Skip to content

Commit aa20879

Browse files
vsapsaivsapsai
committedApr 25, 2018
[libcxx] func.wrap.func.con: Unset function before destroying anything
Be defensive against a reentrant std::function::operator=(nullptr_t), in case the held function object has a non-trivial destructor. Destroying the function object in-place can lead to the destructor being called twice. Patch by Duncan P. N. Exon Smith. C++03 support by Volodymyr Sapsai. rdar://problem/32836603 Reviewers: EricWF, mclow.lists Reviewed By: mclow.lists Subscribers: cfe-commits, arphaman Differential Revision: https://reviews.llvm.org/D34331 llvm-svn: 330885
·
llvmorg-21-initllvmorg-7.0.0-rc1
1 parent 2c6430f commit aa20879

File tree

4 files changed

+134
-29
lines changed

4 files changed

+134
-29
lines changed
 

‎libcxx/include/__functional_03

+36-20
Original file line numberDiff line numberDiff line change
@@ -600,19 +600,23 @@ template<class _Rp>
600600
function<_Rp()>&
601601
function<_Rp()>::operator=(const function& __f)
602602
{
603-
function(__f).swap(*this);
603+
if (__f)
604+
function(__f).swap(*this);
605+
else
606+
*this = nullptr;
604607
return *this;
605608
}
606609

607610
template<class _Rp>
608611
function<_Rp()>&
609612
function<_Rp()>::operator=(nullptr_t)
610613
{
611-
if (__f_ == (__base*)&__buf_)
612-
__f_->destroy();
613-
else if (__f_)
614-
__f_->destroy_deallocate();
614+
__base* __t = __f_;
615615
__f_ = 0;
616+
if (__t == (__base*)&__buf_)
617+
__t->destroy();
618+
else if (__t)
619+
__t->destroy_deallocate();
616620
return *this;
617621
}
618622

@@ -876,19 +880,23 @@ template<class _Rp, class _A0>
876880
function<_Rp(_A0)>&
877881
function<_Rp(_A0)>::operator=(const function& __f)
878882
{
879-
function(__f).swap(*this);
883+
if (__f)
884+
function(__f).swap(*this);
885+
else
886+
*this = nullptr;
880887
return *this;
881888
}
882889

883890
template<class _Rp, class _A0>
884891
function<_Rp(_A0)>&
885892
function<_Rp(_A0)>::operator=(nullptr_t)
886893
{
887-
if (__f_ == (__base*)&__buf_)
888-
__f_->destroy();
889-
else if (__f_)
890-
__f_->destroy_deallocate();
894+
__base* __t = __f_;
891895
__f_ = 0;
896+
if (__t == (__base*)&__buf_)
897+
__t->destroy();
898+
else if (__t)
899+
__t->destroy_deallocate();
892900
return *this;
893901
}
894902

@@ -1152,19 +1160,23 @@ template<class _Rp, class _A0, class _A1>
11521160
function<_Rp(_A0, _A1)>&
11531161
function<_Rp(_A0, _A1)>::operator=(const function& __f)
11541162
{
1155-
function(__f).swap(*this);
1163+
if (__f)
1164+
function(__f).swap(*this);
1165+
else
1166+
*this = nullptr;
11561167
return *this;
11571168
}
11581169

11591170
template<class _Rp, class _A0, class _A1>
11601171
function<_Rp(_A0, _A1)>&
11611172
function<_Rp(_A0, _A1)>::operator=(nullptr_t)
11621173
{
1163-
if (__f_ == (__base*)&__buf_)
1164-
__f_->destroy();
1165-
else if (__f_)
1166-
__f_->destroy_deallocate();
1174+
__base* __t = __f_;
11671175
__f_ = 0;
1176+
if (__t == (__base*)&__buf_)
1177+
__t->destroy();
1178+
else if (__t)
1179+
__t->destroy_deallocate();
11681180
return *this;
11691181
}
11701182

@@ -1428,19 +1440,23 @@ template<class _Rp, class _A0, class _A1, class _A2>
14281440
function<_Rp(_A0, _A1, _A2)>&
14291441
function<_Rp(_A0, _A1, _A2)>::operator=(const function& __f)
14301442
{
1431-
function(__f).swap(*this);
1443+
if (__f)
1444+
function(__f).swap(*this);
1445+
else
1446+
*this = nullptr;
14321447
return *this;
14331448
}
14341449

14351450
template<class _Rp, class _A0, class _A1, class _A2>
14361451
function<_Rp(_A0, _A1, _A2)>&
14371452
function<_Rp(_A0, _A1, _A2)>::operator=(nullptr_t)
14381453
{
1439-
if (__f_ == (__base*)&__buf_)
1440-
__f_->destroy();
1441-
else if (__f_)
1442-
__f_->destroy_deallocate();
1454+
__base* __t = __f_;
14431455
__f_ = 0;
1456+
if (__t == (__base*)&__buf_)
1457+
__t->destroy();
1458+
else if (__t)
1459+
__t->destroy_deallocate();
14441460
return *this;
14451461
}
14461462

‎libcxx/include/functional

+6-9
Original file line numberDiff line numberDiff line change
@@ -1818,11 +1818,7 @@ template<class _Rp, class ..._ArgTypes>
18181818
function<_Rp(_ArgTypes...)>&
18191819
function<_Rp(_ArgTypes...)>::operator=(function&& __f) _NOEXCEPT
18201820
{
1821-
if ((void *)__f_ == &__buf_)
1822-
__f_->destroy();
1823-
else if (__f_)
1824-
__f_->destroy_deallocate();
1825-
__f_ = 0;
1821+
*this = nullptr;
18261822
if (__f.__f_ == 0)
18271823
__f_ = 0;
18281824
else if ((void *)__f.__f_ == &__f.__buf_)
@@ -1842,11 +1838,12 @@ template<class _Rp, class ..._ArgTypes>
18421838
function<_Rp(_ArgTypes...)>&
18431839
function<_Rp(_ArgTypes...)>::operator=(nullptr_t) _NOEXCEPT
18441840
{
1845-
if ((void *)__f_ == &__buf_)
1846-
__f_->destroy();
1847-
else if (__f_)
1848-
__f_->destroy_deallocate();
1841+
__base* __t = __f_;
18491842
__f_ = 0;
1843+
if ((void *)__t == &__buf_)
1844+
__t->destroy();
1845+
else if (__t)
1846+
__t->destroy_deallocate();
18501847
return *this;
18511848
}
18521849

‎libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp

+46
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,46 @@
1+
//===----------------------------------------------------------------------===//
2+
//
3+
// The LLVM Compiler Infrastructure
4+
//
5+
// This file is dual licensed under the MIT and the University of Illinois Open
6+
// Source Licenses. See LICENSE.TXT for details.
7+
//
8+
//===----------------------------------------------------------------------===//
9+
10+
// <functional>
11+
12+
// class function<R(ArgTypes...)>
13+
14+
// function& operator=(function &&);
15+
16+
#include <functional>
17+
#include <cassert>
18+
19+
#include "test_macros.h"
20+
21+
struct A
22+
{
23+
static std::function<void()> global;
24+
static bool cancel;
25+
26+
~A() {
27+
DoNotOptimize(cancel);
28+
if (cancel)
29+
global = std::function<void()>(nullptr);
30+
}
31+
void operator()() {}
32+
};
33+
34+
std::function<void()> A::global;
35+
bool A::cancel = false;
36+
37+
int main()
38+
{
39+
A::global = A();
40+
assert(A::global.target<A>());
41+
42+
// Check that we don't recurse in A::~A().
43+
A::cancel = true;
44+
A::global = std::function<void()>(nullptr);
45+
assert(!A::global.target<A>());
46+
}

‎libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp

+46
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,46 @@
1+
//===----------------------------------------------------------------------===//
2+
//
3+
// The LLVM Compiler Infrastructure
4+
//
5+
// This file is dual licensed under the MIT and the University of Illinois Open
6+
// Source Licenses. See LICENSE.TXT for details.
7+
//
8+
//===----------------------------------------------------------------------===//
9+
10+
// <functional>
11+
12+
// class function<R(ArgTypes...)>
13+
14+
// function& operator=(nullptr_t);
15+
16+
#include <functional>
17+
#include <cassert>
18+
19+
#include "test_macros.h"
20+
21+
struct A
22+
{
23+
static std::function<void()> global;
24+
static bool cancel;
25+
26+
~A() {
27+
DoNotOptimize(cancel);
28+
if (cancel)
29+
global = nullptr;
30+
}
31+
void operator()() {}
32+
};
33+
34+
std::function<void()> A::global;
35+
bool A::cancel = false;
36+
37+
int main()
38+
{
39+
A::global = A();
40+
assert(A::global.target<A>());
41+
42+
// Check that we don't recurse in A::~A().
43+
A::cancel = true;
44+
A::global = nullptr;
45+
assert(!A::global.target<A>());
46+
}

0 commit comments

Comments
 (0)
Please sign in to comment.