Bug 234952 – [RISCV64] riscv64 backend should lower offlineasm instructions

• Component: New Bugs
• Status: RESOLVED FIXED

[Zan Dobersek]

[RISCV64] riscv64 backend should lower offlineasm instructions

[Zan Dobersek]

Created attachment 448577 [details]
Patch

[Zan Dobersek]

Created attachment 448723 [details]
Patch

With additional shift-amount validation.

[Yusuke Suzuki]

Comment on attachment 448723 [details]
Patch

r=me

[EWS]

Committed r287912 (245945@main): <https://commits.webkit.org/245945@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 448723 [details].

[Radar WebKit Bug Importer]

<rdar://problem/87440612>

[WebKit Commit Bot]

Re-opened since this is blocked by bug 235164

[Zan Dobersek]

With regards to the regression that initiated the rollout in #235164, the only thing that could affect ARM64/ARM64E is the additional lowering of misplaced addresses for any baddi*, bsubi* and bmuli* instructions. But these should already be lowered by the time that Sequence.getModifiedListARM64() calls riscLowerMisplacedAddresses(), due to already calling riscLowerSimpleBranchOps() and riscLowerHardBranchOps64() before that.

Don't know. I can implement Sequence.lowerMisplacedAddressesRISCV64() and manually lower these instructions there, not affecting any other architecture.

[Zan Dobersek]

Created attachment 449048 [details]
Patch

[Zan Dobersek]

Comment on attachment 449048 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=449048&action=review

> Source/JavaScriptCore/offlineasm/riscv64.rb:406
> +def riscv64LowerMisplacedAddresses(list)
> +    newList = []
> +    list.each {
> +        | node |
> +        if node.is_a? Instruction
> +            case node.opcode
> +            when /^baddi/, /^bsubi/, /^bmuli/
> +                postInstructions = []
> +                newList << node.riscCloneWithOperandsLowered(newList, postInstructions, "i")
> +                newList += postInstructions

These specific instructions are now handled in a separate, RISCV64-specific lowering pass. Didn't use Instruction.lowerMisplacedAddressesRISCV64() to keep the lowering passes uniformly implemented in helper functions.

[Yusuke Suzuki]

Comment on attachment 449048 [details]
Patch

r=me

[EWS]

Committed r288007 (246033@main): <https://commits.webkit.org/246033@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 449048 [details].