https://gcc.gnu.org/g:b48785e9aba68639ab6e16c37efdd82eaf974055
commit r13-9535-gb48785e9aba68639ab6e16c37efdd82eaf974055
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Wed Jun 26 14:09:07 2024 +0100
libstdc++: Do not use C++11 alignof in C++98 mode [PR104395]
When -faligned-new (or Clang's -faligned-allocation) is used our
allocators try to support extended alignments, gated on the
__cpp_aligned_new macro. However, because they use alignof(_Tp) which is
not a keyword in C++98 mode, using -std=c++98 -faligned-new results in
errors from <memory> and other headers.
We could change them to use __alignof__ instead of alignof, but that
would potentially alter the result of the conditions, because e.g.
alignof(long long) != __alignof__(long long) on some targets. That's
probably not an issue for any types with extended alignment, so maybe it
would be a safe change.
For now, it seems acceptable to just disable the extended alignment
support in C++98 mode, so that -faligned-new enables std::align_val_t
and the corresponding operator new overloads, but doesn't affect
std::allocator, __gnu_cxx::__bitmap_allocator etc.
libstdc++-v3/ChangeLog:
PR libstdc++/104395
* include/bits/new_allocator.h: Disable extended alignment
support in C++98 mode.
* include/ext/bitmap_allocator.h: Likewise.
* include/ext/malloc_allocator.h: Likewise.
* include/ext/mt_allocator.h: Likewise.
* include/ext/pool_allocator.h: Likewise.
* testsuite/ext/104395.cc: New test.
(cherry picked from commit 03d3aeb0e0fa7dec9bd702cabf57ef73cdc32704)
Diff:
---
libstdc++-v3/include/bits/new_allocator.h | 4 ++--
libstdc++-v3/include/ext/bitmap_allocator.h | 4 ++--
libstdc++-v3/include/ext/malloc_allocator.h | 2 +-
libstdc++-v3/include/ext/mt_allocator.h | 4 ++--
libstdc++-v3/include/ext/pool_allocator.h | 4 ++--
libstdc++-v3/testsuite/ext/104395.cc | 8 ++++++++
6 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/libstdc++-v3/include/bits/new_allocator.h
b/libstdc++-v3/include/bits/new_allocator.h
index 357700292edc..5e7acc27fb44 100644
--- a/libstdc++-v3/include/bits/new_allocator.h
+++ b/libstdc++-v3/include/bits/new_allocator.h
@@ -140,7 +140,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
std::__throw_bad_alloc();
}
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
std::align_val_t __al = std::align_val_t(alignof(_Tp));
@@ -161,7 +161,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
# define _GLIBCXX_SIZED_DEALLOC(p, n) (p)
#endif
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
_GLIBCXX_OPERATOR_DELETE(_GLIBCXX_SIZED_DEALLOC(__p, __n),
diff --git a/libstdc++-v3/include/ext/bitmap_allocator.h
b/libstdc++-v3/include/ext/bitmap_allocator.h
index 5393d0620733..5421000b2975 100644
--- a/libstdc++-v3/include/ext/bitmap_allocator.h
+++ b/libstdc++-v3/include/ext/bitmap_allocator.h
@@ -1017,7 +1017,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__n > this->max_size())
std::__throw_bad_alloc();
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
if (alignof(value_type) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
const size_type __b = __n * sizeof(value_type);
@@ -1044,7 +1044,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
if (__builtin_expect(__p != 0, true))
{
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
// Types with extended alignment are handled by operator delete.
if (alignof(value_type) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
diff --git a/libstdc++-v3/include/ext/malloc_allocator.h
b/libstdc++-v3/include/ext/malloc_allocator.h
index cfdb042bd190..90e805f8830c 100644
--- a/libstdc++-v3/include/ext/malloc_allocator.h
+++ b/libstdc++-v3/include/ext/malloc_allocator.h
@@ -120,7 +120,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
_Tp* __ret = 0;
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
#if __cplusplus > 201402L && _GLIBCXX_HAVE_ALIGNED_ALLOC
if (alignof(_Tp) > alignof(std::max_align_t))
{
diff --git a/libstdc++-v3/include/ext/mt_allocator.h
b/libstdc++-v3/include/ext/mt_allocator.h
index 9184fc0b1d95..14c09819fe5a 100644
--- a/libstdc++-v3/include/ext/mt_allocator.h
+++ b/libstdc++-v3/include/ext/mt_allocator.h
@@ -693,7 +693,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__n > this->max_size())
std::__throw_bad_alloc();
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
// Types with extended alignment are handled by operator new/delete.
if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
@@ -748,7 +748,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
if (__builtin_expect(__p != 0, true))
{
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
// Types with extended alignment are handled by operator new/delete.
if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
diff --git a/libstdc++-v3/include/ext/pool_allocator.h
b/libstdc++-v3/include/ext/pool_allocator.h
index 3476b2ff5215..a6d0180b3cd2 100644
--- a/libstdc++-v3/include/ext/pool_allocator.h
+++ b/libstdc++-v3/include/ext/pool_allocator.h
@@ -224,7 +224,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const size_t __bytes = __n * sizeof(_Tp);
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
std::align_val_t __al = std::align_val_t(alignof(_Tp));
@@ -272,7 +272,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using std::size_t;
if (__builtin_expect(__n != 0 && __p != 0, true))
{
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
::operator delete(__p, std::align_val_t(alignof(_Tp)));
diff --git a/libstdc++-v3/testsuite/ext/104395.cc
b/libstdc++-v3/testsuite/ext/104395.cc
new file mode 100644
index 000000000000..252c40c96980
--- /dev/null
+++ b/libstdc++-v3/testsuite/ext/104395.cc
@@ -0,0 +1,8 @@
+// { dg-options "-std=gnu++98 -faligned-new" }
+// { dg-do compile }
+#include <ext/memory>
+#include <ext/bitmap_allocator.h>
+#include <ext/mt_allocator.h>
+#include <ext/malloc_allocator.h>
+#include <ext/new_allocator.h>
+#include <ext/pool_allocator.h>
