Reduce the number of virtual function in hydrogen-instruction.h classes

Instead of using virtual type-tester functions we can just
generate non-virtual ones for all concrete IR classes.

This is changes reduces the V8 binary size by ~2%.

I also simplified the macros to declare new hydrogen instructions slightly.
The name used for debug output is no longer passed as a separate string.
Instead we just use the class name.
Review URL: http://codereview.chromium.org/6880014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7659 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-instructions.cc

@@ -317,6 +317,17 @@ intptr_t HValue::Hashcode() {
 }
 
 
+const char* HValue::Mnemonic() const {
+  switch (opcode()) {
+#define MAKE_CASE(type) case k##type: return #type;
+    HYDROGEN_CONCRETE_INSTRUCTION_LIST(MAKE_CASE)
+#undef MAKE_CASE
+    case kPhi: return "Phi";
+    default: return "";
+  }
+}
+
+
 void HValue::SetOperandAt(int index, HValue* value) {
   ASSERT(value == NULL || !value->representation().IsNone());
   RegisterUse(index, value);