[PATCH 3/5] timevar.h: Add an auto_timevar class

[David Malcolm <dmalcolm at redhat dot com>]

This is used in a couple of places in jit/jit-playback.c to ensure
that we pop the timevar on every exit path from a function.

I could rewrite them if need be, but it does simplify things.

Written by Tom Tromey.

gcc/ChangeLog:
	* timevar.h (class auto_timevar): New class.
---
 gcc/timevar.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/gcc/timevar.h b/gcc/timevar.h
index 6703cc9..f018e39 100644
--- a/gcc/timevar.h
+++ b/gcc/timevar.h
@@ -110,6 +110,30 @@ timevar_pop (timevar_id_t tv)
     timevar_pop_1 (tv);
 }
 
+// This is a simple timevar wrapper class that pushes a timevar in its
+// constructor and pops the timevar in its destructor.
+class auto_timevar
+{
+ public:
+  auto_timevar (timevar_id_t tv)
+    : m_tv (tv)
+  {
+    timevar_push (m_tv);
+  }
+
+  ~auto_timevar ()
+  {
+    timevar_pop (m_tv);
+  }
+
+ private:
+
+  // Private to disallow copies.
+  auto_timevar (const auto_timevar &);
+
+  timevar_id_t m_tv;
+};
+
 extern void print_time (const char *, long);
 
 #endif /* ! GCC_TIMEVAR_H */
-- 
1.8.5.3