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11c5d4741a
Summary: We've had a couple CockroachDB users fail to build RocksDB on exotic platforms, so I figured I'd try my hand at solving these issues upstream. The problems stem from a) `USE_SSE=1` being too aggressive about turning on SSE4.2, even on toolchains that don't support SSE4.2 and b) RocksDB attempting to detect support for thread-local storage based on OS, even though it can vary by compiler on the same OS. See the individual commit messages for details. Regarding SSE support, this PR should change virtually nothing for non-CMake based builds. `make`, `PORTABLE=1 make`, `USE_SSE=1 make`, and `PORTABLE=1 USE_SSE=1 make` function exactly as before, except that SSE support will be automatically disabled when a simple SSE4.2-using test program fails to compile, as it does on OpenBSD. (OpenBSD's ports GCC supports SSE4.2, but its binutils do not, so `__SSE_4_2__` is defined but an SSE4.2-using program will fail to assemble.) A warning is emitted in this case. The CMake build is modified to support the same set of options, except that `USE_SSE` is spelled `FORCE_SSE42` because `USE_SSE` is rather useless now that we can automatically detect SSE support, and I figure changing options in the CMake build is less disruptive than changing the non-CMake build. I've tested these changes on all the platforms I can get my hands on (macOS, Windows MSVC, Windows MinGW, and OpenBSD) and it all works splendidly. Let me know if there's anything you object to—I obviously don't mean to break any of your build pipelines in the process of fixing ours downstream. Closes https://github.com/facebook/rocksdb/pull/2199 Differential Revision: D5054042 Pulled By: yiwu-arbug fbshipit-source-id: 938e1fc665c049c02ae15698e1409155b8e72171
94 lines
3.3 KiB
C++
94 lines
3.3 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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// This source code is also licensed under the GPLv2 license found in the
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// COPYING file in the root directory of this source tree.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include <atomic>
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#include <functional>
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#include <memory>
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#include <unordered_map>
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#include <vector>
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#include "util/autovector.h"
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#include "port/port.h"
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namespace rocksdb {
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// Cleanup function that will be called for a stored thread local
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// pointer (if not NULL) when one of the following happens:
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// (1) a thread terminates
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// (2) a ThreadLocalPtr is destroyed
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typedef void (*UnrefHandler)(void* ptr);
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// ThreadLocalPtr stores only values of pointer type. Different from
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// the usual thread-local-storage, ThreadLocalPtr has the ability to
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// distinguish data coming from different threads and different
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// ThreadLocalPtr instances. For example, if a regular thread_local
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// variable A is declared in DBImpl, two DBImpl objects would share
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// the same A. However, a ThreadLocalPtr that is defined under the
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// scope of DBImpl can avoid such confliction. As a result, its memory
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// usage would be O(# of threads * # of ThreadLocalPtr instances).
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class ThreadLocalPtr {
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public:
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explicit ThreadLocalPtr(UnrefHandler handler = nullptr);
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~ThreadLocalPtr();
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// Return the current pointer stored in thread local
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void* Get() const;
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// Set a new pointer value to the thread local storage.
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void Reset(void* ptr);
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// Atomically swap the supplied ptr and return the previous value
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void* Swap(void* ptr);
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// Atomically compare the stored value with expected. Set the new
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// pointer value to thread local only if the comparison is true.
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// Otherwise, expected returns the stored value.
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// Return true on success, false on failure
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bool CompareAndSwap(void* ptr, void*& expected);
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// Reset all thread local data to replacement, and return non-nullptr
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// data for all existing threads
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void Scrape(autovector<void*>* ptrs, void* const replacement);
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typedef std::function<void(void*, void*)> FoldFunc;
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// Update res by applying func on each thread-local value. Holds a lock that
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// prevents unref handler from running during this call, but clients must
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// still provide external synchronization since the owning thread can
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// access the values without internal locking, e.g., via Get() and Reset().
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void Fold(FoldFunc func, void* res);
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// Add here for testing
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// Return the next available Id without claiming it
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static uint32_t TEST_PeekId();
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// Initialize the static singletons of the ThreadLocalPtr.
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//
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// If this function is not called, then the singletons will be
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// automatically initialized when they are used.
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//
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// Calling this function twice or after the singletons have been
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// initialized will be no-op.
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static void InitSingletons();
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class StaticMeta;
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private:
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static StaticMeta* Instance();
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const uint32_t id_;
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};
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} // namespace rocksdb
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