1563510 - Optimize BaselineCodeGen::emitPrologue a bit

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task, P1)

Description

[Jan de Mooij [:jandem]]

We can easily eliminate some instructions from both the interpreter and compiler.

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Bug 1563510 part 1 - Fold emitPreInitEnvironmentChain into emitInitFrameFields. r?djvj!

This eliminates some branches and simplifies the code.

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Bug 1563510 part 2 - Store function environment directly in emitInitFrameFields instead of storing nullptr first. r?djvj!

Instead of initializing frame->environmentChain to nullptr first and then setting it to
fun->environment() later, we can store fun->environment immediately. This also means the
interpreter doesn't need to load and untag the callee token a second time.

Depends on D36903

Comment 3

[Jan de Mooij [:jandem]]

Attachment: Bug 1563510 part 3 - Use toggled jumps for more debugger instrumentation. r?djvj!

We now have a Vector of offsets instead of a single offset.

Depends on D36904

Comment 4

[Jan de Mooij [:jandem]]

Attachment: Bug 1563510 part 4 - Change JSFunction::hasJITCode to JSFunction::hasJitScript. r?iain!

This prevents slowdowns when we increase the Baseline JIT threshold and
is more predictable when we move BaselineCompiler off-thread.

Depends on D36905

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e13e7f4d5f05
part 1 - Fold emitPreInitEnvironmentChain into emitInitFrameFields. r=djvj
https://hg.mozilla.org/integration/autoland/rev/914ab31ebc59
part 2 - Store function environment directly in emitInitFrameFields instead of storing nullptr first. r=djvj
https://hg.mozilla.org/integration/autoland/rev/77bc29e90670
part 3 - Use toggled jumps for more debugger instrumentation. r=djvj
https://hg.mozilla.org/integration/autoland/rev/6a3e9d8abe2c
part 4 - Change JSFunction::hasJITCode to JSFunction::hasJitScript. r=iain

Comment 6

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/e13e7f4d5f05
https://hg.mozilla.org/mozilla-central/rev/914ab31ebc59
https://hg.mozilla.org/mozilla-central/rev/77bc29e90670
https://hg.mozilla.org/mozilla-central/rev/6a3e9d8abe2c