Commit Graph

21631 Commits

Author SHA1 Message Date
mstarzinger
8fb6660e76 Fix runtime assert in %LiveEditCheckAndDropActivations.
R=jarin@chromium.org
BUG=chromium:465663
LOG=n

Review URL: https://codereview.chromium.org/989743004

Cr-Commit-Position: refs/heads/master@{#27089}
2015-03-10 09:48:18 +00:00
titzer
0b3f4af12c [turbofan] Fix --turbo-osr for OSRing into inner loop inside for-in.
R=mstarzinger@chromium.org
BUG=chromium:462775
LOG=Y

Review URL: https://codereview.chromium.org/988423003

Cr-Commit-Position: refs/heads/master@{#27088}
2015-03-10 09:27:40 +00:00
dcarney
66969fb2ad convert Function and Promise to maybe
BUG=

Review URL: https://codereview.chromium.org/993883002

Cr-Commit-Position: refs/heads/master@{#27087}
2015-03-10 09:15:59 +00:00
bmeurer
022ea7e057 [turbofan] Unify Math.floor / Math.ceil optimization.
Provide an intrinsic %MathFloor / %_MathFloor that is used to optimize
both Math.ceil and Math.floor, and use the JS inlining mechanism to
inline Math.ceil into TurboFan code. Although we need to touch code
outside of TurboFan to make this work, this does not affect the way we
handle Math.ceil and/or Math.floor in CrankShaft, because for CrankShaft
the old-style builtin function id based inlining still kicks in first.

Once this solution is stabilized, we can use it for Math.floor as well.
And once that is settled, we can establish it as the unified way to
inline builtins, and get rid of the specialized builtin function id
based inlining at some point.

Note that "builtin" applies to basically every piece of internal
JavaScript/intrinsics based code, so this also applies to the yet to be
defined JavaScript based code stubs and handlers.

BUG=v8:3953
LOG=n
R=yangguo@chromium.org,svenpanne@chromium.org

Review URL: https://codereview.chromium.org/990963003

Cr-Commit-Position: refs/heads/master@{#27086}
2015-03-10 08:42:53 +00:00
bmeurer
a556a104c0 [turbofan] Context specialize during inlining.
Context specialization enables inlining (at least currently it is the
only enabler for inlining), but inlining enables more possibilities for
context specialization. So we really need to run them together.

This is especially important with the "module based builtins" that we're
working towards.

BUG=v8:3952
LOG=n

Review URL: https://codereview.chromium.org/988423004

Cr-Commit-Position: refs/heads/master@{#27085}
2015-03-10 08:37:26 +00:00
dcarney
60c1ad026d remove phantom naming from the api
since the old style weakness is slated for removal, we might as well reuse the name to limit confusion.  additionally I simplified the callback type to a enum to either get internal field values or not

this should be a non-breaking change with the exception of PhantomPersistentValueMap, which is unused.

R=jochen@chromium.org, erikcorry@chromium.org

BUG=

Review URL: https://codereview.chromium.org/989153003

Cr-Commit-Position: refs/heads/master@{#27084}
2015-03-09 21:48:09 +00:00
balazs.kilvady
18bf4c27b5 Fix 'MIPS: [turbofan] Support for %_DoubleHi, %_DoubleLo and %_ConstructDouble.'
BUG=

Review URL: https://codereview.chromium.org/988243004

Cr-Commit-Position: refs/heads/master@{#27083}
2015-03-09 17:47:04 +00:00
machenbach
fcbe10739b Fix full rebuilding after clang rolls.
BUG=chromium:464657
LOG=n
TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/990253002

Cr-Commit-Position: refs/heads/master@{#27082}
2015-03-09 17:22:33 +00:00
machenbach
1bbe1da661 Force full rebuilding after clang rolls.
BUG=chromium:464657
LOG=n

Review URL: https://codereview.chromium.org/987063002

Cr-Commit-Position: refs/heads/master@{#27081}
2015-03-09 16:24:46 +00:00
svenpanne
ea2f15e2a9 Handle *all* runtime versions of intrinsics in the serializer.
Note that this is done only for consistency at this point in time.
The change should probably have been in
https://codereview.chromium.org/984963002/ already.

BUG=v8:3947
LOG=n

Review URL: https://codereview.chromium.org/992683002

Cr-Commit-Position: refs/heads/master@{#27080}
2015-03-09 15:11:46 +00:00
jochen
34c43513a3 Make VerifyMarking work in the presence of grey objects
R=hpayer@chromium.org
LOG=n
BUG=none

Review URL: https://codereview.chromium.org/990203002

Cr-Commit-Position: refs/heads/master@{#27079}
2015-03-09 15:01:42 +00:00
titzer
0f6702562e Extract ParseInfo from CompilationInfo.
Rationale: separate the inputs and outputs of parsing + analysis from the business of compiling (i.e. generating machine code).

BUG=

Review URL: https://codereview.chromium.org/974213002

Cr-Commit-Position: refs/heads/master@{#27078}
2015-03-09 14:51:24 +00:00
marja
bb69648804 Debugger & classes: add debugger tests for classes.
R=dslomov@chromium.org
BUG=

Review URL: https://codereview.chromium.org/977123002

Cr-Commit-Position: refs/heads/master@{#27077}
2015-03-09 14:49:54 +00:00
loislo
66ab309e73 CpuProfiler: fix for GetDeoptReason code.
The original code always returned the first entry from RelocInfo that matched with
bailout_id. But we may have a few different deopt reasons for one bailout_id.
So we need to get the one which matches with a particular call from JumpTable.

We can do this by checking not 'target_address' (it maps to bailout_id)
but 'from' address which maps to a particular JumpTable entry.

The test was reworked so it tests identical functions against different reasons.

BUG=chromium:452067
LOG=n

Review URL: https://codereview.chromium.org/984773003

Cr-Commit-Position: refs/heads/master@{#27076}
2015-03-09 14:43:40 +00:00
marja
4a709dd658 [strong] Fix scoping related errors for methods.
Methods can refer to the class name.

BUG=v8:3927
LOG=N

Review URL: https://codereview.chromium.org/968263002

Cr-Commit-Position: refs/heads/master@{#27075}
2015-03-09 14:30:40 +00:00
yangguo
9dedcc3dfc Simplify promise event on throw handling.
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/991833002

Cr-Commit-Position: refs/heads/master@{#27074}
2015-03-09 13:41:55 +00:00
hpayer
ded6ffbb2a Recorded slots in store buffer are never in free space. Remove migration consistency check.
After establishing the invariant that the store buffer always has valid slots after marking, the store buffer integrity check is not needed anymore.

BUG=454157
LOG=n

Review URL: https://codereview.chromium.org/990173002

Cr-Commit-Position: refs/heads/master@{#27073}
2015-03-09 13:33:16 +00:00
yangguo
67bc45c278 Hide Math function implementations in a closure.
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/990883002

Cr-Commit-Position: refs/heads/master@{#27072}
2015-03-09 13:25:44 +00:00
jarin
6f559b7ec3 [turbofan] Fix lazy deopt for JSToNumber conversions in binary operations.
This slightly hacky change provides lazy deopt points for to-number conversions in binops: When we deopt from a to-number conversion, we create a frame state with the already-converted value(s) so that we do not repeat the side effect of the conversion.

Embenchen numbers are below. It is not quite clear what happened to fasta - the hot code looks nearly identical.

Current: EmbenchenBox2d(RunTime): 12746 ms.
d8-master: EmbenchenBox2d(RunTime): 13861 ms.
----------- bullet.js
Current: EmbenchenBullet(RunTime): 17680 ms.
d8-master: EmbenchenBullet(RunTime): 19170 ms.
----------- copy.js
Current: EmbenchenCopy(RunTime): 4939 ms.
d8-master: EmbenchenCopy(RunTime): 4943 ms.
----------- corrections.js
Current: EmbenchenCorrections(RunTime): 6639 ms.
d8-master: EmbenchenCorrections(RunTime): 6728 ms.
----------- fannkuch.js
Current: EmbenchenFannkuch(RunTime): 4630 ms.
d8-master: EmbenchenFannkuch(RunTime): 4872 ms.
----------- fasta.js
Current: EmbenchenFasta(RunTime): 10209 ms.
d8-master: EmbenchenFasta(RunTime): 9673 ms.
----------- lua_binarytrees.js
Current: EmbenchenLuaBinaryTrees(RunTime): 12936 ms.
d8-master: EmbenchenLuaBinaryTrees(RunTime): 15529 ms.
----------- memops.js
Current: EmbenchenMemOps(RunTime): 7357 ms.
d8-master: EmbenchenMemOps(RunTime): 7340 ms.
----------- primes.js
Current: EmbenchenPrimes(RunTime): 7530 ms.
d8-master: EmbenchenPrimes(RunTime): 7457 ms.
----------- skinning.js
Current: EmbenchenSkinning(RunTime): 15832 ms.
d8-master: EmbenchenSkinning(RunTime): 15630 ms.
----------- zlib.js
Current: EmbenchenZLib(RunTime): 11176 ms.
d8-master: EmbenchenZLib(RunTime): 11324 ms.

BUG=

Review URL: https://codereview.chromium.org/985713003

Cr-Commit-Position: refs/heads/master@{#27071}
2015-03-09 13:24:42 +00:00
mstarzinger
dcb502a4ee [turbofan] Only reduce inline %DeoptimizeNow.
This makes sure only the %_DeoptimizeNow intrinsic is inlined, and
not the %DeoptimizeNow one. It hence re-establishes the invariant
that JSIntrinsicLowering only deals with inline intrinsics.

R=jarin@chromium.org
TEST=mjsunit/compiler/eager-deopt-simple

Review URL: https://codereview.chromium.org/988333003

Cr-Commit-Position: refs/heads/master@{#27070}
2015-03-09 13:20:26 +00:00
Benedikt Meurer
eacd6d8b7d [turbofan] Make inlining independent of typing.
The JSInliner used to load the context from the JSFunction node at
runtime, which introduced a HeapConstant (because we had to materialize
the JSFunction after context specialization) and a LoadField operation,
independent whether the inlinee actually uses the context. This is
rather cumbersome currently, and therefore this is now changed to just
embed the context constant instead. Once we do inlining based on
SharedFunctionInfo rather than JSFunction, we should reconsider this
decision and come up with a proper heuristic.

BUG=v8:3952
LOG=n
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/994523002

Cr-Commit-Position: refs/heads/master@{#27069}
2015-03-09 13:01:44 +00:00
hpayer
aee169ec65 Eliminate invalid pointers in store buffer after marking.
The store buffer can contain stale store buffer entries, i.e., slot in dead objects pointing to new space objects. These slots are treaded as live slots which cause problems with non-pointer fields and makes concurrent sweeping complicated. Removing these pointers from the store buffer before it is used makes life easier.

BUG=

Review URL: https://codereview.chromium.org/985453003

Cr-Commit-Position: refs/heads/master@{#27068}
2015-03-09 12:49:58 +00:00
verwaest
a9a3623604 Revert of Store the next serial number in the function cache rather than in the isolate.Don't overwrite existi (patchset #4 id:60001 of https://codereview.chromium.org/988693003/)
Reason for revert:
This doesn't do what it's supposed to do. The problem seems to lie on the blink side, people aren't reusing their FunctionTemplates (or creating them when not necessary).

Original issue's description:
> Don't overwrite existing serial numbers on the function template, otherwise instantiating the function for a new context causes the serial number to bump.
>
> Committed: https://crrev.com/1e638c3610ec6938e5fb16c42018642195782fb2
> Cr-Commit-Position: refs/heads/master@{#27048}

TBR=yangguo@chromium.org,dcarney@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/993533003

Cr-Commit-Position: refs/heads/master@{#27067}
2015-03-09 12:30:16 +00:00
dcarney
d7f25f557c use a hash table for the function cache as blink is leaking functiontemplates
BUG=

Review URL: https://codereview.chromium.org/988283003

Cr-Commit-Position: refs/heads/master@{#27066}
2015-03-09 12:26:28 +00:00
Benedikt Meurer
d18bfa1130 [x86] Faster/shorter code for stack checks.
Avoid loading the stack pointer and the stack limit into allocatable
registers first, but generate a cmp rsp,[limit] instead.

R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/989203002

Cr-Commit-Position: refs/heads/master@{#27065}
2015-03-09 11:06:45 +00:00
Jaroslav Sevcik
82a28adf05 Do not set target in deoptimized code in keyed store IC.
BUG=chromium:460937
R=ishell@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/989093002

Cr-Commit-Position: refs/heads/master@{#27064}
2015-03-09 10:11:13 +00:00
ishell@chromium.org
67a02321c2 Revert of Remove slots that point to unboxed doubles from the StoreBuffer/SlotsBuffer. (patchset #4 id:230001 of https://codereview.chromium.org/957273002/)
Reason for revert:
It caused a lot of Canary crashes.

Original issue's description:
> Remove slots that point to unboxed doubles from the StoreBuffer/SlotsBuffer.
>
> The problem is that tagged slot could become a double slot after migrating of an object to another map with "shifted" fields (for example as a result of generalizing immutable data property to a data field).
> This CL also adds useful machinery that helps triggering incremental write barriers.
>
> BUG=chromium:454297
> LOG=Y
>
> Committed: https://crrev.com/9633ebabd405c264d33f603f8798c31f59418dcd
> Cr-Commit-Position: refs/heads/master@{#27054}

TBR=verwaest@chromium.org,hpayer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:454297

Review URL: https://codereview.chromium.org/991793002

Cr-Commit-Position: refs/heads/master@{#27063}
2015-03-09 10:10:46 +00:00
Benedikt Meurer
5abc724e82 [turbofan] Minor cleanup for JSGenericLowering.
Include what you use, and move implementation details to .cc file.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/986243002

Cr-Commit-Position: refs/heads/master@{#27062}
2015-03-09 10:08:06 +00:00
Dan Carney
47154aa8b2 add V8_DEPRECATE_SOON macros to make it easier to identify calls which need deprecation
BUG=
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/990873002

Cr-Commit-Position: refs/heads/master@{#27061}
2015-03-09 09:49:28 +00:00
Jaroslav Sevcik
02e318517f [turbofan] Add an extra frame state for deoptimization before binary op.
BUG=
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/983153002

Cr-Commit-Position: refs/heads/master@{#27060}
2015-03-09 08:37:17 +00:00
Benedikt Meurer
25895aeeaf [turbofan] Add support for inlining of builtins.
We mark certain builtins for inlining, and those should always be
inlined into optimized code (CrankShaft already handles it this way), so
we should support that in TurboFan as well. Currently this mainly
affects a certain set of Math functions, but once have the basics in
place we can extend this to any kind of builtin/code stub/accessor.

This adds a new flag --turbo_builtin_inlining (enabled by default), that
forces the inliner to always inline builtins marked for inlining, but
does not affect inlining of other functions (this is still controlled by
the --turbo-inlining flag).

BUG=v8:3952
LOG=n
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/993473002

Cr-Commit-Position: refs/heads/master@{#27059}
2015-03-09 08:05:45 +00:00
Benedikt Meurer
4b6afb8432 [turbofan] Skip function entry stack check for inlinee.
This is currently the cleanest approach to avoid the useless stack check
during inlining. We might be able to just remove the useless stack
checks later when we have a phase that also takes care of removing
redundant stack checks on loop back edges (which we do not generate
currently).

On the other hand, the flag introduced here might be useful when
building code stubs/builtins/dom stubs using JS based DSL, because you
certainly don't want a JS-level stack check in a code stub.

R=jarin@chromium.org
BUG=v8:3952
LOG=n

Review URL: https://codereview.chromium.org/994433002

Cr-Commit-Position: refs/heads/master@{#27058}
2015-03-09 07:31:00 +00:00
Benedikt Meurer
9bce5b347f [fdlibm] Inline coefficients for __kernel_sin and __kernel_cos.
Loading the coefficients from a the constants typed array is currently
blocking inlining MathSin and MathCos into TurboFan generated code,
because there is no type feedback and hence TurboFan has to generate a
LOAD_IC for every coefficient.

R=yanggou@chromium.org
BUG=v8:3952
LOG=n

Review URL: https://codereview.chromium.org/989133002

Cr-Commit-Position: refs/heads/master@{#27057}
2015-03-09 07:30:09 +00:00
Benedikt Meurer
3c4a32dcdc [turbofan] Introduce JSStackCheck operator.
The key idea here is that the stack check should be explicit, such that
we can eliminate unnecessary stack checks after graph building and
potentially inlining.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/981243002

Cr-Commit-Position: refs/heads/master@{#27056}
2015-03-09 05:02:12 +00:00
Weiliang Lin
a5fa093d0b introduce android_x64 build target
BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/966773005

Cr-Commit-Position: refs/heads/master@{#27055}
2015-03-09 03:23:12 +00:00
ishell
9633ebabd4 Remove slots that point to unboxed doubles from the StoreBuffer/SlotsBuffer.
The problem is that tagged slot could become a double slot after migrating of an object to another map with "shifted" fields (for example as a result of generalizing immutable data property to a data field).
This CL also adds useful machinery that helps triggering incremental write barriers.

BUG=chromium:454297
LOG=Y

Review URL: https://codereview.chromium.org/957273002

Cr-Commit-Position: refs/heads/master@{#27054}
2015-03-06 23:55:13 +00:00
Michael Achenbach
5a3f085de9 Whitespace change to test recipe trigger.
Cr-Commit-Position: refs/heads/master@{#27053}
2015-03-06 19:55:19 +00:00
rmcilroy
087c8298a0 Revert of Revert of Revert of Turn on job based recompilation (patchset #1 id:1 of https://codereview.chromium.org/955723002/)
Reason for revert:
Breaks Octane on Arm64 running on Chrome.

BUG=464538

Original issue's description:
> Revert of Revert of Turn on job based recompilation (patchset #1 id:1 of https://codereview.chromium.org/937263004/)
>
> Reason for revert:
> reland
>
> Original issue's description:
> > Revert of Turn on job based recompilation (patchset #1 id:1 of https://codereview.chromium.org/935243003/)
> >
> > Reason for revert:
> > waterfall disagrees
> >
> > Original issue's description:
> > > Turn on job based recompilation
> > >
> > > BUG=v8:3608
> > > R=yangguo@chromium.org
> > > LOG=y
> > >
> > > Committed: https://crrev.com/4ae82f64b09cdc0182cee3a5cc619a9117ac5fbc
> > > Cr-Commit-Position: refs/heads/master@{#26826}
> >
> > TBR=yangguo@chromium.org
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=v8:3608
> >
> > Committed: https://crrev.com/35cc692aecdea54fb07479b8d7b71059851e07e8
> > Cr-Commit-Position: refs/heads/master@{#26827}
>
> TBR=yangguo@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:3608
>
> Committed: https://crrev.com/3735a0851a9e2726f8b50a46a3bc770992328264
> Cr-Commit-Position: refs/heads/master@{#26829}

TBR=yangguo@chromium.org,jochen@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:3608

Review URL: https://codereview.chromium.org/984463003

Cr-Commit-Position: refs/heads/master@{#27052}
2015-03-06 18:24:40 +00:00
caitpotter88
9e482baf81 [parser] better error message for generator constructors
BUG=
LOG=N
R=arv@chromium.org

Review URL: https://codereview.chromium.org/982153003

Cr-Commit-Position: refs/heads/master@{#27051}
2015-03-06 16:54:39 +00:00
dusan.milosavljevic
6f946d6c02 MIPS: Update test status files.
TEST=
BUG=

Review URL: https://codereview.chromium.org/987653005

Cr-Commit-Position: refs/heads/master@{#27050}
2015-03-06 16:41:35 +00:00
kalman
c23035cdd0 Add MoveOnlyTypeForCPP03 to UniquePersistent for compatibility with Chromium.
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/986463005

Cr-Commit-Position: refs/heads/master@{#27049}
2015-03-06 16:39:16 +00:00
verwaest
1e638c3610 Don't overwrite existing serial numbers on the function template, otherwise instantiating the function for a new context causes the serial number to bump.
Review URL: https://codereview.chromium.org/988693003

Cr-Commit-Position: refs/heads/master@{#27048}
2015-03-06 15:25:57 +00:00
yangguo
206303f703 Do not include code objects for functions in the start-up snapshot.
Review URL: https://codereview.chromium.org/981213002

Cr-Commit-Position: refs/heads/master@{#27047}
2015-03-06 15:07:06 +00:00
svenpanne
e2ce456754 Intrinsics in the RUNTIME_FUNCTION_LIST are now available with '_', too.
Now the three intrinsic lists only differ in their compiler
support. Unifying the lists and making the logic what is supported in
which compiler local to the compilers themselves is handled in a
follow-up CL.

BUG=v8:3947
LOG=n

Review URL: https://codereview.chromium.org/983183002

Cr-Commit-Position: refs/heads/master@{#27046}
2015-03-06 14:58:48 +00:00
yangguo
5de20c05d5 Do not use eternal handles when creating a start-up snapshot.
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/984833003

Cr-Commit-Position: refs/heads/master@{#27045}
2015-03-06 14:44:51 +00:00
jkummerow
233ea0eef8 Reland: Simplify and compact transitions storage
Original issue: https://codereview.chromium.org/980573002/

Simple transitions are now stored in a map's "transitions" field (as a WeakCell wrapping the target map); full TransitionArrays are used when that's not sufficient.
To encapsulate these storage format implementation details, functions for manipulating and querying transitions have been refactored to be static functions on the TransitionArray class, and take maps as inputs.

Review URL: https://codereview.chromium.org/988703002

Cr-Commit-Position: refs/heads/master@{#27044}
2015-03-06 14:08:47 +00:00
svenpanne
d8416f5524 Intrinsics in the INLINE_FUNCTION_LIST are now avaliable without '_', too.
This involved renaming apart a few more intrinsics. In the long run,
we want to clean up redundant intrinsics which just delegate.

BUG=v8:3947
LOG=n

Review URL: https://codereview.chromium.org/984963002

Cr-Commit-Position: refs/heads/master@{#27043}
2015-03-06 13:50:06 +00:00
machenbach
934dd88d3b Make automated branch creation gnumbd-save.
This makes now the same simplification as the chromium
release scripts do. For creating branch B from a gnumbd'ed
(aka real) commit X do:
1. Branch Y off the real X
2. Set refs/pending/heads/B to Y
3. Set refs/pending-tags/B to X
4. Set refs/heads/B to X

The old algorithm tried to branch off the pending
correspondent of X. That commit was determined by comparing
tree objects of the real X and commits on pending.
Unfortunately, multiple commits on one branch can refer to
the same tree object, e.g., for commits P, Q, R with R being
the revert of Q, P and R refer to the same tree object.

TBR=tandrii@chromium.org
NOTRY=true
TEST=./script_test.py
TEST=tools/release/create_release.py -a me -r you --dry-run

Review URL: https://codereview.chromium.org/979243004

Cr-Commit-Position: refs/heads/master@{#27042}
2015-03-06 13:10:33 +00:00
jarin
9b40c5d0d2 [turbofan] Fix the deopt ids in assignment.
BUG=chromium:463028
LOG=n
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/987733003

Cr-Commit-Position: refs/heads/master@{#27041}
2015-03-06 12:50:47 +00:00
ulan
1b00451f57 Retain maps embedded in optimized code for several garbage collections.
This keeps dying maps alive for FLAG_retain_maps_for_n_gc garbage collections
to increase chances of them being reused for new objects in future and
decrease number of deoptimizations.

BUG=v8:3664
LOG=N
TEST=cctest/test-heap/MapRetaining

Review URL: https://codereview.chromium.org/980523004

Cr-Commit-Position: refs/heads/master@{#27040}
2015-03-06 12:36:32 +00:00