/******************************** -*- C -*- ****************************
*
 *	Symbol Table module.
 *
 *
 ***********************************************************************/

/***********************************************************************
 *
 * Copyright 1988,89,90,91,92,94,95,99,2000,2001,2002,2003,2005,2006,2007
 * Free Software Foundation, Inc.
 * Written by Steve Byrne.
 *
 * This file is part of GNU Smalltalk.
 *
 * GNU Smalltalk is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2, or (at your option) any later 
 * version.
 * 
 * Linking GNU Smalltalk statically or dynamically with other modules is
 * making a combined work based on GNU Smalltalk.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * In addition, as a special exception, the Free Software Foundation
 * give you permission to combine GNU Smalltalk with free software
 * programs or libraries that are released under the GNU LGPL and with
 * independent programs running under the GNU Smalltalk virtual machine.
 *
 * You may copy and distribute such a system following the terms of the
 * GNU GPL for GNU Smalltalk and the licenses of the other code
 * concerned, provided that you include the source code of that other
 * code when and as the GNU GPL requires distribution of source code.
 *
 * Note that people who make modified versions of GNU Smalltalk are not
 * obligated to grant this special exception for their modified
 * versions; it is their choice whether to do so.  The GNU General
 * Public License gives permission to release a modified version without
 * this exception; this exception also makes it possible to release a
 * modified version which carries forward this exception.
 *
 * GNU Smalltalk 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
 * GNU Smalltalk; see the file COPYING.  If not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  
 *
 ***********************************************************************/


#include "gstpriv.h"

typedef struct
{
  OBJ_HEADER;
  OOP nextLink;
  OOP symbol;
}
 *sym_link;

typedef struct symbol_list *symbol_list;

struct symbol_list
{
  OOP symbol;
  mst_Boolean readOnly;
  int index;
  symbol_list prevSymbol;
};

/* Represents all the identifiers, both arguments and temporaries,
   which are declared in a given scope.  Nested scopes result in
   nested instances of the scope struct, with the current scope always
   being the innermost at any point during the compilation.  */
typedef struct scope *scope;
struct scope
{
  scope prevScope;
  unsigned int numArguments;
  unsigned int numTemporaries;
  symbol_list symbols;
};


typedef struct symbol_info
{
  OOP *symbolVar;
  const char *value;
}
symbol_info;


/* These variables hold various symbols needed mostly by the compiler
   and the C interface.  It is important that these symbols are *not*
   included in the builtin selectors list (builtins.gperf) because
   of the way we create symbols in _gst_init_symbols_pass1.  */

OOP _gst_and_symbol = NULL;
OOP _gst_as_scaled_decimal_radix_scale_symbol = NULL;
OOP _gst_bad_return_error_symbol = NULL;
OOP _gst_boolean_symbol = NULL;
OOP _gst_byte_array_out_symbol = NULL;
OOP _gst_byte_array_symbol = NULL;
OOP _gst_c_object_ptr_symbol = NULL;
OOP _gst_c_object_symbol = NULL;
OOP _gst_category_symbol = NULL;
OOP _gst_char_symbol = NULL;
OOP _gst_does_not_understand_symbol = NULL;
OOP _gst_double_symbol = NULL;
OOP _gst_false_symbol = NULL;
OOP _gst_float_symbol = NULL;
OOP _gst_if_false_if_true_symbol = NULL;
OOP _gst_if_false_symbol = NULL;
OOP _gst_if_true_if_false_symbol = NULL;
OOP _gst_if_true_symbol = NULL;
OOP _gst_int_symbol = NULL;
OOP _gst_long_double_symbol = NULL;
OOP _gst_long_symbol = NULL;
OOP _gst_must_be_boolean_symbol = NULL;
OOP _gst_nil_symbol = NULL;
OOP _gst_or_symbol = NULL;
OOP _gst_permission_symbol = NULL;
OOP _gst_primitive_symbol = NULL;
OOP _gst_repeat_symbol = NULL;
OOP _gst_self_smalltalk_symbol = NULL;
OOP _gst_self_symbol = NULL;
OOP _gst_short_symbol = NULL;
OOP _gst_smalltalk_symbol = NULL;
OOP _gst_smalltalk_namespace_symbol = NULL;
OOP _gst_start_execution_symbol = NULL;
OOP _gst_string_out_symbol = NULL;
OOP _gst_string_symbol = NULL;
OOP _gst_super_symbol = NULL;
OOP _gst_symbol_symbol = NULL;
OOP _gst_symbol_out_symbol = NULL;
OOP _gst_symbol_table = NULL;
OOP _gst_terminate_symbol = NULL;
OOP _gst_times_repeat_symbol = NULL;
OOP _gst_to_by_do_symbol = NULL;
OOP _gst_to_do_symbol = NULL;
OOP _gst_true_symbol = NULL;
OOP _gst_uchar_symbol = NULL;
OOP _gst_uint_symbol = NULL;
OOP _gst_ulong_symbol = NULL;
OOP _gst_ushort_symbol = NULL;
OOP _gst_undeclared_symbol = NULL;
OOP _gst_unknown_symbol = NULL;
OOP _gst_value_with_rec_with_args_symbol = NULL;
OOP _gst_variadic_smalltalk_symbol = NULL;
OOP _gst_variadic_symbol = NULL;
OOP _gst_vm_primitives_symbol = NULL;
OOP _gst_void_symbol = NULL;
OOP _gst_wchar_symbol = NULL;
OOP _gst_wstring_symbol = NULL;
OOP _gst_wstring_out_symbol = NULL;
OOP _gst_while_false_colon_symbol = NULL;
OOP _gst_while_false_symbol = NULL;
OOP _gst_while_true_colon_symbol = NULL;
OOP _gst_while_true_symbol = NULL;
OOP _gst_current_namespace = NULL;

OOP temporaries_dictionary = NULL;

/* The list of selectors for the send immediate bytecode.  */
struct builtin_selector _gst_builtin_selectors[256] = {};

/* True if undeclared globals can be considered forward references.  */
enum undeclared_strategy _gst_use_undeclared = UNDECLARED_TEMPORARIES;

/* Answer whether OOP is a Smalltalk String LEN characters long and
   these characters match the first LEN characters of STR (which must
   not have embedded NULs).  */
static mst_Boolean is_same_string (const char *str,
				   OOP oop,
				   int len);

/* Allocate memory for a symbol of length LEN and whose contents are STR.
   This function does not fill in the object's class because it is called
   upon image loading, when the classes have not been initialized yet.  */
static OOP alloc_symbol_oop (const char *str, int len);

/* Link SYMBOLOOP into the symbol table (using the given hash table index),
   and fill the class slot of the symbol.  */
static OOP alloc_symlink (OOP symbolOOP, uintptr_t index);

/* Answer whether C is considered a white space character in Smalltalk
   programs.  */
static mst_Boolean is_white_space (char c);

/* Free the list of symbols declared in the given SCOPE.  */
static void free_scope_symbols (scope scope);

/* Scans a variable name (letters and digits, initial letter), and
   return a symbol for it. PP is a pointer to a pointer to the start
   of the string to be scanned, which may be pointing at either
   whitespace or start of variable.  At end, it points to the first
   character after the initial whitespace, if any.  ENDP instead is
   initialized by the function to point to first character after the
   parsed variable name, which may be NUL.  */
static void parse_variable_name (const char ** pp,
				 const char ** endp);

/* This fills ENT's fields with the contents of its parameters.  */
static void fill_symbol_entry (symbol_entry * ent,
			       scope_type scope,
			       mst_Boolean readOnly,
			       OOP symbol,
			       int index,
			       unsigned int scopeDistance);

/* Scans a variable name (letters and digits, initial letter), and
   return a symbol for it. PP is a pointer to a pointer to the start
   of the string to be scanned.  May be pointing at either whitespace
   or start of variable.  At end, points to first character after the
   parsed variable name, which may be NUL.  The output is a Smalltalk
   Symbol, _gst_nil_oop if no variable name is found.  */
static OOP scan_name (const char ** pp);

/* This creates a Symbol containing LEN bytes starting at STR and puts
   it in the symbol list, or returns an existing one if it is
   found.  */
static OOP intern_counted_string (const char *str,
				  int len);

/* This is a hack.  It is the same as _gst_intern_string except that,
   if the given symbol is pointed to by PTESTOOP, we increment
   PTESTOOP and return the old value.  This works and speeds up image
   loading, because we are careful to create the same symbols in
   _gst_init_symbols_passN and _gst_restore_symbols.  */
static inline OOP
intern_string_fast (const char *str, OOP *pTestOOP);

/* This looks for SYMBOL among the instance variables that the current
   class declares, and returns the index of the variable if one is
   found.  */
static int instance_variable_index (OOP symbol);

/* This checks if the INDEX-th instance variable among those that the
   current class declares is read-only.  Read-only index variables are
   those that are declared by a trusted super-class of an untrusted
   subclass.  */
static mst_Boolean is_instance_variable_read_only (int index);

/* This looks for SYMBOL among the arguments and temporary variables
   that the current scope sees, and returns the entry in the symbol
   list for the variable if it is found.  */
static symbol_list find_local_var (scope scope,
				   OOP symbol);

/* This looks for SYMBOL among the global variables that the current
   scope sees, including superspaces if any, and returns the entry in
   the symbol list for the variable if it is found.  */
static OOP find_class_variable (OOP varName);

static scope cur_scope = NULL;

/* This is an array of symbols which the virtual machine knows about,
   and is used to restore the global variables upon image load.  */
static const symbol_info sym_info[] = {
  {&_gst_and_symbol, "and:"},
  {&_gst_as_scaled_decimal_radix_scale_symbol, "asScaledDecimal:radix:scale:"},
  {&_gst_bad_return_error_symbol, "badReturnError"},
  {&_gst_byte_array_symbol, "byteArray"},
  {&_gst_byte_array_out_symbol, "byteArrayOut"},
  {&_gst_boolean_symbol, "boolean"},
  {&_gst_c_object_symbol, "cObject"},
  {&_gst_c_object_ptr_symbol, "cObjectPtr"},
  {&_gst_category_symbol, "category:"},
  {&_gst_char_symbol, "char"},
  {&_gst_uchar_symbol, "uChar"},
  {&_gst_does_not_understand_symbol, "doesNotUnderstand:"},
  {&_gst_float_symbol, "float"},
  {&_gst_double_symbol, "double"},
  {&_gst_false_symbol, "false"},
  {&_gst_if_false_if_true_symbol, "ifFalse:ifTrue:"},
  {&_gst_if_false_symbol, "ifFalse:"},
  {&_gst_if_true_if_false_symbol, "ifTrue:ifFalse:"},
  {&_gst_if_true_symbol, "ifTrue:"},
  {&_gst_int_symbol, "int"},
  {&_gst_uint_symbol, "uInt"},
  {&_gst_long_double_symbol, "longDouble"},
  {&_gst_long_symbol, "long"},
  {&_gst_ulong_symbol, "uLong"},
  {&_gst_must_be_boolean_symbol, "mustBeBoolean"},
  {&_gst_nil_symbol, "nil"},
  {&_gst_or_symbol, "or:"},
  {&_gst_primitive_symbol, "primitive:"},
  {&_gst_repeat_symbol, "repeat"},
  {&_gst_self_symbol, "self"},
  {&_gst_self_smalltalk_symbol, "selfSmalltalk"},
  {&_gst_short_symbol, "short"},
  {&_gst_ushort_symbol, "uShort"},
  {&_gst_smalltalk_symbol, "smalltalk"},
  {&_gst_smalltalk_namespace_symbol, "Smalltalk"},
  {&_gst_start_execution_symbol, "startExecution:"},
  {&_gst_string_out_symbol, "stringOut"},
  {&_gst_string_symbol, "string"},
  {&_gst_super_symbol, "super"},
  {&_gst_symbol_symbol, "symbol"},
  {&_gst_symbol_out_symbol, "symbolOut"},
  {&_gst_terminate_symbol, "__terminate"},
  {&_gst_times_repeat_symbol, "timesRepeat:"},
  {&_gst_to_by_do_symbol, "to:by:do:"},
  {&_gst_to_do_symbol, "to:do:"},
  {&_gst_true_symbol, "true"},
  {&_gst_undeclared_symbol, "Undeclared"},
  {&_gst_unknown_symbol, "unknown"},
  {&_gst_value_with_rec_with_args_symbol, "valueWithReceiver:withArguments:"},
  {&_gst_variadic_symbol, "variadic"},
  {&_gst_variadic_smalltalk_symbol, "variadicSmalltalk"},
  {&_gst_vm_primitives_symbol, "VMPrimitives"},
  {&_gst_void_symbol, "void"},
  {&_gst_wchar_symbol, "wchar"},
  {&_gst_wstring_symbol, "wstring"},
  {&_gst_wstring_out_symbol, "wstringOut"},
  {&_gst_while_false_colon_symbol, "whileFalse:"},
  {&_gst_while_false_symbol, "whileFalse"},
  {&_gst_while_true_colon_symbol, "whileTrue:"},
  {&_gst_while_true_symbol, "whileTrue"},
  {NULL, NULL},
};


const char *
_gst_get_scope_kind (scope_type scope)
{
  switch (scope)
    {
    case SCOPE_TEMPORARY: return "argument";
    case SCOPE_RECEIVER: return "instance variable";
    case SCOPE_GLOBAL: return "global variable";
    case SCOPE_SPECIAL: return "special variable";
    default: abort ();
    }
}

int
_gst_get_arg_count (void)
{
  return (cur_scope->numArguments);
}

int
_gst_get_temp_count (void)
{
  return (cur_scope->numTemporaries);
}

void
_gst_push_new_scope (void)
{
  scope newScope;
  newScope = (scope) xmalloc (sizeof (*newScope));
  newScope->prevScope = cur_scope;
  newScope->symbols = NULL;
  newScope->numArguments = 0;
  newScope->numTemporaries = 0;
  cur_scope = newScope;
}

void
_gst_pop_old_scope (void)
{
  scope oldScope;

  oldScope = cur_scope;
  cur_scope = cur_scope->prevScope;

  free_scope_symbols (oldScope);
  xfree (oldScope);
}

void
_gst_pop_all_scopes (void)
{
  while (cur_scope)
    _gst_pop_old_scope ();
}


int
_gst_declare_arguments (tree_node args)
{
  if (args->nodeType == TREE_UNARY_EXPR)
    return (0);

  else if (args->nodeType == TREE_BINARY_EXPR)
    _gst_declare_name (args->v_expr.expression->v_list.name, false, false);

  else
    {
      for (args = args->v_expr.expression; args != NULL;
	   args = args->v_list.next)
	if (_gst_declare_name (args->v_list.value->v_list.name, false, false) == -1)
	  return -1;
    }

  /* Arguments are always declared first! */
  cur_scope->numArguments = cur_scope->numTemporaries;
  cur_scope->numTemporaries = 0;
  return (cur_scope->numArguments);
}

int
_gst_declare_temporaries (tree_node temps)
{
  int n;
  for (n = 0; temps != NULL; n++, temps = temps->v_list.next)
    if (_gst_declare_name (temps->v_list.name, true, false) == -1)
      return -1;

  return (n);
}

int
_gst_declare_block_arguments (tree_node args)
{
  for (; args != NULL; args = args->v_list.next)
    if (_gst_declare_name (args->v_list.name, false, false) == -1)
      return -1;

  /* Arguments are always declared first! */
  cur_scope->numArguments = cur_scope->numTemporaries;
  cur_scope->numTemporaries = 0;
  return (cur_scope->numArguments);
}

void
_gst_undeclare_name (void)
{
  symbol_list oldList;

  oldList = cur_scope->symbols;
  cur_scope->symbols = cur_scope->symbols->prevSymbol;
  xfree (oldList);
}


int
_gst_declare_name (const char *name,
		   mst_Boolean writeable,
		   mst_Boolean allowDup)
{
  symbol_list newList;
  OOP symbol = _gst_intern_string (name);

  if (!allowDup && find_local_var (cur_scope, symbol) != NULL)
    return -1;

  newList = (symbol_list) xmalloc (sizeof (struct symbol_list));
  newList->symbol = symbol;
  newList->index = cur_scope->numArguments + cur_scope->numTemporaries;
  newList->readOnly = !writeable;
  newList->prevSymbol = cur_scope->symbols;

  /* Arguments are always declared first, so we can assume it is a
     temporary -- if it is not, _gst_declare_arguments and
     _gst_declare_block_arguments will fix it.  */
  cur_scope->numTemporaries++;
  cur_scope->symbols = newList;
  return (newList->index);
}


static void
free_scope_symbols (scope scope)
{
  symbol_list oldList;

  for (oldList = scope->symbols; oldList != NULL;
       oldList = scope->symbols)
    {
      scope->symbols = oldList->prevSymbol;
      xfree (oldList);
    }
}


OOP
_gst_get_class_object (OOP classOOP)
{
  if (OOP_CLASS (classOOP) == _gst_metaclass_class)
    classOOP = METACLASS_INSTANCE (classOOP);

  while (OOP_CLASS (classOOP) == _gst_behavior_class
	 || OOP_CLASS (classOOP) == _gst_class_description_class)
    classOOP = SUPERCLASS (classOOP);

  return classOOP;
}

OOP
find_class_variable (OOP varName)
{
  OOP class_oop, assocOOP, poolDictionaryOOP;
  OOP myClass;
  int numPools, i;
  gst_class class;

  myClass = _gst_get_class_object (_gst_this_class);

  /* Now search in the class pools */
  for (class_oop = myClass; !IS_NIL (class_oop);
       class_oop = SUPERCLASS (class_oop))
    {
      assocOOP =
	dictionary_association_at (_gst_class_variable_dictionary
				   (class_oop), varName);

      if (!IS_NIL (assocOOP))
	return (assocOOP);
    }

  /* Now search in the `environments' */
  for (class_oop = myClass; !IS_NIL (class_oop);
       class_oop = SUPERCLASS (class_oop))
    {
      class = (gst_class) OOP_TO_OBJ (class_oop);
      assocOOP =
	_gst_namespace_association_at (class->environment, varName);
      if (!IS_NIL (assocOOP))
	return (assocOOP);
    }

  /* and in the shared pools */
  for (class_oop = myClass; !IS_NIL (class_oop);
       class_oop = SUPERCLASS (class_oop))
    {
      class = (gst_class) OOP_TO_OBJ (class_oop);
      numPools = NUM_OOPS (OOP_TO_OBJ (class->sharedPools));
      for (i = 0; i < numPools; i++)
	{
	  poolDictionaryOOP = ARRAY_AT (class->sharedPools, i + 1);
	  assocOOP =
	    _gst_namespace_association_at (poolDictionaryOOP, varName);
	  if (!IS_NIL (assocOOP))
	    return (assocOOP);
	}
    }

  return (_gst_nil_oop);
}


int
_gst_set_undeclared (enum undeclared_strategy new)
{
  enum undeclared_strategy old = _gst_use_undeclared;
  if (new != UNDECLARED_CURRENT)
    _gst_use_undeclared = new;
  return old;
}

OOP
_gst_push_temporaries_dictionary (void)
{
  OOP old = temporaries_dictionary;
  temporaries_dictionary = _gst_dictionary_new (8);
  _gst_register_oop (temporaries_dictionary);
  return old;
}

void
_gst_pop_temporaries_dictionary (OOP dictionaryOOP)
{
  _gst_unregister_oop (temporaries_dictionary);
  temporaries_dictionary = dictionaryOOP;
}


tree_node
_gst_find_variable_binding (tree_node list)
{
  OOP symbol, root, assocOOP;
  tree_node elt;

  symbol = _gst_intern_string (list->v_list.name);
  assocOOP = find_class_variable (symbol);

  for (elt = list; assocOOP != _gst_nil_oop && (elt = elt->v_list.next); )
    {
      root = ASSOCIATION_VALUE (assocOOP);
      symbol = _gst_intern_string (elt->v_list.name);
      assocOOP = _gst_namespace_association_at (root, symbol);
    }

  if (!IS_NIL (assocOOP))
    return _gst_make_oop_constant (&list->location, assocOOP);

  else if (_gst_use_undeclared == UNDECLARED_GLOBALS
	   && !elt->v_list.next 
	   && isupper (*STRING_OOP_CHARS (symbol)))
    {
      OOP dictOOP = dictionary_at (_gst_smalltalk_dictionary,
				   _gst_undeclared_symbol);
      assocOOP = _gst_namespace_association_at (dictOOP, symbol);
      if (IS_NIL (assocOOP))
        assocOOP = NAMESPACE_AT_PUT (dictOOP, symbol, _gst_nil_oop);
      return _gst_make_oop_constant (&list->location, assocOOP);
    }

  /* For temporaries, make a deferred binding so that we can try using
     a global variable.  Unlike namespaces, the temporaries dictionary
     does not know anything about Undeclared.  */
  else if (_gst_use_undeclared == UNDECLARED_TEMPORARIES)
    return _gst_make_deferred_binding_constant (&list->location, list);

  else
    return NULL;
}

OOP
_gst_get_undeclared_dictionary ()
{
  assert (_gst_use_undeclared == UNDECLARED_TEMPORARIES);
  return temporaries_dictionary;
}

mst_Boolean
_gst_find_variable (symbol_entry * se,
		    tree_node list)
{
  tree_node resolved;
  int index;
  unsigned int scopeDistance;
  scope scope;
  symbol_list s;
  OOP varAssoc;
  OOP symbol;

  symbol = _gst_intern_string (list->v_list.name);
  if (symbol == _gst_self_symbol || symbol == _gst_super_symbol)
    {
      fill_symbol_entry (se, SCOPE_SPECIAL, true, symbol, RECEIVER_INDEX,
			 0);
      return (true);
    }
  else if (symbol == _gst_true_symbol)
    {
      fill_symbol_entry (se, SCOPE_SPECIAL, true, symbol, TRUE_INDEX, 0);
      return (true);
    }
  else if (symbol == _gst_false_symbol)
    {
      fill_symbol_entry (se, SCOPE_SPECIAL, true, symbol, FALSE_INDEX,
			 0);
      return (true);
    }
  else if (symbol == _gst_nil_symbol)
    {
      fill_symbol_entry (se, SCOPE_SPECIAL, true, symbol, NIL_INDEX, 0);
      return (true);
    }
  else if (symbol == _gst_builtin_selectors[THIS_CONTEXT_SPECIAL].symbol)
    {
      fill_symbol_entry (se, SCOPE_SPECIAL, true, symbol,
			 THIS_CONTEXT_INDEX, 0);
      return (true);
    }

  for (scope = cur_scope, scopeDistance = 0; scope != NULL;
       scope = scope->prevScope, scopeDistance++)
    {
      s = find_local_var (scope, symbol);
      if (s)
	{
	  fill_symbol_entry (se, SCOPE_TEMPORARY,
			     s->readOnly, symbol, s->index,
			     scopeDistance);
	  return (true);
	}
    }

  index = instance_variable_index (symbol);
  if (index >= 0)
    {
      fill_symbol_entry (se, SCOPE_RECEIVER, 
			 is_instance_variable_read_only (index),
			 symbol, index, 0);
      return (true);
    }

  resolved = _gst_find_variable_binding (list);
  if (!resolved)
    return (false);

  varAssoc = _gst_make_constant_oop (resolved);
  index = _gst_add_forced_object (varAssoc);

  fill_symbol_entry (se, SCOPE_GLOBAL, 
		     _gst_untrusted_methods && !IS_OOP_UNTRUSTED (varAssoc),
		     varAssoc, index, 0);
  return (true);
}

static mst_Boolean
is_instance_variable_read_only (int index)
{
  int numVars;
  OOP class_oop;

  if (!_gst_untrusted_methods)
    return (false);

  for (class_oop = _gst_this_class; IS_OOP_UNTRUSTED (class_oop);
       class_oop = SUPERCLASS (class_oop))
    ;

  numVars = CLASS_FIXED_FIELDS (class_oop);
  return index + 1 <= numVars;
}

static int
instance_variable_index (OOP symbol)
{
  OOP arrayOOP;
  int index, numVars;

  arrayOOP = _gst_instance_variable_array (_gst_this_class);
  numVars = NUM_OOPS (OOP_TO_OBJ (arrayOOP));

  for (index = numVars; index >= 1; index--)
    if (ARRAY_AT (arrayOOP, index) == symbol)
      return (index - 1);

  return (-1);
}


static symbol_list
find_local_var (scope scope,
		OOP symbol)
{
  symbol_list s;

  for (s = scope->symbols; s != NULL && symbol != s->symbol;
       s = s->prevSymbol);

  return (s);
}

static void
fill_symbol_entry (symbol_entry * ent,
		   scope_type scope,
		   mst_Boolean readOnly,
		   OOP symbol,
		   int index,
		   unsigned int scopeDistance)
{
  ent->scope = scope;
  ent->readOnly = readOnly;
  ent->symbol = symbol;
  ent->varIndex = index;
  ent->scopeDistance = scopeDistance;
}

void
_gst_print_symbol_entry (symbol_entry * ent)
{
  printf ("%#O", ent->symbol);
  switch (ent->scope)
    {
    case SCOPE_RECEIVER:
      printf (" (inst.var. #%d)", ent->varIndex);
      break;

    case SCOPE_GLOBAL:
      printf (" (global)");
      break;

    case SCOPE_TEMPORARY:
      printf (" (temp.var. #");
      if (ent->scopeDistance)
	printf ("%d.", ent->scopeDistance);

      printf ("%d)", ent->varIndex);
      break;

    case SCOPE_SPECIAL:
      printf (" (special)");
      break;
    }
}



OOP
_gst_find_pragma_handler (OOP classOOP,
			  OOP symbolOOP)
{
  OOP class_oop, myClass;

  myClass = _gst_get_class_object (_gst_this_class);

  /* Now search in the class pools */
  for (class_oop = myClass; !IS_NIL (class_oop);
       class_oop = SUPERCLASS (class_oop))
    {
      gst_class class = (gst_class) OOP_TO_OBJ (class_oop);
      OOP handlerOOP;

      if (IS_NIL (class->pragmaHandlers))
	continue;

      handlerOOP = _gst_identity_dictionary_at (class->pragmaHandlers,
                                                symbolOOP);
      if (!IS_NIL (handlerOOP))
	return handlerOOP;
    }

  return (_gst_nil_oop);
}

OOP
_gst_make_instance_variable_array (OOP superclassOOP,
				   const char * variableString)
{
  OOP arrayOOP, superArrayOOP, name;
  int index, numInstanceVars, superInstanceVars;
  const char *p;
  inc_ptr incPtr;
  gst_object array;

  if (variableString == NULL)
    variableString = "";

  if (IS_NIL (superclassOOP))
    {
      superArrayOOP = _gst_nil_oop;
      superInstanceVars = numInstanceVars = 0;
    }
  else
    {
      superArrayOOP = _gst_instance_variable_array (superclassOOP);
      superInstanceVars = numInstanceVars =
	NUM_OOPS (OOP_TO_OBJ (superArrayOOP));
    }

  for (p = variableString; *p;)
    {
      /* skip intervening whitespace */
      name = scan_name (&p);
      if (!IS_NIL (name))
	numInstanceVars++;
    }

  if (numInstanceVars == 0)
    return (_gst_nil_oop);	/* no instances here */

  incPtr = INC_SAVE_POINTER ();

  array = instantiate_with (_gst_array_class, numInstanceVars, &arrayOOP);
  INC_ADD_OOP (arrayOOP);

  /* inherit variables from parent */
  for (index = 1; index <= superInstanceVars; index++)
    array->data[index - 1] = ARRAY_AT (superArrayOOP, index);

  /* now add our own variables */
  for (p = variableString; *p; index++)
    {
      /* skip intervening whitespace */
      name = scan_name (&p);
      /* don't need to add name to incubator -- it's a symbol so it's
         already held onto */

      array = OOP_TO_OBJ (arrayOOP);
      if (!IS_NIL (name))
	array->data[index - 1] = name;
    }

  INC_RESTORE_POINTER (incPtr);
  return (arrayOOP);
}

OOP
_gst_make_class_variable_dictionary (const char *variableNames,
				     OOP classOOP)
{
  OOP dictionaryOOP, name;
  const char *p;
  inc_ptr incPtr;

  if (variableNames == NULL)
    variableNames = (gst_uchar *) "";

  incPtr = INC_SAVE_POINTER ();

  dictionaryOOP = _gst_nil_oop;
  for (p = variableNames; *p;)
    {
      name = scan_name (&p);
      if (!IS_NIL (name))
	{
	  if (IS_NIL (dictionaryOOP))
	    {
	      dictionaryOOP = _gst_binding_dictionary_new (8, classOOP);
	      INC_ADD_OOP (dictionaryOOP);
	    }

	  /* ### error if already exists */
	  /* don't need to add name to incubator -- it's a symbol so
	     it's already held onto */
	  NAMESPACE_AT_PUT (dictionaryOOP, name, _gst_nil_oop);
	}
    }

  INC_RESTORE_POINTER (incPtr);
  return (dictionaryOOP);
}

OOP
_gst_make_pool_array (const char * poolNames)
{
  OOP poolsOOP, name;
  gst_object pools;
  int numPools, i;
  const char *p, *e;
  inc_ptr incPtr;

  if (poolNames == NULL)
    poolNames = (char *) "";

  /* count the number of new pool names */
  for (p = poolNames, numPools = 0; *p;)
    {
      parse_variable_name (&p, &e);
      if (p != e)
	{
	  numPools++;
	  p = e;
	}
    }

  incPtr = INC_SAVE_POINTER ();

  poolsOOP = _gst_nil_oop;	/* ### maybe change this to leave empty 
				   array */

  for (p = poolNames, i = 0; *p; i++)
    {
      name = scan_name (&p);
      if (!IS_NIL (name))
	{
	  /* don't need to add name to incubator -- it's a symbol so
	     it's already held onto.  */

	  /* ### error if already exists in parent?, or if value isn't
	     a dictionary */
	  /* ### should I keep these as names? or associations? Should
	     I look up the names somewhere other than in the smalltalk
	     dictionary? Need to check for undefineds? */
	  if (poolsOOP == _gst_nil_oop)
	    {
	      instantiate_with (_gst_array_class, numPools, &poolsOOP);
	      INC_ADD_OOP (poolsOOP);
	    }

	  pools = OOP_TO_OBJ (poolsOOP);
	  pools->data[i] = dictionary_at (_gst_smalltalk_dictionary,
					  name);
	}
    }


  INC_RESTORE_POINTER (incPtr);
  return (poolsOOP);
}



static OOP
scan_name (const char ** pp)
{
  const char *end;
  char *str;
  size_t len;

  parse_variable_name (pp, &end);
  len = end - *pp;
  if (len == 0)
    return (_gst_nil_oop);

  str = (char *) alloca (len + 1);
  strncpy (str, *pp, len);
  str[len] = '\0';

  *pp = end;

  return (_gst_intern_string (str));
}

static void
parse_variable_name (const char ** pp,
		     const char ** endp)
{
  const char *p, *e;

  p = *pp;
  while (is_white_space (*p))
    p++;
  *pp = p;

  /* check for non-null here and not alnum; we've jammed on a bogus 
     char and it's an error */

  if (isalpha (*p)) {
    /* variable name extends from p to e-1 */
    for (e = p; *e; e++)
      if (!isalnum (*e) && *e != '_')
	break;

    *endp = e;
  } else
    *endp = p;
}

static mst_Boolean
is_white_space (char c)
{
  return (c == ' ' || c == '\r' || c == '\t' || c == '\n' || c == '\f');
}



OOP
_gst_intern_string_oop (OOP stringOOP)
{
  unsigned int len;
  char copyBuf[100], *copyPtr;
  OOP symbolOOP;

  len = _gst_string_oop_len (stringOOP);

  /* do this slightly more complicated bit of code because: 1) we don't 
     want to call malloc/free if we can help it 2) if we just used
     STRING_OOP_CHARS (as we used to), we pass the *dereferenced* value 
     of the stringOOP.  intern_counted_string can do allocations.  If
     it allocates, and the gc runs, stringOOP can move, meaning the
     dereferenced set of chars becomes invalid.  So instead we make a
     non-moving copy and use that.  */
  if (len < sizeof (copyBuf))
    copyPtr = copyBuf;
  else
    copyPtr = (char *) xmalloc (len);

  memcpy (copyPtr, STRING_OOP_CHARS (stringOOP), len);

  symbolOOP = intern_counted_string (copyPtr, len);

  if (len >= sizeof (copyBuf))
    xfree (copyPtr);

  return symbolOOP;
}

OOP
_gst_intern_string (const char *str)
{
  int len;

  len = strlen (str);
  return (intern_counted_string (str, len));
}

static uintptr_t
hash_symbol (const char *str, int len)
{
  uintptr_t index = scramble (_gst_hash_string (str, len));
  return (index & (SYMBOL_TABLE_SIZE - 1)) + 1;
}

static OOP
alloc_symlink (OOP symbolOOP, uintptr_t index)
{
  gst_symbol symbol;
  sym_link link;
  OOP linkOOP;

  symbol = (gst_symbol) OOP_TO_OBJ (symbolOOP);
  symbol->objClass = _gst_symbol_class;

  link = (sym_link) new_instance (_gst_sym_link_class, &linkOOP);
  link->nextLink = ARRAY_AT (_gst_symbol_table, index);
  link->symbol = symbolOOP;
  ARRAY_AT_PUT (_gst_symbol_table, index, linkOOP);

  return (symbolOOP);
}

static OOP
intern_counted_string (const char *str,
		       int len)
{
  uintptr_t index;
  OOP symbolOOP, linkOOP;
  sym_link link;
  inc_ptr incPtr;

  index = hash_symbol (str, len);
  for (linkOOP = ARRAY_AT (_gst_symbol_table, index); !IS_NIL (linkOOP);
       linkOOP = link->nextLink)
    {
      link = (sym_link) OOP_TO_OBJ (linkOOP);
      if (is_same_string (str, link->symbol, len))
	return (link->symbol);
    }

  /* no match, have to add it to head of list */
#ifdef HAVE_READLINE
  _gst_add_symbol_completion (str, len);
#endif

  incPtr = INC_SAVE_POINTER ();
  symbolOOP = alloc_symbol_oop (str, len);
  INC_ADD_OOP (symbolOOP);

  alloc_symlink (symbolOOP, index);
  INC_RESTORE_POINTER (incPtr);

  return (symbolOOP);
}

static OOP
alloc_symbol_oop (const char *str, int len)
{
  int numBytes, alignedBytes;
  gst_symbol symbol;
  OOP symbolOOP;

  numBytes = sizeof(gst_object_header) + len;
  alignedBytes = ROUNDED_BYTES (numBytes);
  symbol = (gst_symbol) _gst_alloc_obj (alignedBytes, &symbolOOP);
  INIT_UNALIGNED_OBJECT (symbolOOP, alignedBytes - numBytes);

  memcpy (symbol->symString, str, len);
  symbolOOP->flags |= F_READONLY;
  return symbolOOP;
}

static mst_Boolean
is_same_string (const char *str,
		OOP oop,
		int len)
{
  if (_gst_string_oop_len (oop) == len)
    return (strncmp
	    (str, ((gst_symbol) OOP_TO_OBJ (oop))->symString,
	     len) == 0);

  return (false);
}

int
_gst_string_oop_len (OOP oop)
{
  return (OOP_SIZE_BYTES (oop) - (oop->flags & EMPTY_BYTES));
}

uintptr_t
_gst_hash_string (const char *str,
		  int len)
{
  uintptr_t hashVal = 1497032417;    /* arbitrary value */

  while (len--)
    {
      hashVal += *str++;
      hashVal += (hashVal << 10);
      hashVal ^= (hashVal >> 6);
    }

  return hashVal & MAX_ST_INT;
}

char *
_gst_symbol_as_string (OOP symbolOOP)
{
  static char stringBuf[256];	/* probably large enough for most
				   symbols */
  unsigned int len;
  gst_symbol symbol;

  symbol = (gst_symbol) OOP_TO_OBJ (symbolOOP);

  len = _gst_string_oop_len (symbolOOP);
  if (len >= sizeof (stringBuf))
    _gst_errorf ("symbol name too long: %d, max is %d", len,
		 sizeof (stringBuf));

  strncpy (stringBuf, symbol->symString, len);
  stringBuf[len] = '\0';
  return (stringBuf);
}



void
_gst_check_symbol_chain (void)
{
  int i;

  for (i = 1; i <= SYMBOL_TABLE_SIZE; i++)
    {
      sym_link link;
      OOP linkOOP;
      for (linkOOP = ARRAY_AT (_gst_symbol_table, i); !IS_NIL (linkOOP);
	   linkOOP = link->nextLink)
	{
	  link = (sym_link) OOP_TO_OBJ (linkOOP);
	  if (OOP_CLASS (linkOOP) != _gst_sym_link_class ||
	      OOP_CLASS (link->symbol) != _gst_symbol_class)
	    {
	      printf ("Bad symbol %p\n", linkOOP);
	      abort ();
	    }
	}
    }
}

#ifdef HAVE_READLINE
void
_gst_add_all_symbol_completions (void)
{
  int i;

  for (i = 1; i <= SYMBOL_TABLE_SIZE; i++)
    {
      sym_link link;
      OOP linkOOP;
      char *string;
      int len;
      for (linkOOP = ARRAY_AT (_gst_symbol_table, i); !IS_NIL (linkOOP);
	   linkOOP = link->nextLink)
	{
	  link = (sym_link) OOP_TO_OBJ (linkOOP);
	  string = _gst_to_cstring (link->symbol);
	  len = _gst_string_oop_len (link->symbol);
	  _gst_add_symbol_completion (string, len);
	  xfree (string);
	}
    }
}
#endif



int
_gst_selector_num_args (OOP symbolOOP)
{
  char *bytes;
  int numArgs, len;

  len = _gst_string_oop_len (symbolOOP);
  bytes = (char *) (OOP_TO_OBJ (symbolOOP)->data);
  if (bytes[0] < 'A' || bytes[0] > 'z')
    return (1);

  if (bytes[0] > 'Z' && bytes[0] < 'a')
    return (1);

  for (numArgs = 0; len;)
    if (bytes[--len] == ':')
      numArgs++;

  return (numArgs);
}

#include "builtins.inl"

void
_gst_init_symbols_pass1 (void)
{
  const symbol_info *si;
  struct builtin_selector *bs;

  for (si = sym_info; si->symbolVar; si++)
    *si->symbolVar = alloc_symbol_oop (si->value, strlen (si->value));

  /* Complete gperf's generated table with each symbol's OOP,
     and prepare a kind of reverse mapping from the 256 bytecodes
     to the hash table entries.  */
  for (bs = _gst_builtin_selectors_hash;
       bs - _gst_builtin_selectors_hash <
	 sizeof (_gst_builtin_selectors_hash) / sizeof (_gst_builtin_selectors_hash[0]);
       bs++)
    if (bs->offset != -1)
      {
	const char *name = bs->offset + _gst_builtin_selectors_names;
	bs->symbol = alloc_symbol_oop (name, strlen (name));
        _gst_builtin_selectors[bs->bytecode] = *bs;
      }
}

void
_gst_init_symbols_pass2 (void)
{
  const symbol_info *si;
  struct builtin_selector *bs;

  for (si = sym_info; si->symbolVar; si++)
    alloc_symlink (*si->symbolVar, hash_symbol (si->value, strlen (si->value)));

  /* Complete gperf's generated table with each symbol's OOP,
     and prepare a kind of reverse mapping from the 256 bytecodes
     to the hash table entries.  */
  for (bs = _gst_builtin_selectors_hash;
       bs - _gst_builtin_selectors_hash <
	 sizeof (_gst_builtin_selectors_hash) / sizeof (_gst_builtin_selectors_hash[0]);
       bs++)
    if (bs->offset != -1)
      {
	const char *name = bs->offset + _gst_builtin_selectors_names;
	alloc_symlink (bs->symbol, hash_symbol (name, strlen (name)));
      }
}

static inline OOP
intern_string_fast (const char *str, OOP *pTestOOP)
{
  int len = strlen (str);
  OOP testOOP = *pTestOOP;

  if (is_same_string (str, testOOP, len))
    {
      (*pTestOOP)++;
      return testOOP;
    }
  else
    return intern_counted_string (str, len);
}

void
_gst_restore_symbols (void)
{
  const symbol_info *si;
  struct builtin_selector *bs;
  OOP currentOOP = _gst_symbol_table + 1;

  for (si = sym_info; si->symbolVar; si++)
    *si->symbolVar = intern_string_fast (si->value, &currentOOP);

  /* Complete gperf's generated table with each symbol's OOP,
     and prepare a kind of reverse mapping from the 256 bytecodes
     to the hash table entries.  */
  for (bs = _gst_builtin_selectors_hash;
       bs - _gst_builtin_selectors_hash <
	 sizeof (_gst_builtin_selectors_hash) / sizeof (_gst_builtin_selectors_hash[0]);
       bs++)
    if (bs->offset != -1)
      {
	const char *name = bs->offset + _gst_builtin_selectors_names;
	bs->symbol = intern_string_fast (name, &currentOOP);
        _gst_builtin_selectors[bs->bytecode] = *bs;
      }
}