5199556263
* Reduce code duplication. The Apple and Haiku PALs both had *almost* identical code to the POSIX PAL, differing only in some small argument variables. This is fragile and easy to accidentally get out of sync. For example, the changes to `reserve_at_least` involved copying identical code into multiple PALs and it's easy to accidentally miss one. This change introduces two optional fields on POSIX-derived PALs: - `default_mmap_flags` allows a PAL to provide additional `MAP_*` flags to all `mmap` calls. - `anonymous_memory_fd` allows the PAL to override the default file descriptor used for memory mappings. If a PAL does not provide these, default values are used. Fixes #219
41 lines
1.2 KiB
C++
41 lines
1.2 KiB
C++
#pragma once
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#ifdef __APPLE__
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# include "pal_bsd.h"
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# include <mach/vm_statistics.h>
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# include <utility>
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namespace snmalloc
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{
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/**
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* PAL implementation for Apple systems (macOS, iOS, watchOS, tvOS...).
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*/
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template<int PALAnonID = PALAnonDefaultID>
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class PALApple : public PALBSD<PALApple<>>
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{
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public:
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/**
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* The features exported by this PAL.
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*
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* Currently, these are identical to the generic BSD PAL. This field is
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* declared explicitly to remind anyone who modifies this class that they
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* should add any required features.
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*/
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static constexpr uint64_t pal_features = PALBSD::pal_features;
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/**
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* Anonymous page tag ID.
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*
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* Darwin platform allows to gives an ID to anonymous pages via
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* the VM_MAKE_TAG's macro, from 240 up to 255 are guaranteed
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* to be free of usage, however eventually a lower could be taken
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* (e.g. LLVM sanitizers has 99) so we can monitor their states
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* via vmmap for instance. This value is provided to `mmap` as the file
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* descriptor for the mapping.
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*/
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static constexpr int anonymous_memory_fd = VM_MAKE_TAG(PALAnonID);
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};
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} // namespace snmalloc
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#endif
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