gcc/config/i386/winnt-cxx.c

   1 /* Target support for C++ classes on Windows.
   2    Contributed by Danny Smith (dannysmith@users.sourceforge.net)
   3    Copyright (C) 2005
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  21 Boston, MA 02110-1301, USA.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tm.h"
  27 #include "rtl.h"
  28 #include "regs.h"
  29 #include "hard-reg-set.h"
  30 #include "output.h"
  31 #include "tree.h"
  32 #include "cp/cp-tree.h" /* this is why we're a separate module */
  33 #include "flags.h"
  34 #include "tm_p.h"
  35 #include "toplev.h"
  36 #include "hashtab.h"
  37
  38 bool
  39 i386_pe_type_dllimport_p (tree decl)
  40 {
  41   gcc_assert (TREE_CODE (decl) == VAR_DECL
  42               || TREE_CODE (decl) == FUNCTION_DECL);
  43
  44   if (TARGET_NOP_FUN_DLLIMPORT && TREE_CODE (decl) == FUNCTION_DECL)
  45     return false;
  46
  47   /* We ignore the dllimport attribute for inline member functions.
  48      This differs from MSVC behavior which treats it like GNUC
  49      'extern inline' extension.  Also ignore for template
  50      instantiations with linkonce semantics and artificial methods.  */
  51   if (TREE_CODE (decl) ==  FUNCTION_DECL
  52       && (DECL_DECLARED_INLINE_P (decl)
  53           || DECL_TEMPLATE_INSTANTIATION (decl)
  54           || DECL_ARTIFICIAL (decl)))
  55     return false;
  56
  57
  58   /* Don't mark defined functions as dllimport.  This code will only be
  59      reached if we see a non-inline function defined out-of-class.  */
  60   else if (TREE_CODE (decl) ==  FUNCTION_DECL
  61            && (DECL_INITIAL (decl)))
  62     return false;
  63
  64   /*  Don't allow definitions of static data members in dllimport class,
  65       If vtable data is marked as DECL_EXTERNAL, import it; otherwise just
  66       ignore the class attribute.  */
  67   else if (TREE_CODE (decl) == VAR_DECL
  68            && TREE_STATIC (decl) && TREE_PUBLIC (decl)
  69            && !DECL_EXTERNAL (decl))
  70     {
  71       if (!DECL_VIRTUAL_P (decl))
  72           error ("definition of static data member %q+D of "
  73                  "dllimport'd class", decl);
  74       return false;
  75     }
  76
  77   return true;
  78 }
  79
  80
  81 bool
  82 i386_pe_type_dllexport_p (tree decl)
  83 {
  84    gcc_assert (TREE_CODE (decl) == VAR_DECL
  85                || TREE_CODE (decl) == FUNCTION_DECL);
  86    /* Avoid exporting compiler-generated default dtors and copy ctors.
  87       The only artificial methods that need to be exported are virtual
  88       and non-virtual thunks.  */
  89    if (TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE
  90        && DECL_ARTIFICIAL (decl) && !DECL_THUNK_P (decl))
  91      return false;
  92    return true;
  93 }
  94
  95 static inline void maybe_add_dllimport (tree decl)
  96 {
  97   if (i386_pe_type_dllimport_p (decl))
  98     DECL_DLLIMPORT_P (decl) = 1;
  99 }
 100
 101 void
 102 i386_pe_adjust_class_at_definition (tree t)
 103 {
 104   tree member;
 105
 106   gcc_assert (CLASS_TYPE_P (t));
 107
 108  /* We only look at dllimport.  The only thing that dllexport does is
 109     add stuff to a '.drectiv' section at end-of-file, so no need to do
 110     anything for dllexport'd classes until we generate RTL. */
 111   if (lookup_attribute ("dllimport", TYPE_ATTRIBUTES (t)) == NULL_TREE)
 112     return;
 113
 114   /* We don't actually add the attribute to the decl, just set the flag
 115      that signals that the address of this symbol is not a compile-time
 116      constant.   Any subsequent out-of-class declaration of members wil
 117      cause the DECL_DLLIMPORT_P flag to be unset.
 118      (See  tree.c: merge_dllimport_decl_attributes).
 119      That is just right since out-of class declarations can only be a
 120      definition.  We recheck the class members  at RTL generation to
 121      emit warnings if this has happened.  Definition of static data member
 122      of dllimport'd class always causes an error (as per MS compiler).
 123   */
 124
 125   /* Check static VAR_DECL's.  */
 126   for (member = TYPE_FIELDS (t); member; member = TREE_CHAIN (member))
 127     if (TREE_CODE (member) == VAR_DECL)
 128       maybe_add_dllimport (member);
 129
 130   /* Check FUNCTION_DECL's.  */
 131   for (member = TYPE_METHODS (t); member;  member = TREE_CHAIN (member))
 132     if (TREE_CODE (member) == FUNCTION_DECL)
 133       maybe_add_dllimport (member);
 134
 135   /* Check vtables  */
 136   for (member = CLASSTYPE_VTABLES (t); member;  member = TREE_CHAIN (member))
 137     if (TREE_CODE (member) == VAR_DECL)
 138       maybe_add_dllimport (member);
 139
 140 /* We leave typeinfo tables alone.  We can't mark TI objects as
 141      dllimport, since the address of a secondary VTT may be needed
 142      for static initialization of a primary VTT.  VTT's  of
 143      dllimport'd classes should always be link-once COMDAT.  */
 144 }