Replace __init__ function in asm-wasm-builder with the start function section

Replace __init__ function in asm-wasm-builder with the start function section

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=mjsunit/asm-wasm
R=titzer@chromium.org,bradnelson@chromium.org
LOG=N

Committed: https://crrev.com/4537f09374d3c4110f30f775b176404819a490dc
Cr-Commit-Position: refs/heads/master@{#34375}

[aseemgarg, 2016-03-01 01:19:26]

Wasn't able to write a unit test for encoder as this is not supported in
compileAndRunWasmModule
@Brad, we'll also need to update the embenchen tests to drop the init function
calls. They are not working currently, so didn't touch them yet.

[titzer, 2016-03-01 02:09:33]

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc
File src/wasm/encoder.cc (right):

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc#newcode494
src/wasm/encoder.cc:494: do {
Let's lift out this varint encoding into a helper and use it elsewhere (we
currently create temporary std::vectors for LEB encodings!)

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.h
File src/wasm/encoder.h (right):

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.h#newcode123
src/wasm/encoder.h:123: bool has_start_function_;
Just make me an int with a value -1 indicating no starting function.

[aseemgarg, 2016-03-01 02:37:34]

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc
File src/wasm/encoder.cc (right):

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc#newcode494
src/wasm/encoder.cc:494: do {
On 2016/03/01 02:09:33, titzer wrote:
> Let's lift out this varint encoding into a helper and use it elsewhere (we
> currently create temporary std::vectors for LEB encodings!)

This is enclosed in AddSection for other. Just for this one since the section
might be created even with a 0 value is it separate. This is smaller than adding
a flag to the existing method.

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.h
File src/wasm/encoder.h (right):

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.h#newcode123
src/wasm/encoder.h:123: bool has_start_function_;
On 2016/03/01 02:09:33, titzer wrote:
> Just make me an int with a value -1 indicating no starting function.

Done.

[titzer, 2016-03-01 02:43:58]

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc
File src/wasm/encoder.cc (right):

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc#newcode494
src/wasm/encoder.cc:494: do {
On 2016/03/01 02:37:34, aseemgarg wrote:
> On 2016/03/01 02:09:33, titzer wrote:
> > Let's lift out this varint encoding into a helper and use it elsewhere (we
> > currently create temporary std::vectors for LEB encodings!)
> 
> This is enclosed in AddSection for other. Just for this one since the section
> might be created even with a 0 value is it separate. This is smaller than
adding
> a flag to the existing method.

At least lift it out to a helper that computes the size of the varint for
documentation.

[aseemgarg, 2016-03-01 03:00:24]

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc
File src/wasm/encoder.cc (right):

https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc#newcode494
src/wasm/encoder.cc:494: do {
On 2016/03/01 02:43:58, titzer wrote:
> On 2016/03/01 02:37:34, aseemgarg wrote:
> > On 2016/03/01 02:09:33, titzer wrote:
> > > Let's lift out this varint encoding into a helper and use it elsewhere (we
> > > currently create temporary std::vectors for LEB encodings!)
> > 
> > This is enclosed in AddSection for other. Just for this one since the
section
> > might be created even with a 0 value is it separate. This is smaller than
> adding
> > a flag to the existing method.
> 
> At least lift it out to a helper that computes the size of the varint for
> documentation.

Done.

[titzer, 2016-03-01 03:08:08]

On 2016/03/01 03:00:24, aseemgarg wrote:
> https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc
> File src/wasm/encoder.cc (right):
> 
>
https://codereview.chromium.org/1750153002/diff/1/src/wasm/encoder.cc#newcode494
> src/wasm/encoder.cc:494: do {
> On 2016/03/01 02:43:58, titzer wrote:
> > On 2016/03/01 02:37:34, aseemgarg wrote:
> > > On 2016/03/01 02:09:33, titzer wrote:
> > > > Let's lift out this varint encoding into a helper and use it elsewhere
(we
> > > > currently create temporary std::vectors for LEB encodings!)
> > > 
> > > This is enclosed in AddSection for other. Just for this one since the
> section
> > > might be created even with a 0 value is it separate. This is smaller than
> > adding
> > > a flag to the existing method.
> > 
> > At least lift it out to a helper that computes the size of the varint for
> > documentation.
> 
> Done.

lgtm

[aseemgarg, 2016-03-01 05:15:13]

The CQ bit was checked by aseemgarg@chromium.org

[commit-bot: I haz the power, 2016-03-01 05:15:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1750153002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1750153002/40001

[commit-bot: I haz the power, 2016-03-01 05:49:58]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-03-01 05:51:06]

Description was changed from

==========
Replace __init__ function in asm-wasm-builder with the start function section

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=mjsunit/asm-wasm
R=titzer@chromium.org,bradnelson@chromium.org
LOG=N
==========

to

==========
Replace __init__ function in asm-wasm-builder with the start function section

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=mjsunit/asm-wasm
R=titzer@chromium.org,bradnelson@chromium.org
LOG=N

Committed: https://crrev.com/4537f09374d3c4110f30f775b176404819a490dc
Cr-Commit-Position: refs/heads/master@{#34375}
==========

[commit-bot: I haz the power, 2016-03-01 05:51:07]

Patchset 3 (id:??) landed as
https://crrev.com/4537f09374d3c4110f30f775b176404819a490dc
Cr-Commit-Position: refs/heads/master@{#34375}