[google][4.7]Port function reordering via linker plugin from google/gcc-4_6 branch

gcc/common.opt

Index: gcc/common.opt 
=================================================================== 
--- gcc/common.opt	(revision 187620) 
+++ gcc/common.opt	(working copy) 
@@ -952,10 +952,6 @@ fcaller-saves 
 Common Report Var(flag_caller_saves) Optimization 
 Save registers around function calls 
 
-fcallgraph-profiles-sections 
-Common Report Var(flag_callgraph_profiles_sections) Init(0) 
-Generate .note.callgraph.text sections listing callees and edge counts. 
- 
 fcheck-data-deps 
 Common Report Var(flag_check_data_deps) 
 Compare the results of several data dependence analyzers. 
@@ -1785,6 +1781,16 @@ freorder-functions 
 Common Report Var(flag_reorder_functions) Optimization 
 Reorder functions to improve code placement 
 
+freorder-functions= 
+Common Joined RejectNegative Enum(function_reorder) Var(flag_reorder_functions) Init(0) Optimization 
+-freorder-functions=[callgraph]	Select the scheme for function reordering. This invokes a linker plugin. Generate .gnu.callgraph.text sections listing callees and edge counts. 
+ 
+Enum 
+Name(function_reorder) Type(int) UnknownError(unrecognized function reorder value %qs) 
+ 
+EnumValue 
+Enum(function_reorder) String(callgraph) Value(2) 
+ 
 frerun-cse-after-loop 
 Common Report Var(flag_rerun_cse_after_loop) Optimization 
 Add a common subexpression elimination pass after loop optimizations