[RFA jit 2/2] introduce scoped_timevar

[Tom Tromey <tromey@redhat.com>]

This introduces a new scoped_timevar class.  It pushes a given timevar
in its constructor, and pops it in the destructor, giving a much
simpler way to use timevars in the typical case where they can be
scoped.
---
 gcc/ChangeLog.jit      |  4 ++++
 gcc/jit/ChangeLog.jit  |  4 ++++
 gcc/jit/internal-api.c | 16 +++++-----------
 gcc/timevar.h          | 24 +++++++++++++++++++++++-
 4 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/gcc/jit/internal-api.c b/gcc/jit/internal-api.c
index 6a4d2ae..8285c64 100644
--- a/gcc/jit/internal-api.c
+++ b/gcc/jit/internal-api.c
@@ -3737,8 +3737,6 @@ compile ()
   if (get_bool_option (GCC_JIT_BOOL_OPTION_DUMP_GENERATED_CODE))
    dump_generated_code ();
 
-  timevar_push (TV_ASSEMBLE);
-
   /* Gross hacks follow:
      We have a .s file; we want a .so file.
      We could reuse parts of gcc/gcc.c to do this.
@@ -3746,6 +3744,8 @@ compile ()
    */
   /* FIXME: totally faking it for now, not even using pex */
   {
+    scoped_timevar assemble_timevar (TV_ASSEMBLE);
+
     char cmd[1024];
     snprintf (cmd, 1024, "gcc -shared %s -o %s",
               m_path_s_file, m_path_so_file);
@@ -3753,20 +3753,16 @@ compile ()
       printf ("cmd: %s\n", cmd);
     int ret = system (cmd);
     if (ret)
-      {
-	timevar_pop (TV_ASSEMBLE);
-	return NULL;
-      }
+      return NULL;
   }
-  timevar_pop (TV_ASSEMBLE);
 
   // TODO: split out assembles vs linker
 
   /* dlopen the .so file. */
   {
-    const char *error;
+    scoped_timevar load_timevar (TV_LOAD);
 
-    timevar_push (TV_LOAD);
+    const char *error;
 
     /* Clear any existing error.  */
     dlerror ();
@@ -3779,8 +3775,6 @@ compile ()
       result_obj = new result (handle);
     else
       result_obj = NULL;
-
-    timevar_pop (TV_LOAD);
   }
 
   return result_obj;
diff --git a/gcc/timevar.h b/gcc/timevar.h
index dc2a8bc..eb8bf0d 100644
--- a/gcc/timevar.h
+++ b/gcc/timevar.h
@@ -1,5 +1,5 @@
 /* Timing variables for measuring compiler performance.
-   Copyright (C) 2000-2013 Free Software Foundation, Inc.
+   Copyright (C) 2000-2014 Free Software Foundation, Inc.
    Contributed by Alex Samuel <samuel@codesourcery.com>
 
    This file is part of GCC.
@@ -110,6 +110,28 @@ timevar_pop (timevar_id_t tv)
     timevar_pop_1 (tv);
 }
 
+class scoped_timevar
+{
+ public:
+  scoped_timevar (timevar_id_t tv)
+    : m_tv (tv)
+  {
+    timevar_push (m_tv);
+  }
+
+  ~scoped_timevar ()
+  {
+    timevar_push (m_tv);
+  }
+
+ private:
+
+  // Private to disallow copies.
+  scoped_timevar (const scoped_timevar &);
+
+  timevar_id_t m_tv;
+};
+
 extern void print_time (const char *, long);
 
 #endif /* ! GCC_TIMEVAR_H */
-- 
1.8.5.3