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Fix invalid casts in <functional>.

Browse Source 
static_cast of a pointer to object before the start of the object's
lifetime has undefined behavior.

This code triggers CFI warnings.

This change replaces C-style casts with reinterpret_cast, which is
fine per the standard, add applies an attribute to silence CFI (which
barks on reinterpret_cast, too).

llvm-svn: 260441
This commit is contained in:
Evgeniy Stepanov 2016-02-10 21:53:28 +00:00
parent fa61bb5be9
commit 3e58a6a7b2
2 changed files with 37 additions and 29 deletions
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6
libcxx/include/__config
View File

@ -180,6 +180,12 @@
# endif
#endif // !defined(_LIBCPP_LITTLE_ENDIAN) || !defined(_LIBCPP_BIG_ENDIAN)
#if __has_attribute(__no_sanitize__)
#define _LIBCPP_NO_CFI __attribute__((__no_sanitize__("cfi")))
#else
#define _LIBCPP_NO_CFI
#endif
#ifdef _WIN32
// only really useful for a DLL

60
libcxx/include/functional
View File

@ -1564,6 +1564,10 @@ class _LIBCPP_TYPE_VIS_ONLY function<_Rp(_ArgTypes...)>
typename aligned_storage<3*sizeof(void*)>::type __buf_;
__base* __f_;
_LIBCPP_NO_CFI static __base *__as_base(void *p) {
return reinterpret_cast<__base*>(p);
}
template <class _Fp, bool = !is_same<_Fp, function>::value &&
__invokable<_Fp&, _ArgTypes...>::value>
struct __callable;
@ -1660,9 +1664,9 @@ function<_Rp(_ArgTypes...)>::function(const function& __f)
{
if (__f.__f_ == 0)
__f_ = 0;
else if (__f.__f_ == (const __base*)&__f.__buf_)
else if ((void *)__f.__f_ == &__f.__buf_)
{
__f_ = (__base*)&__buf_;
__f_ = __as_base(&__buf_);
__f.__f_->__clone(__f_);
}
else
@ -1676,9 +1680,9 @@ function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc&,
{
if (__f.__f_ == 0)
__f_ = 0;
else if (__f.__f_ == (const __base*)&__f.__buf_)
else if ((void *)__f.__f_ == &__f.__buf_)
{
__f_ = (__base*)&__buf_;
__f_ = __as_base(&__buf_);
__f.__f_->__clone(__f_);
}
else
@ -1690,9 +1694,9 @@ function<_Rp(_ArgTypes...)>::function(function&& __f) _NOEXCEPT
{
if (__f.__f_ == 0)
__f_ = 0;
else if (__f.__f_ == (__base*)&__f.__buf_)
else if ((void *)__f.__f_ == &__f.__buf_)
{
__f_ = (__base*)&__buf_;
__f_ = __as_base(&__buf_);
__f.__f_->__clone(__f_);
}
else
@ -1709,9 +1713,9 @@ function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc&,
{
if (__f.__f_ == 0)
__f_ = 0;
else if (__f.__f_ == (__base*)&__f.__buf_)
else if ((void *)__f.__f_ == &__f.__buf_)
{
__f_ = (__base*)&__buf_;
__f_ = __as_base(&__buf_);
__f.__f_->__clone(__f_);
}
else
@ -1736,8 +1740,7 @@ function<_Rp(_ArgTypes...)>::function(_Fp __f,
typedef __function::__func<_Fp, allocator<_Fp>, _Rp(_ArgTypes...)> _FF;
if (sizeof(_FF) <= sizeof(__buf_) && is_nothrow_copy_constructible<_Fp>::value)
{
__f_ = (__base*)&__buf_;
::new (__f_) _FF(_VSTD::move(__f));
__f_ = ::new((void*)&__buf_) _FF(_VSTD::move(__f));
}
else
{
@ -1766,8 +1769,7 @@ function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc& __a0, _Fp _
if (sizeof(_FF) <= sizeof(__buf_) &&
is_nothrow_copy_constructible<_Fp>::value && is_nothrow_copy_constructible<_Ap>::value)
{
__f_ = (__base*)&__buf_;
::new (__f_) _FF(_VSTD::move(__f), _Alloc(__a));
__f_ = ::new((void*)&__buf_) _FF(_VSTD::move(__f), _Alloc(__a));
}
else
{
@ -1791,16 +1793,16 @@ template<class _Rp, class ..._ArgTypes>
function<_Rp(_ArgTypes...)>&
function<_Rp(_ArgTypes...)>::operator=(function&& __f) _NOEXCEPT
{
if (__f_ == (__base*)&__buf_)
if ((void *)__f_ == &__buf_)
__f_->destroy();
else if (__f_)
__f_->destroy_deallocate();
__f_ = 0;
if (__f.__f_ == 0)
__f_ = 0;
else if (__f.__f_ == (__base*)&__f.__buf_)
else if ((void *)__f.__f_ == &__f.__buf_)
{
__f_ = (__base*)&__buf_;
__f_ = __as_base(&__buf_);
__f.__f_->__clone(__f_);
}
else
@ -1815,7 +1817,7 @@ template<class _Rp, class ..._ArgTypes>
function<_Rp(_ArgTypes...)>&
function<_Rp(_ArgTypes...)>::operator=(nullptr_t) _NOEXCEPT
{
if (__f_ == (__base*)&__buf_)
if ((void *)__f_ == &__buf_)
__f_->destroy();
else if (__f_)
__f_->destroy_deallocate();
@ -1840,7 +1842,7 @@ function<_Rp(_ArgTypes...)>::operator=(_Fp&& __f)
template<class _Rp, class ..._ArgTypes>
function<_Rp(_ArgTypes...)>::~function()
{
if (__f_ == (__base*)&__buf_)
if ((void *)__f_ == &__buf_)
__f_->destroy();
else if (__f_)
__f_->destroy_deallocate();
@ -1850,34 +1852,34 @@ template<class _Rp, class ..._ArgTypes>
void
function<_Rp(_ArgTypes...)>::swap(function& __f) _NOEXCEPT
{
if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
if ((void *)__f_ == &__buf_ && (void *)__f.__f_ == &__f.__buf_)
{
typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
__base* __t = (__base*)&__tempbuf;
__base* __t = __as_base(&__tempbuf);
__f_->__clone(__t);
__f_->destroy();
__f_ = 0;
__f.__f_->__clone((__base*)&__buf_);
__f.__f_->__clone(__as_base(&__buf_));
__f.__f_->destroy();
__f.__f_ = 0;
__f_ = (__base*)&__buf_;
__t->__clone((__base*)&__f.__buf_);
__f_ = __as_base(&__buf_);
__t->__clone(__as_base(&__f.__buf_));
__t->destroy();
__f.__f_ = (__base*)&__f.__buf_;
__f.__f_ = __as_base(&__f.__buf_);
}
else if (__f_ == (__base*)&__buf_)
else if ((void *)__f_ == &__buf_)
{
__f_->__clone((__base*)&__f.__buf_);
__f_->__clone(__as_base(&__f.__buf_));
__f_->destroy();
__f_ = __f.__f_;
__f.__f_ = (__base*)&__f.__buf_;
__f.__f_ = __as_base(&__f.__buf_);
}
else if (__f.__f_ == (__base*)&__f.__buf_)
else if ((void *)__f.__f_ == &__f.__buf_)
{
__f.__f_->__clone((__base*)&__buf_);
__f.__f_->__clone(__as_base(&__buf_));
__f.__f_->destroy();
__f.__f_ = __f_;
__f_ = (__base*)&__buf_;
__f_ = __as_base(&__buf_);
}
else
_VSTD::swap(__f_, __f.__f_);