Add frame pointer to CommonFrameLayout
Categories
(Core :: JavaScript Engine: JIT, task, P3)
Tracking
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| Tracking | Status | |
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| firefox103 | --- | fixed |
People
(Reporter: jandem, Assigned: jandem)
References
Details
Attachments
(3 files)
All frames now push the caller's frame pointer. It would be better to move this field to the CommonFrameLayout now so that we don't have to add/subtract FramePointerOffset in a number of places.
JitFrameLayout is currently 16-byte aligned on the return address. This makes adding a new field somewhat annoying, but one option is to combine the argc field with the descriptor that now only uses a few bits since bug 1774390. This way we don't have to change the size of JitFrameLayout.
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Assignee | |
Comment 1•2 years ago
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Also simplify BaselineFrame::numActualArgs by forwarding to JitFrameLayout::numActualArgs.
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Assignee | |
Comment 2•2 years ago
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This renames the numActualArgs_ field to unused_ and stores a constant there
for now. The next patch will remove this field and simultaneously add the frame
pointer to CommonFrameLayout, preserving the current JitFrameLayout size.
Depends on D149758
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Assignee | |
Comment 3•2 years ago
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Now that all frames store the caller's frame pointer, we can add it to CommonFrameLayout
and get rid of FramePointerOffset.
This also removes JitFrameLayout::unused_. This has to happen at the same time so that
sizeof(JitFrameLayout) doesn't change (a lot of code depends on that for alignment).
JitFrameLayout is now aligned on the frame pointer instead of the return address.
This lets us simplify some of the Wasm stubs code (especially for ARM64) where we had
to workaround the old aligned-after-return-address invariant.
Depends on D149759
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Comment 5•2 years ago
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| bugherder | ||
https://hg.mozilla.org/mozilla-central/rev/57fa270767c8
https://hg.mozilla.org/mozilla-central/rev/3b67acc061e9
https://hg.mozilla.org/mozilla-central/rev/103f879d45ff
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Comment 6•2 years ago
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(In reply to Pulsebot from comment #4)
Pushed by jdemooij@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/57fa270767c8
part 1 - Add MacroAssembler::loadNumActualArgs. r=iain
https://hg.mozilla.org/integration/autoland/rev/3b67acc061e9
part 2 - Store number of arguments in the frame descriptor. r=iain
https://hg.mozilla.org/integration/autoland/rev/103f879d45ff
part 3 - Store caller frame pointer in CommonFrameLayout. r=iain,rhunt
== Change summary for alert #34685 (as of Thu, 30 Jun 2022 04:54:36 GMT) ==
Improvements:
| Ratio | Test | Platform | Options | Absolute values (old vs new) |
|---|---|---|---|---|
| 4% | assorted-dom | windows10-64-shippable-qr | fission webrender | 20.44 -> 19.55 |
For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=34685
Description
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