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/bits/stl_tempbuf.h: Likewise.
	* 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 --git a/libstdc++-v3/include/bits/new_allocator.h b/libstdc++-v3/include/bits/new_allocator.h
index 21e7e22cae009b6bd4b318adee4074a12eb35fbc..3a749dc91dbb4bf4a2e0094526f5ee884b026783 100644 (file)
--- 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/bits/stl_tempbuf.h b/libstdc++-v3/include/bits/stl_tempbuf.h
index 759c4937744b661eed5c0fa5233f46e168c49a32..0f267054613f0549d7cf55b28bfe488772f149ad 100644 (file)
--- a/libstdc++-v3/include/bits/stl_tempbuf.h
+++ b/libstdc++-v3/include/bits/stl_tempbuf.h
@@ -85,7 +85,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        if (__builtin_expect(size_t(__len) > (size_t(-1) / sizeof(_Tp)), 0))
          return 0;
 
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
        if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
          return (_Tp*) _GLIBCXX_OPERATOR_NEW(__len * sizeof(_Tp),
                                              align_val_t(alignof(_Tp)),
@@ -107,7 +107,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 # define _GLIBCXX_SIZED_DEALLOC(T, 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(_Tp, __p, __len),
@@ -168,7 +168,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline void
     return_temporary_buffer(_Tp* __p)
     {
-#if __cpp_aligned_new
+#if __cpp_aligned_new && __cplusplus >= 201103L
       if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
        _GLIBCXX_OPERATOR_DELETE(__p, align_val_t(alignof(_Tp)));
       else

diff --git a/libstdc++-v3/include/ext/bitmap_allocator.h b/libstdc++-v3/include/ext/bitmap_allocator.h
index ef2ee13187b97426f6b35a6d25c48d2cf75acd48..45b2283ca30da687260388e9877117e7e496b867 100644 (file)
--- 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 cde06d83241a50bb02a04a27264b4041c131f7ad..2a58847b8a952d0c8f0e6bf72a0de73edf5e324e 100644 (file)
--- 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 0b0bf8dc5f7c50d64e0f6ff8d9d8c24093d0a1cd..77f7dcd276201b7ff3f94216ed55d7dc1a56b8e3 100644 (file)
--- 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 13895b2f71a21d454ec9d8cf6f63843d24314a27..679b4b3d276e75e7158748639fb423ea66fdccd7 100644 (file)
--- 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 (file)
index 0000000..252c40c
--- /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>