[wasm] Split the wasm compilation into two phases for parallel compilation.

[wasm] Split the wasm compilation into two phases for parallel compilation.

Graph construction, graph scheduling, instruction selection, and register
allocation has been moved to ExecuteCompilation, which will eventually be
executed on the background threads. Code generation remains in
FinishCompilation because it has to be executed by the main thread.

Additionally, WasmCompilationUnits are finished more eagerly in
wasm-module.cc to save memory.

R=titzer@chromium.org

Committed: https://crrev.com/18c380c39610264ad0fa9d85eab271e83913222b
Cr-Commit-Position: refs/heads/master@{#35973}

[titzer, 2016-05-02 14:49:46]

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
File src/compiler/wasm-compiler.cc (right):

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
src/compiler/wasm-compiler.cc:3039: base::ElapsedTimer compile_timer;
Move this timer after the check for success (otherwise it is started but never
stopped).

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
src/compiler/wasm-compiler.cc:3048: if (!code.is_null()) {
If the job succeeded, shouldn't the code always be non-null?

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
src/compiler/wasm-compiler.cc:3079: return info_.code();
You can you use the local variable {code} here.

https://codereview.chromium.org/1942773002/diff/20001/src/wasm/wasm-module.cc
File src/wasm/wasm-module.cc (right):

https://codereview.chromium.org/1942773002/diff/20001/src/wasm/wasm-module.cc...
src/wasm/wasm-module.cc:512: std::queue<compiler::WasmCompilationUnit*>
finished_units;
A better name might be "executed_units", since the units are put here after
execution, but before finish.

https://codereview.chromium.org/1942773002/diff/20001/src/wasm/wasm-module.cc...
src/wasm/wasm-module.cc:536: results[i] = compiler::FinishCompilation(unit);
This will go out of the bounds of the vector.

[ahaas, 2016-05-02 16:21:59]

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
File src/compiler/wasm-compiler.cc (right):

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
src/compiler/wasm-compiler.cc:3039: base::ElapsedTimer compile_timer;
On 2016/05/02 at 14:49:45, titzer wrote:
> Move this timer after the check for success (otherwise it is started but never
stopped).

Done.

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
src/compiler/wasm-compiler.cc:3048: if (!code.is_null()) {
On 2016/05/02 at 14:49:45, titzer wrote:
> If the job succeeded, shouldn't the code always be non-null?

I replaced the "if (!code.is_null())" by a "DCHECK(!code.is_null())"

https://codereview.chromium.org/1942773002/diff/20001/src/compiler/wasm-compi...
src/compiler/wasm-compiler.cc:3079: return info_.code();
On 2016/05/02 at 14:49:45, titzer wrote:
> You can you use the local variable {code} here.

Done.

https://codereview.chromium.org/1942773002/diff/20001/src/wasm/wasm-module.cc
File src/wasm/wasm-module.cc (right):

https://codereview.chromium.org/1942773002/diff/20001/src/wasm/wasm-module.cc...
src/wasm/wasm-module.cc:512: std::queue<compiler::WasmCompilationUnit*>
finished_units;
On 2016/05/02 at 14:49:45, titzer wrote:
> A better name might be "executed_units", since the units are put here after
execution, but before finish.

Done.

https://codereview.chromium.org/1942773002/diff/20001/src/wasm/wasm-module.cc...
src/wasm/wasm-module.cc:536: results[i] = compiler::FinishCompilation(unit);
On 2016/05/02 at 14:49:46, titzer wrote:
> This will go out of the bounds of the vector.

I preallocate the vector with functions.size(), so I should not run out of
bounds.

[titzer, 2016-05-03 08:54:53]

lgtm

[ahaas, 2016-05-03 11:01:44]

The CQ bit was checked by ahaas@chromium.org

[commit-bot: I haz the power, 2016-05-03 11:01:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1942773002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1942773002/40001

[commit-bot: I haz the power, 2016-05-03 11:12:46]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-05-03 11:13:18]

Description was changed from

==========
[wasm] Split the wasm compilation into two phases for parallel compilation.

Graph construction, graph scheduling, instruction selection, and register
allocation has been moved to ExecuteCompilation, which will eventually be
executed on the background threads. Code generation remains in
FinishCompilation because it has to be executed by the main thread.

Additionally, WasmCompilationUnits are finished more eagerly in
wasm-module.cc to save memory.

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

to

==========
[wasm] Split the wasm compilation into two phases for parallel compilation.

Graph construction, graph scheduling, instruction selection, and register
allocation has been moved to ExecuteCompilation, which will eventually be
executed on the background threads. Code generation remains in
FinishCompilation because it has to be executed by the main thread.

Additionally, WasmCompilationUnits are finished more eagerly in
wasm-module.cc to save memory.

R=titzer@chromium.org

Committed: https://crrev.com/18c380c39610264ad0fa9d85eab271e83913222b
Cr-Commit-Position: refs/heads/master@{#35973}
==========

[commit-bot: I haz the power, 2016-05-03 11:13:18]

Patchset 3 (id:??) landed as
https://crrev.com/18c380c39610264ad0fa9d85eab271e83913222b
Cr-Commit-Position: refs/heads/master@{#35973}