assert: Support types without operator== (int) [BZ #21972]

This commit is contained in:
Florian Weimer 2017-08-21 13:03:29 +02:00
parent 41e673c1e7
commit b5889d25e9
5 changed files with 128 additions and 7 deletions

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@ -1,3 +1,14 @@
2017-08-21 Florian Weimer <fweimer@redhat.com>
[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 <hongjiu.lu@intel.com>
[BZ #18822]

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@ -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

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@ -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 <bool> (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 \

78
assert/tst-assert-c++.cc Normal file
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@ -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
<http://www.gnu.org/licenses/>. */
#include <assert.h>
/* 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 <class T> bool operator== (T) const; /* No definition. */
template <class T> 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 <class T> bool operator== (T) const; /* No definition. */
template <class T> bool operator!= (T) const; /* No definition. */
};
static int
do_test ()
{
{
no_int value;
assert (value);
}
{
bool_and_int value;
assert (value);
}
return 0;
}
#include <support/test-driver.c>

19
assert/tst-assert-g++.cc Normal file
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@ -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
<http://www.gnu.org/licenses/>. */
#include <tst-assert-c++.cc>