[tsan] Enable ignore_noninstrumented_modules=1 on Darwin by default

TSan recently got the "ignore_noninstrumented_modules" flag, which disables tracking of read and writes that come from noninstrumented modules (via interceptors). This is a way of suppressing false positives coming from system libraries and other noninstrumented code. This patch turns this on by default on Darwin, where it's supposed to replace the previous solution, "ignore_interceptors_accesses", which disables tracking in *all* interceptors. The new approach should re-enable TSan's ability to find races via interceptors on Darwin.

Differential Revision: https://reviews.llvm.org/D29041

llvm-svn: 292981

compiler-rt/lib/tsan/rtl/tsan_flags.inc

@@ -79,7 +79,7 @@ TSAN_FLAG(bool, die_after_fork, true,
 TSAN_FLAG(const char *, suppressions, "", "Suppressions file name.")
 TSAN_FLAG(bool, ignore_interceptors_accesses, false,
           "Ignore reads and writes from all interceptors.")
-TSAN_FLAG(bool, ignore_noninstrumented_modules, false,
+TSAN_FLAG(bool, ignore_noninstrumented_modules, SANITIZER_MAC ? true : false,
           "Interceptors should only detect races when called from instrumented "
           "modules.")
 TSAN_FLAG(bool, shared_ptr_interceptor, true,

compiler-rt/test/tsan/Darwin/dispatch_main.mm

@@ -2,7 +2,7 @@
 // quits the main thread.
 
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/dispatch_once_deadlock.mm

@@ -1,7 +1,7 @@
 // Check that calling dispatch_once from a report callback works.
 
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 not %run %t 2>&1 | FileCheck %s
+// RUN: not %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 #import <pthread.h>

compiler-rt/test/tsan/Darwin/gcd-after.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-apply-race.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-apply.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-async-norace.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-async-race.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-barrier-race.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-barrier.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-blocks.mm

@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-data.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-fd.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-groups-destructor.mm

@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-groups-leave.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-groups-norace.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-groups-stress.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-io-barrier-race.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-io-barrier.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-io-cleanup.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-io-race.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
 
 // REQUIRES: disabled
 

compiler-rt/test/tsan/Darwin/gcd-io.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-once.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-semaphore-norace.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-serial-queue-norace.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-source-cancel.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-source-cancel2.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-source-event.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-source-event2.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-source-registration.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-source-registration2.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-source-serial.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-suspend.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-sync-norace.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-sync-race.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/gcd-target-queue-norace.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/ignore-noninstrumented.mm

@@ -3,7 +3,7 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
 
 // Check that without the flag, there are false positives.
-// RUN: %deflake %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-RACE
+// RUN: %env_tsan_opts=ignore_noninstrumented_modules=0 %deflake %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-RACE
 
 // With ignore_noninstrumented_modules=1, no races are reported.
 // RUN: %env_tsan_opts=ignore_noninstrumented_modules=1 %run %t 2>&1 | FileCheck %s

compiler-rt/test/tsan/Darwin/ignored-interceptors.mm

@@ -6,13 +6,13 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
 
 // Check that without the flag, there are false positives.
-// RUN: %deflake %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-RACE
+// RUN: %env_tsan_opts=ignore_noninstrumented_modules=0 %deflake %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-RACE
 
 // With ignore_interceptors_accesses=1, no races are reported.
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_tsan_opts=ignore_noninstrumented_modules=0:ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
 
 // With ignore_interceptors_accesses=1, races in user's code are still reported.
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t race 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-RACE
+// RUN: %env_tsan_opts=ignore_noninstrumented_modules=0:ignore_interceptors_accesses=1 %deflake %run %t race 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-RACE
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/libcxx-call-once.mm

@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t -framework Foundation -std=c++11
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/libcxx-future.mm

@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #include <iostream>
 #include <future>

compiler-rt/test/tsan/Darwin/libcxx-shared-ptr-recursive.mm

@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/libcxx-shared-ptr-stress.mm

@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/libcxx-shared-ptr.mm

@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/lit.local.cfg

@@ -7,3 +7,5 @@ root = getRoot(config)
 
 if root.host_os not in ['Darwin']:
   config.unsupported = True
+
+config.environment['TSAN_OPTIONS'] += ':ignore_noninstrumented_modules=1'

compiler-rt/test/tsan/Darwin/norace-objcxx-run-time.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -lc++ -fobjc-arc -lobjc -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 // Check that we do not report races between:
 // - Object retain and initialize

compiler-rt/test/tsan/Darwin/objc-double-property.mm

@@ -1,7 +1,7 @@
-// RUN: %clangxx_tsan -O0 %s -o %t -framework Foundation && %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
-// RUN: %clangxx_tsan -O1 %s -o %t -framework Foundation && %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
-// RUN: %clangxx_tsan -O2 %s -o %t -framework Foundation && %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
-// RUN: %clangxx_tsan -O3 %s -o %t -framework Foundation && %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O0 %s -o %t -framework Foundation && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O1 %s -o %t -framework Foundation && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O2 %s -o %t -framework Foundation && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O3 %s -o %t -framework Foundation && %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/objc-simple.mm

@@ -1,7 +1,7 @@
 // Test that a simple Obj-C program runs and exits without any warnings.
 
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 

compiler-rt/test/tsan/Darwin/xpc-race.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 #import <xpc/xpc.h>

compiler-rt/test/tsan/Darwin/xpc.mm

@@ -1,5 +1,5 @@
 // RUN: %clang_tsan %s -o %t -framework Foundation
-// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+// RUN: %run %t 2>&1 | FileCheck %s
 
 #import <Foundation/Foundation.h>
 #import <xpc/xpc.h>

compiler-rt/test/tsan/Unit/lit.site.cfg.in

@@ -14,3 +14,10 @@ config.test_source_root = config.test_exec_root
 
 if config.host_os == 'Darwin':
   config.parallelism_group = config.darwin_sanitizer_parallelism_group_func
+
+  # On Darwin, we default to ignore_noninstrumented_modules=1, which also
+  # suppresses some races the tests are supposed to find.  See tsan/lit.cfg.
+  if 'TSAN_OPTIONS' in config.environment:
+    config.environment['TSAN_OPTIONS'] += ':ignore_noninstrumented_modules=0'
+  else:
+    config.environment['TSAN_OPTIONS'] = 'ignore_noninstrumented_modules=0'

compiler-rt/test/tsan/lit.cfg

@@ -24,6 +24,10 @@ if config.host_os == 'Darwin':
   # On Darwin, we default to `abort_on_error=1`, which would make tests run
   # much slower. Let's override this and run lit tests with 'abort_on_error=0'.
   default_tsan_opts += ':abort_on_error=0'
+  # On Darwin, we default to ignore_noninstrumented_modules=1, which also
+  # suppresses some races the tests are supposed to find. Let's run without this
+  # setting, but turn it back on for Darwin tests (see Darwin/lit.local.cfg).
+  default_tsan_opts += ':ignore_noninstrumented_modules=0'
 
 # Platform-specific default TSAN_OPTIONS for lit tests.
 if default_tsan_opts: