compiler: print runtime.hex in hex

    
    The gc compiler recognizes the type runtime.hex and prints values
    in this type as hex. Do the same here. This makes debugging
    runtime crashes slightly better.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/190597

From-SVN: r274591

gcc/go/gofrontend/MERGE

-480477ca64c3001b9c7e92ef8b978dc92a5912d2
+0f6d673d5b1a3474c3424cb6994ae8ff9baed255
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/expressions.cc

@@ -10294,7 +10294,13 @@ Builtin_call_expression::do_get_backend(Translate_context* context)
 		  {
 		    Type* itype = Type::lookup_integer_type("uint64");
 		    arg = Expression::make_cast(itype, arg, location);
-                    code = Runtime::PRINTUINT;
+                    if (gogo->compiling_runtime()
+                        && type->named_type() != NULL
+                        && gogo->unpack_hidden_name(type->named_type()->name())
+                           == "hex")
+                      code = Runtime::PRINTHEX;
+                    else
+                      code = Runtime::PRINTUINT;
 		  }
 		else if (type->integer_type() != NULL)
 		  {

gcc/go/gofrontend/runtime.def

@@ -384,6 +384,9 @@ DEF_GO_RUNTIME(PRINTSTRING, "runtime.printstring", P1(STRING), R0())
 // Print a uint64 (for print/println).
 DEF_GO_RUNTIME(PRINTUINT, "runtime.printuint", P1(UINT64), R0())
 
+// Print a uint64 in hex (for print/println, used for runtime.hex type).
+DEF_GO_RUNTIME(PRINTHEX, "runtime.printhex", P1(UINT64), R0())
+
 // Print a int64 (for print/println).
 DEF_GO_RUNTIME(PRINTINT, "runtime.printint", P1(INT64), R0())