Disable frame pointer elimination when using -pg 

(Re-apply patch after bug fixing)

This diff makes sure that the driver does not pass
-fomit-frame-pointer or -momit-leaf-frame-pointer to
the frontend when -pg is used. Currently, clang gives 
an error if -fomit-frame-pointer is used in combination 
with -pg, but -momit-leaf-frame-pointer was forgotten.
Also, disable frame pointer elimination in the frontend 
when -pg is set.

Patch by Stefan Kempf.

llvm-svn: 253886
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 413967e..3bd2ffb 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -2794,6 +2794,8 @@
   if (Arg *A = Args.getLastArg(options::OPT_fno_omit_frame_pointer,
                                options::OPT_fomit_frame_pointer))
     return A->getOption().matches(options::OPT_fno_omit_frame_pointer);
+  if (Args.hasArg(options::OPT_pg))
+    return true;
 
   return shouldUseFramePointerForTarget(Args, Triple);
 }
@@ -2803,6 +2805,8 @@
   if (Arg *A = Args.getLastArg(options::OPT_mno_omit_leaf_frame_pointer,
                                options::OPT_momit_leaf_frame_pointer))
     return A->getOption().matches(options::OPT_mno_omit_leaf_frame_pointer);
+  if (Args.hasArg(options::OPT_pg))
+    return true;
 
   if (Triple.isPS4CPU())
     return false;