parse.c

gcc-2.95.3 Linux下最常用的C编译器

parse_modulion (label)
     tree label;
{
  tree module_name;

  label = set_module_name (label);
  module_name = push_module (label, 0);
  FORWARD_TOKEN();

  push_action ();
  parse_body();
  expect(END, "expected END here");
  parse_opt_handler ();
  parse_opt_end_label_semi_colon (label);
  find_granted_decls ();
  pop_module ();
}

static void
parse_spec_module (label)
     tree label;
{
  int save_ignoring = ignoring;

  push_module (set_module_name (label), 1);
  ignoring = pass == 2;
  FORWARD_TOKEN(); /* SKIP SPEC */
  expect (MODULE, "expected 'MODULE' here");

  while (parse_definition (1)) { }
  if (parse_action ())
    error ("action not allowed in SPEC MODULE");
  expect(END, "expected END here");
  parse_opt_end_label_semi_colon (label);
  find_granted_decls ();
  pop_module ();
  ignoring = save_ignoring;
}

/* Matches:  <name_string> ( "," <name_string> )*
   Returns either a single IDENTIFIER_NODE,
   or a chain (TREE_LIST) of IDENTIFIER_NODES.
   (Since a single identifier is the common case, we avoid wasting space
   (twice, once for each pass) with extra TREE_LIST nodes in that case.)
   (Will not return NULL_TREE even if ignoring is true.) */

static tree
parse_defining_occurrence_list ()
{
  tree chain = NULL_TREE;
  tree name = parse_defining_occurrence ();
  if (name == NULL_TREE)
    {
      error("missing defining occurrence");
      return NULL_TREE;
    }
  if (! check_token (COMMA))
    return name;
  chain = build_tree_list (NULL_TREE, name);
  for (;;)
    {
      name = parse_defining_occurrence ();
      if (name == NULL)
	{
	  error ("bad defining occurrence following ','");
	  break;
	}
      chain = tree_cons (NULL_TREE, name, chain);
      if (! check_token (COMMA))
	break;
    }
  return nreverse (chain);
}

static void
parse_mode_definition (is_newmode)
     int is_newmode;
{
  tree mode, names;
  int save_ignoring = ignoring;
  ignoring = pass == 2;
  names = parse_defining_occurrence_list ();
  expect (EQL, "missing '=' in mode definition");
  mode = parse_mode ();
  if (names == NULL_TREE || TREE_CODE (names) == TREE_LIST)
    {
      for ( ; names != NULL_TREE; names = TREE_CHAIN (names))
	push_modedef (names, mode, is_newmode);
    }
  else
    push_modedef (names, mode, is_newmode);
  ignoring = save_ignoring;
}

void
parse_mode_definition_statement (is_newmode)
     int is_newmode;
{
  FORWARD_TOKEN (); /* skip SYNMODE or NEWMODE */
  parse_mode_definition (is_newmode);
  while (PEEK_TOKEN () == COMMA)
    {
      FORWARD_TOKEN ();
      parse_mode_definition (is_newmode);
    }
  parse_semi_colon ();
}

static void
parse_synonym_definition ()
{ tree expr = NULL_TREE;
  tree names = parse_defining_occurrence_list ();
  tree mode = parse_opt_mode ();
  if (! expect (EQL, "missing '=' in synonym definition"))
    mode = error_mark_node;
  else
    {
      if (mode)
	expr = parse_untyped_expr ();
      else
	expr = parse_expression ();
    }
  if (names == NULL_TREE || TREE_CODE (names) == TREE_LIST)
    {
      for ( ; names != NULL_TREE; names = TREE_CHAIN (names))
	push_syndecl (names, mode, expr);
    }
  else
    push_syndecl (names, mode, expr);
}

static void
parse_synonym_definition_statement()
{
  int save_ignoring= ignoring;
  ignoring = pass == 2;
  require (SYN);
  parse_synonym_definition ();
  while (PEEK_TOKEN () == COMMA)
    {
      FORWARD_TOKEN ();
      parse_synonym_definition ();
    }
  ignoring = save_ignoring;
  parse_semi_colon ();
}

/* Attempts to match: "(" <exception list> ")" ":".
   Return NULL_TREE on failure, and non-NULL on success.
   On success, if pass 1, return a TREE_LIST of IDENTIFIER_NODEs. */

static tree
parse_on_exception_list ()
{
  tree name;
  tree list = NULL_TREE;
  int tok1 = PEEK_TOKEN ();
  int tok2 = PEEK_TOKEN1 ();

  /* This requires a lot of look-ahead, because we cannot
     easily a priori distinguish an exception-list from an expression. */
  if (tok1 != LPRN || tok2 != NAME)
    {
      if (tok1 == NAME && tok2 == COLON && pass == 1)
	error ("missing '(' in exception list");
      return 0;
    }
  require (LPRN);
  name = parse_name_string ();
  if (PEEK_TOKEN () == RPRN && PEEK_TOKEN1 () == COLON)
    {
      /* Matched: '(' <name_string> ')' ':' */
      FORWARD_TOKEN (); FORWARD_TOKEN ();
      return pass == 1 ? build_tree_list (NULL_TREE, name) : name;
    }
  if (PEEK_TOKEN() == COMMA)
    {
      if (pass == 1)
	list = build_tree_list (NULL_TREE, name);
      while (check_token (COMMA))
	{
	  tree old_names = list;
	  name = parse_name_string ();
	  if (pass == 1)
	    {
	      for ( ; old_names != NULL_TREE; old_names = TREE_CHAIN (old_names))
		{
		  if (TREE_VALUE (old_names) == name)
		    {
		      error ("ON exception names must be unique");
		      goto continue_parsing;
		    }
		}
	      list = tree_cons (NULL_TREE, name, list);
	    continue_parsing:
	      ;
	    }
	}
      if (! check_token (RPRN) || ! check_token(COLON))
	error ("syntax error in exception list");
      return pass == 1 ? nreverse (list) : name;
    }
  /* Matched: '(' name_string
     but it doesn't match the syntax of an exception list.
     It could be the beginning of an expression, so back up. */
  pushback_token (NAME, name);
  pushback_token (LPRN, 0);
  return NULL_TREE;
}

static void
parse_on_alternatives ()
{
  for (;;)
    {
      tree except_list = parse_on_exception_list ();
      if (except_list != NULL)
	chill_handle_on_labels (except_list);
      else if (parse_action ())
	expand_exit_needed = 1;
      else
	break;
    }
}

static tree
parse_opt_handler ()
{
  if (! check_token (ON))
    {
      POP_UNUSED_ON_CONTEXT;
      return NULL_TREE;
    }
  if (check_token (END))
    {
      pedwarn ("empty ON-condition"); 
      POP_UNUSED_ON_CONTEXT;
      return NULL_TREE;
    } 
  if (! ignoring)
    {
      chill_start_on ();
      expand_exit_needed = 0;
    }
  if (PEEK_TOKEN () != ELSE)
    {
      parse_on_alternatives ();
      if (! ignoring && expand_exit_needed)
	expand_exit_something (); 
    }
  if (check_token (ELSE))
    {
      chill_start_default_handler ();
      label = NULL_TREE;
      parse_opt_actions ();
      if (! ignoring)
	{
	  emit_line_note (input_filename, lineno); 
	  expand_exit_something (); 
	} 
    }
  expect (END, "missing 'END' after");
  if (! ignoring)
    chill_finish_on ();
  POP_USED_ON_CONTEXT;
  return integer_zero_node; 
}

static void
parse_loc_declaration (in_spec_module)
     int in_spec_module;
{
  tree names = parse_defining_occurrence_list ();
  int save_ignoring = ignoring;
  int is_static, lifetime_bound;
  tree mode, init_value = NULL_TREE;
  int loc_decl = 0;

  ignoring = pass == 2;
  mode = parse_mode ();
  ignoring = save_ignoring;
  is_static = check_token (STATIC);
  if (check_token (BASED))
    {
      expect(LPRN, "BASED must be followed by (NAME)");
      do_based_decls (names, mode, parse_name_string ());
      expect(RPRN, "BASED must be followed by (NAME)");
      return;
    }
  if (check_token (LOC))
    {
      /* loc-identity declaration */
      if (pass == 1)
	mode = build_chill_reference_type (mode);
      loc_decl = 1;
    }
  lifetime_bound = check_token (INIT);
  if (lifetime_bound && loc_decl)
    {
      if (pass == 1)
	error ("INIT not allowed at loc-identity declaration");
      lifetime_bound = 0;
    }
  if (PEEK_TOKEN () == ASGN || PEEK_TOKEN() == EQL)
    {
      save_ignoring = ignoring;
      ignoring = pass == 1;
      if (PEEK_TOKEN() == EQL)
	{
	  if (pass == 1)
	    error ("'=' used where ':=' is required");
	}
      FORWARD_TOKEN();
      if (! lifetime_bound)
	push_handler ();
      init_value = parse_untyped_expr ();
      if (in_spec_module)
	{
	  error ("initialization is not allowed in spec module");
	  init_value = NULL_TREE;
	}
      if (! lifetime_bound)
	parse_opt_handler ();
      ignoring = save_ignoring;
    }
  if (init_value == NULL_TREE && loc_decl && pass == 1)
    error ("loc-identity declaration without initialisation");
  do_decls (names, mode,
	    is_static || global_bindings_p ()
	    /* the variable becomes STATIC if all_static_flag is set and
	       current functions doesn't have the RECURSIVE attribute */
	    || (all_static_flag && !CH_DECL_RECURSIVE (current_function_decl)),
	    lifetime_bound, init_value, in_spec_module);

  /* Free any temporaries we made while initializing the decl.  */
  free_temp_slots ();
}

static void
parse_declaration_statement (in_spec_module)
     int in_spec_module;
{
  int save_ignoring = ignoring;
  ignoring = pass == 2;
  require (DCL);
  parse_loc_declaration (in_spec_module);
  while (PEEK_TOKEN () == COMMA)
    {
      FORWARD_TOKEN ();
      parse_loc_declaration (in_spec_module);
    }
  ignoring = save_ignoring;
  parse_semi_colon ();
}

tree
parse_optforbid ()
{
  if (check_token (FORBID) == 0)
    return NULL_TREE;
  if (check_token (ALL))
    return ignoring ? NULL_TREE : build_int_2 (-1, -1);
#if 0
  if (check_token (LPRN))
    {
      tree list = parse_forbidlist ();
      expect (RPRN, "missing ')' after FORBID list");
      return list;
    }
#endif
  error ("bad syntax following FORBID");
  return NULL_TREE;
}

/* Matches: <grant postfix> or <seize postfix>
   Returns: A (singleton) TREE_LIST. */

tree
parse_postfix (grant_or_seize)
     enum terminal grant_or_seize;
{
  tree name = parse_opt_name_string (1);
  tree forbid = NULL_TREE;
  if (name == NULL_TREE)
    {
      error ("expected a postfix name here");
      name = error_mark_node;
    }
  if (grant_or_seize == GRANT)
    forbid = parse_optforbid ();
  return build_tree_list (forbid, name);
}

tree
parse_postfix_list (grant_or_seize)
     enum terminal grant_or_seize;
{
  tree list = parse_postfix (grant_or_seize);
  while (check_token (COMMA))
    list = chainon (list, parse_postfix (grant_or_seize));
  return list;
}

void
parse_rename_clauses (grant_or_seize)
     enum terminal grant_or_seize;
{
  for (;;)
    {
      tree rename_old_prefix, rename_new_prefix, postfix;
      require (LPRN);
      rename_old_prefix = parse_opt_name_string (0);
      expect (ARROW, "missing '->' in rename clause");
      rename_new_prefix = parse_opt_name_string (0);
      expect (RPRN,  "missing ')' in rename clause");
      expect ('!',  "missing '!' in rename clause");
      postfix = parse_postfix (grant_or_seize);

      if (grant_or_seize == GRANT)
	chill_grant (rename_old_prefix, rename_new_prefix,
		     TREE_VALUE (postfix), TREE_PURPOSE (postfix));
      else
	chill_seize (rename_old_prefix, rename_new_prefix,
		     TREE_VALUE (postfix));

      if (PEEK_TOKEN () != COMMA)
	break;
      FORWARD_TOKEN ();
      if (PEEK_TOKEN () != LPRN)
	{
	  error ("expected another rename clause");
	  break;
	}
    }
}

static tree
parse_opt_prefix_clause ()
{
  if (check_token (PREFIXED) == 0)
    return NULL_TREE;
  return build_prefix_clause (parse_opt_name_string (0));
}

void
parse_grant_statement ()
{
  require (GRANT);
  if (PEEK_TOKEN () == LPRN)
    parse_rename_clauses (GRANT);
  else
    {
      tree window = parse_postfix_list (GRANT);
      tree new_prefix = parse_opt_prefix_clause ();
      tree t;
      for (t = window; t; t = TREE_CHAIN (t))
	chill_grant (NULL_TREE, new_prefix, TREE_VALUE (t), TREE_PURPOSE (t));
    }
}

void
parse_seize_statement ()
{
  require (SEIZE);
  if (PEEK_TOKEN () == LPRN)
    parse_rename_clauses (SEIZE);
  else
    {
      tree seize_window = parse_postfix_list (SEIZE);
      tree old_prefix = parse_opt_prefix_clause ();
      tree t;
      for (t = seize_window; t; t = TREE_CHAIN (t))
	chill_seize (old_prefix, NULL_TREE, TREE_VALUE (t));
    }
}

/* In pass 1, this returns a TREE_LIST, one node for each parameter.
   In pass 2, we get a list of PARM_DECLs chained together.
   In either case, the list is in reverse order. */

static tree
parse_param_name_list ()
{
  tree list = NULL_TREE;
  do
    {
      tree new_link;
      tree name = parse_defining_occurrence ();
      if (name == NULL_TREE)
	{
	  error ("syntax error in parameter name list");
	  return list;
	}
      if (pass == 1)
	new_link = build_tree_list (NULL_TREE, name);
      /* else if (current_module->is_spec_module) ; nothing */
      else  /* pass == 2 */
	{
	  new_link = make_node (PARM_DECL);
	  DECL_NAME (new_link) = name;
	  DECL_ASSEMBLER_NAME (new_link) = name;
	}

      TREE_CHAIN (new_link) = list;
      list = new_link;
    } while (check_token (COMMA));
  return list;
}

static tree
parse_param_attr ()
{
  tree attr;
  switch (PEEK_TOKEN ())
    {
    case PARAMATTR:          /* INOUT is returned here */
      attr = PEEK_TREE ();
      FORWARD_TOKEN ();
      return attr;
    case IN:
      FORWARD_TOKEN ();
      return ridpointers[(int) RID_IN];
    case LOC:
      FORWARD_TOKEN ();
      return ridpointers[(int) RID_LOC];
#if 0
    case DYNAMIC:
      FORWARD_TOKEN ();
      return ridpointers[(int) RID_DYNAMIC];
#endif