1 /* Target support for C++ classes on Windows.
2 Contributed by Danny Smith (dannysmith@users.sourceforge.net)
3 Copyright (C) 2005-2016 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 "cp/cp-tree.h" /* This is why we're a separate module. */
25 #include "stringpool.h"
26 #include "attribs.h"
27
28 bool
i386_pe_type_dllimport_p(tree decl)29 i386_pe_type_dllimport_p (tree decl)
30 {
31 gcc_assert (TREE_CODE (decl) == VAR_DECL
32 || TREE_CODE (decl) == FUNCTION_DECL);
33
34 if (TARGET_NOP_FUN_DLLIMPORT && TREE_CODE (decl) == FUNCTION_DECL)
35 return false;
36
37 /* We ignore the dllimport attribute for inline member functions.
38 This differs from MSVC behavior which treats it like GNUC
39 'extern inline' extension. Also ignore for template
40 instantiations with linkonce semantics and artificial methods. */
41 if (TREE_CODE (decl) == FUNCTION_DECL
42 && (DECL_DECLARED_INLINE_P (decl)
43 || DECL_TEMPLATE_INSTANTIATION (decl)
44 || DECL_ARTIFICIAL (decl)))
45 return false;
46
47 /* Overrides of the class dllimport decls by out-of-class definitions are
48 handled by tree.c:merge_dllimport_decl_attributes. */
49 return true;
50 }
51
52 bool
i386_pe_type_dllexport_p(tree decl)53 i386_pe_type_dllexport_p (tree decl)
54 {
55 gcc_assert (TREE_CODE (decl) == VAR_DECL
56 || TREE_CODE (decl) == FUNCTION_DECL);
57
58 /* Avoid exporting compiler-generated default dtors and copy ctors.
59 The only artificial methods that need to be exported are virtual
60 and non-virtual thunks. */
61 if (TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE
62 && DECL_ARTIFICIAL (decl) && !DECL_THUNK_P (decl))
63 return false;
64 if (TREE_CODE (decl) == FUNCTION_DECL
65 && DECL_DECLARED_INLINE_P (decl))
66 {
67 if (DECL_REALLY_EXTERN (decl)
68 || !flag_keep_inline_dllexport)
69 return false;
70 }
71 return true;
72 }
73
maybe_add_dllimport(tree decl)74 static inline void maybe_add_dllimport (tree decl)
75 {
76 if (i386_pe_type_dllimport_p (decl))
77 DECL_DLLIMPORT_P (decl) = 1;
78 }
79
maybe_add_dllexport(tree decl)80 static inline void maybe_add_dllexport (tree decl)
81 {
82 if (i386_pe_type_dllexport_p (decl))
83 {
84 tree decl_attrs = DECL_ATTRIBUTES (decl);
85 if (lookup_attribute ("dllexport", decl_attrs) != NULL_TREE)
86 /* Already done. */
87 return;
88 DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("dllexport"),
89 NULL_TREE, decl_attrs);
90 }
91 }
92
93 void
i386_pe_adjust_class_at_definition(tree t)94 i386_pe_adjust_class_at_definition (tree t)
95 {
96 tree member;
97
98 gcc_assert (CLASS_TYPE_P (t));
99
100
101 if (lookup_attribute ("dllexport", TYPE_ATTRIBUTES (t)) != NULL_TREE)
102 {
103 tree tmv = TYPE_MAIN_VARIANT (t);
104
105 /* Make sure that we set dllexport attribute to typeinfo's
106 base declaration, as otherwise it would fail to be exported as
107 it isn't a class-member. */
108 if (tmv != NULL_TREE
109 && CLASSTYPE_TYPEINFO_VAR (tmv) != NULL_TREE)
110 {
111 tree na, ti_decl = CLASSTYPE_TYPEINFO_VAR (tmv);
112 na = tree_cons (get_identifier ("dllexport"), NULL_TREE,
113 NULL_TREE);
114 decl_attributes (&ti_decl, na, 0);
115 }
116
117 /* Check static VAR_DECL's. */
118 for (member = TYPE_FIELDS (t); member; member = DECL_CHAIN (member))
119 if (TREE_CODE (member) == VAR_DECL)
120 maybe_add_dllexport (member);
121
122 /* Check FUNCTION_DECL's. */
123 for (member = TYPE_METHODS (t); member; member = DECL_CHAIN (member))
124 if (TREE_CODE (member) == FUNCTION_DECL)
125 {
126 tree thunk;
127 maybe_add_dllexport (member);
128
129 /* Also add the attribute to its thunks. */
130 for (thunk = DECL_THUNKS (member); thunk;
131 thunk = TREE_CHAIN (thunk))
132 maybe_add_dllexport (thunk);
133 }
134 /* Check vtables */
135 for (member = CLASSTYPE_VTABLES (t); member; member = DECL_CHAIN (member))
136 if (TREE_CODE (member) == VAR_DECL)
137 maybe_add_dllexport (member);
138 }
139
140 else if (lookup_attribute ("dllimport", TYPE_ATTRIBUTES (t)) != NULL_TREE)
141 {
142 /* We don't actually add the attribute to the decl, just set the flag
143 that signals that the address of this symbol is not a compile-time
144 constant. Any subsequent out-of-class declaration of members wil
145 cause the DECL_DLLIMPORT_P flag to be unset.
146 (See tree.c: merge_dllimport_decl_attributes).
147 That is just right since out-of class declarations can only be a
148 definition. */
149
150 /* Check static VAR_DECL's. */
151 for (member = TYPE_FIELDS (t); member; member = DECL_CHAIN (member))
152 if (TREE_CODE (member) == VAR_DECL)
153 maybe_add_dllimport (member);
154
155 /* Check FUNCTION_DECL's. */
156 for (member = TYPE_METHODS (t); member; member = DECL_CHAIN (member))
157 if (TREE_CODE (member) == FUNCTION_DECL)
158 {
159 tree thunk;
160 maybe_add_dllimport (member);
161
162 /* Also add the attribute to its thunks. */
163 for (thunk = DECL_THUNKS (member); thunk;
164 thunk = DECL_CHAIN (thunk))
165 maybe_add_dllimport (thunk);
166 }
167
168 /* Check vtables */
169 for (member = CLASSTYPE_VTABLES (t); member; member = DECL_CHAIN (member))
170 if (TREE_CODE (member) == VAR_DECL)
171 maybe_add_dllimport (member);
172
173 /* We leave typeinfo tables alone. We can't mark TI objects as
174 dllimport, since the address of a secondary VTT may be needed
175 for static initialization of a primary VTT. VTT's of
176 dllimport'd classes should always be link-once COMDAT. */
177 }
178 }
179