[llvm] r307925 - Put std::mutex usage behind #ifdefs to pacify the sanitizer buildbot

[Reid Kleckner via llvm-commits]

Author: rnk
Date: Thu Jul 13 09:56:24 2017
New Revision: 307925

URL: http://llvm.org/viewvc/llvm-project?rev=307925&view=rev
Log:
Put std::mutex usage behind #ifdefs to pacify the sanitizer buildbot

Modified:
    llvm/trunk/lib/Support/ErrorHandling.cpp

Modified: llvm/trunk/lib/Support/ErrorHandling.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/ErrorHandling.cpp?rev=307925&r1=307924&r2=307925&view=diff
==============================================================================
--- llvm/trunk/lib/Support/ErrorHandling.cpp (original)
+++ llvm/trunk/lib/Support/ErrorHandling.cpp Thu Jul 13 09:56:24 2017
@@ -45,22 +45,36 @@ static void *ErrorHandlerUserData = null
 static fatal_error_handler_t BadAllocErrorHandler = nullptr;
 static void *BadAllocErrorHandlerUserData = nullptr;
 
+#if LLVM_ENABLE_THREADS == 1
 // Mutexes to synchronize installing error handlers and calling error handlers.
 // Do not use ManagedStatic, or that may allocate memory while attempting to
 // report an OOM.
+//
+// This usage of std::mutex has to be conditionalized behind ifdefs because
+// of this script:
+//   compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh
+// That script attempts to statically link the LLVM symbolizer library with the
+// STL and hide all of its symbols with 'opt -internalize'. To reduce size, it
+// cuts out the threading portions of the hermetic copy of libc++ that it
+// builds. We can remove these ifdefs if that script goes away.
 static std::mutex ErrorHandlerMutex;
 static std::mutex BadAllocErrorHandlerMutex;
+#endif
 
 void llvm::install_fatal_error_handler(fatal_error_handler_t handler,
                                        void *user_data) {
+#if LLVM_ENABLE_THREADS == 1
   std::lock_guard<std::mutex> Lock(ErrorHandlerMutex);
+#endif
   assert(!ErrorHandler && "Error handler already registered!\n");
   ErrorHandler = handler;
   ErrorHandlerUserData = user_data;
 }
 
 void llvm::remove_fatal_error_handler() {
+#if LLVM_ENABLE_THREADS == 1
   std::lock_guard<std::mutex> Lock(ErrorHandlerMutex);
+#endif
   ErrorHandler = nullptr;
   ErrorHandlerUserData = nullptr;
 }
@@ -83,7 +97,9 @@ void llvm::report_fatal_error(const Twin
   {
     // Only acquire the mutex while reading the handler, so as not to invoke a
     // user-supplied callback under a lock.
+#if LLVM_ENABLE_THREADS == 1
     std::lock_guard<std::mutex> Lock(ErrorHandlerMutex);
+#endif
     handler = ErrorHandler;
     handlerData = ErrorHandlerUserData;
   }
@@ -112,14 +128,18 @@ void llvm::report_fatal_error(const Twin
 
 void llvm::install_bad_alloc_error_handler(fatal_error_handler_t handler,
                                            void *user_data) {
+#if LLVM_ENABLE_THREADS == 1
   std::lock_guard<std::mutex> Lock(BadAllocErrorHandlerMutex);
+#endif
   assert(!ErrorHandler && "Bad alloc error handler already registered!\n");
   BadAllocErrorHandler = handler;
   BadAllocErrorHandlerUserData = user_data;
 }
 
 void llvm::remove_bad_alloc_error_handler() {
+#if LLVM_ENABLE_THREADS == 1
   std::lock_guard<std::mutex> Lock(BadAllocErrorHandlerMutex);
+#endif
   BadAllocErrorHandler = nullptr;
   BadAllocErrorHandlerUserData = nullptr;
 }
@@ -130,7 +150,9 @@ void llvm::report_bad_alloc_error(const
   {
     // Only acquire the mutex while reading the handler, so as not to invoke a
     // user-supplied callback under a lock.
+#if LLVM_ENABLE_THREADS == 1
     std::lock_guard<std::mutex> Lock(BadAllocErrorHandlerMutex);
+#endif
     Handler = BadAllocErrorHandler;
     HandlerData = BadAllocErrorHandlerUserData;
   }