Backport r183875 from trunk and gcc-4.7 to fix PR51811 ([C++0x] Incorrect increment/decrement of atomic pointers).
Tested: 1) --testers=crosstool. 2) unit test in Google ref b/6702865 OK for google-4_6 branch? Thanks, Jing 2012-07-19 Jing Yu <jin...@google.com> Backport r183875 to fix wrong atomic<_Tp*> add_fetch. PR libstdc++/51811, Google ref b/6702865 * include/bits/atomic_0.h (atomic<_Tp*>): Fix offsets. * include/bits/atomic_2.h: Likewise. * testsuite/29_atomics/atomic/operators/51811.cc: New. * testsuite/29_atomics/atomic/operators/pointer_partial_void.cc: New. Index: include/bits/atomic_0.h =================================================================== --- include/bits/atomic_0.h (revision 189589) +++ include/bits/atomic_0.h (working copy) @@ -620,7 +620,7 @@ namespace __atomic0 __return_pointer_type fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) { - void* __v = _ATOMIC_MODIFY_(this, +=, __d, __m); + void* __v = _ATOMIC_MODIFY_(this, +=, __d * sizeof(_PTp), __m); return reinterpret_cast<__return_pointer_type>(__v); } @@ -628,14 +628,14 @@ namespace __atomic0 fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile { - void* __v = _ATOMIC_MODIFY_(this, +=, __d, __m); + void* __v = _ATOMIC_MODIFY_(this, +=, __d * sizeof(_PTp), __m); return reinterpret_cast<__return_pointer_type>(__v); } __return_pointer_type fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) { - void* __v = _ATOMIC_MODIFY_(this, -=, __d, __m); + void* __v = _ATOMIC_MODIFY_(this, -=, __d * sizeof(_PTp), __m); return reinterpret_cast<__return_pointer_type>(__v); } @@ -643,7 +643,7 @@ namespace __atomic0 fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile { - void* __v = _ATOMIC_MODIFY_(this, -=, __d, __m); + void* __v = _ATOMIC_MODIFY_(this, -=, __d * sizeof(_PTp), __m); return reinterpret_cast<__return_pointer_type>(__v); } }; Index: include/bits/atomic_2.h =================================================================== --- include/bits/atomic_2.h (revision 189589) +++ include/bits/atomic_2.h (working copy) @@ -644,21 +644,21 @@ namespace __atomic2 __pointer_type fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) - { return __sync_fetch_and_add(&_M_p, __d); } + { return __sync_fetch_and_add(&_M_p, __d * sizeof(_PTp)); } __pointer_type fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile - { return __sync_fetch_and_add(&_M_p, __d); } + { return __sync_fetch_and_add(&_M_p, __d * sizeof(_PTp)); } __pointer_type fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) - { return __sync_fetch_and_sub(&_M_p, __d); } + { return __sync_fetch_and_sub(&_M_p, __d * sizeof(_PTp)); } __pointer_type fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile - { return __sync_fetch_and_sub(&_M_p, __d); } + { return __sync_fetch_and_sub(&_M_p, __d * sizeof(_PTp)); } }; } // namespace __atomic2 Index: testsuite/29_atomics/atomic/operators/pointer_partial_void.cc =================================================================== --- testsuite/29_atomics/atomic/operators/pointer_partial_void.cc (revision 0) +++ testsuite/29_atomics/atomic/operators/pointer_partial_void.cc (revision 0) @@ -0,0 +1,71 @@ +// { dg-require-atomic-builtins "" } +// { dg-options "-std=gnu++0x" } + +// Copyright (C) 2012 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This 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 General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <atomic> +#include <cstdlib> //std::abs +#include <testsuite_hooks.h> + +// pointer arithimetic vs. atomic<void*>. +// atomic<void*> vs. explicitly specialized w/o operators, like atomic_bool? +int main(void) +{ + // bool test __attribute__((unused)) = true; + + using namespace std; + + typedef int value_type; + const size_t n = 2; + value_type value = 42; + value_type* p = &value; + void* vp = p; + ptrdiff_t dist(0); + + atomic<void*> a(vp); + + // operator++ + void* vp2(a); + a++; + void* vp3(a); + dist = reinterpret_cast<char*>(vp2) - reinterpret_cast<char*>(vp3); + // VERIFY ( std::abs(dist) == sizeof(void*)); + + // operator-- + void* vp4(a); + a--; + void* vp5(a); + dist = reinterpret_cast<char*>(vp4) - reinterpret_cast<char*>(vp5); + // VERIFY ( std::abs(dist) == sizeof(void*)); + + // operator+= + void* vp6(a); + a+=n; + void* vp7(a); + dist = reinterpret_cast<char*>(vp6) - reinterpret_cast<char*>(vp7); + // VERIFY ( std::abs(dist) == sizeof(void*) * n); + + // operator-= + void* vp8(a); + a-=n; + void* vp9(a); + dist = reinterpret_cast<char*>(vp8) - reinterpret_cast<char*>(vp9); + //VERIFY ( std::abs(dist) == sizeof(void*) * n); + + return 0; +} Index: testsuite/29_atomics/atomic/operators/51811.cc =================================================================== --- testsuite/29_atomics/atomic/operators/51811.cc (revision 0) +++ testsuite/29_atomics/atomic/operators/51811.cc (revision 0) @@ -0,0 +1,90 @@ +// { dg-options "-std=gnu++0x" } + +// Copyright (C) 2012 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This 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 General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <atomic> +#include <cstdlib> //std::abs +#include <testsuite_hooks.h> + +// libstdc++/51811 +// pointer arithimetic vs. atomic<_Tp*> specialization +int main(void) +{ + bool test __attribute__((unused)) = true; + + using namespace std; + + typedef int value_type; + const size_t n = 2; + value_type value = 42; + atomic<value_type*> p, p2, p3; + + // operator++ + { + p = &value; + p2 = p++; + VERIFY (p != p2); + + value_type* vp(p); + value_type* vp2(p2); + ptrdiff_t dist = reinterpret_cast<char*>(vp) - reinterpret_cast<char*>(vp2); + VERIFY ( std::abs(dist) == sizeof(value_type)); + + p = &value; + p3 = ++p; + VERIFY (p == p3); + } + + // operator-- + { + p = &value; + p2 = p--; + VERIFY (p != p2); + + value_type* vp(p); + value_type* vp2(p2); + ptrdiff_t dist = reinterpret_cast<char*>(vp) - reinterpret_cast<char*>(vp2); + VERIFY ( std::abs(dist) == sizeof(value_type)); + + p = &value; + p3 = --p; + VERIFY (p == p3); + } + + // operator+= + { + p = &value; + value_type* vp(p); + p+=n; + value_type* vp2(p); + ptrdiff_t dist = reinterpret_cast<char*>(vp) - reinterpret_cast<char*>(vp2); + VERIFY ( std::abs(dist) == sizeof(value_type) * n); + } + + // operator-= + { + p = &value; + value_type* vp(p); + p-=n; + value_type* vp2(p); + ptrdiff_t dist = reinterpret_cast<char*>(vp) - reinterpret_cast<char*>(vp2); + VERIFY ( std::abs(dist) == sizeof(value_type) * n); + } + + return 0; +} -- This patch is available for review at http://codereview.appspot.com/6428056