@@ -421,7 +421,12 @@ namespace pmr {
do_allocate(size_t __bytes, size_t __alignment) override
{
if (__alignment <= __guaranteed_alignment<_Alloc>::value)
- return _M_alloc.allocate(__bytes);
+ {
+ if (__bytes < __alignment)
+ __bytes = __alignment;
+ return _M_alloc.allocate(__bytes);
+ }
+
const _AlignMgr __mgr(__bytes, __alignment);
// Assume _M_alloc returns 1-byte aligned memory, so allocate enough
@@ -437,6 +442,8 @@ namespace pmr {
auto __ptr = static_cast<char*>(__p);
if (__alignment <= __guaranteed_alignment<_Alloc>::value)
{
+ if (__bytes < __alignment)
+ __bytes = __alignment;
_M_alloc.deallocate(__ptr, __bytes);
return;
}
@@ -109,11 +109,13 @@ test03()
using std::size_t;
void* p = nullptr;
+ auto max = [](int n, int a) { return n > a ? n : a; };
+
bytes_allocated = 0;
memory_resource* r1 = new_delete_resource();
- p = r1->allocate(1);
- VERIFY( bytes_allocated == 1 );
+ p = r1->allocate(1); // uses alignment = alignof(max_align_t)
+ VERIFY( bytes_allocated <= alignof(max_align_t) );
VERIFY( aligned<max_align_t>(p) );
r1->deallocate(p, 1);
VERIFY( bytes_allocated == 0 );
@@ -125,13 +127,13 @@ test03()
VERIFY( bytes_allocated == 0 );
p = r1->allocate(3, alignof(short));
- VERIFY( bytes_allocated == 3 );
+ VERIFY( bytes_allocated == max(3, alignof(short)) );
VERIFY( aligned<short>(p) );
r1->deallocate(p, 3, alignof(short));
VERIFY( bytes_allocated == 0 );
p = r1->allocate(4, alignof(long));
- VERIFY( bytes_allocated == 4 );
+ VERIFY( bytes_allocated == max(4, alignof(long)) );
VERIFY( aligned<long>(p) );
r1->deallocate(p, 4, alignof(long));
VERIFY( bytes_allocated == 0 );
It's not safe to assume that malloc(n) returns memory aligned to more than n, so when relying on the guaranteed alignment of malloc ensure that the number of bytes allocated is at least as large as the alignment. PR libstdc++/77691 * include/experimental/memory_resource (__resource_adaptor_imp): Do not allocate sizes smaller than alignment when relying on guaranteed alignment. * testsuite/experimental/memory_resource/new_delete_resource.cc: Adjust expected number of bytes allocated for alignof(max_align_t). Tested x86_64-linux, committed to trunk. commit 100292bfb473df26817d99ffa56ad6728177732b Author: Jonathan Wakely <jwakely@redhat.com> Date: Fri Oct 12 00:10:27 2018 +0100 PR libstdc++/77691 increase allocation size to at least alignment It's not safe to assume that malloc(n) returns memory aligned to more than n, so when relying on the guaranteed alignment of malloc ensure that the number of bytes allocated is at least as large as the alignment. PR libstdc++/77691 * include/experimental/memory_resource (__resource_adaptor_imp): Do not allocate sizes smaller than alignment when relying on guaranteed alignment. * testsuite/experimental/memory_resource/new_delete_resource.cc: Adjust expected number of bytes allocated for alignof(max_align_t).