53 lines · cpp
1// RUN: %clang_cc1 -triple x86_64-linux -Wunused -x c -verify %s2// RUN: %clang_cc1 -triple x86_64-linux -Wunused -verify=expected,cxx %s3 4#ifdef __cplusplus5extern "C" {6#endif7static int f(void) { return 42; }8int g(void) __attribute__((alias("f")));9 10static int foo [] = { 42, 0xDEAD }; // cxx-warning{{variable 'foo' is not needed and will not be emitted}}11extern typeof(foo) bar __attribute__((unused, alias("foo")));12 13/// https://github.com/llvm/llvm-project/issues/8859314/// We report a warning in C++ mode because the internal linkage `resolver` gets15/// mangled as it does not have a language linkage. GCC does not mangle16/// `resolver` or report a warning.17static int (*resolver(void))(void) { return f; } // cxx-warning{{unused function 'resolver'}}18int ifunc(void) __attribute__((ifunc("resolver")));19 20static int __attribute__((overloadable)) f0(int x) { return x; }21static float __attribute__((overloadable)) f0(float x) { return x; } // expected-warning{{unused function 'f0'}}22int g0(void) __attribute__((alias("_ZL2f0i")));23 24#ifdef __cplusplus25static int f1() { return 42; }26int g1(void) __attribute__((alias("_ZL2f1v")));27}28 29/// We demangle alias/ifunc target and mark all found functions as used.30 31static int f2(int) { return 42; } // cxx-warning{{unused function 'f2'}}32static int f2() { return 42; }33int g2() __attribute__((alias("_ZL2f2v")));34 35static int (*resolver1())() { return f; } // cxx-warning{{unused function 'resolver1'}}36static int (*resolver1(int))() { return f; }37int ifunc1() __attribute__((ifunc("_ZL9resolver1i")));38 39/// TODO: We should report "unused function" for f3(int).40namespace ns {41static int f3(int) { return 42; } // cxx-warning{{unused function 'f3'}}42static int f3() { return 42; } // cxx-warning{{unused function 'f3'}}43int g3() __attribute__((alias("_ZN2nsL2f3Ev")));44}45 46template <class T>47static void *f4(T) { return nullptr; }48static void *f4() { return nullptr; } // cxx-warning{{unused function 'f4'}}49extern void g4_int() __attribute__((ifunc("_ZL2f4IiEPvT_")));50extern void g4_char() __attribute__((ifunc("_ZL2f4IcEPcT_"))); // rejected by CodeGen51void *use4 = f4(0);52#endif53