Commit Graph

544 Commits

Author SHA1 Message Date
danno@chromium.org
0c3575c874 Generate the TransitionElementsStub using Crankshaft
This includes:
* Adding support for saving callee-clobbered double registers in Crankshaft code.
* Adding a new "HTrapAllocationMemento" hydrogen instruction to handle AllocationSiteInfo data in crankshafted stubs.
* Adding a new "HAllocate" hydrogen instruction that can allocate raw memory from the GC in crankshafted code.
* Support for manipulation of the hole in HChange instructions for Crankshafted stubs.
* Utility routines to manually build loops and if statements containing hydrogen code.

Review URL: https://codereview.chromium.org/11659022

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13585 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-02-04 12:01:59 +00:00
mmassi@chromium.org
3b8a61dcf3 Base iDef update code.
Review URL: https://codereview.chromium.org/12079042

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13575 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-02-01 10:16:16 +00:00
mmassi@chromium.org
89c4153581 Foundation for the use of informative definitions in Crankshaft.
Review URL: https://codereview.chromium.org/12090021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13543 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-29 15:46:34 +00:00
mstarzinger@chromium.org
fe8e97798e Allow inlining of multiple closures from shared function.
This allows Crankshaft to allow inlining of multiple different closures
that were all derived from the same shared function info. This pattern
appears when libraries provide generic closures that are used over and
over again at different call-sites.

R=jkummerow@chromium.org
TEST=mjsunit/compiler/inline-closures

Review URL: https://codereview.chromium.org/12071002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13522 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-25 16:55:00 +00:00
svenpanne@chromium.org
47d2fa5c51 Slightly improved Hydrogen stats output for long-running compilations.
Replaced a scary pointer comparison by strcmp on the way.

Review URL: https://codereview.chromium.org/12035101

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13510 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-25 13:55:02 +00:00
svenpanne@chromium.org
b5cb682be6 Avoid excessive memory usage during redundant phi elimination.
Basically, the work list for the fixed point iteration has been removed.

BUG=v8:2510

Review URL: https://codereview.chromium.org/12052075

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13505 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-25 11:51:48 +00:00
mstarzinger@chromium.org
44ffa0dcd3 Allow monomorphic loads when static type is known.
This allows Crankshaft to generate monomorphic loads when the receiver
type is statically known even though the load site has polymorphic type
feedback. This applies to inlined constructor calls and literals.

R=jkummerow@chromium.org
TEST=mjsunit/compiler/property-static

Review URL: https://codereview.chromium.org/12051058

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13500 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-24 17:54:30 +00:00
yangguo@chromium.org
c14b9b3703 Fix --hydrogen-stats.
V8 crashes with this flag when trying to compile hydrogen stubs.

R=jkummerow@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/12045048

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13487 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-24 08:39:35 +00:00
yangguo@chromium.org
3c22524119 Avoid handle dereference during graph optimization.
With parallel recompilation enabled, objects made accessible by handles may
have changed between graph construction and graph optimization. Therefore
we must not assume that information on those objects remain the same between
those two phases. To police this, we forbid handle dereferencing during
graph optimization.
Exceptions to this rule are:
 - Dereferencing the handle to obtain the raw location of the object. This
   is safe since parallel recompilation acquires RelocationLock
 - Some places that dereference the handle for a type check. These are checked
   to be safe on a case-by-case basis.

R=jkummerow@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/12049012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13475 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-23 13:52:00 +00:00
ulan@chromium.org
79a0e3b017 Fix pattern detection for replacing shifts by rotation.
BUG=2499
R=svenpanne@chromium.org

Review URL: https://chromiumcodereview.appspot.com/12047015
Patch from Hirofumi Mako <mkhrfm@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13464 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-22 13:55:22 +00:00
mstarzinger@chromium.org
f8d5260af7 Allow loading constant function from proto chain.
This enables Crankshaft to use HConstant for loading constant functions
on the prototype chain when building a monomorphic load. This pattern
appears in several JavaScript frameworks.

R=svenpanne@chromium.org
TEST=mjsunit/compiler/proto-chain-constant

Review URL: https://codereview.chromium.org/12052008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13463 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-22 12:03:35 +00:00
yangguo@chromium.org
7f331f6280 Make HCheckPrototypeMaps compatible with parallel recompilation.
HCheckPrototypeMaps currently records the prototype and the holder of the
prototype chain (both ends of the chain) and assumes that the chain elements
and their maps did not change in during the entirety of Crankshaft. The actual
traversal of the prototype chain happens in Lithium at code generation.
With parallel compilation, this assumption is not longer correct.

R=mstarzinger@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/11864013

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13454 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-21 15:49:00 +00:00
jkummerow@chromium.org
b7079a5dfb Disable elimination of unreachable code after HSoftDeopts
Review URL: https://codereview.chromium.org/12036011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13448 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-21 14:11:25 +00:00
jkummerow@chromium.org
8a6221b1ed Don't insert HDummyUses for control instructions
Review URL: https://codereview.chromium.org/11941013

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13421 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-18 09:19:11 +00:00
mmassi@chromium.org
ca78326b66 Revert r13409 ("Make the array bounds check elimination phase optional (and set the foundation for introducing SSI in a simple way).") because of a crash in octane/mandreel.
Review URL: https://chromiumcodereview.appspot.com/11962041

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13416 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-17 16:09:08 +00:00
jkummerow@chromium.org
a496e0d06a Don't emit code for instructions that are hiding behind an HSoftDeoptimize
Review URL: https://codereview.chromium.org/11377135

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13412 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-17 14:07:47 +00:00
mmassi@chromium.org
583f67b54b Make the array bounds check elimination phase optional (and set the foundation for introducing SSI in a simple way).
BUG=

Review URL: https://chromiumcodereview.appspot.com/11783055

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13409 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-17 12:39:16 +00:00
mvstanton@chromium.org
7884216804 Additional work to get array literal allocation tracking working, even with --always-opt
BUG=

Review URL: https://codereview.chromium.org/11817017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13406 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-17 08:41:27 +00:00
mstarzinger@chromium.org
0484ddcf50 Fix arguments materialization for inlined apply().
This fixes materialization of the arguments object in case the constant
function check if TryCallApply() inside an inlined frame fails.

R=svenpanne@chromium.org
BUG=v8:2489
TEST=mjsunit/regress/regress-2489

Review URL: https://codereview.chromium.org/11931012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13386 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-16 09:25:45 +00:00
yangguo@chromium.org
45f20e366a Introduce ENABLE_LATIN_1 compile flag
Mostly a bunch of renaming when flag is disabled.

R=yangguo@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/11759008
Patch from Dan Carney <dcarney@google.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13340 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-09 10:30:54 +00:00
svenpanne@chromium.org
eb9a22cc8b Environment bookkeping has linear time complexity now, not a quadratic one.
This reduces the time take for mjsunit/limit-locals from 56.8s to 15.1s in debug
mode and from 12.0s to 1.6s in release mode.

Note that GrowableBitVector and BitVector should really be merged, and probably
have their allocation strategy parmeterized. The current state of affairs
involving tons of checks and delegation is extremely ugly, and it is far from
clear if all that special casing is a clear win. STL FTW! :-P

Review URL: https://codereview.chromium.org/11775016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13327 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-07 15:28:20 +00:00
verwaest@chromium.org
11c2557452 Check interceptor before optimizing load/store
Review URL: https://chromiumcodereview.appspot.com/11753027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13324 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-01-07 12:14:36 +00:00
danno@chromium.org
45a012ec2c Elide unnecessary context reload in generated stubs.
Review URL: https://codereview.chromium.org/11550005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13290 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-28 16:25:38 +00:00
rossberg@chromium.org
97eba9d3cd Object.observe: fix observation for optimised in/decrement and compound assignment.
R=svenpanne@chromium.org
BUG=v8:2409

Review URL: https://codereview.chromium.org/11642042

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13255 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-20 15:03:30 +00:00
danno@chromium.org
1f4b4625ff Re-land Crankshaft-generated KeyedLoad stubs.
R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/11528003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13236 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-18 16:25:45 +00:00
mmassi@chromium.org
ae54f9cfe0 Fix for when array bounds check elimination tries to modify a phi index.
BUG=

Review URL: https://chromiumcodereview.appspot.com/11486007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13193 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-11 14:23:04 +00:00
mmassi@chromium.org
3b0ee64664 Revert r13176.
BUG=

Review URL: https://chromiumcodereview.appspot.com/11503011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13182 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-10 12:55:50 +00:00
danno@chromium.org
64fc1f99cb Revert 13157, 13145 and 13140: Crankshaft code stubs.
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/11498006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13179 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-10 11:09:12 +00:00
mmassi@chromium.org
1aa2891ca4 Make keyed operations use the unchecked index but still depend on the checked one.
BUG=

Review URL: https://chromiumcodereview.appspot.com/11445016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13176 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-10 08:56:24 +00:00
yangguo@chromium.org
c75ca45000 Improve array to string conversion.
BUG=v8:2435

Review URL: https://chromiumcodereview.appspot.com/11348349

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13144 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-05 15:49:22 +00:00
danno@chromium.org
f19959cd22 Enable stub generation using Hydrogen/Lithium (again)
This initial implementation generates only KeyedLoadICs using the new Hydrogen stub infrastructure.

Committed: https://code.google.com/p/v8/source/detail?r=13105

Committed: https://code.google.com/p/v8/source/detail?r=13117

Review URL: https://codereview.chromium.org/10701054

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13140 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-05 11:04:10 +00:00
danno@chromium.org
66f6a8182c Revert 13117: "Enable stub generation using Hydrogen/Lithium (again)"
TBR=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/11415261

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13120 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-03 17:16:51 +00:00
danno@chromium.org
78b09625d5 Enable stub generation using Hydrogen/Lithium (again)
This initial implementation generates only KeyedLoadICs using the new Hydrogen stub infrastructure.

Committed: https://code.google.com/p/v8/source/detail?r=13105

Review URL: https://codereview.chromium.org/10701054

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13117 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-12-03 15:51:05 +00:00
danno@chromium.org
0a3bcc8c05 Revert 13105: "Enable stub generation using Hydrogen/Lithium."
TBR=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/11414262

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13106 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-30 17:45:45 +00:00
danno@chromium.org
c115ff4e33 Enable stub generation using Hydrogen/Lithium.
This initial implementation generates only KeyedLoadICs using the new Hydrogen stub infrastructure.

Review URL: https://codereview.chromium.org/10701054

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13105 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-30 17:31:30 +00:00
jkummerow@chromium.org
79563b22c9 Faster implementation of Math.exp()
Review URL: https://codereview.chromium.org/11418149

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13054 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-26 13:12:35 +00:00
mmassi@chromium.org
a0582112f8 Revert r13025 and r13026 (they introduced a bug on arm and regressed octane crypto).
BUG=

Review URL: https://chromiumcodereview.appspot.com/11316151

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13039 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-23 10:53:03 +00:00
rossberg@chromium.org
ce05280bfc Get rid of static module allocation, do it in code.
Modules now have their own local scope, represented by their own context.
Module instance objects have an accessor for every export that forwards
access to the respective slot from the module's context. (Exports that are
modules themselves, however, are simple data properties.)

All modules have a _hosting_ scope/context, which (currently) is the
(innermost) enclosing global scope. To deal with recursion, nested modules
are hosted by the same scope as global ones.

For every (global or nested) module literal, the hosting context has an
internal slot that points directly to the respective module context. This
enables quick access to (statically resolved) module members by 2-dimensional
access through the hosting context. For example,

  module A {
    let x;
    module B { let y; }
  }
  module C { let z; }

allocates contexts as follows:

[header| .A | .B | .C | A | C ]  (global)
          |    |    |
          |    |    +-- [header| z ]  (module)
          |    |
          |    +------- [header| y ]  (module)
          |
          +------------ [header| x | B ]  (module)

Here, .A, .B, .C are the internal slots pointing to the hosted module
contexts, whereas A, B, C hold the actual instance objects (note that every
module context also points to the respective instance object through its
extension slot in the header).

To deal with arbitrary recursion and aliases between modules,
they are created and initialized in several stages. Each stage applies to
all modules in the hosting global scope, including nested ones.

1. Allocate: for each module _literal_, allocate the module contexts and
   respective instance object and wire them up. This happens in the
   PushModuleContext runtime function, as generated by AllocateModules
   (invoked by VisitDeclarations in the hosting scope).

2. Bind: for each module _declaration_ (i.e. literals as well as aliases),
   assign the respective instance object to respective local variables. This
   happens in VisitModuleDeclaration, and uses the instance objects created
   in the previous stage.
   For each module _literal_, this phase also constructs a module descriptor
   for the next stage. This happens in VisitModuleLiteral.

3. Populate: invoke the DeclareModules runtime function to populate each
   _instance_ object with accessors for it exports. This is generated by
   DeclareModules (invoked by VisitDeclarations in the hosting scope again),
   and uses the descriptors generated in the previous stage.

4. Initialize: execute the module bodies (and other code) in sequence. This
   happens by the separate statements generated for module bodies. To reenter
   the module scopes properly, the parser inserted ModuleStatements.

R=mstarzinger@chromium.org,svenpanne@chromium.org
BUG=

Review URL: https://codereview.chromium.org/11093074

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13033 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-22 10:25:22 +00:00
mmassi@chromium.org
ce81fb7b13 Fix build (and fix brown paper bug as well...).
BUG=

Review URL: https://chromiumcodereview.appspot.com/11419115

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13026 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-21 12:17:18 +00:00
mmassi@chromium.org
5e7f30a596 Use the property load IC for accessing the array length.
BUG=

Review URL: https://chromiumcodereview.appspot.com/11299004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13025 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-21 11:49:15 +00:00
yangguo@chromium.org
2b5e6bae60 Fix --hydrogen-stats.
Timing happens in a scope.  Since crankshaft has been chopped up into three methods, this approach is wrong.

BUG=

Review URL: https://chromiumcodereview.appspot.com/11411065

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12998 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-19 14:20:57 +00:00
svenpanne@chromium.org
d5f589808d Removed a bunch of GetExistingThreadLocal calls by threading the Isolate.
For Octane, the number of calls go down from 7341629 to 1947880, i.e. they are
reduced by more than 73%. TLS access is not especially cheap, so this exercise
seems worthwhile.

Review URL: https://codereview.chromium.org/11412007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12979 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-16 08:38:11 +00:00
jkummerow@chromium.org
1c086d1202 Lattice-based representation inference, powered by left/right specific type feedback for BinaryOps and comparisons
Review URL: https://chromiumcodereview.appspot.com/10837165

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12961 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-14 15:59:45 +00:00
verwaest@chromium.org
deae08bd23 Consolidate polymorphic calls due to elements transitions.
Review URL: https://chromiumcodereview.appspot.com/11359104

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12960 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-14 12:10:51 +00:00
svenpanne@chromium.org
50f6e07e67 Nano-refactoring: Simplify initialization
Review URL: https://codereview.chromium.org/11368078

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12856 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-05 14:37:28 +00:00
ulan@chromium.org
f106c9c9f7 Add rotate-right instruction to hydrogen and use it instead of bitwise operations
of the form ((x >>> i) | (x << (32 - i))).

This CL is based on https://chromiumcodereview.appspot.com/10984057/
by Jay Conrod <dconrod@codeaurora.org>.

R=danno@chromium.org,mstarzinger@chromium.org,dconrod@codeaurora.org

Review URL: https://chromiumcodereview.appspot.com/11033005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12855 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-05 13:28:10 +00:00
svenpanne@chromium.org
24bb0668e6 Simplified HCheckMaps handling a bit.
This is a refactoring-only CL which simplifies the way we emit combinations of
Smi+map checks.

Review URL: https://codereview.chromium.org/11343011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12848 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-05 10:06:24 +00:00
svenpanne@chromium.org
9de1d40d28 Improve handling of property loads on the proto chain.
Previously Crankshaft emitted a generic load for these, now we emit a load of a
named field, guarded by a proto chain check.

LCheckPrototypeMaps now returns the holder, which is for free, because it
already had to check its map as the last step, anyway. This is in sync with what
StubCompiler::CheckPrototype does.

Review URL: https://codereview.chromium.org/11338030

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12847 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-05 08:53:54 +00:00
mvstanton@chromium.org
a85fd03caa Consolidated all the key store/load classes in the Hydrogen and Lithium
space into just two:
HLoadKeyed/HLoadKeyedGeneric and HStoreKeyed/HStoreKeyedGeneric
LLoadKeyed/LLoadKeyedGeneric and LStoreKeyed/LStoreKeyedGeneric
BUG=

Review URL: https://codereview.chromium.org/11238016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12839 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-11-02 09:18:53 +00:00
svenpanne@chromium.org
5a0176222b Consistently make the bounds check for AccessArgumentsAt explicit.
This has the advantage that AccessArgumentsAt itself can't deopt anymore and the
bounds check is visible for the elimination phase. Furthermore, things are
simply more consistent now, a good thing in itself. :-)

Review URL: https://codereview.chromium.org/11106012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12721 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-10-15 07:25:20 +00:00