From b5889d25e9bf944a89fdd7bcabf3b6c6f6bb6f7c Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Mon, 21 Aug 2017 13:03:29 +0200 Subject: [PATCH] assert: Support types without operator== (int) [BZ #21972] --- ChangeLog | 11 ++++++ assert/Makefile | 11 +++++- assert/assert.h | 16 +++++---- assert/tst-assert-c++.cc | 78 ++++++++++++++++++++++++++++++++++++++++ assert/tst-assert-g++.cc | 19 ++++++++++ 5 files changed, 128 insertions(+), 7 deletions(-) create mode 100644 assert/tst-assert-c++.cc create mode 100644 assert/tst-assert-g++.cc diff --git a/ChangeLog b/ChangeLog index 620bf81f83..bfc20d6881 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,14 @@ +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. + 2017-08-21 H.J. Lu [BZ #18822] diff --git a/assert/Makefile b/assert/Makefile index 1c3be9b01f..9ec1be81a9 100644 --- a/assert/Makefile +++ b/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 diff --git a/assert/assert.h b/assert/assert.h index 6801cfeb10..640c95c063 100644 --- a/assert/assert.h +++ b/assert/assert.h @@ -85,7 +85,12 @@ __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) \ @@ -93,12 +98,11 @@ __END_DECLS # 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 explicit comparison against zero is - required to support function pointers and bit fields in this - context, and to suppress the evaluation of variable length - arrays. */ + 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) == 0), __extension__ ({ \ + ((void) sizeof ((expr) ? 1 : 0), __extension__ ({ \ if (expr) \ ; /* empty */ \ else \ diff --git a/assert/tst-assert-c++.cc b/assert/tst-assert-c++.cc new file mode 100644 index 0000000000..12a5e690cb --- /dev/null +++ b/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 diff --git a/assert/tst-assert-g++.cc b/assert/tst-assert-g++.cc new file mode 100644 index 0000000000..8c06402825 --- /dev/null +++ b/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