c-decl.c

早期freebsd实现

     Put it into forward order, just for cleanliness.  */
  tree decls;
  tree tags = current_binding_level->tags;
  tree subblocks = current_binding_level->blocks;
  tree block = 0;
  tree decl;
  int block_previously_created;

  keep |= current_binding_level->keep;

  /* This warning is turned off because it causes warnings for
     declarations like `extern struct foo *x'.  */
#if 0
  /* Warn about incomplete structure types in this level.  */
  for (link = tags; link; link = TREE_CHAIN (link))
    if (TYPE_SIZE (TREE_VALUE (link)) == 0)
      {
	tree type = TREE_VALUE (link);
	char *errmsg;
	switch (TREE_CODE (type))
	  {
	  case RECORD_TYPE:
	    errmsg = "`struct %s' incomplete in scope ending here";
	    break;
	  case UNION_TYPE:
	    errmsg = "`union %s' incomplete in scope ending here";
	    break;
	  case ENUMERAL_TYPE:
	    errmsg = "`enum %s' incomplete in scope ending here";
	    break;
	  }
	if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
	  error (errmsg, IDENTIFIER_POINTER (TYPE_NAME (type)));
	else
	  /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
	  error (errmsg, IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))));
      }
#endif /* 0 */

  /* Get the decls in the order they were written.
     Usually current_binding_level->names is in reverse order.
     But parameter decls were previously put in forward order.  */

  if (reverse)
    current_binding_level->names
      = decls = nreverse (current_binding_level->names);
  else
    decls = current_binding_level->names;

  /* Output any nested inline functions within this block
     if they weren't already output.  */

  for (decl = decls; decl; decl = TREE_CHAIN (decl))
    if (TREE_CODE (decl) == FUNCTION_DECL
	&& ! TREE_ASM_WRITTEN (decl)
	&& DECL_INITIAL (decl) != 0
	&& TREE_ADDRESSABLE (decl))
      {
	/* If this decl was copied from a file-scope decl
	   on account of a block-scope extern decl,
	   propagate TREE_ADDRESSABLE to the file-scope decl.  */
	if (DECL_ABSTRACT_ORIGIN (decl) != 0)
	  TREE_ADDRESSABLE (DECL_ABSTRACT_ORIGIN (decl)) = 1;
	else
	  output_inline_function (decl);
      }

  /* If there were any declarations or structure tags in that level,
     or if this level is a function body,
     create a BLOCK to record them for the life of this function.  */

  block = 0;
  block_previously_created = (current_binding_level->this_block != 0);
  if (block_previously_created)
    block = current_binding_level->this_block;
  else if (keep || functionbody
	   || (current_binding_level->keep_if_subblocks && subblocks != 0))
    block = make_node (BLOCK);
  if (block != 0)
    {
      BLOCK_VARS (block) = decls;
      BLOCK_TYPE_TAGS (block) = tags;
      BLOCK_SUBBLOCKS (block) = subblocks;
      remember_end_note (block);
    }

  /* In each subblock, record that this is its superior.  */

  for (link = subblocks; link; link = TREE_CHAIN (link))
    BLOCK_SUPERCONTEXT (link) = block;

  /* Clear out the meanings of the local variables of this level.  */

  for (link = decls; link; link = TREE_CHAIN (link))
    {
      if (DECL_NAME (link) != 0)
	{
	  /* If the ident. was used or addressed via a local extern decl,
	     don't forget that fact.  */
	  if (DECL_EXTERNAL (link))
	    {
	      if (TREE_USED (link))
		TREE_USED (DECL_NAME (link)) = 1;
	      if (TREE_ADDRESSABLE (link))
		TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (link)) = 1;
	    }
	  IDENTIFIER_LOCAL_VALUE (DECL_NAME (link)) = 0;
	}
    }

  /* Restore all name-meanings of the outer levels
     that were shadowed by this level.  */

  for (link = current_binding_level->shadowed; link; link = TREE_CHAIN (link))
    IDENTIFIER_LOCAL_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);

  /* If the level being exited is the top level of a function,
     check over all the labels, and clear out the current
     (function local) meanings of their names.  */

  if (functionbody)
    {
      /* If this is the top level block of a function,
	 the vars are the function's parameters.
	 Don't leave them in the BLOCK because they are
	 found in the FUNCTION_DECL instead.  */

      BLOCK_VARS (block) = 0;

      /* Clear out the definitions of all label names,
	 since their scopes end here,
	 and add them to BLOCK_VARS.  */

      for (link = named_labels; link; link = TREE_CHAIN (link))
	{
	  register tree label = TREE_VALUE (link);

	  if (DECL_INITIAL (label) == 0)
	    {
	      error_with_decl (label, "label `%s' used but not defined");
	      /* Avoid crashing later.  */
	      define_label (input_filename, lineno,
			    DECL_NAME (label));
	    }
	  else if (warn_unused && !TREE_USED (label))
	    warning_with_decl (label, "label `%s' defined but not used");
	  IDENTIFIER_LABEL_VALUE (DECL_NAME (label)) = 0;

	  /* Put the labels into the "variables" of the
	     top-level block, so debugger can see them.  */
	  TREE_CHAIN (label) = BLOCK_VARS (block);
	  BLOCK_VARS (block) = label;
	}
    }

  /* Pop the current level, and free the structure for reuse.  */

  {
    register struct binding_level *level = current_binding_level;
    current_binding_level = current_binding_level->level_chain;

    level->level_chain = free_binding_level;
    free_binding_level = level;
  }

  /* Dispose of the block that we just made inside some higher level.  */
  if (functionbody)
    DECL_INITIAL (current_function_decl) = block;
  else if (block)
    {
      if (!block_previously_created)
        current_binding_level->blocks
          = chainon (current_binding_level->blocks, block);
    }
  /* If we did not make a block for the level just exited,
     any blocks made for inner levels
     (since they cannot be recorded as subblocks in that level)
     must be carried forward so they will later become subblocks
     of something else.  */
  else if (subblocks)
    current_binding_level->blocks
      = chainon (current_binding_level->blocks, subblocks);

  /* Set the TYPE_CONTEXTs for all of the tagged types belonging to this
     binding contour so that they point to the appropriate construct, i.e.
     either to the current FUNCTION_DECL node, or else to the BLOCK node
     we just constructed.

     Note that for tagged types whose scope is just the formal parameter
     list for some function type specification, we can't properly set
     their TYPE_CONTEXTs here, because we don't have a pointer to the
     appropriate FUNCTION_TYPE node readily available to us.  For those
     cases, the TYPE_CONTEXTs of the relevant tagged type nodes get set
     in `grokdeclarator' as soon as we have created the FUNCTION_TYPE
     node which will represent the "scope" for these "parameter list local"
     tagged types.
  */

  if (functionbody)
    for (link = tags; link; link = TREE_CHAIN (link))
      TYPE_CONTEXT (TREE_VALUE (link)) = current_function_decl;
  else if (block)
    for (link = tags; link; link = TREE_CHAIN (link))
      TYPE_CONTEXT (TREE_VALUE (link)) = block;

  if (block)
    TREE_USED (block) = 1;
  return block;
}

/* Delete the node BLOCK from the current binding level.
   This is used for the block inside a stmt expr ({...})
   so that the block can be reinserted where appropriate.  */

void
delete_block (block)
     tree block;
{
  tree t;
  if (current_binding_level->blocks == block)
    current_binding_level->blocks = TREE_CHAIN (block);
  for (t = current_binding_level->blocks; t;)
    {
      if (TREE_CHAIN (t) == block)
	TREE_CHAIN (t) = TREE_CHAIN (block);
      else
	t = TREE_CHAIN (t);
    }
  TREE_CHAIN (block) = NULL;
  /* Clear TREE_USED which is always set by poplevel.
     The flag is set again if insert_block is called.  */
  TREE_USED (block) = 0;
}

/* Insert BLOCK at the end of the list of subblocks of the
   current binding level.  This is used when a BIND_EXPR is expanded,
   to handle the BLOCK node inside teh BIND_EXPR.  */

void
insert_block (block)
     tree block;
{
  TREE_USED (block) = 1;
  current_binding_level->blocks
    = chainon (current_binding_level->blocks, block);
}

/* Set the BLOCK node for the innermost scope
   (the one we are currently in).  */

void
set_block (block)
     register tree block;
{
  current_binding_level->this_block = block;
}

void
push_label_level ()
{
  register struct binding_level *newlevel;

  /* Reuse or create a struct for this binding level.  */

  if (free_binding_level)
    {
      newlevel = free_binding_level;
      free_binding_level = free_binding_level->level_chain;
    }
  else
    {
      newlevel = make_binding_level ();
    }

  /* Add this level to the front of the chain (stack) of label levels.  */

  newlevel->level_chain = label_level_chain;
  label_level_chain = newlevel;

  newlevel->names = named_labels;
  newlevel->shadowed = shadowed_labels;
  named_labels = 0;
  shadowed_labels = 0;
}

void
pop_label_level ()
{
  register struct binding_level *level = label_level_chain;
  tree link, prev;

  /* Clear out the definitions of the declared labels in this level.
     Leave in the list any ordinary, non-declared labels.  */
  for (link = named_labels, prev = 0; link;)
    {
      if (C_DECLARED_LABEL_FLAG (TREE_VALUE (link)))
	{
	  if (DECL_SOURCE_LINE (TREE_VALUE (link)) == 0)
	    {
	      error_with_decl ("label `%s' used but not defined",
			       TREE_VALUE (link));
	      /* Avoid crashing later.  */
	      define_label (input_filename, lineno,
			    DECL_NAME (TREE_VALUE (link)));
	    }
	  else if (warn_unused && !TREE_USED (TREE_VALUE (link)))
	    warning_with_decl (TREE_VALUE (link), 
			       "label `%s' defined but not used");
	  IDENTIFIER_LABEL_VALUE (DECL_NAME (TREE_VALUE (link))) = 0;

	  /* Delete this element from the list.  */
	  link = TREE_CHAIN (link);
	  if (prev)
	    TREE_CHAIN (prev) = link;
	  else
	    named_labels = link;
	}
      else
	{
	  prev = link;
	  link = TREE_CHAIN (link);
	}
    }

  /* Bring back all the labels that were shadowed.  */
  for (link = shadowed_labels; link; link = TREE_CHAIN (link))
    if (DECL_NAME (TREE_VALUE (link)) != 0)
      IDENTIFIER_LABEL_VALUE (DECL_NAME (TREE_VALUE (link)))
	= TREE_VALUE (link);

  named_labels = chainon (named_labels, level->names);
  shadowed_labels = level->shadowed;

  /* Pop the current level, and free the structure for reuse.  */
  label_level_chain = label_level_chain->level_chain;
  level->level_chain = free_binding_level;
  free_binding_level = level;
}

/* Push a definition or a declaration of struct, union or enum tag "name".
   "type" should be the type node.
   We assume that the tag "name" is not already defined.

   Note that the definition may really be just a forward reference.
   In that case, the TYPE_SIZE will be zero.  */

void
pushtag (name, type)
     tree name, type;
{
  register struct binding_level *b;

  /* Find the proper binding level for this type tag.  */

  for (b = current_binding_level; b->tag_transparent; b = b->level_chain)
    continue;

  if (name)
    {
      /* Record the identifier as the type's name if it has none.  */

      if (TYPE_NAME (type) == 0)
	TYPE_NAME (type) = name;
    }

  if (b == global_binding_level)
    b->tags = perm_tree_cons (name, type, b->tags);
  else
    b->tags = saveable_tree_cons (name, type, b->tags);

  /* Create a fake NULL-named TYPE_DECL node whose TREE_TYPE will be the
     tagged type we just added to the current binding level.  This fake
     NULL-named TYPE_DECL node helps dwarfout.c to know when it needs
     to output a representation of a tagged type, and it also gives
     us a convenient place to record the "scope start" address for the
     tagged type.  */

  TYPE_STUB_DECL (type) = pushdecl (build_decl (TYPE_DECL, NULL_TREE, type));
}

/* Handle when a new declaration NEWDECL
   has the same name as an old one OLDDECL
   in the same binding contour.
   Prints an error message if appropriate.

   If safely possible, alter OLDDECL to look like NEWDECL, and return 1.
   Otherwise, return 0.  */

static int
duplicate_decls (newdecl, olddecl)
     register tree newdecl, olddecl;
{
  int types_match = comptypes (TREE_TYPE (newdecl), TREE_TYPE (olddecl));
  int new_is_definition = (TREE_CODE (newdecl) == FUNCTION_DECL
			   && DECL_INITIAL (newdecl) != 0);
  tree oldtype = TREE_TYPE (olddecl);
  tree newtype = TREE_TYPE (newdecl);

  if (TREE_CODE (newtype) == ERROR_MARK
      || TREE_CODE (oldtype) == ERROR_MARK)
    types_match = 0;

  /* New decl is completely inconsistent with the old one =>
     tell caller to replace the old one.
     This is always an error except in the case of shadowing a builtin.  */
  if (TREE_CODE (olddecl) != TREE_CODE (newdecl))
    {
      if (TREE_CODE (olddecl) == FUNCTION_DECL
	  && DECL_BUILT_IN (olddecl))