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, 2007
   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 3, 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 COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "rtl.h"
  27 #include "regs.h"
  28 #include "hard-reg-set.h"
  29 #include "output.h"
  30 #include "tree.h"
  31 #include "cp/cp-tree.h" /* this is why we're a separate module */
  32 #include "flags.h"
  33 #include "tm_p.h"
  34 #include "toplev.h"
  35 #include "hashtab.h"
  36
  37 bool
  38 i386_pe_type_dllimport_p (tree decl)
  39 {
  40   gcc_assert (TREE_CODE (decl) == VAR_DECL
  41               || TREE_CODE (decl) == FUNCTION_DECL);
  42
  43   if (TARGET_NOP_FUN_DLLIMPORT && TREE_CODE (decl) == FUNCTION_DECL)
  44     return false;
  45
  46   /* We ignore the dllimport attribute for inline member functions.
  47      This differs from MSVC behavior which treats it like GNUC
  48      'extern inline' extension.  Also ignore for template
  49      instantiations with linkonce semantics and artificial methods.  */
  50   if (TREE_CODE (decl) ==  FUNCTION_DECL
  51       && (DECL_DECLARED_INLINE_P (decl)
  52           || DECL_TEMPLATE_INSTANTIATION (decl)
  53           || DECL_ARTIFICIAL (decl)))
  54     return false;
  55
  56
  57   /* Don't mark defined functions as dllimport.  This code will only be
  58      reached if we see a non-inline function defined out-of-class.  */
  59   else if (TREE_CODE (decl) ==  FUNCTION_DECL
  60            && (DECL_INITIAL (decl)))
  61     return false;
  62
  63   /*  Don't allow definitions of static data members in dllimport class,
  64       If vtable data is marked as DECL_EXTERNAL, import it; otherwise just
  65       ignore the class attribute.  */
  66   else if (TREE_CODE (decl) == VAR_DECL
  67            && TREE_STATIC (decl) && TREE_PUBLIC (decl)
  68            && !DECL_EXTERNAL (decl))
  69     {
  70       if (!DECL_VIRTUAL_P (decl))
  71           error ("definition of static data member %q+D of "
  72                  "dllimport'd class", decl);
  73       return false;
  74     }
  75
  76   return true;
  77 }
  78
  79
  80 bool
  81 i386_pe_type_dllexport_p (tree decl)
  82 {
  83    gcc_assert (TREE_CODE (decl) == VAR_DECL
  84                || TREE_CODE (decl) == FUNCTION_DECL);
  85    /* Avoid exporting compiler-generated default dtors and copy ctors.
  86       The only artificial methods that need to be exported are virtual
  87       and non-virtual thunks.  */
  88    if (TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE
  89        && DECL_ARTIFICIAL (decl) && !DECL_THUNK_P (decl))
  90      return false;
  91    return true;
  92 }
  93
  94 static inline void maybe_add_dllimport (tree decl)
  95 {
  96   if (i386_pe_type_dllimport_p (decl))
  97     DECL_DLLIMPORT_P (decl) = 1;
  98 }
  99
 100 void
 101 i386_pe_adjust_class_at_definition (tree t)
 102 {
 103   tree member;
 104
 105   gcc_assert (CLASS_TYPE_P (t));
 106
 107  /* We only look at dllimport.  The only thing that dllexport does is
 108     add stuff to a '.drectiv' section at end-of-file, so no need to do
 109     anything for dllexport'd classes until we generate RTL. */
 110   if (lookup_attribute ("dllimport", TYPE_ATTRIBUTES (t)) == NULL_TREE)
 111     return;
 112
 113   /* We don't actually add the attribute to the decl, just set the flag
 114      that signals that the address of this symbol is not a compile-time
 115      constant.   Any subsequent out-of-class declaration of members wil
 116      cause the DECL_DLLIMPORT_P flag to be unset.
 117      (See  tree.c: merge_dllimport_decl_attributes).
 118      That is just right since out-of class declarations can only be a
 119      definition.  We recheck the class members  at RTL generation to
 120      emit warnings if this has happened.  Definition of static data member
 121      of dllimport'd class always causes an error (as per MS compiler).
 122   */
 123
 124   /* Check static VAR_DECL's.  */
 125   for (member = TYPE_FIELDS (t); member; member = TREE_CHAIN (member))
 126     if (TREE_CODE (member) == VAR_DECL)
 127       maybe_add_dllimport (member);
 128
 129   /* Check FUNCTION_DECL's.  */
 130   for (member = TYPE_METHODS (t); member;  member = TREE_CHAIN (member))
 131     if (TREE_CODE (member) == FUNCTION_DECL)
 132       maybe_add_dllimport (member);
 133
 134   /* Check vtables  */
 135   for (member = CLASSTYPE_VTABLES (t); member;  member = TREE_CHAIN (member))
 136     if (TREE_CODE (member) == VAR_DECL)
 137       maybe_add_dllimport (member);
 138
 139 /* We leave typeinfo tables alone.  We can't mark TI objects as
 140      dllimport, since the address of a secondary VTT may be needed
 141      for static initialization of a primary VTT.  VTT's  of
 142      dllimport'd classes should always be link-once COMDAT.  */
 143 }