Use SRWlocks for js mutexes on Windows.

1 files changed, 3 insertions, 44 deletions

diff --git a/js/src/threading/windows/MutexImpl.cpp b/js/src/threading/windows/MutexImpl.cpp
index 385d1c8de..e838459b5 100644
--- a/js/src/threading/windows/MutexImpl.cpp
+++ b/js/src/threading/windows/MutexImpl.cpp
@@ -13,35 +13,6 @@
 #include "threading/Mutex.h"
 #include "threading/windows/MutexPlatformData.h"
 
-namespace {
-
-// We build with a toolkit that supports WinXP, so we have to probe
-// for modern features at runtime. This is necessary because Vista and
-// later automatically allocate and subsequently leak a debug info
-// object for each critical section that we allocate unless we tell it
-// not to. In order to tell it not to, we need the extra flags field
-// provided by the Ex version of InitializeCriticalSection.
-struct MutexNativeImports
-{
-  using InitializeCriticalSectionExT = BOOL (WINAPI*)(CRITICAL_SECTION*, DWORD, DWORD);
-  InitializeCriticalSectionExT InitializeCriticalSectionEx;
-
-  MutexNativeImports() {
-    HMODULE kernel32_dll = GetModuleHandle("kernel32.dll");
-    MOZ_RELEASE_ASSERT(kernel32_dll != NULL);
-    InitializeCriticalSectionEx = reinterpret_cast<InitializeCriticalSectionExT>(
-      GetProcAddress(kernel32_dll, "InitializeCriticalSectionEx"));
-  }
-
-  bool hasInitializeCriticalSectionEx() const {
-    return InitializeCriticalSectionEx;
-  }
-};
-
-static MutexNativeImports NativeImports;
-
-} // (anonymous namespace)
-
 js::detail::MutexImpl::MutexImpl()
 {
   AutoEnterOOMUnsafeRegion oom;
@@ -49,18 +20,7 @@ js::detail::MutexImpl::MutexImpl()
   if (!platformData_)
     oom.crash("js::Mutex::Mutex");
 
-  // This number was adopted from NSPR.
-  const static DWORD LockSpinCount = 1500;
-  BOOL r;
-  if (NativeImports.hasInitializeCriticalSectionEx()) {
-    r = NativeImports.InitializeCriticalSectionEx(&platformData()->criticalSection,
-                                                  LockSpinCount,
-                                                  CRITICAL_SECTION_NO_DEBUG_INFO);
-  } else {
-    r = InitializeCriticalSectionAndSpinCount(&platformData()->criticalSection,
-                                              LockSpinCount);
-  }
-  MOZ_RELEASE_ASSERT(r);
+  InitializeSRWLock(&platformData()->lock);
 }
 
 js::detail::MutexImpl::~MutexImpl()
@@ -68,18 +28,17 @@ js::detail::MutexImpl::~MutexImpl()
   if (!platformData_)
     return;
 
-  DeleteCriticalSection(&platformData()->criticalSection);
   js_delete(platformData());
 }
 
 void
 js::detail::MutexImpl::lock()
 {
-  EnterCriticalSection(&platformData()->criticalSection);
+  AcquireSRWLockExclusive(&platformData()->lock);
 }
 
 void
 js::detail::MutexImpl::unlock()
 {
-  LeaveCriticalSection(&platformData()->criticalSection);
+  ReleaseSRWLockExclusive(&platformData()->lock);
 }