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Diffstat (limited to 'llvm/lib/CAS/OnDiskDataAllocator.cpp')
| -rw-r--r-- | llvm/lib/CAS/OnDiskDataAllocator.cpp | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/llvm/lib/CAS/OnDiskDataAllocator.cpp b/llvm/lib/CAS/OnDiskDataAllocator.cpp new file mode 100644 index 0000000..13bbd66 --- /dev/null +++ b/llvm/lib/CAS/OnDiskDataAllocator.cpp @@ -0,0 +1,234 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +/// +/// \file Implements OnDiskDataAllocator. +/// +//===----------------------------------------------------------------------===// + +#include "llvm/CAS/OnDiskDataAllocator.h" +#include "DatabaseFile.h" +#include "llvm/Config/llvm-config.h" + +using namespace llvm; +using namespace llvm::cas; +using namespace llvm::cas::ondisk; + +#if LLVM_ENABLE_ONDISK_CAS + +//===----------------------------------------------------------------------===// +// DataAllocator data structures. +//===----------------------------------------------------------------------===// + +namespace { +/// DataAllocator table layout: +/// - [8-bytes: Generic table header] +/// - 8-bytes: AllocatorOffset (reserved for implementing free lists) +/// - 8-bytes: Size for user data header +/// - <user data buffer> +/// +/// Record layout: +/// - <data> +class DataAllocatorHandle { +public: + static constexpr TableHandle::TableKind Kind = + TableHandle::TableKind::DataAllocator; + + struct Header { + TableHandle::Header GenericHeader; + std::atomic<int64_t> AllocatorOffset; + const uint64_t UserHeaderSize; + }; + + operator TableHandle() const { + if (!H) + return TableHandle(); + return TableHandle(*Region, H->GenericHeader); + } + + Expected<MutableArrayRef<char>> allocate(MappedFileRegionArena &Alloc, + size_t DataSize) { + assert(&Alloc.getRegion() == Region); + auto Ptr = Alloc.allocate(DataSize); + if (LLVM_UNLIKELY(!Ptr)) + return Ptr.takeError(); + return MutableArrayRef(*Ptr, DataSize); + } + + explicit operator bool() const { return H; } + const Header &getHeader() const { return *H; } + MappedFileRegion &getRegion() const { return *Region; } + + MutableArrayRef<uint8_t> getUserHeader() { + return MutableArrayRef(reinterpret_cast<uint8_t *>(H + 1), + H->UserHeaderSize); + } + + static Expected<DataAllocatorHandle> + create(MappedFileRegionArena &Alloc, StringRef Name, uint32_t UserHeaderSize); + + DataAllocatorHandle() = default; + DataAllocatorHandle(MappedFileRegion &Region, Header &H) + : Region(&Region), H(&H) {} + DataAllocatorHandle(MappedFileRegion &Region, intptr_t HeaderOffset) + : DataAllocatorHandle( + Region, *reinterpret_cast<Header *>(Region.data() + HeaderOffset)) { + } + +private: + MappedFileRegion *Region = nullptr; + Header *H = nullptr; +}; + +} // end anonymous namespace + +struct OnDiskDataAllocator::ImplType { + DatabaseFile File; + DataAllocatorHandle Store; +}; + +Expected<DataAllocatorHandle> +DataAllocatorHandle::create(MappedFileRegionArena &Alloc, StringRef Name, + uint32_t UserHeaderSize) { + // Allocate. + auto Offset = + Alloc.allocateOffset(sizeof(Header) + UserHeaderSize + Name.size() + 1); + if (LLVM_UNLIKELY(!Offset)) + return Offset.takeError(); + + // Construct the header and the name. + assert(Name.size() <= UINT16_MAX && "Expected smaller table name"); + auto *H = new (Alloc.getRegion().data() + *Offset) + Header{{TableHandle::TableKind::DataAllocator, + static_cast<uint16_t>(Name.size()), + static_cast<int32_t>(sizeof(Header) + UserHeaderSize)}, + /*AllocatorOffset=*/{0}, + /*UserHeaderSize=*/UserHeaderSize}; + // Memset UserHeader. + char *UserHeader = reinterpret_cast<char *>(H + 1); + memset(UserHeader, 0, UserHeaderSize); + // Write database file name (null-terminated). + char *NameStorage = UserHeader + UserHeaderSize; + llvm::copy(Name, NameStorage); + NameStorage[Name.size()] = 0; + return DataAllocatorHandle(Alloc.getRegion(), *H); +} + +Expected<OnDiskDataAllocator> OnDiskDataAllocator::create( + const Twine &PathTwine, const Twine &TableNameTwine, uint64_t MaxFileSize, + std::optional<uint64_t> NewFileInitialSize, uint32_t UserHeaderSize, + function_ref<void(void *)> UserHeaderInit) { + assert(!UserHeaderSize || UserHeaderInit); + SmallString<128> PathStorage; + StringRef Path = PathTwine.toStringRef(PathStorage); + SmallString<128> TableNameStorage; + StringRef TableName = TableNameTwine.toStringRef(TableNameStorage); + + // Constructor for if the file doesn't exist. + auto NewDBConstructor = [&](DatabaseFile &DB) -> Error { + auto Store = + DataAllocatorHandle::create(DB.getAlloc(), TableName, UserHeaderSize); + if (LLVM_UNLIKELY(!Store)) + return Store.takeError(); + + if (auto E = DB.addTable(*Store)) + return E; + + if (UserHeaderSize) + UserHeaderInit(Store->getUserHeader().data()); + return Error::success(); + }; + + // Get or create the file. + Expected<DatabaseFile> File = + DatabaseFile::create(Path, MaxFileSize, NewDBConstructor); + if (!File) + return File.takeError(); + + // Find the table and validate it. + std::optional<TableHandle> Table = File->findTable(TableName); + if (!Table) + return createTableConfigError(std::errc::argument_out_of_domain, Path, + TableName, "table not found"); + if (Error E = checkTable("table kind", (size_t)DataAllocatorHandle::Kind, + (size_t)Table->getHeader().Kind, Path, TableName)) + return std::move(E); + auto Store = Table->cast<DataAllocatorHandle>(); + assert(Store && "Already checked the kind"); + + // Success. + OnDiskDataAllocator::ImplType Impl{DatabaseFile(std::move(*File)), Store}; + return OnDiskDataAllocator(std::make_unique<ImplType>(std::move(Impl))); +} + +Expected<OnDiskDataAllocator::OnDiskPtr> +OnDiskDataAllocator::allocate(size_t Size) { + auto Data = Impl->Store.allocate(Impl->File.getAlloc(), Size); + if (LLVM_UNLIKELY(!Data)) + return Data.takeError(); + + return OnDiskPtr(FileOffset(Data->data() - Impl->Store.getRegion().data()), + *Data); +} + +Expected<ArrayRef<char>> OnDiskDataAllocator::get(FileOffset Offset, + size_t Size) const { + assert(Offset); + assert(Impl); + if (Offset.get() + Size >= Impl->File.getAlloc().size()) + return createStringError(make_error_code(std::errc::protocol_error), + "requested size too large in allocator"); + return ArrayRef<char>{Impl->File.getRegion().data() + Offset.get(), Size}; +} + +MutableArrayRef<uint8_t> OnDiskDataAllocator::getUserHeader() { + return Impl->Store.getUserHeader(); +} + +size_t OnDiskDataAllocator::size() const { return Impl->File.size(); } +size_t OnDiskDataAllocator::capacity() const { + return Impl->File.getRegion().size(); +} + +OnDiskDataAllocator::OnDiskDataAllocator(std::unique_ptr<ImplType> Impl) + : Impl(std::move(Impl)) {} + +#else // !LLVM_ENABLE_ONDISK_CAS + +struct OnDiskDataAllocator::ImplType {}; + +Expected<OnDiskDataAllocator> OnDiskDataAllocator::create( + const Twine &Path, const Twine &TableName, uint64_t MaxFileSize, + std::optional<uint64_t> NewFileInitialSize, uint32_t UserHeaderSize, + function_ref<void(void *)> UserHeaderInit) { + return createStringError(make_error_code(std::errc::not_supported), + "OnDiskDataAllocator is not supported"); +} + +Expected<OnDiskDataAllocator::OnDiskPtr> +OnDiskDataAllocator::allocate(size_t Size) { + return createStringError(make_error_code(std::errc::not_supported), + "OnDiskDataAllocator is not supported"); +} + +Expected<ArrayRef<char>> OnDiskDataAllocator::get(FileOffset Offset, + size_t Size) const { + return createStringError(make_error_code(std::errc::not_supported), + "OnDiskDataAllocator is not supported"); +} + +MutableArrayRef<uint8_t> OnDiskDataAllocator::getUserHeader() { return {}; } + +size_t OnDiskDataAllocator::size() const { return 0; } +size_t OnDiskDataAllocator::capacity() const { return 0; } + +#endif // LLVM_ENABLE_ONDISK_CAS + +OnDiskDataAllocator::OnDiskDataAllocator(OnDiskDataAllocator &&RHS) = default; +OnDiskDataAllocator & +OnDiskDataAllocator::operator=(OnDiskDataAllocator &&RHS) = default; +OnDiskDataAllocator::~OnDiskDataAllocator() = default; |