[Wasm] Convert many of the fixed-size values to LEB128.

[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* br_table target count
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org

Committed: https://crrev.com/78f6f838f0fdf2ce49a498e1548511b75535d19b
Cr-Commit-Position: refs/heads/master@{#34603}

[binji, 2016-03-08 09:59:45]

PTAL. More tests?

[titzer, 2016-03-08 10:06:53]

Mostly looks good, but I think we want to undo the br_table change.

https://codereview.chromium.org/1775873002/diff/1/src/wasm/ast-decoder.h
File src/wasm/ast-decoder.h (right):

https://codereview.chromium.org/1775873002/diff/1/src/wasm/ast-decoder.h#newc...
src/wasm/ast-decoder.h:150: inline BranchTableOperand(Decoder* decoder, const
byte* pc) {
Maybe we can leave the branch table target as uint16? They encode depth, so I
hope that 64k should be enough for anybody. The design PR doesn't update this
yet, so let's be consistent and leave it.

https://codereview.chromium.org/1775873002/diff/1/src/wasm/ast-decoder.h#newc...
src/wasm/ast-decoder.h:181: while (next_entry_index <= i) {
Linear search; that's no good. Definitely gotta go back to uint16.

https://codereview.chromium.org/1775873002/diff/1/src/wasm/encoder.cc
File src/wasm/encoder.cc (right):

https://codereview.chromium.org/1775873002/diff/1/src/wasm/encoder.cc#newcode59
src/wasm/encoder.cc:59: size_t SizeOfVarInt(size_t value) {
gah. Time for a common header. leb-helper.h?

[binji, 2016-03-08 16:30:15]

https://codereview.chromium.org/1775873002/diff/1/src/wasm/ast-decoder.h
File src/wasm/ast-decoder.h (right):

https://codereview.chromium.org/1775873002/diff/1/src/wasm/ast-decoder.h#newc...
src/wasm/ast-decoder.h:150: inline BranchTableOperand(Decoder* decoder, const
byte* pc) {
On 2016/03/08 10:06:53, titzer wrote:
> Maybe we can leave the branch table target as uint16? They encode depth, so I
> hope that 64k should be enough for anybody.

:)

> The design PR doesn't update this yet, so let's be consistent and leave it.

Yeah, it does:
https://github.com/WebAssembly/design/pull/592/files#diff-7c076c52f23f4a77097...

https://codereview.chromium.org/1775873002/diff/1/src/wasm/ast-decoder.h#newc...
src/wasm/ast-decoder.h:181: while (next_entry_index <= i) {
On 2016/03/08 10:06:53, titzer wrote:
> Linear search; that's no good. Definitely gotta go back to uint16.

It shouldn't actually end up being linear here. In both uses of read_entry, the
entire table is looped over, in order. So I cache the previous offset. This was
just defensive coding, but I could put a DCHECK here instead to enforce it.

https://codereview.chromium.org/1775873002/diff/1/src/wasm/encoder.cc
File src/wasm/encoder.cc (right):

https://codereview.chromium.org/1775873002/diff/1/src/wasm/encoder.cc#newcode59
src/wasm/encoder.cc:59: size_t SizeOfVarInt(size_t value) {
On 2016/03/08 10:06:53, titzer wrote:
> gah. Time for a common header. leb-helper.h?

Maybe, though to be fair, I just moved this up from below.

[binji, 2016-03-08 18:48:22]

Description was changed from

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if/br_table break depth
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org
==========

to

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org
==========

[binji, 2016-03-08 18:48:35]

Description was changed from

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org
==========

to

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* br_table target count
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org
==========

[binji, 2016-03-08 18:48:54]

switched br_table targets back to u16, ptal

[titzer, 2016-03-08 20:04:30]

On 2016/03/08 18:48:54, binji wrote:
> switched br_table targets back to u16, ptal

Ok. It's uint32_t now though 0_o.

[binji, 2016-03-08 20:24:48]

On 2016/03/08 20:04:30, titzer wrote:
> On 2016/03/08 18:48:54, binji wrote:
> > switched br_table targets back to u16, ptal
> 
> Ok. It's uint32_t now though 0_o.

Yep :)

[titzer, 2016-03-08 20:25:53]

On 2016/03/08 20:24:48, binji wrote:
> On 2016/03/08 20:04:30, titzer wrote:
> > On 2016/03/08 18:48:54, binji wrote:
> > > switched br_table targets back to u16, ptal
> > 
> > Ok. It's uint32_t now though 0_o.
> 
> Yep :)

lgtm

[binji, 2016-03-08 21:28:42]

The CQ bit was checked by binji@chromium.org

[binji, 2016-03-08 21:28:42]

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/1775873002/#ps100001
(title: "merge master")

[commit-bot: I haz the power, 2016-03-08 21:28:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1775873002/100001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1775873002/100001

[commit-bot: I haz the power, 2016-03-08 21:33:17]

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

[commit-bot: I haz the power, 2016-03-08 21:33:18]

Try jobs failed on following builders:
  v8_win_compile_dbg on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_compile_dbg/builds/1...)
  v8_win_rel_ng on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_rel_ng/builds/3988)

[binji, 2016-03-08 21:54:01]

The CQ bit was checked by binji@chromium.org

[binji, 2016-03-08 21:54:01]

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/1775873002/#ps120001
(title: "fix windows")

[commit-bot: I haz the power, 2016-03-08 21:54:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1775873002/120001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1775873002/120001

[commit-bot: I haz the power, 2016-03-08 21:57:58]

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

[commit-bot: I haz the power, 2016-03-08 21:57:59]

Try jobs failed on following builders:
  v8_linux_arm64_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/1...)

[binji, 2016-03-08 22:53:03]

The CQ bit was checked by binji@chromium.org

[commit-bot: I haz the power, 2016-03-08 22:53:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1775873002/120001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1775873002/120001

[commit-bot: I haz the power, 2016-03-08 22:54:49]

Description was changed from

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* br_table target count
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org
==========

to

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* br_table target count
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org
==========

[commit-bot: I haz the power, 2016-03-08 22:54:50]

Committed patchset #7 (id:120001)

[commit-bot: I haz the power, 2016-03-08 22:56:25]

Description was changed from

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* br_table target count
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org
==========

to

==========
[Wasm] Convert many of the fixed-size values to LEB128.

This CL modifies the following to be LEB128:
* Function table indices
* Import table signature indices
* Export table function indices
* Function signature param count
* br/br_if break depth
* br_table target count
* block/loop expression count

Still to do:
* Import/export names (LEB128 count + inline data)
* Data segments (LEB128 offset + size + inline data)
* Function header stuff (should seperate into function sig and body sections)
* Memory access alignment + offset (still discussing)

BUG=
R=titzer@chromium.org

Committed: https://crrev.com/78f6f838f0fdf2ce49a498e1548511b75535d19b
Cr-Commit-Position: refs/heads/master@{#34603}
==========

[commit-bot: I haz the power, 2016-03-08 22:56:27]

Patchset 7 (id:??) landed as
https://crrev.com/78f6f838f0fdf2ce49a498e1548511b75535d19b
Cr-Commit-Position: refs/heads/master@{#34603}