Merged r16772, r18000, r18298, r18319 into 3.21 branch.

src/arguments.cc

Index: src/arguments.cc
diff --git a/src/arguments.cc b/src/arguments.cc
index 287805717e5199dff4117761e0d75e2b38ca3c1f..aecb26547b37a88c2a48296cc73535c3334293e7 100644
--- a/src/arguments.cc
+++ b/src/arguments.cc
@@ -117,5 +117,13 @@ FOR_EACH_CALLBACK_TABLE_MAPPING_2_VOID_RETURN(WRITE_CALL_2_VOID)
 #undef WRITE_CALL_2_VOID
 
 
+double ClobberDoubleRegisters(double x1, double x2, double x3, double x4) {
+  // TODO(ulan): This clobbers only subset of registers depending on compiler,
+  // Rewrite this in assembly to really clobber all registers.
+  // GCC for ia32 uses the FPU and does not touch XMM registers.
+  return x1 * 1.01 + x2 * 2.02 + x3 * 3.03 + x4 * 4.04;
+}
+
+
 } }  // namespace v8::internal