f7d32078e5
Adds a CAS logging interface to track mutations of the CAS and action cache database files. This is designed to aid in the debugging of data corruption and other issues with the low-level on-disk representation. To enable logging, set the environment variable LLVM_CAS_LOG to 1 or 2. Level 2 includes logging of all allocations inside the index, action cache, and datapool, which increases the overhead. The log file is placed inside the top-level directory of the unified cache. For now it is a human-readable textual format with one line per entry.
126 lines
4.8 KiB
C++
126 lines
4.8 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file This file implements the common abstractions for CAS database file.
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///
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//===----------------------------------------------------------------------===//
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#include "DatabaseFile.h"
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using namespace llvm;
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using namespace llvm::cas;
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using namespace llvm::cas::ondisk;
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Error ondisk::createTableConfigError(std::errc ErrC, StringRef Path,
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StringRef TableName, const Twine &Msg) {
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return createStringError(make_error_code(ErrC),
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Path + "[" + TableName + "]: " + Msg);
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}
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Error ondisk::checkTable(StringRef Label, size_t Expected, size_t Observed,
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StringRef Path, StringRef TrieName) {
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if (Expected == Observed)
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return Error::success();
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return createTableConfigError(std::errc::invalid_argument, Path, TrieName,
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"mismatched " + Label +
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" (expected: " + Twine(Expected) +
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", observed: " + Twine(Observed) + ")");
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}
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Expected<DatabaseFile>
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DatabaseFile::create(const Twine &Path, uint64_t Capacity,
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std::shared_ptr<OnDiskCASLogger> Logger,
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function_ref<Error(DatabaseFile &)> NewDBConstructor) {
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// Constructor for if the file doesn't exist.
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auto NewFileConstructor = [&](MappedFileRegionArena &Alloc) -> Error {
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if (Alloc.capacity() <
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sizeof(Header) + sizeof(MappedFileRegionArena::Header))
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return createTableConfigError(std::errc::argument_out_of_domain,
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Path.str(), "datafile",
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"Allocator too small for header");
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(void)new (Alloc.data()) Header{getMagic(), getVersion(), {0}};
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DatabaseFile DB(Alloc);
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return NewDBConstructor(DB);
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};
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// Get or create the file.
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MappedFileRegionArena Alloc;
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if (Error E =
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MappedFileRegionArena::create(Path, Capacity, sizeof(Header),
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std::move(Logger), NewFileConstructor)
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.moveInto(Alloc))
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return std::move(E);
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return DatabaseFile::get(
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std::make_unique<MappedFileRegionArena>(std::move(Alloc)));
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}
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Error DatabaseFile::addTable(TableHandle Table) {
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assert(Table);
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assert(&Table.getRegion() == &getRegion());
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int64_t ExistingRootOffset = 0;
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const int64_t NewOffset =
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reinterpret_cast<const char *>(&Table.getHeader()) - getRegion().data();
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if (H->RootTableOffset.compare_exchange_strong(ExistingRootOffset, NewOffset))
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return Error::success();
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// Silently ignore attempts to set the root to itself.
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if (ExistingRootOffset == NewOffset)
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return Error::success();
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// Return an proper error message.
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TableHandle Root(getRegion(), ExistingRootOffset);
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if (Root.getName() == Table.getName())
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return createStringError(
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make_error_code(std::errc::not_supported),
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"collision with existing table of the same name '" + Table.getName() +
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"'");
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return createStringError(make_error_code(std::errc::not_supported),
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"cannot add new table '" + Table.getName() +
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"'"
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" to existing root '" +
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Root.getName() + "'");
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}
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std::optional<TableHandle> DatabaseFile::findTable(StringRef Name) {
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int64_t RootTableOffset = H->RootTableOffset.load();
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if (!RootTableOffset)
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return std::nullopt;
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TableHandle Root(getRegion(), RootTableOffset);
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if (Root.getName() == Name)
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return Root;
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return std::nullopt;
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}
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Error DatabaseFile::validate(MappedFileRegion &Region) {
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if (Region.size() < sizeof(Header))
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return createStringError(std::errc::invalid_argument,
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"database: missing header");
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// Check the magic and version.
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auto *H = reinterpret_cast<Header *>(Region.data());
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if (H->Magic != getMagic())
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return createStringError(std::errc::invalid_argument,
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"database: bad magic");
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if (H->Version != getVersion())
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return createStringError(std::errc::invalid_argument,
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"database: wrong version");
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auto *MFH = reinterpret_cast<MappedFileRegionArena::Header *>(Region.data() +
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sizeof(Header));
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// Check the bump-ptr, which should point past the header.
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if (MFH->BumpPtr.load() < (int64_t)sizeof(Header))
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return createStringError(std::errc::invalid_argument,
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"database: corrupt bump-ptr");
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return Error::success();
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}
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