[C++11] Replace LLVM atomics with std::atomic.

[oota-llvm.git] / include / llvm / ADT / Statistic.h

diff --git a/include/llvm/ADT/Statistic.h b/include/llvm/ADT/Statistic.h
index 484ff5fbebc6ca5cc5f17cc3e62d3f13d4525bc7..5e7a433e44111a20f9b54acf591ca9990ac383da 100644 (file)
--- a/include/llvm/ADT/Statistic.h
+++ b/include/llvm/ADT/Statistic.h
@@ -26,15 +26,17 @@
 #ifndef LLVM_ADT_STATISTIC_H
 #define LLVM_ADT_STATISTIC_H
 
-#include "llvm/System/Atomic.h"
+#include "llvm/Support/Valgrind.h"
+#include <atomic>
 
 namespace llvm {
+class raw_ostream;
 
 class Statistic {
 public:
   const char *Name;
   const char *Desc;
-  unsigned Value;
+  std::atomic<unsigned> Value;
   bool Initialized;
 
   unsigned getValue() const { return Value; }
@@ -49,60 +51,115 @@ public:
 
   // Allow use of this class as the value itself.
   operator unsigned() const { return Value; }
-  const Statistic &operator=(unsigned Val) {
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
+   const Statistic &operator=(unsigned Val) {
     Value = Val;
     return init();
   }
-  
+
   const Statistic &operator++() {
-    sys::AtomicIncrement(&Value);
+    // FIXME: This function and all those that follow carefully use an
+    // atomic operation to update the value safely in the presence of
+    // concurrent accesses, but not to read the return value, so the
+    // return value is not thread safe.
+    ++Value;
     return init();
   }
-  
+
   unsigned operator++(int) {
     init();
-    unsigned OldValue = Value;
-    sys::AtomicIncrement(&Value);
+    unsigned OldValue = Value++;
     return OldValue;
   }
-  
+
   const Statistic &operator--() {
-    sys::AtomicDecrement(&Value);
+    --Value;
     return init();
   }
-  
+
   unsigned operator--(int) {
     init();
-    unsigned OldValue = Value;
-    sys::AtomicDecrement(&Value);
+    unsigned OldValue = Value--;
     return OldValue;
   }
-  
+
   const Statistic &operator+=(const unsigned &V) {
-    sys::AtomicAdd(&Value, V);
+    if (!V) return *this;
+    Value += V;
     return init();
   }
-  
+
   const Statistic &operator-=(const unsigned &V) {
-    sys::AtomicAdd(&Value, -V);
+    if (!V) return *this;
+    Value -= V;
     return init();
   }
-  
+
   const Statistic &operator*=(const unsigned &V) {
-    sys::AtomicMul(&Value, V);
+    unsigned Original, Result;
+    do {
+      Original = Value;
+      Result = Original * V;
+    } while (!Value.compare_exchange_strong(Original, Result));
     return init();
   }
-  
+
   const Statistic &operator/=(const unsigned &V) {
-    sys::AtomicDiv(&Value, V);
+    unsigned Original, Result;
+    do {
+      Original = Value;
+      Result = Original / V;
+    } while (!Value.compare_exchange_strong(Original, Result));
     return init();
   }
 
+#else  // Statistics are disabled in release builds.
+
+  const Statistic &operator=(unsigned Val) {
+    return *this;
+  }
+
+  const Statistic &operator++() {
+    return *this;
+  }
+
+  unsigned operator++(int) {
+    return 0;
+  }
+
+  const Statistic &operator--() {
+    return *this;
+  }
+
+  unsigned operator--(int) {
+    return 0;
+  }
+
+  const Statistic &operator+=(const unsigned &V) {
+    return *this;
+  }
+
+  const Statistic &operator-=(const unsigned &V) {
+    return *this;
+  }
+
+  const Statistic &operator*=(const unsigned &V) {
+    return *this;
+  }
+
+  const Statistic &operator/=(const unsigned &V) {
+    return *this;
+  }
+
+#endif  // !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
+
 protected:
   Statistic &init() {
     bool tmp = Initialized;
-    sys::MemoryFence();
+    std::atomic_thread_fence(std::memory_order_seq_cst);
     if (!tmp) RegisterStatistic();
+    TsanHappensAfter(this);
     return *this;
   }
   void RegisterStatistic();
@@ -111,7 +168,19 @@ protected:
 // STATISTIC - A macro to make definition of statistics really simple.  This
 // automatically passes the DEBUG_TYPE of the file into the statistic.
 #define STATISTIC(VARNAME, DESC) \
-  static llvm::Statistic VARNAME = { DEBUG_TYPE, DESC, 0, 0 }
+  static llvm::Statistic VARNAME = { DEBUG_TYPE, DESC, {}, 0 }
+
+/// \brief Enable the collection and printing of statistics.
+void EnableStatistics();
+
+/// \brief Check if statistics are enabled.
+bool AreStatisticsEnabled();
+
+/// \brief Print statistics to the file returned by CreateInfoOutputFile().
+void PrintStatistics();
+
+/// \brief Print statistics to the given output stream.
+void PrintStatistics(raw_ostream &OS);
 
 } // End llvm namespace