Subzero: Add a few performance measurement tools.

--timing-funcs - Produces a sorted list of total time spent translating each function.

--timing-focus=<F> - Turns on the --timing equivalent just for one function.  Use '*' to do this for all functions, i.e. get complete timing breakdowns across all functions.

--verbose-focus=<F> - Temporarily turns on --verbose=all for one function.

BUG= none
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/620373004

src/IceTargetLoweringX8632.cpp

diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index 3217141..9cac11d 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -313,9 +313,7 @@
 }
 
 void TargetX8632::translateO2() {
-  GlobalContext *Context = Func->getContext();
-  static TimerIdT IDO2 = GlobalContext::getTimerID("O2");
-  TimerMarker T(IDO2, Context);
+  TimerMarker T(TimerStack::TT_O2, Func);
 
   // Lower Phi instructions.
   Func->placePhiLoads();
@@ -400,9 +398,7 @@
 }
 
 void TargetX8632::translateOm1() {
-  GlobalContext *Context = Func->getContext();
-  static TimerIdT IDOm1 = GlobalContext::getTimerID("Om1");
-  TimerMarker T(IDOm1, Context);
+  TimerMarker T(TimerStack::TT_Om1, Func);
   Func->placePhiLoads();
   if (Func->hasError())
     return;
@@ -4305,8 +4301,7 @@
 void TargetX8632::postLower() {
   if (Ctx->getOptLevel() != Opt_m1)
     return;
-  static TimerIdT IDpostLower = GlobalContext::getTimerID("postLower");
-  TimerMarker T(IDpostLower, Ctx);
+  TimerMarker T(TimerStack::TT_postLower, Func);
   // TODO: Avoid recomputing WhiteList every instruction.
   RegSetMask RegInclude = RegSet_All;
   RegSetMask RegExclude = RegSet_StackPointer;