1 /* Target support for C++ classes on Windows.
2 Contributed by Danny Smith (dannysmith@users.sourceforge.net)
3 Copyright (C) 2005-2014 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
i386_pe_type_dllimport_p(tree decl)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
i386_pe_type_dllexport_p(tree decl)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
maybe_add_dllimport(tree decl)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
maybe_add_dllexport(tree decl)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
i386_pe_adjust_class_at_definition(tree t)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 }
185