Expressed the thread-safety annotations in code, replacing the existing comment-based system (by Aaron Jacobs).

include/gtest/gtest.h

@@ -1107,11 +1107,13 @@ class GTEST_API_ UnitTest {
 
   // Returns the TestCase object for the test that's currently running,
   // or NULL if no test is running.
-  const TestCase* current_test_case() const;
+  const TestCase* current_test_case() const
+      GTEST_LOCK_EXCLUDED_(mutex_);
 
   // Returns the TestInfo object for the test that's currently running,
   // or NULL if no test is running.
-  const TestInfo* current_test_info() const;
+  const TestInfo* current_test_info() const
+      GTEST_LOCK_EXCLUDED_(mutex_);
 
   // Returns the random seed used at the start of the current test run.
   int random_seed() const;
@@ -1121,7 +1123,8 @@ class GTEST_API_ UnitTest {
   // value-parameterized tests and instantiate and register them.
   //
   // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
-  internal::ParameterizedTestCaseRegistry& parameterized_test_registry();
+  internal::ParameterizedTestCaseRegistry& parameterized_test_registry()
+      GTEST_LOCK_EXCLUDED_(mutex_);
 #endif  // GTEST_HAS_PARAM_TEST
 
   // Gets the number of successful test cases.
@@ -1194,7 +1197,8 @@ class GTEST_API_ UnitTest {
                          const char* file_name,
                          int line_number,
                          const internal::String& message,
-                         const internal::String& os_stack_trace);
+                         const internal::String& os_stack_trace)
+      GTEST_LOCK_EXCLUDED_(mutex_);
 
   // Adds a TestProperty to the current TestResult object. If the result already
   // contains a property with the same key, the value will be updated.
@@ -1227,10 +1231,12 @@ class GTEST_API_ UnitTest {
 
   // Pushes a trace defined by SCOPED_TRACE() on to the per-thread
   // Google Test trace stack.
-  void PushGTestTrace(const internal::TraceInfo& trace);
+  void PushGTestTrace(const internal::TraceInfo& trace)
+      GTEST_LOCK_EXCLUDED_(mutex_);
 
   // Pops a trace from the per-thread Google Test trace stack.
-  void PopGTestTrace();
+  void PopGTestTrace()
+      GTEST_LOCK_EXCLUDED_(mutex_);
 
   // Protects mutable state in *impl_.  This is mutable as some const
   // methods need to lock it too.

include/gtest/internal/gtest-linked_ptr.h

@@ -105,8 +105,8 @@ class linked_ptr_internal {
   // framework.
 
   // Join an existing circle.
-  // L < g_linked_ptr_mutex
-  void join(linked_ptr_internal const* ptr) {
+  void join(linked_ptr_internal const* ptr)
+      GTEST_LOCK_EXCLUDED_(g_linked_ptr_mutex) {
     MutexLock lock(&g_linked_ptr_mutex);
 
     linked_ptr_internal const* p = ptr;
@@ -117,8 +117,8 @@ class linked_ptr_internal {
 
   // Leave whatever circle we're part of.  Returns true if we were the
   // last member of the circle.  Once this is done, you can join() another.
-  // L < g_linked_ptr_mutex
-  bool depart() {
+  bool depart()
+      GTEST_LOCK_EXCLUDED_(g_linked_ptr_mutex) {
     MutexLock lock(&g_linked_ptr_mutex);
 
     if (next_ == this) return true;

include/gtest/internal/gtest-port.h

@@ -1789,6 +1789,10 @@ typedef TypeWithSize<8>::Int TimeInMillis;  // Represents time in milliseconds.
 #define GTEST_DEFINE_string_(name, default_val, doc) \
     GTEST_API_ ::testing::internal::String GTEST_FLAG(name) = (default_val)
 
+// Thread annotations
+#define GTEST_EXCLUSIVE_LOCK_REQUIRED_(locks)
+#define GTEST_LOCK_EXCLUDED_(locks)
+
 // Parses 'str' for a 32-bit signed integer.  If successful, writes the result
 // to *value and returns true; otherwise leaves *value unchanged and returns
 // false.