Change-Id: Id8693208d2741c55a7b0474d1264f2112019d11f

Change-Id: I06292964a6882ea2d0c17c5c962db95e46b01543

The root visitor has been used by the concurrent collector during the
re-mark phase.  This change makes both the initial mark use the same
visitor routine and obsoletes all of the one-off markers scattered
throughout the runtime sources.

Change-Id: I08ea86d875f235cc628754240ad30ea5dfe2ce70

Strings can be intered by the class loader, in the case of string
literals, or by the user, through String.intern.  Literal strings
exist for the life of their referencing classes.  User strings are
weak and may be garbage collected when unreferenced.  These two
classes of strings are kept in seprate tables for the conveniance of
the garbage collector during root traversal.

When a class loader interns a string that was already interned by the
user the runtime must move the string from the intern table to the
literal table to increase the reference strength.  Previously, this
was implemented by inserting the incoming string into the literal
table and removing any matching strings in the intern table.  This
transition lost pointer equality.  With this change we first insert
the exact string from the intern table into the literal table and
secondly remove its reference from the intern table.  By moving the
string between tables pointer equality is preserved.

At this point lookupInternedString should be split into two functions,
possibly by pulled up the relevant bits into the public interface
functions.  Since this change will be merged to gingerbread I will
leave the clean up to a separate change.

Bug: 3098960

Card table verification occurs just before scanning the card table
during a concurrent GC.  Each object in the bitmap is visited and the
number of white (unmarked) references are counted.  If an object has
unmarked objects it is by definition gray and must reside on a dirty
card.  If the object is not on a dirty card, the verification routine
aborts the VM.

Because the processing of weak roots and references has yet to occur,
reachable reference objects with unmarked referents and weak interned
strings may still be gray.  These objects are checked during the card
table scan and ignored if their card is not dirty.

Change-Id: I64d145aa4719fb52eb9e3bb91efaf4dcfacd6e0c

The old implementation of the intern table stole the lsb to denote
that a string was "immortal" meaning that it was loaded from a dex
file.  Before clients can use strings from this table they must be
aware of the bit and clear it before chasing the pointer.

The new intern table separates strings that are interned by a call to
String.intern and strings that are interned by the class loader.  This
adds a small cost to each intern call.  Fortunately, there is a
payback in the garbage collector as we can scan just the literal
strings during root marking and scan just the user interned strings
before sweeping to clear them.  Also we no longer have to special case
walking through reference-containing locations in the intern table.

Change-Id: I1192fdcc99e1bb2c606f74f54b3056ec60b6f39b