Removed a bunch of GetExistingThreadLocal calls by threading the Isolate.

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.

Committed: https://code.google.com/p/v8/source/detail?r=12979

[Michael Starzinger, 2012-11-15 21:24:25]

LGTM if comments are addressed.

https://codereview.chromium.org/11412007/diff/2001/src/factory.cc
File src/factory.cc (right):

https://codereview.chromium.org/11412007/diff/2001/src/factory.cc#newcode1422
src/factory.cc:1422: Handle<Object> instance_template =
Handle<Object>(desc->instance_template(),
Use the handle constructor, that's easier to read I think.

Handle<Object> instance_template(desc->instance_template(), isolate());

https://codereview.chromium.org/11412007/diff/2001/src/hydrogen.cc
File src/hydrogen.cc (right):

https://codereview.chromium.org/11412007/diff/2001/src/hydrogen.cc#newcode3240
src/hydrogen.cc:3240: Handle<Object>
maybe_type_info(unoptimized_code->type_feedback_info(),
I know this isn't your change, it must be something pretty recent. But I really
don't like this maybe-handle pattern. The following is much easier to read and
doesn't need an explicit isolate parameter.

Handle<TypeFeedbackInfo> type_info(
    TypeFeedbackInfo::cast(unoptimized_code->type_feedback_info()));

https://codereview.chromium.org/11412007/diff/2001/src/hydrogen.cc#newcode7119
src/hydrogen.cc:7119: Handle<Object>
maybe_type_info(unoptimized_code->type_feedback_info(),
Likewise.

https://codereview.chromium.org/11412007/diff/2001/src/runtime.cc
File src/runtime.cc (right):

https://codereview.chromium.org/11412007/diff/2001/src/runtime.cc#newcode3156
src/runtime.cc:3156: Handle<String>
empty_string(isolate->heap()->empty_string());
Just use "Handle<String> empty_string = isolate->factory()->empty_string();"
here, saves the handle allocation completely.

[Sven Panne, 2012-11-16 08:24:36]

Landing...

https://codereview.chromium.org/11412007/diff/2001/src/factory.cc
File src/factory.cc (right):

https://codereview.chromium.org/11412007/diff/2001/src/factory.cc#newcode1422
src/factory.cc:1422: Handle<Object> instance_template =
Handle<Object>(desc->instance_template(),
On 2012/11/15 21:24:25, Michael Starzinger wrote:
> Use the handle constructor, that's easier to read I think.
> 
> Handle<Object> instance_template(desc->instance_template(), isolate());

Done. In general I like the proposed direct initialization much more, too,
because it is conceptually simpler: It is similar to a normal function call with
the usual overloading resolution, just for constructors. The previous code uses
copy initialization, which is much more tricky: Conceptually it tries to create
a temporary of the type of the LHS (possibly involving conversion
functions/operators) and uses a copy constructor to move the values into the
LHS. Luckily enough, GCC is clever enough to avoid the intermediate steps, but
why should we make things more complicated than necessary? :-)

https://codereview.chromium.org/11412007/diff/2001/src/hydrogen.cc
File src/hydrogen.cc (right):

https://codereview.chromium.org/11412007/diff/2001/src/hydrogen.cc#newcode3240
src/hydrogen.cc:3240: Handle<Object>
maybe_type_info(unoptimized_code->type_feedback_info(),
On 2012/11/15 21:24:25, Michael Starzinger wrote:
> I know this isn't your change, it must be something pretty recent. But I
really
> don't like this maybe-handle pattern. The following is much easier to read and
> doesn't need an explicit isolate parameter.
> 
> Handle<TypeFeedbackInfo> type_info(
>     TypeFeedbackInfo::cast(unoptimized_code->type_feedback_info()));

Done.

https://codereview.chromium.org/11412007/diff/2001/src/hydrogen.cc#newcode7119
src/hydrogen.cc:7119: Handle<Object>
maybe_type_info(unoptimized_code->type_feedback_info(),
On 2012/11/15 21:24:25, Michael Starzinger wrote:
> Likewise.

Done.

https://codereview.chromium.org/11412007/diff/2001/src/runtime.cc
File src/runtime.cc (right):

https://codereview.chromium.org/11412007/diff/2001/src/runtime.cc#newcode3156
src/runtime.cc:3156: Handle<String>
empty_string(isolate->heap()->empty_string());
On 2012/11/15 21:24:25, Michael Starzinger wrote:
> Just use "Handle<String> empty_string = isolate->factory()->empty_string();"
> here, saves the handle allocation completely.

Done.