[compiler-rt] r349609 - tsan: align default value of detect_deadlocks flag with actual behavior

[Dmitry Vyukov via llvm-commits]

Author: dvyukov
Date: Wed Dec 19 01:34:13 2018
New Revision: 349609

URL: http://llvm.org/viewvc/llvm-project?rev=349609&view=rev
Log:
tsan: align default value of detect_deadlocks flag with actual behavior

I tricked myself into thinking that deadlock detection is off by default in TSan by looking at the default value of the detect_deadlocks flag and outdated docs. (Created a pull request to update docs.)
I even managed to confuse others: https://groups.google.com/forum/#!topic/thread-sanitizer/xYvnAYwtoDk

However, the default value is overwritten in code (TSan_flags.cc:InitializeFlags). The TSan/deadlock tests also rely on this

This changes aligns the default value of the flag with the actual default behavior.

Author: yln (Julian Lettner)
Reviewed in: https://reviews.llvm.org/D55846


Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc
    compiler-rt/trunk/lib/tsan/rtl/tsan_flags.cc
    compiler-rt/trunk/test/tsan/deadlock_detector_stress_test.cc
    compiler-rt/trunk/test/tsan/mutex_cycle2.c

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc?rev=349609&r1=349608&r2=349609&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc Wed Dec 19 01:34:13 2018
@@ -103,7 +103,7 @@ COMMON_FLAG(bool, allow_user_segv_handle
             "handle_*=1 will be upgraded to handle_*=2.")
 COMMON_FLAG(bool, use_sigaltstack, true,
             "If set, uses alternate stack for signal handling.")
-COMMON_FLAG(bool, detect_deadlocks, false,
+COMMON_FLAG(bool, detect_deadlocks, true,
             "If set, deadlock detection is enabled.")
 COMMON_FLAG(
     uptr, clear_shadow_mmap_threshold, 64 * 1024,

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_flags.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_flags.cc?rev=349609&r1=349608&r2=349609&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_flags.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_flags.cc Wed Dec 19 01:34:13 2018
@@ -61,8 +61,7 @@ void InitializeFlags(Flags *f, const cha
       // Does not work as expected for Go: runtime handles SIGABRT and crashes.
       cf.abort_on_error = false;
       // Go does not have mutexes.
-    } else {
-      cf.detect_deadlocks = true;
+      cf.detect_deadlocks = false;
     }
     cf.print_suppressions = false;
     cf.stack_trace_format = "    #%n %f %S %M";

Modified: compiler-rt/trunk/test/tsan/deadlock_detector_stress_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/tsan/deadlock_detector_stress_test.cc?rev=349609&r1=349608&r2=349609&view=diff
==============================================================================
--- compiler-rt/trunk/test/tsan/deadlock_detector_stress_test.cc (original)
+++ compiler-rt/trunk/test/tsan/deadlock_detector_stress_test.cc Wed Dec 19 01:34:13 2018
@@ -1,12 +1,12 @@
 // RUN: %clangxx_tsan %s -o %t -DLockType=PthreadMutex
-// RUN: %env_tsan_opts=detect_deadlocks=1 %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOT-SECOND
-// RUN: %env_tsan_opts=detect_deadlocks=1:second_deadlock_stack=1 %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SECOND
+// RUN: %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOT-SECOND
+// RUN: %env_tsan_opts=second_deadlock_stack=1 %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SECOND
 // RUN: %clangxx_tsan %s -o %t -DLockType=PthreadSpinLock
-// RUN: %env_tsan_opts=detect_deadlocks=1 %deflake %run %t | FileCheck %s
+// RUN: %deflake %run %t | FileCheck %s
 // RUN: %clangxx_tsan %s -o %t -DLockType=PthreadRWLock
-// RUN: %env_tsan_opts=detect_deadlocks=1 %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-RD
+// RUN: %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-RD
 // RUN: %clangxx_tsan %s -o %t -DLockType=PthreadRecursiveMutex
-// RUN: %env_tsan_opts=detect_deadlocks=1 %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-REC
+// RUN: %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-REC
 #include "test.h"
 #undef NDEBUG
 #include <assert.h>

Modified: compiler-rt/trunk/test/tsan/mutex_cycle2.c
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/tsan/mutex_cycle2.c?rev=349609&r1=349608&r2=349609&view=diff
==============================================================================
--- compiler-rt/trunk/test/tsan/mutex_cycle2.c (original)
+++ compiler-rt/trunk/test/tsan/mutex_cycle2.c Wed Dec 19 01:34:13 2018
@@ -1,5 +1,5 @@
 // RUN: %clangxx_tsan %s -o %t
-// RUN:                                 not %run %t 2>&1 | FileCheck %s
+// RUN:                                   not %run %t 2>&1 | FileCheck %s
 // RUN: %env_tsan_opts=detect_deadlocks=1 not %run %t 2>&1 | FileCheck %s
 // RUN: %env_tsan_opts=detect_deadlocks=0     %run %t 2>&1 | FileCheck %s --check-prefix=DISABLED
 // RUN: echo "deadlock:main" > %t.supp