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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
116 lines
3.4 KiB
C++
116 lines
3.4 KiB
C++
//===-- llvm/Support/ManagedStatic.h - Static Global wrapper ----*- C++ -*-===//
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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 defines the ManagedStatic class and the llvm_shutdown() function.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_MANAGED_STATIC_H
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#define LLVM_SUPPORT_MANAGED_STATIC_H
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#include "llvm/Support/Atomic.h"
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#include "llvm/Support/Threading.h"
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#include "llvm/Support/Valgrind.h"
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namespace llvm {
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/// object_creator - Helper method for ManagedStatic.
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template<class C>
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void* object_creator() {
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return new C();
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}
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/// object_deleter - Helper method for ManagedStatic.
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///
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template<typename T> struct object_deleter {
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static void call(void * Ptr) { delete (T*)Ptr; }
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};
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template<typename T, size_t N> struct object_deleter<T[N]> {
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static void call(void * Ptr) { delete[] (T*)Ptr; }
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};
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/// ManagedStaticBase - Common base class for ManagedStatic instances.
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class ManagedStaticBase {
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protected:
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// This should only be used as a static variable, which guarantees that this
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// will be zero initialized.
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mutable void *Ptr;
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mutable void (*DeleterFn)(void*);
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mutable const ManagedStaticBase *Next;
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void RegisterManagedStatic(void *(*creator)(), void (*deleter)(void*)) const;
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public:
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/// isConstructed - Return true if this object has not been created yet.
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bool isConstructed() const { return Ptr != 0; }
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void destroy() const;
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};
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/// ManagedStatic - This transparently changes the behavior of global statics to
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/// be lazily constructed on demand (good for reducing startup times of dynamic
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/// libraries that link in LLVM components) and for making destruction be
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/// explicit through the llvm_shutdown() function call.
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///
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template<class C>
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class ManagedStatic : public ManagedStaticBase {
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public:
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// Accessors.
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C &operator*() {
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void* tmp = Ptr;
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if (llvm_is_multithreaded()) sys::MemoryFence();
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if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
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TsanHappensAfter(this);
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return *static_cast<C*>(Ptr);
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}
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C *operator->() {
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void* tmp = Ptr;
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if (llvm_is_multithreaded()) sys::MemoryFence();
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if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
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TsanHappensAfter(this);
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return static_cast<C*>(Ptr);
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}
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const C &operator*() const {
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void* tmp = Ptr;
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if (llvm_is_multithreaded()) sys::MemoryFence();
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if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
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TsanHappensAfter(this);
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return *static_cast<C*>(Ptr);
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}
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const C *operator->() const {
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void* tmp = Ptr;
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if (llvm_is_multithreaded()) sys::MemoryFence();
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if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
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TsanHappensAfter(this);
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return static_cast<C*>(Ptr);
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}
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};
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/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
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void llvm_shutdown();
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/// llvm_shutdown_obj - This is a simple helper class that calls
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/// llvm_shutdown() when it is destroyed.
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struct llvm_shutdown_obj {
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llvm_shutdown_obj() { }
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explicit llvm_shutdown_obj(bool multithreaded) {
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if (multithreaded) llvm_start_multithreaded();
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}
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~llvm_shutdown_obj() { llvm_shutdown(); }
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};
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}
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#endif
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