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4d0a9ff365
These annotations are disabled entirely when either ENABLE_THREADS is off, or building a release build. When enabled, they add calls to functions with no statements to ManagedStatic's getters. Use these annotations to inform tsan that the race used inside ManagedStatic initialization is actually benign. Thanks to Kostya Serebryany for helping write this patch! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144567 91177308-0d34-0410-b5e6-96231b3b80d8
82 lines
2.3 KiB
C++
82 lines
2.3 KiB
C++
//===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the ManagedStatic class and llvm_shutdown().
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/ManagedStatic.h"
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#include "llvm/Config/config.h"
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#include "llvm/Support/Atomic.h"
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#include <cassert>
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using namespace llvm;
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static const ManagedStaticBase *StaticList = 0;
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void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
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void (*Deleter)(void*)) const {
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if (llvm_is_multithreaded()) {
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llvm_acquire_global_lock();
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if (Ptr == 0) {
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void* tmp = Creator ? Creator() : 0;
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TsanHappensBefore(this);
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sys::MemoryFence();
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// This write is racy against the first read in the ManagedStatic
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// accessors. The race is benign because it does a second read after a
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// memory fence, at which point it isn't possible to get a partial value.
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TsanIgnoreWritesBegin();
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Ptr = tmp;
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TsanIgnoreWritesEnd();
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DeleterFn = Deleter;
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// Add to list of managed statics.
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Next = StaticList;
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StaticList = this;
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}
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llvm_release_global_lock();
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} else {
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assert(Ptr == 0 && DeleterFn == 0 && Next == 0 &&
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"Partially initialized ManagedStatic!?");
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Ptr = Creator ? Creator() : 0;
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DeleterFn = Deleter;
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// Add to list of managed statics.
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Next = StaticList;
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StaticList = this;
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}
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}
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void ManagedStaticBase::destroy() const {
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assert(DeleterFn && "ManagedStatic not initialized correctly!");
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assert(StaticList == this &&
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"Not destroyed in reverse order of construction?");
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// Unlink from list.
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StaticList = Next;
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Next = 0;
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// Destroy memory.
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DeleterFn(Ptr);
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// Cleanup.
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Ptr = 0;
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DeleterFn = 0;
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}
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/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
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void llvm::llvm_shutdown() {
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while (StaticList)
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StaticList->destroy();
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if (llvm_is_multithreaded()) llvm_stop_multithreaded();
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}
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