cmd/6g: doasm: notfound from=75 to=75 00000 (/Users/dfc/src/panic.go:10) CMPQ $0,$0

[davecheney]

What steps will reproduce the problem?

package main

import "runtime"

func main() {
        defer func() {
                runtime.GC() // triggers stack walk
                recover()
        }()
        func() { _ = *(*int)(nil) }()
}

Credit to Minux Ma for the original code.

What is the expected output? What do you see instead?

Expected, no compilation error, no output

Got

odessa(~/src) % go run panic.go
# command-line-arguments
./panic.go:11: doasm: notfound from=75 to=75 00000
(/Users/dfc/src/panic.go:10)    CMPQ    $0,$0

Please use labels and text to provide additional information.

odessa(~/src) % uname -a
Darwin odessa.fritz.box 13.0.0 Darwin Kernel Version 13.0.0: Thu Sep 19 22:22:27 PDT
2013; root:xnu-2422.1.72~6/RELEASE_X86_64 x86_64
odessa(~/src) % go version
go version devel +4f9dee8402af Mon Feb 17 14:33:00 2014 +1100 darwin/amd64

[davecheney]

Comment 1:

Interesting, this code also fails with Go 1.2
odessa(~/src) % go run panic.go
# command-line-arguments
main.func·002: doasm: notfound from=75 to=75 (10)  CMPQ    $0,$0
odessa(~/src) % go version
go version go1.2 darwin/amd64

[davecheney]

Comment 2:

Even simpler repro,
package main
func main() {
        _ = *(*int)(nil)
}
odessa(~/src) % go run panic.go
# command-line-arguments
./panic.go:5: doasm: notfound from=75 to=75 00000 (/Users/dfc/src/panic.go:4)   CMPQ    $0,$0

[remyoudompheng]

Comment 3:

https://golang.org/cl/69050044

Status changed to Started.

[remyoudompheng]

Comment 4:

This issue was closed by revision 52e6d7c.

Status changed to Fixed.

[davecheney]

Comment 5:

Issue #7965 has been merged into this issue.