Add premonomorphic store ICs.

Add premonomorphic store ICs

BUG=
R=jkummerow@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16509

[Toon Verwaest, 2013-09-02 15:42:11]

PTAL

[Jakob Kummerow, 2013-09-03 09:58:59]

LGTM with a formatting suggestion.

Please have a close eye on performance; if there's other code somewhere that
needs to be updated to reflect these changes then that could cause tanking in
some corner cases.

https://chromiumcodereview.appspot.com/23442016/diff/9001/src/ic.cc
File src/ic.cc (right):

https://chromiumcodereview.appspot.com/23442016/diff/9001/src/ic.cc#newcode1713
src/ic.cc:1713: if (!can_store &&
nit: I'm finding this heterogeneous if/else cascade a little hard to read, and I
think I'd prefer the following alternative formatting:

  bool can_store = LookupForWrite(receiver, name, value, &lookup, &state);
  if (!can_store &&
      strict_mode == kStrictMode &&
      !(lookup.IsProperty() && lookup.IsReadOnly()) &&
      IsUndeclaredGlobal(object)) {
    // Strict mode doesn't allow setting non-existent global property.
    return ReferenceError("not_defined", name);
  }
  if (FLAG_use_ic) {
    if (state == UNINITIALIZED) {
      Handle<Code> stub = (strict_mode == kStrictMode)
          ? pre_monomorphic_stub_strict()
          : pre_monomorphic_stub();
      set_target(*stub);
      TRACE_IC("StoreIC", name, state, *stub);
    } else if (can_store) {
      UpdateCaches(&lookup, state, strict_mode, receiver, name, value);
    } else if (!name->IsCacheable(isolate()) ||
               lookup.IsNormal() ||
               (lookup.IsField() && lookup.CanHoldValue(value))) {
      Handle<Code> stub = (strict_mode == kStrictMode) ? generic_stub_strict()
                                                       : generic_stub();
      set_target(*stub);
    }
  }

I leave the decision up to you, though.

[Toon Verwaest, 2013-09-03 13:32:08]

Addressed comment, landing.
I obviously have been monitoring performance ;)

[Toon Verwaest, 2013-09-03 13:34:09]

Committed patchset #2 manually as r16509 (presubmit successful).