cmd/compile: 'unexpected source op' spam in GOSSAFUNC output

[mundaym]

What version of Go are you using (go version)?

Tip (go version devel +212c9479e3 Tue May 15 16:29:04 2018 +0000 darwin/amd64).

Does this issue reproduce with the latest release?

No (tested 1.10.1).

What operating system and processor architecture are you using (go env)?

darwin/amd64, but probably a universal issue.

What did you do?

go get -u golang.org/x/crypto
cd $GOPATH/src/golang.org/x/crypto/internal/chacha20
GOSSAFUNC=\(*Cipher\).XORKeyStream go test -c

What did you expect to see?

No extra output.

What did you see instead?

...
unexpected at 2721:load with unexpected source op v3278unexpected at 2775:load with 
unexpected source op v3281unexpected at 2249:load with unexpected source op 
v3289unexpected at 2875:load with unexpected source op v3278unexpected at 2232:load 
with unexpected source op v286unexpected at 2231:load with unexpected source op v3291unexpected at 2784:load with unexpected source op v3289unexpected at 2785:load 
with unexpected source op v3291
...

This appears to be generated by

go/src/cmd/compile/internal/ssa/debug.go

Line 480 in 212c947

state.unexpected(v, "load with unexpected source op %v", a)

. The unexpected op in question appears to always be a Phi.

[randall77]

@heschik

[gopherbot]

Change https://golang.org/cl/113275 mentions this issue: cmd/compile: improve error message emitted by debug info generation

[heschi]

Thanks. There are three issues here:

• I forgot the newline at the end of the log message.
• The debug information should definitely understand a load from a phi.
• There's no context for the log message.

Most of the unexpected() calls have gone by the wayside in refactoring passes, so I could probably just convert these to log statements now.

[gopherbot]

Change https://golang.org/cl/114008 mentions this issue: cmd/compile: fix debug info generation for loads from Phis

[gopherbot]

Change https://golang.org/cl/114007 mentions this issue: cmd/compile: clean up debug info generation logging