[wasm] Introduce EmitVarInt and EmitWithVarInt

[wasm] Introduce EmitVarInt and EmitWithVarInt

Use them to encode int32 constants properly.
This reduces the generated wasm size in the unity benchmark from
21.6 MB to 16.8 MB (-22.2%).
This hopefully also translates to increased performance especially on
mobile because of lower memory usage.

R=bradnelson@chromium.org, titzer@chromium.org

Review-Url: https://codereview.chromium.org/2692943002
Cr-Commit-Position: refs/heads/master@{#43200}
Committed: https://chromium.googlesource.com/v8/v8/+/494fd7156b36213bc7718bc7177424596013f4ba

[Clemens Hammacher, 2017-02-13 18:30:58]

The CQ bit was checked by clemensh@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-02-13 18:31:09]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Clemens Hammacher, 2017-02-13 18:31:34]

Description was changed from

==========
[wasm] Introduce EmitVarInt and EmitWithVarInt

Use them to encode int32 constants properly.
This reduces the generated wasm size from 21.6 MB to 16.8 MB (-22.2%).
This hopefully also translates to increased performance especially on
mobile because of lower memory usage.

R=bradnelson@chromium.org, titzer@chromium.org
==========

to

==========
[wasm] Introduce EmitVarInt and EmitWithVarInt

Use them to encode int32 constants properly.
This reduces the generated wasm size in the unity benchmark from
21.6 MB to 16.8 MB (-22.2%).
This hopefully also translates to increased performance especially on
mobile because of lower memory usage.

R=bradnelson@chromium.org, titzer@chromium.org
==========

[titzer, 2017-02-13 18:49:36]

lgtm with nit

https://codereview.chromium.org/2692943002/diff/1/src/asmjs/asm-wasm-builder.cc
File src/asmjs/asm-wasm-builder.cc (right):

https://codereview.chromium.org/2692943002/diff/1/src/asmjs/asm-wasm-builder....
src/asmjs/asm-wasm-builder.cc:691:
current_function_builder_->EmitI32Const(static_cast<int32_t>(u));
static_cast<int32_t> isn't really safe. should probably be a bit_cast.

[commit-bot: I haz the power, 2017-02-13 18:53:46]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-02-13 18:53:47]

Dry run: This issue passed the CQ dry run.

[Clemens Hammacher, 2017-02-13 18:54:53]

The CQ bit was checked by clemensh@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-02-13 18:54:56]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Clemens Hammacher, 2017-02-13 18:56:02]

https://codereview.chromium.org/2692943002/diff/1/src/asmjs/asm-wasm-builder.cc
File src/asmjs/asm-wasm-builder.cc (right):

https://codereview.chromium.org/2692943002/diff/1/src/asmjs/asm-wasm-builder....
src/asmjs/asm-wasm-builder.cc:691:
current_function_builder_->EmitI32Const(static_cast<int32_t>(u));
On 2017/02/13 at 18:49:36, titzer wrote:
> static_cast<int32_t> isn't really safe. should probably be a bit_cast.

Done.

[commit-bot: I haz the power, 2017-02-13 19:24:05]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-02-13 19:24:06]

Dry run: This issue passed the CQ dry run.

[bradnelson, 2017-02-13 20:54:06]

The CQ bit was checked by bradnelson@chromium.org

[bradnelson, 2017-02-13 20:54:06]

lgtm

[bradnelson, 2017-02-13 20:54:06]

The patchset sent to the CQ was uploaded after l-g-t-m from titzer@chromium.org
Link to the patchset: https://codereview.chromium.org/2692943002/#ps20001
(title: "Use bit_cast instead of static_cast")

[commit-bot: I haz the power, 2017-02-13 20:54:14]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-02-13 20:54:15]

This CL has an open dependency (Issue 2694633003 Patch 1). Please resolve the
dependency and try again.
If you are sure that there is no real dependency, please use one of the options
listed in https://goo.gl/9Es4OR to land the CL.

[Clemens Hammacher, 2017-02-14 18:13:50]

The CQ bit was checked by clemensh@chromium.org

[commit-bot: I haz the power, 2017-02-14 18:13:57]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-14 18:15:32]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1487096030542330,
"parent_rev": "2f8ad11f2bf35e0e63b30337a5b4966839ed14c9", "commit_rev":
"494fd7156b36213bc7718bc7177424596013f4ba"}

[commit-bot: I haz the power, 2017-02-14 18:15:37]

Description was changed from

==========
[wasm] Introduce EmitVarInt and EmitWithVarInt

Use them to encode int32 constants properly.
This reduces the generated wasm size in the unity benchmark from
21.6 MB to 16.8 MB (-22.2%).
This hopefully also translates to increased performance especially on
mobile because of lower memory usage.

R=bradnelson@chromium.org, titzer@chromium.org
==========

to

==========
[wasm] Introduce EmitVarInt and EmitWithVarInt

Use them to encode int32 constants properly.
This reduces the generated wasm size in the unity benchmark from
21.6 MB to 16.8 MB (-22.2%).
This hopefully also translates to increased performance especially on
mobile because of lower memory usage.

R=bradnelson@chromium.org, titzer@chromium.org

Review-Url: https://codereview.chromium.org/2692943002
Cr-Commit-Position: refs/heads/master@{#43200}
Committed:
https://chromium.googlesource.com/v8/v8/+/494fd7156b36213bc7718bc717742459601...
==========

[commit-bot: I haz the power, 2017-02-14 18:15:38]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/494fd7156b36213bc7718bc717742459601...