[compiler-rt] r255136 - [TSan] Try harder to avoid compiler-generated memset calls.

[Alexey Samsonov via llvm-commits]

Author: samsonov
Date: Wed Dec  9 12:48:10 2015
New Revision: 255136

URL: http://llvm.org/viewvc/llvm-project?rev=255136&view=rev
Log:
[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.

Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.h
    compiler-rt/trunk/lib/tsan/rtl/tsan_dense_alloc.h
    compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc
    compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_report.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.cc?rev=255136&r1=255135&r2=255136&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.cc Wed Dec  9 12:48:10 2015
@@ -127,7 +127,7 @@ void SuppressionContext::Parse(const cha
         Printf("%s: failed to parse suppressions\n", SanitizerToolName);
         Die();
       }
-      Suppression s = {};
+      Suppression s;
       s.type = suppression_types_[type];
       s.templ = (char*)InternalAlloc(end2 - line + 1);
       internal_memcpy(s.templ, line, end2 - line);

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.h?rev=255136&r1=255135&r2=255136&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_suppressions.h Wed Dec  9 12:48:10 2015
@@ -20,6 +20,7 @@
 namespace __sanitizer {
 
 struct Suppression {
+  Suppression() { internal_memset(this, 0, sizeof(*this)); }
   const char *type;
   char *templ;
   atomic_uint32_t hit_count;

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_dense_alloc.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_dense_alloc.h?rev=255136&r1=255135&r2=255136&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_dense_alloc.h (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_dense_alloc.h Wed Dec  9 12:48:10 2015
@@ -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;

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc?rev=255136&r1=255135&r2=255136&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc Wed Dec  9 12:48:10 2015
@@ -109,7 +109,8 @@ void FillProfileCallback(uptr p, uptr rs
 }
 
 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,

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_report.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_report.cc?rev=255136&r1=255135&r2=255136&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_report.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_report.cc Wed Dec  9 12:48:10 2015
@@ -186,7 +186,7 @@ void ScopedReport::AddThread(const Threa
       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 SyncVa
       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;