1/* Target support for C++ classes on Windows. 2 Contributed by Danny Smith (dannysmith@users.sourceforge.net) 3 Copyright (C) 2005-2020 Free Software Foundation, Inc. 4 5This file is part of GCC. 6 7GCC is free software; you can redistribute it and/or modify it under 8the terms of the GNU General Public License as published by the Free 9Software Foundation; either version 3, or (at your option) any later 10version. 11 12GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13WARRANTY; without even the implied warranty of MERCHANTABILITY or 14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15for more details. 16 17You should have received a copy of the GNU General Public License 18along with GCC; see the file COPYING3. If not see 19<http://www.gnu.org/licenses/>. */ 20 21#define IN_TARGET_CODE 1 22 23#include "config.h" 24#include "system.h" 25#include "coretypes.h" 26#include "cp/cp-tree.h" /* This is why we're a separate module. */ 27#include "stringpool.h" 28#include "attribs.h" 29 30bool 31i386_pe_type_dllimport_p (tree decl) 32{ 33 gcc_assert (TREE_CODE (decl) == VAR_DECL 34 || TREE_CODE (decl) == FUNCTION_DECL); 35 36 if (TARGET_NOP_FUN_DLLIMPORT && TREE_CODE (decl) == FUNCTION_DECL) 37 return false; 38 39 /* We ignore the dllimport attribute for inline member functions. 40 This differs from MSVC behavior which treats it like GNUC 41 'extern inline' extension. Also ignore for template 42 instantiations with linkonce semantics and artificial methods. */ 43 if (TREE_CODE (decl) == FUNCTION_DECL 44 && (DECL_DECLARED_INLINE_P (decl) 45 || DECL_TEMPLATE_INSTANTIATION (decl) 46 || DECL_ARTIFICIAL (decl))) 47 return false; 48 49 /* Overrides of the class dllimport decls by out-of-class definitions are 50 handled by tree.c:merge_dllimport_decl_attributes. */ 51 return true; 52} 53 54bool 55i386_pe_type_dllexport_p (tree decl) 56{ 57 gcc_assert (TREE_CODE (decl) == VAR_DECL 58 || TREE_CODE (decl) == FUNCTION_DECL); 59 60 /* Avoid exporting compiler-generated default dtors and copy ctors. 61 The only artificial methods that need to be exported are virtual 62 and non-virtual thunks. */ 63 if (TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE 64 && DECL_ARTIFICIAL (decl) && !DECL_THUNK_P (decl)) 65 return false; 66 if (TREE_CODE (decl) == FUNCTION_DECL 67 && DECL_DECLARED_INLINE_P (decl)) 68 { 69 if (DECL_REALLY_EXTERN (decl) 70 || !flag_keep_inline_dllexport) 71 return false; 72 } 73 return true; 74} 75 76static inline void maybe_add_dllimport (tree decl) 77{ 78 if (i386_pe_type_dllimport_p (decl)) 79 DECL_DLLIMPORT_P (decl) = 1; 80} 81 82static inline void maybe_add_dllexport (tree decl) 83{ 84 if (i386_pe_type_dllexport_p (decl)) 85 { 86 tree decl_attrs = DECL_ATTRIBUTES (decl); 87 if (lookup_attribute ("dllexport", decl_attrs) != NULL_TREE) 88 /* Already done. */ 89 return; 90 DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("dllexport"), 91 NULL_TREE, decl_attrs); 92 } 93} 94 95void 96i386_pe_adjust_class_at_definition (tree t) 97{ 98 tree member; 99 100 gcc_assert (CLASS_TYPE_P (t)); 101 102 103 if (lookup_attribute ("dllexport", TYPE_ATTRIBUTES (t)) != NULL_TREE) 104 { 105 tree tmv = TYPE_MAIN_VARIANT (t); 106 107 /* Make sure that we set dllexport attribute to typeinfo's 108 base declaration, as otherwise it would fail to be exported as 109 it isn't a class-member. */ 110 if (tmv != NULL_TREE 111 && CLASSTYPE_TYPEINFO_VAR (tmv) != NULL_TREE) 112 { 113 tree na, ti_decl = CLASSTYPE_TYPEINFO_VAR (tmv); 114 na = tree_cons (get_identifier ("dllexport"), NULL_TREE, 115 NULL_TREE); 116 decl_attributes (&ti_decl, na, 0); 117 } 118 119 /* Check FUNCTION_DECL's and static VAR_DECL's. */ 120 for (member = TYPE_FIELDS (t); member; member = DECL_CHAIN (member)) 121 if (TREE_CODE (member) == VAR_DECL) 122 maybe_add_dllexport (member); 123 else if (TREE_CODE (member) == FUNCTION_DECL) 124 { 125 tree thunk; 126 maybe_add_dllexport (member); 127 128 /* Also add the attribute to its thunks. */ 129 for (thunk = DECL_THUNKS (member); thunk; 130 thunk = TREE_CHAIN (thunk)) 131 maybe_add_dllexport (thunk); 132 } 133 134 /* Check vtables */ 135 for (member = CLASSTYPE_VTABLES (t); 136 member; member = DECL_CHAIN (member)) 137 if (TREE_CODE (member) == VAR_DECL) 138 maybe_add_dllexport (member); 139 } 140 141 else if (lookup_attribute ("dllimport", TYPE_ATTRIBUTES (t)) != NULL_TREE) 142 { 143 /* We don't actually add the attribute to the decl, just set the flag 144 that signals that the address of this symbol is not a compile-time 145 constant. Any subsequent out-of-class declaration of members wil 146 cause the DECL_DLLIMPORT_P flag to be unset. 147 (See tree.c: merge_dllimport_decl_attributes). 148 That is just right since out-of class declarations can only be a 149 definition. */ 150 151 /* Check FUNCTION_DECL's and static VAR_DECL's. */ 152 for (member = TYPE_FIELDS (t); member; member = DECL_CHAIN (member)) 153 if (TREE_CODE (member) == VAR_DECL) 154 maybe_add_dllimport (member); 155 else if (TREE_CODE (member) == FUNCTION_DECL) 156 { 157 tree thunk; 158 maybe_add_dllimport (member); 159 160 /* Also add the attribute to its thunks. */ 161 for (thunk = DECL_THUNKS (member); thunk; 162 thunk = DECL_CHAIN (thunk)) 163 maybe_add_dllimport (thunk); 164 } 165 166 /* Check vtables */ 167 for (member = CLASSTYPE_VTABLES (t); 168 member; member = DECL_CHAIN (member)) 169 if (TREE_CODE (member) == VAR_DECL) 170 maybe_add_dllimport (member); 171 172 /* We leave typeinfo tables alone. We can't mark TI objects as 173 dllimport, since the address of a secondary VTT may be needed 174 for static initialization of a primary VTT. VTT's of 175 dllimport'd classes should always be link-once COMDAT. */ 176 } 177} 178