cd70a7856b
- CI merge issues:
- The malloc shim libraries are renamed.
- CMake gets very unhappy if you don't enable the C language and
tries to link with the C compiler instead of the C++ compiler if
you do enable it.
- The Ubuntu packages for QEMU install a `binfmt_misc` activator for
PowerPC64 little-endian, but set the page size to 4 KiB. We then
tried to run the tests (which expect 64 KiB pages) and became very
confused when `mmap` returned 4 KiB-aligned memory.
- Test failures:
- Fix all of the issues UBsan found.
- Underflow in `pointer_offset` when used to add negative offsets.
- `CoreAlloc`'s `LocalState` accessed on a null `CoreAlloc` pointer.
- Out of bounds access in the sizeclass list on attempts to access
more memory than fits in the VA space.
-
- There was an integer overflow in `AddressSpace` that could cause it
to try to allocate a zero-sized object, get a null pointer, and
then try to do something with 0 - {size of the real allocation}.
- The malloc tests weren't setting `errno` to 0 before doing
calling `malloc`, which should set `errno` on failure, and then
checking that `errno` was 0.
- Don't call `PAL::error` on PAL allocation failure, return `nullptr`.
The PALs were inconsistent about that and the new code expects to be
able to report address-space exhaustion.
- The malloc checks can behave differently with 0-sized allocations
on different platforms but were very fragile about their
expectations.
- The malloc test didn't report failure for all of the ways that it
could fail and so was spuriously passing on some platforms.
- The perf test for external pointer is currently very slow on
Windows. The number of loops have been reduced and a timeout added
for the Windows CI runs.
- The logic to capture `errno` across calls was using
`decltype(errno)`, which on some platforms where `errno` is a macro
evaluated to `int&` and so they captured a reference rather than
the value and failed to reset `errno`.
- The Apple PAL can set `errno` on `notify_using` if it's called with
memory that was not previously passed to `notify_not_using` but was
not adequately protected against this and so would sometimes cause
`malloc` to set `errno` to `EINVAL`.
61 lines
1.4 KiB
C++
61 lines
1.4 KiB
C++
#pragma once
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#include "pal_bsd.h"
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namespace snmalloc
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{
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/**
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* FreeBSD-specific platform abstraction layer.
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*
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* This adds aligned allocation using `MAP_ALIGNED` to the generic BSD
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* implementation. This flag is supported by NetBSD and FreeBSD.
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*/
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template<class OS>
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class PALBSD_Aligned : public PALBSD<OS>
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{
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public:
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/**
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* Bitmap of PalFeatures flags indicating the optional features that this
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* PAL supports.
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*
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* This class adds support for aligned allocation.
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*/
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static constexpr uint64_t pal_features =
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AlignedAllocation | PALBSD<OS>::pal_features;
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static SNMALLOC_CONSTINIT_STATIC size_t minimum_alloc_size = 4096;
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/**
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* Reserve memory at a specific alignment.
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*/
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template<bool committed>
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static void* reserve_aligned(size_t size) noexcept
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{
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// Alignment must be a power of 2.
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SNMALLOC_ASSERT(bits::is_pow2(size));
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SNMALLOC_ASSERT(size >= minimum_alloc_size);
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int log2align = static_cast<int>(bits::next_pow2_bits(size));
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#ifdef SNMALLOC_CHECK_CLIENT
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auto prot = committed ? PROT_READ | PROT_WRITE : PROT_NONE;
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#else
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auto prot = PROT_READ | PROT_WRITE;
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#endif
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void* p = mmap(
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nullptr,
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size,
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prot,
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MAP_PRIVATE | MAP_ANONYMOUS | MAP_ALIGNED(log2align),
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-1,
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0);
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if (p == MAP_FAILED)
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return nullptr;
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return p;
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}
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};
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} // namespace snmalloc
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