Segmentation fault during compilation

[benkasminbullock]

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

$ go version
go version go1.16.3 freebsd/386

Does this issue reproduce with the latest release?

This is the latest release on FreeBSD, I checked using pkg upgrade before filing.

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

go env Output

$ go env
GO111MODULE=""
GOARCH="386"
GOBIN=""
GOCACHE="/home/ben/.cache/go-build"
GOENV="/home/ben/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="386"
GOHOSTOS="freebsd"
GOINSECURE=""
GOMODCACHE="/home/ben/software/golib/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="freebsd"
GOPATH="/home/ben/software/golib"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/freebsd_386"
GOVCS=""
GOVERSION="go1.16.3"
GCCGO="gccgo"
GO386="sse2"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/home/ben/oneoff/gobug/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m32 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build1777355294=/tmp/go-build -gno-record-gcc-switches"

What did you do?

The files are here:

https://github.com/benkasminbullock/gobug

I'm able to reproduce the bug from the local repo.

What did you expect to see?

Successful compilation.

What did you see instead?

go build -o ln-http ln-http.go lang2name.go
# command-line-arguments
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x85b9c36]

goroutine 1 [running]:
cmd/compile/internal/gc.findTypeLoop(0x393515c0, 0x393872a0, 0x7fffff00)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:202 +0xc6
cmd/compile/internal/gc.findTypeLoop(0x39351540, 0x393872a0, 0x38ed4300)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:216 +0x21f
cmd/compile/internal/gc.findTypeLoop(0x39351500, 0x393872a0, 0x0)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:202 +0xd5
cmd/compile/internal/gc.findTypeLoop(0x39525440, 0x393872a0, 0x0)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:216 +0x21f
cmd/compile/internal/gc.findTypeLoop(0x39525400, 0x393872a0, 0x39347e5d)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:202 +0xd5
cmd/compile/internal/gc.reportTypeLoop(0x39525400)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:240 +0x62
cmd/compile/internal/gc.dowidth(0x39525400)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:282 +0x113a
cmd/compile/internal/gc.widstruct(0x39351500, 0x39351500, 0x0, 0x0, 0x1, 0x0, 0x3)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:114 +0xb1
cmd/compile/internal/gc.dowidth(0x39351500)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:435 +0x52c
cmd/compile/internal/gc.widstruct(0x39525400, 0x39525400, 0x0, 0x0, 0x1, 0x28c5efff, 0x805a330)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:114 +0xb1
cmd/compile/internal/gc.dowidth(0x39525400)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:435 +0x52c
cmd/compile/internal/gc.widstruct(0x39351540, 0x39351540, 0x0, 0x0, 0x1, 0x6, 0x39023500)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:114 +0xb1
cmd/compile/internal/gc.dowidth(0x39351540)
	/usr/local/go/src/cmd/compile/internal/gc/align.go:435 +0x52c
cmd/compile/internal/gc.resumecheckwidth()
	/usr/local/go/src/cmd/compile/internal/gc/align.go:526 +0x38
cmd/compile/internal/gc.typecheckdef(0x39348510)
	/usr/local/go/src/cmd/compile/internal/gc/typecheck.go:3695 +0x79b
cmd/compile/internal/gc.typecheck1(0x39348510, 0x4, 0x0)
	/usr/local/go/src/cmd/compile/internal/gc/typecheck.go:343 +0xa872
cmd/compile/internal/gc.typecheck(0x39348510, 0x4, 0x0)
	/usr/local/go/src/cmd/compile/internal/gc/typecheck.go:299 +0x67c
cmd/compile/internal/gc.typecheck1(0x392aaf50, 0x1, 0x0)
	/usr/local/go/src/cmd/compile/internal/gc/typecheck.go:2077 +0x469f
cmd/compile/internal/gc.typecheck(0x392aaf50, 0x1, 0x0)
	/usr/local/go/src/cmd/compile/internal/gc/typecheck.go:299 +0x67c
cmd/compile/internal/gc.Main(0x87db970)
	/usr/local/go/src/cmd/compile/internal/gc/main.go:603 +0x276d
main.main()
	/usr/local/go/src/cmd/compile/main.go:52 +0x8d
*** Error code 2

Stop.

[cuonglm]

Duplicated of #44266

[benkasminbullock]

The crash is due to the circular lnhttp -> lnresponse -> lnhttp inclusion of structs.

[randall77]

I'll close - we believe this is fixed at tip, and fixing a compiler crash on an invalid program is not worth the risk of backporting.
Please reopen if you think this isn't fixed at tip, or if you think your program is valid.

[benkasminbullock]

I'll close - we believe this is fixed at tip, and fixing a compiler crash on an invalid program is not worth the risk of backporting.
Please reopen if you think this isn't fixed at tip, or if you think your program is valid.

OK, obviously the program is not valid but a segmentation fault is not a good response. Anyway I assume this will create a better error message in the new version.

I've set the repo containing my code to private, if you need that again for some reason ping me and I'll open it up again.