[NDS32] Add new option -mvh.

gcc/
	* config/nds32/nds32.c (nds32_cpu_cpp_builtins): Modify to define
	__NDS32_VH__ macro.
	* config/nds32/nds32.opt (mvh): New option.

Co-Authored-By: Chung-Ju Wu <jasonwucj@gmail.com>

From-SVN: r258427

gcc/ChangeLog

 2018-03-11  Kito Cheng  <kito.cheng@gmail.com>
 	    Chung-Ju Wu  <jasonwucj@gmail.com>
 
+	* config/nds32/nds32.c (nds32_cpu_cpp_builtins): Modify to define
+	__NDS32_VH__ macro.
+	* config/nds32/nds32.opt (mvh): New option.
+
+2018-03-11  Kito Cheng  <kito.cheng@gmail.com>
+	    Chung-Ju Wu  <jasonwucj@gmail.com>
+
 	* config/nds32/nds32-protos.h (nds32_cpu_cpp_builtins): Declare
 	function.
 	* config/nds32/nds32.c (nds32_cpu_cpp_builtins): New function.

gcc/config/nds32/nds32.c

@@ -2788,6 +2788,8 @@ nds32_cpu_cpp_builtins(struct cpp_reader *pfile)
     builtin_define ("__NDS32_16_BIT__");
   if (TARGET_GP_DIRECT)
     builtin_define ("__NDS32_GP_DIRECT__");
+  if (TARGET_VH)
+    builtin_define ("__NDS32_VH__");
 
   if (TARGET_BIG_ENDIAN)
     builtin_define ("__big_endian__");

gcc/config/nds32/nds32.opt

@@ -77,6 +77,10 @@ m16-bit
 Target Report Mask(16_BIT)
 Generate 16-bit instructions.
 
+mvh
+Target Report Mask(VH)
+Enable Virtual Hosting support.
+
 misr-vector-size=
 Target RejectNegative Joined UInteger Var(nds32_isr_vector_size) Init(NDS32_DEFAULT_ISR_VECTOR_SIZE)
 Specify the size of each interrupt vector, which must be 4 or 16.