gcc/langhooks.c

/* Default language-specific hooks.
   Copyright 2001, 2002 Free Software Foundation, Inc.
   Contributed by Alexandre Oliva  <aoliva@redhat.com>

This file is part of GNU CC.

GNU CC 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.

GNU CC 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 CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "toplev.h"
#include "tree.h"
#include "c-tree.h"
#include "tree-inline.h"
#include "rtl.h"
#include "insn-config.h"
#include "integrate.h"
#include "flags.h"
#include "langhooks.h"
#include "langhooks-def.h"

/* Do nothing; in many cases the default hook.  */

void
lhd_do_nothing ()
{
}

/* Do nothing (tree).  */

void
lhd_do_nothing_t (t)
     tree t ATTRIBUTE_UNUSED;
{
}

/* Do nothing (int).  */

void
lhd_do_nothing_i (i)
     int i ATTRIBUTE_UNUSED;
{
}

/* Do nothing (function).  */

void
lhd_do_nothing_f (f)
     struct function *f ATTRIBUTE_UNUSED;
{
}

/* Do nothing (return the tree node passed).  */

tree
lhd_return_tree (t)
     tree t;
{
  return t;
}

/* Do nothing (return NULL_TREE).  */

tree
lhd_return_null_tree (t)
     tree t ATTRIBUTE_UNUSED;
{
  return NULL_TREE;
}

/* Do nothing; the default hook to decode an option.  */

int
lhd_decode_option (argc, argv)
     int argc ATTRIBUTE_UNUSED;
     char **argv ATTRIBUTE_UNUSED;
{
  return 0;
}

/* Called from by print-tree.c.  */

void
lhd_print_tree_nothing (file, node, indent)
     FILE *file ATTRIBUTE_UNUSED;
     tree node ATTRIBUTE_UNUSED;
     int indent ATTRIBUTE_UNUSED;
{
}

/* Called from safe_from_p.  */

int
lhd_safe_from_p (x, exp)
     rtx x ATTRIBUTE_UNUSED;
     tree exp ATTRIBUTE_UNUSED;
{
  return 1;
}

/* Called from unsafe_for_reeval.  */

int
lhd_unsafe_for_reeval (t)
     tree t ATTRIBUTE_UNUSED;
{
  return -1;
}

/* Called from staticp.  */

int
lhd_staticp (exp)
     tree exp ATTRIBUTE_UNUSED;
{
  return 0;
}

/* Called from check_global_declarations.  */

bool
lhd_warn_unused_global_decl (decl)
     tree decl;
{
  /* This is what used to exist in check_global_declarations.  Probably
     not many of these actually apply to non-C languages.  */

  if (TREE_CODE (decl) == FUNCTION_DECL && DECL_INLINE (decl))
    return false;
  if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
    return false;
  if (DECL_IN_SYSTEM_HEADER (decl))
    return false;

  return true;
}

/* Set the DECL_ASSEMBLER_NAME for DECL.  */
void
lhd_set_decl_assembler_name (decl)
     tree decl;
{
  /* The language-independent code should never use the
     DECL_ASSEMBLER_NAME for lots of DECLs.  Only FUNCTION_DECLs and
     VAR_DECLs for variables with static storage duration need a real
     DECL_ASSEMBLER_NAME.  */
  if (TREE_CODE (decl) == FUNCTION_DECL
      || (TREE_CODE (decl) == VAR_DECL
	  && (TREE_STATIC (decl)
	      || DECL_EXTERNAL (decl)
	      || TREE_PUBLIC (decl))))
    /* By default, assume the name to use in assembly code is the
       same as that used in the source language.  (That's correct
       for C, and GCC used to set DECL_ASSEMBLER_NAME to the same
       value as DECL_NAME in build_decl, so this choice provides
       backwards compatibility with existing front-ends.  */
    SET_DECL_ASSEMBLER_NAME (decl, DECL_NAME (decl));
  else
    /* Nobody should ever be asking for the DECL_ASSEMBLER_NAME of
       these DECLs -- unless they're in language-dependent code, in
       which case set_decl_assembler_name hook should handle things.  */
    abort ();
}

/* By default we always allow bit-field based optimizations.  */
bool
lhd_can_use_bit_fields_p ()
{
  return true;
}

/* Provide a default routine to clear the binding stack.  This is used
   by languages that don't need to do anything special.  */
void
lhd_clear_binding_stack ()
{
  while (! (*lang_hooks.decls.global_bindings_p) ())
    poplevel (0, 0, 0);
}

/* Type promotion for variable arguments.  */
tree
lhd_type_promotes_to (type)
     tree type ATTRIBUTE_UNUSED;
{
  abort ();
}

/* Invalid use of an incomplete type.  */
void
lhd_incomplete_type_error (value, type)
     tree value ATTRIBUTE_UNUSED, type;
{
  if (TREE_CODE (type) == ERROR_MARK)
    return;

  abort ();
}

/* Provide a default routine for alias sets that always returns -1.  This
   is used by languages that don't need to do anything special.  */

HOST_WIDE_INT
lhd_get_alias_set (t)
     tree t ATTRIBUTE_UNUSED;
{
  return -1;
}

/* Provide a hook routine for alias sets that always returns 0.  This is
   used by languages that haven't deal with alias sets yet.  */

HOST_WIDE_INT
hook_get_alias_set_0 (t)
     tree t ATTRIBUTE_UNUSED;
{
  return 0;
}

/* This is the default expand_expr function.  */

rtx
lhd_expand_expr (t, r, mm, em)
     tree t ATTRIBUTE_UNUSED;
     rtx r ATTRIBUTE_UNUSED;
     enum machine_mode mm ATTRIBUTE_UNUSED;
     int em ATTRIBUTE_UNUSED;
{
  abort ();
}

/* This is the default decl_printable_name function.  */

const char *
lhd_decl_printable_name (decl, verbosity)
     tree decl;
     int verbosity ATTRIBUTE_UNUSED;
{
  return IDENTIFIER_POINTER (DECL_NAME (decl));
}

/* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
   after handling common cases, but before walking code-specific
   sub-trees.  If this hook is overridden for a language, it should
   handle language-specific tree codes, as well as language-specific
   information associated to common tree codes.  If a tree node is
   completely handled within this function, it should set *SUBTREES to
   0, so that generic handling isn't attempted.  For language-specific
   tree codes, generic handling would abort(), so make sure it is set
   properly.  Both SUBTREES and *SUBTREES is guaranteed to be nonzero
   when the function is called.  */

tree
lhd_tree_inlining_walk_subtrees (tp,subtrees,func,data,htab)
     tree *tp ATTRIBUTE_UNUSED;
     int *subtrees ATTRIBUTE_UNUSED;
     walk_tree_fn func ATTRIBUTE_UNUSED;
     void *data ATTRIBUTE_UNUSED;
     void *htab ATTRIBUTE_UNUSED;
{
  return NULL_TREE;
}

/* lang_hooks.tree_inlining.cannot_inline_tree_fn is called to
   determine whether there are language-specific reasons for not
   inlining a given function.  */

int
lhd_tree_inlining_cannot_inline_tree_fn (fnp)
     tree *fnp;
{
  if (flag_really_no_inline
      && lookup_attribute ("always_inline", DECL_ATTRIBUTES (*fnp)) == NULL)
    return 1;

  return 0;
}

/* lang_hooks.tree_inlining.disregard_inline_limits is called to
   determine whether a function should be considered for inlining even
   if it would exceed inlining limits.  */

int
lhd_tree_inlining_disregard_inline_limits (fn)
     tree fn;
{
  if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
    return 1;

  return 0;
}

/* lang_hooks.tree_inlining.add_pending_fn_decls is called before
   starting to inline a function, to push any language-specific
   functions that should not be inlined into the current function,
   into VAFNP.  PFN is the top of varray, and should be returned if no
   functions are pushed into VAFNP.  The top of the varray should be
   returned.  */

tree
lhd_tree_inlining_add_pending_fn_decls (vafnp, pfn)
     void *vafnp ATTRIBUTE_UNUSED;
     tree pfn;
{
  return pfn;
}

/* lang_hooks.tree_inlining.tree_chain_matters_p indicates whether the
   TREE_CHAIN of a language-specific tree node is relevant, i.e.,
   whether it should be walked, copied and preserved across copies.  */

int
lhd_tree_inlining_tree_chain_matters_p (t)
     tree t ATTRIBUTE_UNUSED;
{
  return 0;
}

/* lang_hooks.tree_inlining.auto_var_in_fn_p is called to determine
   whether VT is an automatic variable defined in function FT.  */

int
lhd_tree_inlining_auto_var_in_fn_p (var, fn)
     tree var, fn;
{
  return (DECL_P (var) && DECL_CONTEXT (var) == fn
	  && (((TREE_CODE (var) == VAR_DECL || TREE_CODE (var) == PARM_DECL)
	       && ! TREE_STATIC (var))
	      || TREE_CODE (var) == LABEL_DECL
	      || TREE_CODE (var) == RESULT_DECL));
}

/* lang_hooks.tree_inlining.copy_res_decl_for_inlining should return a
   declaration for the result RES of function FN to be inlined into
   CALLER.  NDP points to an integer that should be set in case a new
   declaration wasn't created (presumably because RES was of aggregate
   type, such that a TARGET_EXPR is used for the result).  TEXPS is a
   pointer to a varray with the stack of TARGET_EXPRs seen while
   inlining functions into caller; the top of TEXPS is supposed to
   match RES.  */

tree
lhd_tree_inlining_copy_res_decl_for_inlining (res, fn, caller,
					      dm, ndp, texps)
     tree res, fn, caller;
     void *dm ATTRIBUTE_UNUSED;
     int *ndp ATTRIBUTE_UNUSED;
     void *texps ATTRIBUTE_UNUSED;
{
  return copy_decl_for_inlining (res, fn, caller);
}

/* lang_hooks.tree_inlining.anon_aggr_type_p determines whether T is a
   type node representing an anonymous aggregate (union, struct, etc),
   i.e., one whose members are in the same scope as the union itself.  */

int
lhd_tree_inlining_anon_aggr_type_p (t)
     tree t ATTRIBUTE_UNUSED;
{
  return 0;
}

/* lang_hooks.tree_inlining.start_inlining and end_inlining perform any
   language-specific bookkeeping necessary for processing
   FN. start_inlining returns nonzero if inlining should proceed, zero if
   not.

   For instance, the C++ version keeps track of template instantiations to
   avoid infinite recursion.  */

int
lhd_tree_inlining_start_inlining (fn)
     tree fn ATTRIBUTE_UNUSED;
{
  return 1;
}

void
lhd_tree_inlining_end_inlining (fn)
     tree fn ATTRIBUTE_UNUSED;
{
}

/* lang_hooks.tree_inlining.convert_parm_for_inlining performs any
   language-specific conversion before assigning VALUE to PARM.  */

tree
lhd_tree_inlining_convert_parm_for_inlining (parm, value, fndecl)
     tree parm ATTRIBUTE_UNUSED;
     tree value;
     tree fndecl ATTRIBUTE_UNUSED;
{
  return value;
}

/* lang_hooks.tree_dump.dump_tree:  Dump language-specific parts of tree
   nodes.  Returns nonzero if it does not want the usual dumping of the
   second argument.  */

int
lhd_tree_dump_dump_tree (di, t)
     void *di ATTRIBUTE_UNUSED;
     tree t ATTRIBUTE_UNUSED;
{
  return 0;
}

/* lang_hooks.tree_dump.type_qual:  Determine type qualifiers in a
   language-specific way.  */

int
lhd_tree_dump_type_quals (t)
     tree t;
{
  return TYPE_QUALS (t);
}

/* lang_hooks.expr_size: Determine the size of the value of an expression T
   in a language-specific way.  Returns a tree for the size in bytes.  */

tree
lhd_expr_size (exp)
     tree exp;
{
  if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
      && DECL_SIZE_UNIT (exp) != 0)
    return DECL_SIZE_UNIT (exp);
  else
    return size_in_bytes (TREE_TYPE (exp));
}

/* Return true if decl, which is a function decl, may be called by a
   sibcall.  */

bool
lhd_decl_ok_for_sibcall (decl)
     tree decl ATTRIBUTE_UNUSED;
{
  return true;
}

/* lang_hooks.decls.final_write_globals: perform final processing on
   global variables. */
void
write_global_declarations ()
{
  /* Really define vars that have had only a tentative definition.
     Really output inline functions that must actually be callable
     and have not been output so far.  */

  tree globals = (*lang_hooks.decls.getdecls) ();
  int len = list_length (globals);
  tree *vec = (tree *) xmalloc (sizeof (tree) * len);
  int i;
  tree decl;

    /* Process the decls in reverse order--earliest first.
       Put them into VEC from back to front, then take out from front.  */

  for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
    vec[len - i - 1] = decl;

  wrapup_global_declarations (vec, len);

  check_global_declarations (vec, len);

    /* Clean up.  */
  free (vec);
}