winnt.c

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/* Subroutines for insn-output.c for Windows NT.
   Contributed by Douglas Rupp ([e-mail])
   Copyright (C) 1995, 1997, 1998 Free Software Foundation, Inc.

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 "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "output.h"
#include "tree.h"
#include "flags.h"

/* i386/PE specific attribute support.

   i386/PE has two new attributes:
   dllexport - for exporting a function/variable that will live in a dll
   dllimport - for importing a function/variable from a dll

   Microsoft allows multiple declspecs in one __declspec, separating
   them with spaces.  We do NOT support this.  Instead, use __declspec
   multiple times.
*/

/* Return nonzero if ATTR is a valid attribute for DECL.
   ATTRIBUTES are any existing attributes and ARGS are the arguments
   supplied with ATTR.  */

int
i386_pe_valid_decl_attribute_p (decl, attributes, attr, args)
     tree decl;
     tree attributes;
     tree attr;
     tree args;
{
  if (args == NULL_TREE)
    {
      if (is_attribute_p ("dllexport", attr))
	return 1;
      if (is_attribute_p ("dllimport", attr))
	return 1;
    }

  return i386_valid_decl_attribute_p (decl, attributes, attr, args);
}

/* Return nonzero if ATTR is a valid attribute for TYPE.
   ATTRIBUTES are any existing attributes and ARGS are the arguments
   supplied with ATTR.  */

int
i386_pe_valid_type_attribute_p (type, attributes, attr, args)
     tree type;
     tree attributes;
     tree attr;
     tree args;
{
  if (args == NULL_TREE
      && (TREE_CODE (type) == RECORD_TYPE || TREE_CODE (type) == UNION_TYPE))
    {
      if (is_attribute_p ("dllexport", attr))
	return 1;
      if (is_attribute_p ("dllimport", attr))
	return 1;
    }

  return i386_valid_type_attribute_p (type, attributes, attr, args);
}

/* Merge attributes in decls OLD and NEW.

   This handles the following situation:

   __declspec (dllimport) int foo;
   int foo;

   The second instance of `foo' nullifies the dllimport.  */

tree
i386_pe_merge_decl_attributes (old, new)
     tree old, new;
{
  tree a;
  int delete_dllimport_p;

  old = DECL_MACHINE_ATTRIBUTES (old);
  new = DECL_MACHINE_ATTRIBUTES (new);

  /* What we need to do here is remove from `old' dllimport if it doesn't
     appear in `new'.  dllimport behaves like extern: if a declaration is
     marked dllimport and a definition appears later, then the object
     is not dllimport'd.  */

  if (lookup_attribute ("dllimport", old) != NULL_TREE
      && lookup_attribute ("dllimport", new) == NULL_TREE)
    delete_dllimport_p = 1;
  else
    delete_dllimport_p = 0;

  a = merge_attributes (old, new);

  if (delete_dllimport_p)
    {
      tree prev,t;

      /* Scan the list for dllimport and delete it.  */
      for (prev = NULL_TREE, t = a; t; prev = t, t = TREE_CHAIN (t))
	{
	  if (is_attribute_p ("dllimport", TREE_PURPOSE (t)))
	    {
	      if (prev == NULL_TREE)
		a = TREE_CHAIN (a);
	      else
		TREE_CHAIN (prev) = TREE_CHAIN (t);
	      break;
	    }
	}
    }

  return a;
}

/* Return the type that we should use to determine if DECL is
   imported or exported.  */

static tree
associated_type (decl)
     tree decl;
{
  tree t = NULL_TREE;

  /* In the C++ frontend, DECL_CONTEXT for a method doesn't actually refer
     to the containing class.  So we look at the 'this' arg.  */
  if (TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE)
    {
      /* Artificial methods are not affected by the import/export status of
	 their class unless they are virtual.  */
      if (! DECL_ARTIFICIAL (decl) || DECL_VINDEX (decl))
	t = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (decl))));
    }
  else if (DECL_CONTEXT (decl)
	   && TREE_CODE_CLASS (TREE_CODE (DECL_CONTEXT (decl))) == 't')
    t = DECL_CONTEXT (decl);

  return t;
}

/* Return non-zero if DECL is a dllexport'd object.  */

int
i386_pe_dllexport_p (decl)
     tree decl;
{
  tree exp;

  if (TREE_CODE (decl) != VAR_DECL
      && TREE_CODE (decl) != FUNCTION_DECL)
    return 0;
  exp = lookup_attribute ("dllexport", DECL_MACHINE_ATTRIBUTES (decl));
  if (exp)
    return 1;

  /* Class members get the dllexport status of their class.  */
  if (associated_type (decl))
    {
      exp = lookup_attribute ("dllexport",
			      TYPE_ATTRIBUTES (associated_type (decl)));
      if (exp)
	return 1;
    }

  return 0;
}

/* Return non-zero if DECL is a dllimport'd object.  */

int
i386_pe_dllimport_p (decl)
     tree decl;
{
  tree imp;

  if (TREE_CODE (decl) == FUNCTION_DECL
      && TARGET_NOP_FUN_DLLIMPORT)
    return 0;

  if (TREE_CODE (decl) != VAR_DECL
      && TREE_CODE (decl) != FUNCTION_DECL)
    return 0;
  imp = lookup_attribute ("dllimport", DECL_MACHINE_ATTRIBUTES (decl));
  if (imp)
    return 1;

  /* Class members get the dllimport status of their class.  */
  if (associated_type (decl))
    {
      imp = lookup_attribute ("dllimport",
			      TYPE_ATTRIBUTES (associated_type (decl)));
      if (imp)
	return 1;
    }

  return 0;
}

/* Return non-zero if SYMBOL is marked as being dllexport'd.  */

int
i386_pe_dllexport_name_p (symbol)
     char *symbol;
{
  return symbol[0] == '@' && symbol[1] == 'e' && symbol[2] == '.';
}

/* Return non-zero if SYMBOL is marked as being dllimport'd.  */

int
i386_pe_dllimport_name_p (symbol)
     char *symbol;
{
  return symbol[0] == '@' && symbol[1] == 'i' && symbol[2] == '.';
}

/* Mark a DECL as being dllexport'd.
   Note that we override the previous setting (eg: dllimport).  */

void
i386_pe_mark_dllexport (decl)
     tree decl;
{
  char *oldname, *newname;
  rtx rtlname;
  tree idp;

  rtlname = XEXP (DECL_RTL (decl), 0);
  if (GET_CODE (rtlname) == SYMBOL_REF)
    oldname = XSTR (rtlname, 0);
  else if (GET_CODE (rtlname) == MEM
	   && GET_CODE (XEXP (rtlname, 0)) == SYMBOL_REF)
    oldname = XSTR (XEXP (rtlname, 0), 0);
  else
    abort ();
  if (i386_pe_dllimport_name_p (oldname))
    oldname += 9;
  else if (i386_pe_dllexport_name_p (oldname))
    return; /* already done */

  newname = alloca (strlen (oldname) + 4);
  sprintf (newname, "@e.%s", oldname);

  /* We pass newname through get_identifier to ensure it has a unique
     address.  RTL processing can sometimes peek inside the symbol ref
     and compare the string's addresses to see if two symbols are
     identical.  */
  idp = get_identifier (newname);

  XEXP (DECL_RTL (decl), 0) =
    gen_rtx (SYMBOL_REF, Pmode, IDENTIFIER_POINTER (idp));
}

/* Mark a DECL as being dllimport'd.  */

void
i386_pe_mark_dllimport (decl)
     tree decl;
{
  char *oldname, *newname;
  tree idp;
  rtx rtlname, newrtl;

  rtlname = XEXP (DECL_RTL (decl), 0);
  if (GET_CODE (rtlname) == SYMBOL_REF)
    oldname = XSTR (rtlname, 0);
  else if (GET_CODE (rtlname) == MEM
	   && GET_CODE (XEXP (rtlname, 0)) == SYMBOL_REF)
    oldname = XSTR (XEXP (rtlname, 0), 0);
  else
    abort ();
  if (i386_pe_dllexport_name_p (oldname))
    {
      error ("`%s' declared as both exported to and imported from a DLL.",
             IDENTIFIER_POINTER (DECL_NAME (decl)));
      return;
    }