1504979 - Use resumeOffsets for tableswitch cases

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Jan de Mooij [:jandem]]

We can use the resumeIndex/resumeOffset machinery also for JSOP_TABLESWITCH. That has a few advantages:

(1) Bug 1501316 will become easier to fix.

(2) JSOP_TABLESWITCH will no longer be a variable-length bytecode op so we can get rid of js::GetVariableBytecodeLength. This will simplify and speed up GetBytecodeLength/GetNextPc (these can be somewhat hot).

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Bug 1504979 part 1 - Use offset to 'default' target instead of zero in JSOP_TABLESWITCH offsets. r?nbp

With this change we no longer have to handle the offset == 0 case everywhere.

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Bug 1504979 part 2 - Use resumeIndex/resumeOffsets for JSOP_TABLESWITCH. r?tcampbell

Reasons for doing this:

(1) Bug 1501316 becomes easier to fix.

(2) JSOP_TABLESWITCH is no longer a variable-length bytecode op so we can get
    rid of js::GetVariableBytecodeLength.

Depends on D11018

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/320cb35f35b0
part 1 - Use offset to 'default' target instead of zero in JSOP_TABLESWITCH offsets. r=nbp
https://hg.mozilla.org/integration/autoland/rev/3582cbd2447f
part 2 - Use resumeIndex/resumeOffsets for JSOP_TABLESWITCH. r=tcampbell

Comment 4

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/320cb35f35b0
https://hg.mozilla.org/mozilla-central/rev/3582cbd2447f