mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2025-04-16 14:40:00 +00:00
e87a554529
This patch removes the functions llvm_start_multithreaded() and llvm_stop_multithreaded(), and changes llvm_is_multithreaded() to return a constant value based on the value of the compile-time definition LLVM_ENABLE_THREADS. Previously, it was possible to have compile-time support for threads on, and runtime support for threads off, in which case certain mutexes were not allocated or ever acquired. Now, if the build is created with threads enabled, mutexes are always acquired. A test before/after patch of compiling a very large TU showed no noticeable performance impact of this change. Reviewers: rnk Differential Revision: http://reviews.llvm.org/D4076 llvm-svn: 210600
81 lines
2.2 KiB
C++
81 lines
2.2 KiB
C++
//===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the ManagedStatic class and llvm_shutdown().
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Support/ManagedStatic.h"
|
|
#include "llvm/Config/config.h"
|
|
#include "llvm/Support/Atomic.h"
|
|
#include <cassert>
|
|
#include <mutex>
|
|
using namespace llvm;
|
|
|
|
static const ManagedStaticBase *StaticList = nullptr;
|
|
|
|
void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
|
|
void (*Deleter)(void*)) const {
|
|
assert(Creator);
|
|
if (llvm_is_multithreaded()) {
|
|
std::lock_guard<llvm::recursive_mutex> Lock(llvm_get_global_lock());
|
|
|
|
if (!Ptr) {
|
|
void* tmp = Creator();
|
|
|
|
TsanHappensBefore(this);
|
|
sys::MemoryFence();
|
|
|
|
// This write is racy against the first read in the ManagedStatic
|
|
// accessors. The race is benign because it does a second read after a
|
|
// memory fence, at which point it isn't possible to get a partial value.
|
|
TsanIgnoreWritesBegin();
|
|
Ptr = tmp;
|
|
TsanIgnoreWritesEnd();
|
|
DeleterFn = Deleter;
|
|
|
|
// Add to list of managed statics.
|
|
Next = StaticList;
|
|
StaticList = this;
|
|
}
|
|
|
|
} else {
|
|
assert(!Ptr && !DeleterFn && !Next &&
|
|
"Partially initialized ManagedStatic!?");
|
|
Ptr = Creator();
|
|
DeleterFn = Deleter;
|
|
|
|
// Add to list of managed statics.
|
|
Next = StaticList;
|
|
StaticList = this;
|
|
}
|
|
}
|
|
|
|
void ManagedStaticBase::destroy() const {
|
|
assert(DeleterFn && "ManagedStatic not initialized correctly!");
|
|
assert(StaticList == this &&
|
|
"Not destroyed in reverse order of construction?");
|
|
// Unlink from list.
|
|
StaticList = Next;
|
|
Next = nullptr;
|
|
|
|
// Destroy memory.
|
|
DeleterFn(Ptr);
|
|
|
|
// Cleanup.
|
|
Ptr = nullptr;
|
|
DeleterFn = nullptr;
|
|
}
|
|
|
|
/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
|
|
void llvm::llvm_shutdown() {
|
|
while (StaticList)
|
|
StaticList->destroy();
|
|
}
|