Turn RegExpConstructResultStub into a HydrogenCodeStub.

Turn RegExpConstructResultStub into a HydrogenCodeStub.

This has the additional benefit that it is now possible to
inline the RegExpResult construction code into Hydrogen
builtins.

R=mvstanton@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=18902

[Benedikt Meurer, 2014-01-28 14:30:38]

Kill all the native code stubs! :-)

PTAL

[mvstanton, 2014-01-29 08:51:16]

Indeed! A few questions on the main block,
--Michael

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc
File src/hydrogen.cc (right):

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc#newcode1566
src/hydrogen.cc:1566: HValue* size = length;
Shouldn't you verify length is a smi?

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc#newcode1576
src/hydrogen.cc:1576: size, HType::JSArray(), NOT_TENURED, JS_ARRAY_TYPE);
Actually, why not let allocation folding take care of this? I remember we tried
to remove all instances of manual folding, only keeping the memento case because
it was essential that the objects be physically next to each other.

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc#newcode1584
src/hydrogen.cc:1584: context(),
HObjectAccess::ForContextSlot(Context::GLOBAL_OBJECT_INDEX));
Any reason to use this instead of HGlobalObject? Do we still need HGlobalObject?

[Benedikt Meurer, 2014-01-29 08:55:19]

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc
File src/hydrogen.cc (right):

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc#newcode1566
src/hydrogen.cc:1566: HValue* size = length;
Crankshaft generates an HChange (s->t) implicitly.

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc#newcode1576
src/hydrogen.cc:1576: size, HType::JSArray(), NOT_TENURED, JS_ARRAY_TYPE);
That doesn't work well with variable sized allocations. And we need the exact
size above for the bounds check.

https://codereview.chromium.org/141703018/diff/20001/src/hydrogen.cc#newcode1584
src/hydrogen.cc:1584: context(),
HObjectAccess::ForContextSlot(Context::GLOBAL_OBJECT_INDEX));
HGlobalObject is gone. :-)

[mvstanton, 2014-01-29 09:22:32]

Well played...:)
lgtm.

[Benedikt Meurer, 2014-01-29 13:10:50]

Committed patchset #3 manually as r18902 (presubmit successful).