1 // RUN: %clang_cc1 -fsyntax-only -verify %s 2 3 namespace test1 { 4 extern "C" { test1_f()5 void test1_f() { 6 void test1_g(int); 7 } 8 } 9 } 10 int test1_g(int); 11 12 namespace test2 { 13 extern "C" { test2_f()14 void test2_f() { 15 extern int test2_x; // expected-note {{declared with C language linkage here}} 16 } 17 } 18 } 19 float test2_x; // expected-error {{declaration of 'test2_x' in global scope conflicts with declaration with C language linkage}} 20 21 namespace test3 { 22 extern "C" { test3_f()23 void test3_f() { 24 extern int test3_b; // expected-note {{previous declaration is here}} 25 } 26 } 27 extern "C" { 28 float test3_b; // expected-error {{redefinition of 'test3_b' with a different type: 'float' vs 'int'}} 29 } 30 } 31 32 namespace N { 33 extern "C" { test4_f()34 void test4_f() { 35 extern int test4_b; // expected-note {{declared with C language linkage here}} 36 } 37 } 38 } 39 static float test4_b; // expected-error {{declaration of 'test4_b' in global scope conflicts with declaration with C language linkage}} 40 41 extern "C" { test4c_f()42 void test4c_f() { 43 extern int test4_c; // expected-note {{previous}} 44 } 45 } 46 static float test4_c; // expected-error {{redefinition of 'test4_c' with a different type: 'float' vs 'int'}} 47 48 namespace N { 49 extern "C" { test5_f()50 void test5_f() { 51 extern int test5_b; // expected-note {{declared with C language linkage here}} 52 } 53 } 54 } 55 extern "C" { 56 static float test5_b; // expected-error {{declaration of 'test5_b' in global scope conflicts with declaration with C language linkage}} 57 } 58 59 extern "C" { test5c_f()60 void test5c_f() { 61 extern int test5_c; // expected-note {{previous}} 62 } 63 } 64 extern "C" { 65 static float test5_c; // expected-error {{redefinition of 'test5_c' with a different type: 'float' vs 'int'}} 66 } 67 68 extern "C" { f()69 void f() { 70 extern int test6_b; 71 } 72 } 73 namespace foo { 74 extern "C" { 75 static float test6_b; 76 extern float test6_b; 77 } 78 } 79 80 namespace linkage { 81 namespace redecl { 82 extern "C" { 83 static void linkage_redecl(); 84 static void linkage_redecl(int); 85 void linkage_redecl(); // ok, still not extern "C" 86 void linkage_redecl(int); // ok, still not extern "C" 87 void linkage_redecl(float); // expected-note {{previous}} 88 void linkage_redecl(double); // expected-error {{conflicting types}} 89 } 90 } 91 namespace from_outer { 92 void linkage_from_outer_1(); // expected-note {{previous}} 93 void linkage_from_outer_2(); // expected-note {{previous}} 94 extern "C" { 95 void linkage_from_outer_1(int); 96 void linkage_from_outer_1(); // expected-error {{different language linkage}} 97 void linkage_from_outer_2(); // expected-error {{different language linkage}} 98 } 99 } 100 namespace mixed { 101 extern "C" { 102 void linkage_mixed_1(); 103 static void linkage_mixed_1(int); 104 105 static void linkage_mixed_2(int); 106 void linkage_mixed_2(); 107 } 108 } 109 namespace across_scopes { 110 namespace X { linkage_across_scopes_f()111 extern "C" void linkage_across_scopes_f() { 112 void linkage_across_scopes_g(); // expected-note {{previous}} 113 } 114 } 115 namespace Y { 116 extern "C" void linkage_across_scopes_g(int); // expected-error {{conflicting}} 117 } 118 } 119 } 120 121 int lookup_in_global_f; // expected-note {{here}} 122 namespace lookup_in_global { 123 void lookup_in_global_f(); 124 void lookup_in_global_g(); 125 extern "C" { 126 void lookup_in_global_f(int); // expected-error {{conflicts with declaration in global scope}} 127 void lookup_in_global_g(int); // expected-note {{here}} 128 } 129 } 130 int lookup_in_global_g; // expected-error {{conflicts with declaration with C language linkage}} 131 132 namespace N1 { 133 extern "C" int different_kind_1; // expected-note {{here}} 134 extern "C" void different_kind_2(); // expected-note {{here}} 135 } 136 namespace N2 { 137 extern "C" void different_kind_1(); // expected-error {{different kind of symbol}} 138 extern "C" int different_kind_2; // expected-error {{different kind of symbol}} 139 } 140 141 // We allow all these even though the standard says they are ill-formed. 142 extern "C" { 143 struct stat {}; // expected-warning{{empty struct has size 0 in C, size 1 in C++}} 144 void stat(struct stat); 145 } 146 namespace X { 147 extern "C" { 148 void stat(struct ::stat); 149 } 150 } 151 int stat(int *p); 152 void global_fn_vs_extern_c_var_1(); 153 namespace X { 154 extern "C" int global_fn_vs_extern_c_var_1; 155 extern "C" int global_fn_vs_extern_c_var_2; 156 } 157 void global_fn_vs_extern_c_var_2(); 158 void global_fn_vs_extern_c_fn_1(); 159 namespace X { 160 extern "C" int global_fn_vs_extern_c_fn_1(int); 161 extern "C" int global_fn_vs_extern_c_fn_2(int); 162 } 163 void global_fn_vs_extern_c_fn_2(); 164 extern "C" void name_with_using_decl_1(int); 165 namespace using_decl { 166 void name_with_using_decl_1(); 167 void name_with_using_decl_2(); 168 void name_with_using_decl_3(); 169 } 170 using using_decl::name_with_using_decl_1; 171 using using_decl::name_with_using_decl_2; 172 extern "C" void name_with_using_decl_2(int); 173 extern "C" void name_with_using_decl_3(int); 174 using using_decl::name_with_using_decl_3; 175 176 // We do not allow a global variable and an extern "C" function to have the same 177 // name, because such entities may have the same mangled name. 178 int global_var_vs_extern_c_fn_1; // expected-note {{here}} 179 namespace X { 180 extern "C" void global_var_vs_extern_c_fn_1(); // expected-error {{conflicts with declaration in global scope}} 181 extern "C" void global_var_vs_extern_c_fn_2(); // expected-note {{here}} 182 } 183 int global_var_vs_extern_c_fn_2; // expected-error {{conflicts with declaration with C language linkage}} 184 int global_var_vs_extern_c_var_1; // expected-note {{here}} 185 namespace X { 186 extern "C" double global_var_vs_extern_c_var_1; // expected-error {{conflicts with declaration in global scope}} 187 extern "C" double global_var_vs_extern_c_var_2; // expected-note {{here}} 188 } 189 int global_var_vs_extern_c_var_2; // expected-error {{conflicts with declaration with C language linkage}} 190 191 template <class T> struct pr5065_n1 {}; 192 extern "C" { 193 union pr5065_1 {}; // expected-warning{{empty union has size 0 in C, size 1 in C++}} 194 struct pr5065_2 { int: 0; }; // expected-warning{{struct has size 0 in C, size 1 in C++}} 195 struct pr5065_3 {}; // expected-warning{{empty struct has size 0 in C, size 1 in C++}} 196 struct pr5065_4 { // expected-warning{{empty struct has size 0 in C, size 1 in C++}} 197 struct Inner {}; // expected-warning{{empty struct has size 0 in C, size 1 in C++}} 198 }; 199 // These should not warn 200 class pr5065_n3 {}; 201 pr5065_n1<int> pr5065_v; mpr5065_n4202 struct pr5065_n4 { void m() {} }; 203 struct pr5065_n5 : public pr5065_3 {}; 204 struct pr5065_n6 : public virtual pr5065_3 {}; 205 } 206 struct pr5065_n7 {}; 207 208 namespace tag_hiding { 209 namespace namespace_with_injected_name { 210 class Boo { 211 friend struct ExternCStruct1; 212 }; 213 void ExternCStruct4(); // expected-note 2{{candidate}} 214 } 215 216 class Baz { 217 friend struct ExternCStruct2; 218 friend void ExternCStruct3(); 219 }; 220 221 using namespace namespace_with_injected_name; 222 223 extern "C" { 224 struct ExternCStruct1; 225 struct ExternCStruct2; 226 struct ExternCStruct3; 227 struct ExternCStruct4; // expected-note {{candidate}} 228 } 229 ExternCStruct1 *p1; 230 ExternCStruct2 *p2; 231 ExternCStruct3 *p3; 232 ExternCStruct4 *p4; // expected-error {{ambiguous}} 233 234 extern "C" { 235 struct ExternCStruct1; 236 struct ExternCStruct2; 237 struct ExternCStruct3; 238 struct ExternCStruct4; // expected-note {{candidate}} 239 } 240 ExternCStruct1 *q1 = p1; 241 ExternCStruct2 *q2 = p2; 242 ExternCStruct3 *q3 = p3; 243 ExternCStruct4 *q4 = p4; // expected-error {{ambiguous}} 244 } 245