tsan: say that the memory access is atomic in reports

llvm-svn: 174168

compiler-rt/lib/tsan/lit_tests/atomic_stack.cc

@@ -0,0 +1,29 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %t 2>&1 | FileCheck %s
+#include <pthread.h>
+#include <unistd.h>
+
+int Global;
+
+void *Thread1(void *x) {
+  sleep(1);
+  __atomic_fetch_add(&Global, 1, __ATOMIC_RELAXED);
+  return NULL;
+}
+
+void *Thread2(void *x) {
+  Global++;
+  return NULL;
+}
+
+int main() {
+  pthread_t t[2];
+  pthread_create(&t[0], NULL, Thread1, NULL);
+  pthread_create(&t[1], NULL, Thread2, NULL);
+  pthread_join(t[0], NULL);
+  pthread_join(t[1], NULL);
+}
+
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK:   Atomic write of size 4
+// CHECK:     #0 __tsan_atomic32_fetch_add
+// CHECK:     #1 Thread1

compiler-rt/lib/tsan/lit_tests/race_on_mutex.c

@@ -34,7 +34,7 @@ int main() {
 }
 
 // CHECK:      WARNING: ThreadSanitizer: data race
-// CHECK-NEXT:   Read of size 1 at {{.*}} by thread T2:
+// CHECK-NEXT:   Atomic read of size 1 at {{.*}} by thread T2:
 // CHECK-NEXT:     #0 pthread_mutex_lock
 // CHECK-NEXT:     #1 Thread2{{.*}} {{.*}}race_on_mutex.c:20{{(:3)?}} ({{.*}})
 // CHECK:        Previous write of size 1 at {{.*}} by thread T1:

compiler-rt/lib/tsan/rtl/tsan_interface_atomic.cc

@@ -29,7 +29,8 @@ using namespace __tsan;  // NOLINT
 
 #define SCOPED_ATOMIC(func, ...) \
     const uptr callpc = (uptr)__builtin_return_address(0); \
-    const uptr pc = __sanitizer::StackTrace::GetCurrentPc(); \
+    uptr pc = __sanitizer::StackTrace::GetCurrentPc(); \
+    pc = __sanitizer::StackTrace::GetPreviousInstructionPc(pc); \
     mo = ConvertOrder(mo); \
     mo = flags()->force_seq_cst_atomics ? (morder)mo_seq_cst : mo; \
     ThreadState *const thr = cur_thread(); \

compiler-rt/lib/tsan/rtl/tsan_report.cc

@@ -89,11 +89,17 @@ static void PrintMutexSet(Vector<ReportMopMutex> const& mset) {
   }
 }
 
+static const char *MopDesc(bool first, bool write, bool atomic) {
+  return atomic ? (first ? (write ? "Atomic write" : "Atomic read")
+                : (write ? "Previous atomic write" : "Previous atomic read"))
+                : (first ? (write ? "Write" : "Read")
+                : (write ? "Previous write" : "Previous read"));
+}
+
 static void PrintMop(const ReportMop *mop, bool first) {
   char thrbuf[kThreadBufSize];
   Printf("  %s of size %d at %p by %s",
-      (first ? (mop->write ? "Write" : "Read")
-             : (mop->write ? "Previous write" : "Previous read")),
+      MopDesc(first, mop->write, mop->atomic),
       mop->size, (void*)mop->addr,
       thread_name(thrbuf, mop->tid));
   PrintMutexSet(mop->mset);

compiler-rt/lib/tsan/rtl/tsan_report.h

@@ -48,6 +48,7 @@ struct ReportMop {
   uptr addr;
   int size;
   bool write;
+  bool atomic;
   Vector<ReportMopMutex> mset;
   ReportStack *stack;
 

compiler-rt/lib/tsan/rtl/tsan_rtl_report.cc

@@ -151,6 +151,7 @@ void ScopedReport::AddMemoryAccess(uptr addr, Shadow s,
   mop->addr = addr + s.addr0();
   mop->size = s.size();
   mop->write = s.IsWrite();
+  mop->atomic = s.IsAtomic();
   mop->stack = SymbolizeStack(*stack);
   for (uptr i = 0; i < mset->Size(); i++) {
     MutexSet::Desc d = mset->Get(i);