[compiler-rt] r298378 - tsan: support __ATOMIC_HLE_ACQUIRE/RELEASE flags

[Dmitry Vyukov via llvm-commits]

Author: dvyukov
Date: Tue Mar 21 09:28:55 2017
New Revision: 298378

URL: http://llvm.org/viewvc/llvm-project?rev=298378&view=rev
Log:
tsan: support __ATOMIC_HLE_ACQUIRE/RELEASE flags

HLE flags can be combined with memory order in atomic operations.
Currently tsan runtime crashes on e.g. IsStoreOrder(mo) in atomic store
if any of these additional flags are specified.

Filter these flags out.
See the comment as to why it is safe.


Added:
    compiler-rt/trunk/test/tsan/atomic_hle.cc
Modified:
    compiler-rt/trunk/lib/tsan/rtl/tsan_interface_atomic.cc

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_interface_atomic.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_interface_atomic.cc?rev=298378&r1=298377&r2=298378&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_interface_atomic.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_interface_atomic.cc Tue Mar 21 09:28:55 2017
@@ -450,10 +450,27 @@ static void AtomicFence(ThreadState *thr
 
 // C/C++
 
+static morder covert_morder(morder mo) {
+  if (flags()->force_seq_cst_atomics)
+    return (morder)mo_seq_cst;
+
+  // Filter out additional memory order flags:
+  // MEMMODEL_SYNC        = 1 << 15
+  // __ATOMIC_HLE_ACQUIRE = 1 << 16
+  // __ATOMIC_HLE_RELEASE = 1 << 17
+  //
+  // HLE is an optimization, and we pretend that elision always fails.
+  // MEMMODEL_SYNC is used when lowering __sync_ atomics,
+  // since we use __sync_ atomics for actual atomic operations,
+  // we can safely ignore it as well. It also subtly affects semantics,
+  // but we don't model the difference.
+  return (morder)(mo & 0x7fff);
+}
+
 #define SCOPED_ATOMIC(func, ...) \
     const uptr callpc = (uptr)__builtin_return_address(0); \
     uptr pc = StackTrace::GetCurrentPc(); \
-    mo = flags()->force_seq_cst_atomics ? (morder)mo_seq_cst : mo; \
+    mo = covert_morder(mo); \
     ThreadState *const thr = cur_thread(); \
     if (thr->ignore_interceptors) \
       return NoTsanAtomic##func(__VA_ARGS__); \

Added: compiler-rt/trunk/test/tsan/atomic_hle.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/tsan/atomic_hle.cc?rev=298378&view=auto
==============================================================================
--- compiler-rt/trunk/test/tsan/atomic_hle.cc (added)
+++ compiler-rt/trunk/test/tsan/atomic_hle.cc Tue Mar 21 09:28:55 2017
@@ -0,0 +1,25 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+#include "test.h"
+#include <sanitizer/tsan_interface_atomic.h>
+
+#ifndef __ATOMIC_HLE_ACQUIRE
+#define __ATOMIC_HLE_ACQUIRE (1 << 16)
+#endif
+#ifndef __ATOMIC_HLE_RELEASE
+#define __ATOMIC_HLE_RELEASE (1 << 17)
+#endif
+
+int main() {
+  volatile int x = 0;
+  //__atomic_fetch_add(&x, 1, __ATOMIC_ACQUIRE | __ATOMIC_HLE_ACQUIRE);
+  //__atomic_store_n(&x, 0, __ATOMIC_RELEASE | __ATOMIC_HLE_RELEASE);
+  __tsan_atomic32_fetch_add(&x, 1,
+      (__tsan_memory_order)(__ATOMIC_ACQUIRE | __ATOMIC_HLE_ACQUIRE));
+  __tsan_atomic32_store(&x, 0,
+      (__tsan_memory_order)(__ATOMIC_RELEASE | __ATOMIC_HLE_RELEASE));
+  fprintf(stderr, "DONE\n");
+  return 0;
+}
+
+// CHECK: DONE
+