[TSan] Try harder to avoid compiler-generated memset calls.

check_memcpy test added in r254959 fails on some configurations due to
memset() calls inserted by Clang. Try harder to avoid them:
* Explicitly use internal_memset() instead of empty braced-initializer.
* Replace "new T()" with "new T", as the former generates zero-initialization
  for structs in C++11.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@255136 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 6 insertions, 5 deletions

diff --git a/lib/tsan/rtl/tsan_dense_alloc.h b/lib/tsan/rtl/tsan_dense_alloc.h
index a1cf84b8f..e9815c90a 100644
--- a/lib/tsan/rtl/tsan_dense_alloc.h
+++ b/lib/tsan/rtl/tsan_dense_alloc.h
@@ -108,7 +108,7 @@ class DenseSlabAlloc {
       // Reserve 0 as invalid index.
       IndexT start = fillpos_ == 0 ? 1 : 0;
       for (IndexT i = start; i < kL2Size; i++) {
-        new(batch + i) T();
+        new(batch + i) T;
         *(IndexT*)(batch + i) = i + 1 + fillpos_ * kL2Size;
       }
       *(IndexT*)(batch + kL2Size - 1) = 0;
diff --git a/lib/tsan/rtl/tsan_platform_linux.cc b/lib/tsan/rtl/tsan_platform_linux.cc
index ff7a4b975..77b02b96f 100644
--- a/lib/tsan/rtl/tsan_platform_linux.cc
+++ b/lib/tsan/rtl/tsan_platform_linux.cc
@@ -109,7 +109,8 @@ void FillProfileCallback(uptr p, uptr rss, bool file,
 }
 
 void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
-  uptr mem[MemCount] = {};
+  uptr mem[MemCount];
+  internal_memset(mem, 0, sizeof(mem[0]) * MemCount);
   __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
   StackDepotStats *stacks = StackDepotGetStats();
   internal_snprintf(buf, buf_size,
diff --git a/lib/tsan/rtl/tsan_rtl_report.cc b/lib/tsan/rtl/tsan_rtl_report.cc
index cbbd64eff..5aff6ca56 100644
--- a/lib/tsan/rtl/tsan_rtl_report.cc
+++ b/lib/tsan/rtl/tsan_rtl_report.cc
@@ -186,7 +186,7 @@ void ScopedReport::AddThread(const ThreadContext *tctx, bool suppressable) {
       return;
   }
   void *mem = internal_alloc(MBlockReportThread, sizeof(ReportThread));
-  ReportThread *rt = new(mem) ReportThread();
+  ReportThread *rt = new(mem) ReportThread;
   rep_->threads.PushBack(rt);
   rt->id = tctx->tid;
   rt->pid = tctx->os_id;
@@ -256,7 +256,7 @@ void ScopedReport::AddMutex(const SyncVar *s) {
       return;
   }
   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
-  ReportMutex *rm = new(mem) ReportMutex();
+  ReportMutex *rm = new(mem) ReportMutex;
   rep_->mutexes.PushBack(rm);
   rm->id = s->uid;
   rm->addr = s->addr;
@@ -289,7 +289,7 @@ void ScopedReport::AddDeadMutex(u64 id) {
       return;
   }
   void *mem = internal_alloc(MBlockReportMutex, sizeof(ReportMutex));
-  ReportMutex *rm = new(mem) ReportMutex();
+  ReportMutex *rm = new(mem) ReportMutex;
   rep_->mutexes.PushBack(rm);
   rm->id = id;
   rm->addr = 0;