[NFC][lsan] Refactor LockThreadRegistry/LockAllocator calls

compiler-rt/lib/lsan/lsan_common.h

@@ -224,6 +224,22 @@ bool WordIsPoisoned(uptr addr);
 // Wrappers for ThreadRegistry access.
 void LockThreadRegistry() NO_THREAD_SAFETY_ANALYSIS;
 void UnlockThreadRegistry() NO_THREAD_SAFETY_ANALYSIS;
+
+struct ScopedStopTheWorldLock {
+  ScopedStopTheWorldLock() {
+    LockThreadRegistry();
+    LockAllocator();
+  }
+
+  ~ScopedStopTheWorldLock() {
+    UnlockAllocator();
+    UnlockThreadRegistry();
+  }
+
+  ScopedStopTheWorldLock &operator=(const ScopedStopTheWorldLock &) = delete;
+  ScopedStopTheWorldLock(const ScopedStopTheWorldLock &) = delete;
+};
+
 ThreadRegistry *GetThreadRegistryLocked();
 bool GetThreadRangesLocked(tid_t os_id, uptr *stack_begin, uptr *stack_end,
                            uptr *tls_begin, uptr *tls_end, uptr *cache_begin,

compiler-rt/lib/lsan/lsan_common_fuchsia.cpp

@@ -58,8 +58,7 @@ int ExitHook(int status) {
 
 void LockStuffAndStopTheWorld(StopTheWorldCallback callback,
                               CheckForLeaksParam *argument) {
-  LockThreadRegistry();
-  LockAllocator();
+  ScopedStopTheWorldLock lock;
 
   struct Params {
     InternalMmapVector<uptr> allocator_caches;
@@ -149,9 +148,6 @@ void LockStuffAndStopTheWorld(StopTheWorldCallback callback,
         params->callback(SuspendedThreadsListFuchsia(), params->argument);
       },
       &params);
-
-  UnlockAllocator();
-  UnlockThreadRegistry();
 }
 
 }  // namespace __lsan

compiler-rt/lib/lsan/lsan_common_linux.cpp

@@ -122,12 +122,9 @@ void HandleLeaks() {
 
 static int LockStuffAndStopTheWorldCallback(struct dl_phdr_info *info,
                                             size_t size, void *data) {
-  LockThreadRegistry();
-  LockAllocator();
+  ScopedStopTheWorldLock lock;
   DoStopTheWorldParam *param = reinterpret_cast<DoStopTheWorldParam *>(data);
   StopTheWorld(param->callback, param->argument);
-  UnlockAllocator();
-  UnlockThreadRegistry();
   return 1;
 }
 

compiler-rt/lib/lsan/lsan_common_mac.cpp

@@ -195,11 +195,8 @@ void HandleLeaks() {}
 
 void LockStuffAndStopTheWorld(StopTheWorldCallback callback,
                               CheckForLeaksParam *argument) {
-  LockThreadRegistry();
-  LockAllocator();
+  ScopedStopTheWorldLock lock;
   StopTheWorld(callback, argument);
-  UnlockAllocator();
-  UnlockThreadRegistry();
 }
 
 } // namespace __lsan