1 // RUN: %clang_cc1 -triple x86_64-linux -Wunused -x c -verify %s 2 // RUN: %clang_cc1 -triple x86_64-linux -Wunused -verify=expected,cxx %s 3 4 #ifdef __cplusplus 5 extern "C" { 6 #endif f(void)7static int f(void) { return 42; } 8 int g(void) __attribute__((alias("f"))); 9 10 static int foo [] = { 42, 0xDEAD }; // cxx-warning{{variable 'foo' is not needed and will not be emitted}} 11 extern typeof(foo) bar __attribute__((unused, alias("foo"))); 12 13 /// https://github.com/llvm/llvm-project/issues/88593 14 /// We report a warning in C++ mode because the internal linkage `resolver` gets 15 /// mangled as it does not have a language linkage. GCC does not mangle 16 /// `resolver` or report a warning. resolver(void)17static int (*resolver(void))(void) { return f; } // cxx-warning{{unused function 'resolver'}} 18 int ifunc(void) __attribute__((ifunc("resolver"))); 19 f0(int x)20static int __attribute__((overloadable)) f0(int x) { return x; } f0(float x)21static float __attribute__((overloadable)) f0(float x) { return x; } // expected-warning{{unused function 'f0'}} 22 int g0(void) __attribute__((alias("_ZL2f0i"))); 23 24 #ifdef __cplusplus f1()25static int f1() { return 42; } 26 int g1(void) __attribute__((alias("_ZL2f1v"))); 27 } 28 29 /// We demangle alias/ifunc target and mark all found functions as used. 30 f2(int)31static int f2(int) { return 42; } // cxx-warning{{unused function 'f2'}} f2()32static int f2() { return 42; } 33 int g2() __attribute__((alias("_ZL2f2v"))); 34 resolver1()35static int (*resolver1())() { return f; } // cxx-warning{{unused function 'resolver1'}} resolver1(int)36static int (*resolver1(int))() { return f; } 37 int ifunc1() __attribute__((ifunc("_ZL9resolver1i"))); 38 39 /// TODO: We should report "unused function" for f3(int). 40 namespace ns { f3(int)41static int f3(int) { return 42; } // cxx-warning{{unused function 'f3'}} f3()42static int f3() { return 42; } // cxx-warning{{unused function 'f3'}} 43 int g3() __attribute__((alias("_ZN2nsL2f3Ev"))); 44 } 45 46 template <class T> f4(T)47static void *f4(T) { return nullptr; } f4()48static void *f4() { return nullptr; } // cxx-warning{{unused function 'f4'}} 49 extern void g4_int() __attribute__((ifunc("_ZL2f4IiEPvT_"))); 50 extern void g4_char() __attribute__((ifunc("_ZL2f4IcEPcT_"))); // rejected by CodeGen 51 void *use4 = f4(0); 52 #endif 53