1344476 - Add helper function to emit JSOP_POP or JSOP_POPN for given amount

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Tooru Fujisawa [:arai]]

JSOP_POP is single byte, and JSOP_POPN is 3 bytes, so using JSOP_POP is shorter for popping 1 or 2 values.
it would be better adding dedicated function that receives the amount of values to pop and emit better opcode sequence to it.

Comment 1

[Tooru Fujisawa [:arai]]

Attachment: Add BytecodeEmitter::emitPopN to emit shorter bytecode for given pop count.

regarding bug 1147371 comment #36
> I chose |pop; pop| because it's 2 bytes, and |popn 2| is 3 bytes.

added BytecodeEmitter::emitPopN that emits JSOP_POP when popping 1 or 2 values, and JSOP_POPN for other cases,
and used emitPopN where popping possibly multiple values.

Comment 2

[Shu-yu Guo [:shu]]

Comment on attachment 8844763 [details] [diff] [review]
Add BytecodeEmitter::emitPopN to emit shorter bytecode for given pop count.

Review of attachment 8844763 [details] [diff] [review]:
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Nice, thanks.

Comment 3

[Tooru Fujisawa [:arai]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/5dff3bf590ba88c906073e0a22a9f9b33a77b927
Bug 1344476 - Add BytecodeEmitter::emitPopN to emit shorter bytecode for given pop count. r=shu

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/5dff3bf590ba