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Correct PAL Concept

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The test for NoAllocation/AlignedAllocation/neither was broken and this was
undetected until the sandbox demo came into being with its NoAllocation PAL
instance.  (Sadly, this remained undetected for so long because we can't
routinely build with C++20 because std::atomic_t<>'s initialization rules
changed in ways that make us require oodles and oodles of RAM at compile time.
This patch has been validated with -j1 on a machine with lots of RAM.)

Separately, it's possible that we end up here without `using namespace std`,
which seems like overkill.  So just use `std::size_t` ourselves within the PAL
Concept definition.
This commit is contained in:
Nathaniel Filardo
2021-04-06 22:56:09 +01:00
committed by Nathaniel Wesley Filardo
parent d1acb7979a
commit cfa996692f
1 changed files with 12 additions and 11 deletions
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23
src/pal/pal_concept.h
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@@ -19,7 +19,7 @@ namespace snmalloc
concept ConceptPAL_static_members = requires()
{
typename std::integral_constant<uint64_t, PAL::pal_features>;
typename std::integral_constant<size_t, PAL::page_size>;
typename std::integral_constant<std::size_t, PAL::page_size>;
};
/**
@@ -35,7 +35,7 @@ namespace snmalloc
* PALs expose a basic library of memory operations.
*/
template<typename PAL>
concept ConceptPAL_memops = requires(void* vp, size_t sz)
concept ConceptPAL_memops = requires(void* vp, std::size_t sz)
{
{ PAL::notify_not_using(vp, sz) } noexcept -> ConceptSame<void>;
@@ -52,17 +52,18 @@ namespace snmalloc
* Absent any feature flags, the PAL must support a crude primitive allocator
*/
template<typename PAL>
concept ConceptPAL_reserve_at_least = requires(PAL p, void* vp, size_t sz)
concept ConceptPAL_reserve_at_least =
requires(PAL p, void* vp, std::size_t sz)
{
{ PAL::reserve_at_least(sz) } noexcept
-> ConceptSame<std::pair<void*, size_t>>;
-> ConceptSame<std::pair<void*, std::size_t>>;
};
/**
* Some PALs expose a richer allocator which understands aligned allocations
*/
template<typename PAL>
concept ConceptPAL_reserve_aligned = requires(size_t sz)
concept ConceptPAL_reserve_aligned = requires(std::size_t sz)
{
{ PAL::template reserve_aligned<true>(sz) } noexcept -> ConceptSame<void*>;
{ PAL::template reserve_aligned<false>(sz) } noexcept
@@ -90,13 +91,13 @@ namespace snmalloc
ConceptPAL_static_members<PAL> &&
ConceptPAL_error<PAL> &&
ConceptPAL_memops<PAL> &&
(!(PAL::pal_features & LowMemoryNotification) ||
(!pal_supports<LowMemoryNotification, PAL> ||
ConceptPAL_mem_low_notify<PAL>) &&
(!(PAL::pal_features & NoAllocation) && (
(!!(PAL::pal_features & AlignedAllocation) ||
ConceptPAL_reserve_at_least<PAL>) &&
(!(PAL::pal_features & AlignedAllocation) ||
ConceptPAL_reserve_aligned<PAL>)));
(pal_supports<NoAllocation, PAL> ||
(pal_supports<AlignedAllocation, PAL> &&
ConceptPAL_reserve_aligned<PAL>) ||
(!pal_supports<AlignedAllocation, PAL> &&
ConceptPAL_reserve_at_least<PAL>));
} // namespace snmalloc
#endif