diff options
Diffstat (limited to 'chromium/base/memory/singleton.h')
| -rw-r--r-- | chromium/base/memory/singleton.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/chromium/base/memory/singleton.h b/chromium/base/memory/singleton.h index 0d4fc8990c4..e5e2e3efed0 100644 --- a/chromium/base/memory/singleton.h +++ b/chromium/base/memory/singleton.h @@ -63,10 +63,12 @@ struct DefaultSingletonTraits { // exit. See below for the required call that makes this happen. static const bool kRegisterAtExit = true; +#ifndef NDEBUG // Set to false to disallow access on a non-joinable thread. This is // different from kRegisterAtExit because StaticMemorySingletonTraits allows // access on non-joinable threads, and gracefully handles this. static const bool kAllowedToAccessOnNonjoinableThread = false; +#endif }; @@ -76,7 +78,9 @@ struct DefaultSingletonTraits { template<typename Type> struct LeakySingletonTraits : public DefaultSingletonTraits<Type> { static const bool kRegisterAtExit = false; +#ifndef NDEBUG static const bool kAllowedToAccessOnNonjoinableThread = true; +#endif }; @@ -229,7 +233,9 @@ class Singleton { base::ThreadRestrictions::AssertSingletonAllowed(); #endif - base::subtle::AtomicWord value = base::subtle::NoBarrier_Load(&instance_); + // The load has acquire memory ordering as the thread which reads the + // instance_ pointer must acquire visibility over the singleton data. + base::subtle::AtomicWord value = base::subtle::Acquire_Load(&instance_); if (value != 0 && value != base::internal::kBeingCreatedMarker) { // See the corresponding HAPPENS_BEFORE below. ANNOTATE_HAPPENS_AFTER(&instance_); @@ -248,6 +254,7 @@ class Singleton { // synchronization between different threads calling get(). // See the corresponding HAPPENS_AFTER below and above. ANNOTATE_HAPPENS_BEFORE(&instance_); + // Releases the visibility over instance_ to the readers. base::subtle::Release_Store( &instance_, reinterpret_cast<base::subtle::AtomicWord>(newval)); |