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cmd/compile: use FP-based frame zeroing outside of package runtime on plan9 #19650

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mdempsky opened this Issue Mar 21, 2017 · 0 comments

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mdempsky commented Mar 21, 2017

In 039d455, we changed cmd/compile to avoid using DUFFZERO and other FP-based frame zeroing methods, because they're not permitted within note handlers.

I think this is overly conservative. It should still be safe to use DUFFZERO on plan9 when we're compiling non-runtime packages, because functions from those packages will never be called by sigtramp. This is probably as simple as changing

var isPlan9 = obj.GOOS == "plan9"

to

var isPlan9 = obj.GOOS == "plan9" && compiling_runtime

in cmd/compile/internal/amd64/ggen.go.

Just pointing out since I was looking at related code. Will let some of the plan9 folks decide if this is worth pursuing.

/cc @0intro

@mdempsky mdempsky added the OS-Plan9 label Mar 21, 2017

@mdempsky mdempsky added this to the Unplanned milestone Mar 21, 2017

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