);

    }

}

/* This page contains the functions for adding data to the  struct expression

   being constructed.  */

/* Add one element to the end of the expression.  */

/* To avoid a bug in the Sun 4 compiler, we pass things that can fit into

   a register through here */

void

write_exp_elt (union exp_element expelt)

{

  if (expout_ptr >= expout_size)

    {

      expout_size *= 2;

      expout = (struct expression *)

        xrealloc ((char *) expout, sizeof (struct expression)

                  + EXP_ELEM_TO_BYTES (expout_size));

    }

  expout->elts[expout_ptr++] = expelt;

}

void

write_exp_elt_opcode (enum exp_opcode expelt)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.opcode = expelt;

  write_exp_elt (tmp);

}

void

write_exp_elt_sym (struct symbol *expelt)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.symbol = expelt;

  write_exp_elt (tmp);

}

void

write_exp_elt_block (struct block *b)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.block = b;

  write_exp_elt (tmp);

}

void

write_exp_elt_objfile (struct objfile *objfile)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.objfile = objfile;

  write_exp_elt (tmp);

}

void

write_exp_elt_longcst (LONGEST expelt)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.longconst = expelt;

  write_exp_elt (tmp);

}

void

write_exp_elt_dblcst (DOUBLEST expelt)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.doubleconst = expelt;

  write_exp_elt (tmp);

}

void

write_exp_elt_decfloatcst (gdb_byte expelt[16])

{

  union exp_element tmp;

  int index;

  for (index = 0; index < 16; index++)

    tmp.decfloatconst[index] = expelt[index];

  write_exp_elt (tmp);

}

void

write_exp_elt_type (struct type *expelt)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.type = expelt;

  write_exp_elt (tmp);

}

void

write_exp_elt_intern (struct internalvar *expelt)

{

  union exp_element tmp;

  memset (&tmp, 0, sizeof (union exp_element));

  tmp.internalvar = expelt;

  write_exp_elt (tmp);

}

/* Add a string constant to the end of the expression.

   String constants are stored by first writing an expression element

   that contains the length of the string, then stuffing the string

   constant itself into however many expression elements are needed

   to hold it, and then writing another expression element that contains

   the length of the string.  I.E. an expression element at each end of

   the string records the string length, so you can skip over the

   expression elements containing the actual string bytes from either

   end of the string.  Note that this also allows gdb to handle

   strings with embedded null bytes, as is required for some languages.

   Don't be fooled by the fact that the string is null byte terminated,

   this is strictly for the convenience of debugging gdb itself.

   Gdb does not depend up the string being null terminated, since the

   actual length is recorded in expression elements at each end of the

   string.  The null byte is taken into consideration when computing how

   many expression elements are required to hold the string constant, of

   course. */

void

write_exp_string (struct stoken str)

{

  int len = str.length;

  int lenelt;

  char *strdata;

  /* Compute the number of expression elements required to hold the string

     (including a null byte terminator), along with one expression element

     at each end to record the actual string length (not including the

     null byte terminator). */

  lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);

  /* Ensure that we have enough available expression elements to store

     everything. */

  if ((expout_ptr + lenelt) >= expout_size)

    {

      expout_size = max (expout_size * 2, expout_ptr + lenelt + 10);

      expout = (struct expression *)

        xrealloc ((char *) expout, (sizeof (struct expression)

                                    + EXP_ELEM_TO_BYTES (expout_size)));

    }

  /* Write the leading length expression element (which advances the current

     expression element index), then write the string constant followed by a

     terminating null byte, and then write the trailing length expression

     element. */

  write_exp_elt_longcst ((LONGEST) len);

  strdata = (char *) &expout->elts[expout_ptr];

  memcpy (strdata, str.ptr, len);

  *(strdata + len) = '\0';

  expout_ptr += lenelt - 2;

  write_exp_elt_longcst ((LONGEST) len);

}

/* Add a vector of string constants to the end of the expression.

   This adds an OP_STRING operation, but encodes the contents

   differently from write_exp_string.  The language is expected to

   handle evaluation of this expression itself.

   After the usual OP_STRING header, TYPE is written into the

   expression as a long constant.  The interpretation of this field is

   up to the language evaluator.

   Next, each string in VEC is written.  The length is written as a

   long constant, followed by the contents of the string.  */

void

write_exp_string_vector (int type, struct stoken_vector *vec)

{

  int i, n_slots, len;

  /* Compute the size.  We compute the size in number of slots to

     avoid issues with string padding.  */

  n_slots = 0;

  for (i = 0; i < vec->len; ++i)

    {

      /* One slot for the length of this element, plus the number of

         slots needed for this string.  */

      n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);

    }

  /* One more slot for the type of the string.  */

  ++n_slots;

  /* Now compute a phony string length.  */

  len = EXP_ELEM_TO_BYTES (n_slots) - 1;

  n_slots += 4;

  if ((expout_ptr + n_slots) >= expout_size)

    {

      expout_size = max (expout_size * 2, expout_ptr + n_slots + 10);

      expout = (struct expression *)

        xrealloc ((char *) expout, (sizeof (struct expression)

                                    + EXP_ELEM_TO_BYTES (expout_size)));

    }

  write_exp_elt_opcode (OP_STRING);

  write_exp_elt_longcst (len);

  write_exp_elt_longcst (type);

  for (i = 0; i < vec->len; ++i)

    {

      write_exp_elt_longcst (vec->tokens[i].length);

      memcpy (&expout->elts[expout_ptr], vec->tokens[i].ptr,

              vec->tokens[i].length);

      expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);

    }

  write_exp_elt_longcst (len);

  write_exp_elt_opcode (OP_STRING);

}

/* Add a bitstring constant to the end of the expression.

   Bitstring constants are stored by first writing an expression element

   that contains the length of the bitstring (in bits), then stuffing the

   bitstring constant itself into however many expression elements are

   needed to hold it, and then writing another expression element that

   contains the length of the bitstring.  I.E. an expression element at

   each end of the bitstring records the bitstring length, so you can skip

   over the expression elements containing the actual bitstring bytes from

   either end of the bitstring. */

void

write_exp_bitstring (struct stoken str)

{

  int bits = str.length;        /* length in bits */

  int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;

  int lenelt;

  char *strdata;

  /* Compute the number of expression elements required to hold the bitstring,

     along with one expression element at each end to record the actual

     bitstring length in bits. */

  lenelt = 2 + BYTES_TO_EXP_ELEM (len);

  /* Ensure that we have enough available expression elements to store

     everything. */

  if ((expout_ptr + lenelt) >= expout_size)

    {

      expout_size = max (expout_size * 2, expout_ptr + lenelt + 10);

      expout = (struct expression *)

        xrealloc ((char *) expout, (sizeof (struct expression)

                                    + EXP_ELEM_TO_BYTES (expout_size)));

    }

  /* Write the leading length expression element (which advances the current

     expression element index), then write the bitstring constant, and then

     write the trailing length expression element. */

  write_exp_elt_longcst ((LONGEST) bits);

  strdata = (char *) &expout->elts[expout_ptr];

  memcpy (strdata, str.ptr, len);

  expout_ptr += lenelt - 2;

  write_exp_elt_longcst ((LONGEST) bits);

}

/* Add the appropriate elements for a minimal symbol to the end of

   the expression.  */

void

write_exp_msymbol (struct minimal_symbol *msymbol)

{

  struct objfile *objfile = msymbol_objfile (msymbol);

  struct gdbarch *gdbarch = get_objfile_arch (objfile);

  CORE_ADDR addr = SYMBOL_VALUE_ADDRESS (msymbol);

  struct obj_section *section = SYMBOL_OBJ_SECTION (msymbol);

  enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);

  CORE_ADDR pc;

  /* The minimal symbol might point to a function descriptor;

     resolve it to the actual code address instead.  */

  pc = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, &current_target);

  if (pc != addr)

    {

      /* In this case, assume we have a code symbol instead of

         a data symbol.  */

      type = mst_text;

      section = NULL;

      addr = pc;

    }

  if (overlay_debugging)

    addr = symbol_overlayed_address (addr, section);

  write_exp_elt_opcode (OP_LONG);

  /* Let's make the type big enough to hold a 64-bit address.  */

  write_exp_elt_type (objfile_type (objfile)->builtin_core_addr);

  write_exp_elt_longcst ((LONGEST) addr);

  write_exp_elt_opcode (OP_LONG);

  if (section && section->the_bfd_section->flags & SEC_THREAD_LOCAL)

    {

      write_exp_elt_opcode (UNOP_MEMVAL_TLS);

      write_exp_elt_objfile (objfile);

      write_exp_elt_type (objfile_type (objfile)->nodebug_tls_symbol);

      write_exp_elt_opcode (UNOP_MEMVAL_TLS);

      return;

    }

  write_exp_elt_opcode (UNOP_MEMVAL);

  switch (type)

    {

    case mst_text:

    case mst_file_text:

    case mst_solib_trampoline:

      write_exp_elt_type (objfile_type (objfile)->nodebug_text_symbol);

      break;

    case mst_data:

    case mst_file_data:

    case mst_bss:

    case mst_file_bss:

      write_exp_elt_type (objfile_type (objfile)->nodebug_data_symbol);

      break;

    default:

      write_exp_elt_type (objfile_type (objfile)->nodebug_unknown_symbol);

      break;

    }

  write_exp_elt_opcode (UNOP_MEMVAL);

}

/* Mark the current index as the starting location of a structure

   expression.  This is used when completing on field names.  */

void

mark_struct_expression (void)

{

  expout_last_struct = expout_ptr;

}

/* Recognize tokens that start with '$'.  These include:

   $regname     A native register name or a "standard

   register name".

   $variable    A convenience variable with a name chosen

   by the user.

   $digits              Value history with index <digits>, starting

   from the first value which has index 1.

   $$digits     Value history with index <digits> relative

   to the last value.  I.E. $$0 is the last

   value, $$1 is the one previous to that, $$2

   is the one previous to $$1, etc.

   $ | $0 | $$0 The last value in the value history.

   $$           An abbreviation for the second to the last

   value in the value history, I.E. $$1

 */

void

write_dollar_variable (struct stoken str)

{

  struct symbol *sym = NULL;

  struct minimal_symbol *msym = NULL;

  struct internalvar *isym = NULL;

  /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)

     and $$digits (equivalent to $<-digits> if you could type that). */

  int negate = 0;

  int i = 1;

  /* Double dollar means negate the number and add -1 as well.

     Thus $$ alone means -1.  */

  if (str.length >= 2 && str.ptr[1] == '$')

    {

      negate = 1;

      i = 2;

    }

  if (i == str.length)

    {

      /* Just dollars (one or two) */

      i = -negate;

      goto handle_last;

    }

  /* Is the rest of the token digits?  */

  for (; i < str.length; i++)

    if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))

      break;

  if (i == str.length)

    {

      i = atoi (str.ptr + 1 + negate);

      if (negate)

        i = -i;

      goto handle_last;

    }

  /* Handle tokens that refer to machine registers:

     $ followed by a register name.  */

  i = user_reg_map_name_to_regnum (parse_gdbarch,

                                   str.ptr + 1, str.length - 1);

  if (i >= 0)

    goto handle_register;

  /* Any names starting with $ are probably debugger internal variables.  */

  isym = lookup_only_internalvar (copy_name (str) + 1);

  if (isym)

    {

      write_exp_elt_opcode (OP_INTERNALVAR);

      write_exp_elt_intern (isym);

      write_exp_elt_opcode (OP_INTERNALVAR);

      return;

    }

  /* On some systems, such as HP-UX and hppa-linux, certain system routines

     have names beginning with $ or $$.  Check for those, first. */

  sym = lookup_symbol (copy_name (str), (struct block *) NULL,

                       VAR_DOMAIN, (int *) NULL);

  if (sym)

    {

      write_exp_elt_opcode (OP_VAR_VALUE);

      write_exp_elt_block (block_found);        /* set by lookup_symbol */

      write_exp_elt_sym (sym);

      write_exp_elt_opcode (OP_VAR_VALUE);

      return;

    }

  msym = lookup_minimal_symbol (copy_name (str), NULL, NULL);

  if (msym)

    {

      write_exp_msymbol (msym);

      return;

    }

  /* Any other names are assumed to be debugger internal variables.  */

  write_exp_elt_opcode (OP_INTERNALVAR);

  write_exp_elt_intern (create_internalvar (copy_name (str) + 1));

  write_exp_elt_opcode (OP_INTERNALVAR);

  return;

handle_last:

  write_exp_elt_opcode (OP_LAST);

  write_exp_elt_longcst ((LONGEST) i);

  write_exp_elt_opcode (OP_LAST);

  return;

handle_register:

  write_exp_elt_opcode (OP_REGISTER);

  str.length--;

  str.ptr++;

  write_exp_string (str);

  write_exp_elt_opcode (OP_REGISTER);

  return;

}

char *

find_template_name_end (char *p)

{

  int depth = 1;

  int just_seen_right = 0;

  int just_seen_colon = 0;

  int just_seen_space = 0;

  if (!p || (*p != '<'))

    return 0;

  while (*++p)

    {

      switch (*p)

        {

        case '\'':

        case '\"':

        case '{':

        case '}':

          /* In future, may want to allow these?? */

          return 0;

        case '<':

          depth++;              /* start nested template */

          if (just_seen_colon || just_seen_right || just_seen_space)

            return 0;            /* but not after : or :: or > or space */

          break;

        case '>':

          if (just_seen_colon || just_seen_right)

            return 0;            /* end a (nested?) template */

          just_seen_right = 1;  /* but not after : or :: */

          if (--depth == 0)      /* also disallow >>, insist on > > */

            return ++p;         /* if outermost ended, return */

          break;

        case ':':

          if (just_seen_space || (just_seen_colon > 1))

            return 0;            /* nested class spec coming up */

          just_seen_colon++;    /* we allow :: but not :::: */

          break;

        case ' ':

          break;

        default:

          if (!((*p >= 'a' && *p <= 'z') ||     /* allow token chars */

                (*p >= 'A' && *p <= 'Z') ||

                (*p >= '0' && *p <= '9') ||

                (*p == '_') || (*p == ',') ||   /* commas for template args */

                (*p == '&') || (*p == '*') ||   /* pointer and ref types */