cmd/compile: libFuzzer instrumentation fakePC overflow on 386 arch

[cuonglm]

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

$ go version
go version devel go1.20-4274ffd4b8 Tue Oct 11 04:04:13 2022 +0000 darwin/arm64

Does this issue reproduce with the latest release?

Yes.

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

go env Output

$ go env

What did you do?

Compile following program with -d=libfuzzer:

package p

func f(x, y int) {
	_ = x > y
	_ = y > x
}

What did you expect to see?

Compile ok.

What did you see instead?

$ GOOS=linux GOARCH=386 go tool compile -d=libfuzzer p.go
p.go:5:8: constant 3550266861 overflows int

[cuonglm]

@randall77 @mdempsky seems we need to backport this, it affect go test -fuzz on 386 arch.

[gopherbot]

Change https://go.dev/cl/441996 mentions this issue: all: prevent fakePC overflow on 386 in libfuzzer mode

[cuonglm]

Re-open for backport consideration.

cc @randall77 @mdempsky

[randall77]

@gopherbot please open a backport to 1.19. This bug causes libfuzzer mode to fail to compile. There is no easy workaround.
(I don't think this applies to 1.18.)

[gopherbot]

Backport issue(s) opened: #56167 (for 1.18), #56168 (for 1.19).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://go.dev/wiki/MinorReleases.

[cuonglm]

@gopherbot please open a backport to 1.19. This bug causes libfuzzer mode to fail to compile. There is no easy workaround.

(I don't think this applies to 1.18.)

Yes, this does not happen in go1.18 release. The libfuzzerTrace* and friends are added in 1.19