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) 2005-2013 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "stringpool.h"
  27 #include "attribs.h"
  28 #include "cp/cp-tree.h" /* This is why we're a separate module.  */
  29 #include "flags.h"
  30 #include "tm_p.h"
  31 #include "diagnostic-core.h"
  32 #include "hashtab.h"
  33
  34 bool
  35 i386_pe_type_dllimport_p (tree decl)
  36 {
  37   gcc_assert (TREE_CODE (decl) == VAR_DECL
  38               || TREE_CODE (decl) == FUNCTION_DECL);
  39
  40   if (TARGET_NOP_FUN_DLLIMPORT && TREE_CODE (decl) == FUNCTION_DECL)
  41     return false;
  42
  43   /* We ignore the dllimport attribute for inline member functions.
  44      This differs from MSVC behavior which treats it like GNUC
  45      'extern inline' extension.  Also ignore for template
  46      instantiations with linkonce semantics and artificial methods.  */
  47   if (TREE_CODE (decl) ==  FUNCTION_DECL
  48       && (DECL_DECLARED_INLINE_P (decl)
  49           || DECL_TEMPLATE_INSTANTIATION (decl)
  50           || DECL_ARTIFICIAL (decl)))
  51     return false;
  52
  53   /* Overrides of the class dllimport decls by out-of-class definitions are
  54      handled by tree.c:merge_dllimport_decl_attributes.   */
  55   return true;
  56 }
  57
  58 bool
  59 i386_pe_type_dllexport_p (tree decl)
  60 {
  61   gcc_assert (TREE_CODE (decl) == VAR_DECL
  62               || TREE_CODE (decl) == FUNCTION_DECL);
  63
  64   /* Avoid exporting compiler-generated default dtors and copy ctors.
  65      The only artificial methods that need to be exported are virtual
  66      and non-virtual thunks.  */
  67   if (TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE
  68       && DECL_ARTIFICIAL (decl) && !DECL_THUNK_P (decl))
  69     return false;
  70   if (TREE_CODE (decl) == FUNCTION_DECL
  71       && DECL_DECLARED_INLINE_P (decl))
  72     {
  73       if (DECL_REALLY_EXTERN (decl)
  74           || !flag_keep_inline_dllexport)
  75         return false;
  76     }
  77   return true;
  78 }
  79
  80 static inline void maybe_add_dllimport (tree decl)
  81 {
  82   if (i386_pe_type_dllimport_p (decl))
  83     DECL_DLLIMPORT_P (decl) = 1;
  84 }
  85
  86 static inline void maybe_add_dllexport (tree decl)
  87 {
  88   if (i386_pe_type_dllexport_p (decl))
  89     {
  90       tree decl_attrs = DECL_ATTRIBUTES (decl);
  91       if (lookup_attribute ("dllexport", decl_attrs) != NULL_TREE)
  92         /* Already done.  */
  93         return;
  94       DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("dllexport"),
  95                                           NULL_TREE, decl_attrs);
  96     }
  97 }
  98
  99 void
 100 i386_pe_adjust_class_at_definition (tree t)
 101 {
 102   tree member;
 103
 104   gcc_assert (CLASS_TYPE_P (t));
 105
 106
 107   if (lookup_attribute ("dllexport", TYPE_ATTRIBUTES (t)) != NULL_TREE)
 108     {
 109       tree tmv = TYPE_MAIN_VARIANT (t);
 110
 111       /* Make sure that we set dllexport attribute to typeinfo's
 112          base declaration, as otherwise it would fail to be exported as
 113          it isn't a class-member.  */
 114       if (tmv != NULL_TREE
 115           && CLASSTYPE_TYPEINFO_VAR (tmv) != NULL_TREE)
 116         {
 117           tree na, ti_decl = CLASSTYPE_TYPEINFO_VAR (tmv);
 118           na = tree_cons (get_identifier ("dllexport"), NULL_TREE,
 119                           NULL_TREE);
 120           decl_attributes (&ti_decl, na, 0);
 121         }
 122
 123       /* Check static VAR_DECL's.  */
 124       for (member = TYPE_FIELDS (t); member; member = DECL_CHAIN (member))
 125         if (TREE_CODE (member) == VAR_DECL)
 126           maybe_add_dllexport (member);
 127
 128       /* Check FUNCTION_DECL's.  */
 129       for (member = TYPE_METHODS (t); member;  member = DECL_CHAIN (member))
 130         if (TREE_CODE (member) == FUNCTION_DECL)
 131           {
 132             tree thunk;
 133             maybe_add_dllexport (member);
 134
 135             /* Also add the attribute to its thunks.  */
 136             for (thunk = DECL_THUNKS (member); thunk;
 137                  thunk = TREE_CHAIN (thunk))
 138               maybe_add_dllexport (thunk);
 139         }
 140       /* Check vtables  */
 141       for (member = CLASSTYPE_VTABLES (t); member;  member = DECL_CHAIN (member))
 142         if (TREE_CODE (member) == VAR_DECL)
 143           maybe_add_dllexport (member);
 144     }
 145
 146   else if (lookup_attribute ("dllimport", TYPE_ATTRIBUTES (t)) != NULL_TREE)
 147     {
 148       /* We don't actually add the attribute to the decl, just set the flag
 149          that signals that the address of this symbol is not a compile-time
 150          constant.   Any subsequent out-of-class declaration of members wil
 151          cause the DECL_DLLIMPORT_P flag to be unset.
 152          (See  tree.c: merge_dllimport_decl_attributes).
 153          That is just right since out-of class declarations can only be a
 154          definition.   */
 155
 156       /* Check static VAR_DECL's.  */
 157       for (member = TYPE_FIELDS (t); member; member = DECL_CHAIN (member))
 158         if (TREE_CODE (member) == VAR_DECL)
 159           maybe_add_dllimport (member);
 160
 161       /* Check FUNCTION_DECL's.  */
 162       for (member = TYPE_METHODS (t); member;  member = DECL_CHAIN (member))
 163         if (TREE_CODE (member) == FUNCTION_DECL)
 164           {
 165             tree thunk;
 166             maybe_add_dllimport (member);
 167
 168             /* Also add the attribute to its thunks.  */
 169             for (thunk = DECL_THUNKS (member); thunk;
 170                  thunk = DECL_CHAIN (thunk))
 171               maybe_add_dllimport (thunk);
 172          }
 173
 174       /* Check vtables  */
 175       for (member = CLASSTYPE_VTABLES (t); member;  member = DECL_CHAIN (member))
 176         if (TREE_CODE (member) == VAR_DECL)
 177           maybe_add_dllimport (member);
 178
 179       /* We leave typeinfo tables alone.  We can't mark TI objects as
 180         dllimport, since the address of a secondary VTT may be needed
 181         for static initialization of a primary VTT.  VTT's  of
 182         dllimport'd classes should always be link-once COMDAT.  */
 183     }
 184 }