2017-08-21 Florian Weimer [BZ #21972] * assert/assert.h (assert): Use static_cast (bool) for C++. Use the ternary operator in the warning branch for GNU C. * assert/Makefile (tests): Add tst-assert-c++, tst-assert-g++. (CFLAGS-tst-assert-c++.o): Compile in C++11 mode. (CFLAGS-tst-assert-g++.o): Compile in GnU C++11 mode. (LDLIBS-tst-assert-c++, LDLIBS-tst-assert-g++): Link with libstdc++. * assert/tst-assert-c++.cc, assert/tst-assert-g++.cc: New files. 2017-08-11 Florian Weimer [BZ #21242] * assert/assert.h [__GNUC__ && !__STRICT_ANSI__] (assert): Suppress pedantic warning resulting from statement expression. (__ASSERT_FUNCTION): Add missing __extension__. Index: glibc-2.26/assert/Makefile =================================================================== --- glibc-2.26.orig/assert/Makefile +++ glibc-2.26/assert/Makefile @@ -25,6 +25,15 @@ include ../Makeconfig headers := assert.h routines := assert assert-perr __assert -tests := test-assert test-assert-perr +tests := test-assert test-assert-perr tst-assert-c++ tst-assert-g++ include ../Rules + +ifeq ($(have-cxx-thread_local),yes) +CFLAGS-tst-assert-c++.o = -std=c++11 +LDLIBS-tst-assert-c++ = -lstdc++ +CFLAGS-tst-assert-g++.o = -std=gnu++11 +LDLIBS-tst-assert-g++ = -lstdc++ +else +tests-unsupported += tst-assert-c++ tst-assert-g++ +endif Index: glibc-2.26/assert/assert.h =================================================================== --- glibc-2.26.orig/assert/assert.h +++ glibc-2.26/assert/assert.h @@ -85,19 +85,29 @@ __END_DECLS /* When possible, define assert so that it does not add extra parentheses around EXPR. Otherwise, those added parentheses would suppress warnings we'd expect to be detected by gcc's -Wparentheses. */ -# if !defined __GNUC__ || defined __STRICT_ANSI__ +# if defined __cplusplus +# define assert(expr) \ + (static_cast (expr) \ + ? void (0) \ + : __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION)) +# elif !defined __GNUC__ || defined __STRICT_ANSI__ # define assert(expr) \ ((expr) \ ? __ASSERT_VOID_CAST (0) \ : __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION)) # else +/* The first occurrence of EXPR is not evaluated due to the sizeof, + but will trigger any pedantic warnings masked by the __extension__ + for the second occurrence. The ternary operator is required to + support function pointers and bit fields in this context, and to + suppress the evaluation of variable length arrays. */ # define assert(expr) \ - ({ \ + ((void) sizeof ((expr) ? 1 : 0), __extension__ ({ \ if (expr) \ ; /* empty */ \ else \ __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION); \ - }) + })) # endif # ifdef __USE_GNU @@ -113,7 +123,7 @@ __END_DECLS C9x has a similar variable called __func__, but prefer the GCC one since it demangles C++ function names. */ # if defined __cplusplus ? __GNUC_PREREQ (2, 6) : __GNUC_PREREQ (2, 4) -# define __ASSERT_FUNCTION __PRETTY_FUNCTION__ +# define __ASSERT_FUNCTION __extension__ __PRETTY_FUNCTION__ # else # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L # define __ASSERT_FUNCTION __func__ Index: glibc-2.26/assert/tst-assert-c++.cc =================================================================== --- /dev/null +++ glibc-2.26/assert/tst-assert-c++.cc @@ -0,0 +1,78 @@ +/* Tests for interactions between C++ and assert. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +/* The C++ standard requires that if the assert argument is a constant + subexpression, then the assert itself is one, too. */ +constexpr int +check_constexpr () +{ + return (assert (true), 1); +} + +/* Objects of this class can be contextually converted to bool, but + cannot be compared to int. */ +struct no_int +{ + no_int () = default; + no_int (const no_int &) = delete; + + explicit operator bool () const + { + return true; + } + + bool operator! () const; /* No definition. */ + template bool operator== (T) const; /* No definition. */ + template bool operator!= (T) const; /* No definition. */ +}; + +/* This class tests that operator== is not used by assert. */ +struct bool_and_int +{ + bool_and_int () = default; + bool_and_int (const no_int &) = delete; + + explicit operator bool () const + { + return true; + } + + bool operator! () const; /* No definition. */ + template bool operator== (T) const; /* No definition. */ + template bool operator!= (T) const; /* No definition. */ +}; + +static int +do_test () +{ + { + no_int value; + assert (value); + } + + { + bool_and_int value; + assert (value); + } + + return 0; +} + +#include Index: glibc-2.26/assert/tst-assert-g++.cc =================================================================== --- /dev/null +++ glibc-2.26/assert/tst-assert-g++.cc @@ -0,0 +1,19 @@ +/* Tests for interactions between C++ and assert. GNU C++11 version. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include