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Fix thread-safety (annotalysis) annotations

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tcmalloc contains some thread-safety annotations; however those
annotations have not been exercised for some time, as they used
macros/attributes only supported by a legacy branch of gcc.

Pull request #1251 converted those macros to support modern
versions of clang; this CR fixes the annotations that were
enabled. For the most part, this just requires re-enabling
annotations on member functions that take/release locks. For the
tcmalloc fork (pre-fork and post-fork) handlers, we mark the
functions as exempt from this analysis, as it takes a dynamic
number of locks.
This commit is contained in:
Venkatesh Srinivas 2021-02-17 17:50:43 -08:00
parent cc496aecb8
commit fa412adfe3
4 changed files with 8 additions and 14 deletions
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2
src/base/low_level_alloc.cc
View File

@ -248,7 +248,7 @@ namespace {
this->arena_->mu.Lock();
}
~ArenaLock() { RAW_CHECK(this->left_, "haven't left Arena region"); }
void Leave() /*UNLOCK_FUNCTION()*/ {
void Leave() UNLOCK_FUNCTION() {
this->arena_->mu.Unlock();
#if 0
if (this->mask_valid_) {

12
src/base/spinlock.h
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@ -63,9 +63,7 @@ class LOCKABLE SpinLock {
}
// Acquire this SpinLock.
// TODO(csilvers): uncomment the annotation when we figure out how to
// support this macro with 0 args (see thread_annotations.h)
inline void Lock() /*EXCLUSIVE_LOCK_FUNCTION()*/ {
inline void Lock() EXCLUSIVE_LOCK_FUNCTION() {
if (base::subtle::Acquire_CompareAndSwap(&lockword_, kSpinLockFree,
kSpinLockHeld) != kSpinLockFree) {
SlowLock();
@ -84,9 +82,7 @@ class LOCKABLE SpinLock {
}
// Release this SpinLock, which must be held by the calling thread.
// TODO(csilvers): uncomment the annotation when we figure out how to
// support this macro with 0 args (see thread_annotations.h)
inline void Unlock() /*UNLOCK_FUNCTION()*/ {
inline void Unlock() UNLOCK_FUNCTION() {
uint64 prev_value = static_cast<uint64>(
base::subtle::Release_AtomicExchange(&lockword_, kSpinLockFree));
if (prev_value != kSpinLockHeld) {
@ -127,9 +123,7 @@ class SCOPED_LOCKABLE SpinLockHolder {
: lock_(l) {
l->Lock();
}
// TODO(csilvers): uncomment the annotation when we figure out how to
// support this macro with 0 args (see thread_annotations.h)
inline ~SpinLockHolder() /*UNLOCK_FUNCTION()*/ { lock_->Unlock(); }
inline ~SpinLockHolder() UNLOCK_FUNCTION() { lock_->Unlock(); }
};
// Catch bug where variable name is omitted, e.g. SpinLockHolder (&lock);
#define SpinLockHolder(x) COMPILE_ASSERT(0, spin_lock_decl_missing_var_name)

4
src/central_freelist.h
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@ -82,11 +82,11 @@ class CentralFreeList {
// Lock/Unlock the internal SpinLock. Used on the pthread_atfork call
// to set the lock in a consistent state before the fork.
void Lock() {
void Lock() EXCLUSIVE_LOCK_FUNCTION(lock_) {
lock_.Lock();
}
void Unlock() {
void Unlock() UNLOCK_FUNCTION(lock_) {
lock_.Unlock();
}

4
src/static_vars.cc
View File

@ -52,14 +52,14 @@ namespace tcmalloc {
// sure the central_cache locks remain in a consisten state in the forked
// version of the thread.
void CentralCacheLockAll()
void CentralCacheLockAll() NO_THREAD_SAFETY_ANALYSIS
{
Static::pageheap_lock()->Lock();
for (int i = 0; i < Static::num_size_classes(); ++i)
Static::central_cache()[i].Lock();
}
void CentralCacheUnlockAll()
void CentralCacheUnlockAll() NO_THREAD_SAFETY_ANALYSIS
{
for (int i = 0; i < Static::num_size_classes(); ++i)
Static::central_cache()[i].Unlock();