Runtime asserts are were previously a bit annoying to debug, due to
the lack of a useful error message, even in debug mode. This patch
prints out some more information in debug mode for runtime assert
failures while preserving their exception-throwing semantics. While
we're at it, it requires a semicolon after RUNTIME_ASSERT macro
invocations.

```
$ rlwrap out/Debug/d8 --allow-natives-syntax
V8 version 5.1.0 (candidate)
d8> %ArrayBufferNeuter(1)

#
# Runtime error in ../../src/runtime/runtime-typedarray.cc, line 52
#
# args[0]->IsJSArrayBuffer()

==== C stack trace ===============================

 1: 0xf70ab5
 2: 0xadeebf
 3: 0xadedd4
 4: 0x2ef17630693b
(d8):1: illegal access
%ArrayBufferNeuter(1)
^

d8>
```

Also give the other 'illegal access' case (a special SyntaxError type) a more
descriptive error message for its sole usage.

R=adamk

Review URL: https://codereview.chromium.org/1748183002

Cr-Commit-Position: refs/heads/master@{#34401}

Adds a ForInPrepare Runtime function which returns a triple of
cache_type, cache_array and cache_length.

This requires adding support to CEntryStub to call runtime functions
which return a ObjectTriple - a struct containing three Object*
pointers. Also did some cleanup of the x64 CEntryStub to avoid
replicated code.

Replaces the interpreter's use of the ad-hock InterpreterForInPrepare
Runtime function with ForInPrepare in preparation for fixing deopt in
BytecodeGraphBuilder for ForIn (which will be done in a followup CL).

MIPS port contributed by Balazs Kilvady <balazs.kilvady@imgtec.com>.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1576093004

Cr-Commit-Position: refs/heads/master@{#33334}

This enables linter checking for "readability/namespace" violations
during presubmit and instead marks the few known exceptions that we
allow explicitly.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1371083003

Cr-Commit-Position: refs/heads/master@{#31019}

This is behind the flag "--harmony-atomics", and it only works on
SharedArrayBuffers. This implementation only includes the runtime functions.
The TurboFan implementation will be next.

The draft spec for Atomics can be found here:
https://docs.google.com/document/d/1NDGA_gZJ7M7w1Bh8S0AoDyEqwDdRh4uSoTPSNn77PFk

BUG=
LOG=n

Review URL: https://codereview.chromium.org/1162503002

Cr-Commit-Position: refs/heads/master@{#28796}

In a nutshell: The FILTER_KEY builtin is gone, and was replaced by a
simple runtime call to ForInFilter, which does everything and is even
cheaper (because FILTER_KEY used to call into the runtime anyway).
And ForInFilter returns either the name or undefined, which makes it
possible to remove the control flow construction from the AstGraphBuilder,
and thereby make both the initialization and the per-loop code of for-in
optimizable later (in typed lowering).

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1160983004

Cr-Commit-Position: refs/heads/master@{#28711}

Motivation: Cleanup

BUG=None
R=adamk
LOG=N

Review URL: https://codereview.chromium.org/897633003

Cr-Commit-Position: refs/heads/master@{#26440}

This enables adding more language modes in the future.

For maximum flexibility, LanguageMode is a bitmask, so we're not restricted to
use a sequence of language modes which are progressively stricter, but we can
express the language mode as combination of features.

For now, LanguageMode can only be "sloppy" or "strict", and there are
STATIC_ASSERTS in places which need to change when more modes are added.

LanguageMode is a bit like the old LanguageMode when "extended" mode was still
around (see https://codereview.chromium.org/8417035 and
https://codereview.chromium.org/181543002 ) except that it's transmitted through
all the layers (there's no StrictModeFlag).

BUG=

Review URL: https://codereview.chromium.org/894683003

Cr-Commit-Position: refs/heads/master@{#26419}

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/662413002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24736 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/612023002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24307 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/597943003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24202 ce2b1a6d-e550-0410-aec6-3dcde31c8c00