41 lines · cpp
1// RUN: %clang_cc1 -verify=gnu -std=gnu++11 %s2// RUN: %clang_cc1 -verify=expected,cxx11 -Wvla -std=gnu++11 %s3// RUN: %clang_cc1 -verify=expected,cxx11 -std=c++11 %s4// RUN: %clang_cc1 -verify=expected,cxx98 -std=c++98 %s5// RUN: %clang_cc1 -verify=expected,off -std=c++11 -Wno-vla-extension-static-assert %s6// gnu-no-diagnostics7 8// Demonstrate that we do not diagnose use of VLAs by default in GNU mode, but9// we do diagnose them in C++ mode. Also note that we suggest use of10// static_assert, but only in C++11 and later and only if the warning group is11// not disabled.12 13// C++98 mode does not emit the same notes as C++11 mode because in C++98,14// we're looking for an integer constant expression, whereas in C++11 and later,15// we're looking for a constant expression that is of integer type (these are16// different operations; ICE looks at the syntactic form of the expression, but17// C++11 constant expressions require calculating the expression value).18void func(int n) { // cxx11-note {{declared here}} off-note {{declared here}}19 int vla[n]; // expected-warning {{variable length arrays in C++ are a Clang extension}} \20 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}} \21 off-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}22}23 24void old_style_static_assert(int n) { // cxx11-note 5 {{declared here}} off-note 2 {{declared here}}25 int array1[n != 12 ? 1 : -1]; // cxx11-warning {{variable length arrays in C++ are a Clang extension; did you mean to use 'static_assert'?}} \26 cxx98-warning {{variable length arrays in C++ are a Clang extension}} \27 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}28 int array2[n != 12 ? -1 : 1]; // cxx11-warning {{variable length arrays in C++ are a Clang extension; did you mean to use 'static_assert'?}} \29 cxx98-warning {{variable length arrays in C++ are a Clang extension}} \30 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}31 int array3[n != 12 ? 1 : n]; // expected-warning {{variable length arrays in C++ are a Clang extension}} \32 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}} \33 off-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}34 int array4[(n ? 1 : -1)]; // cxx11-warning {{variable length arrays in C++ are a Clang extension; did you mean to use 'static_assert'?}} \35 cxx98-warning {{variable length arrays in C++ are a Clang extension}} \36 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}37 int array5[n ? 1 : 0]; // expected-warning {{variable length arrays in C++ are a Clang extension}} \38 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}} \39 off-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}40}41