cmd/link: FreeBSD/ARM builder failing with cgo enabled on FreeBSD 11

[paulzhol]

FreeBSD 11.0-CURRENT r288943 switched to clang 3.7 causing the build to fail:

cmd/go
cmd/compile/internal/amd64
cmd/compile/internal/arm
cmd/compile/internal/arm64
cmd/compile/internal/ppc64
cmd/compile/internal/x86
cmd/compile
# cmd/go
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#18: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#19: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#20: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#28: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#29: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#30: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#38: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#39: ignoring  in section 17 (type 0)
...
/tmp/goexp/pkg/tool/freebsd_arm/link: too many errors


cmd/trace
cmd/pprof/internal/commands
cmd/pprof/internal/driver
cmd/pprof
# cmd/trace
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#18: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#19: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#20: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#28: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#29: ignoring  in section 17 (type 0)
/tmp/goexp/pkg/freebsd_arm/net.a(_all.o): sym#30: ignoring  in section 17 (type 0)
...
/tmp/goexp/pkg/tool/freebsd_arm/link: too many errors

According to readelf, section 17 is .debug_str in _all.o obj file in net.a.

Building with CGO_ENABLE=0 succeeds.

[ianlancetaylor]

Can you attach the _all.o file?

[paulzhol]

_all.o
net.a

[ianlancetaylor]

That's weird, the _all.o file has unnamed symbols with no type. The readelf -s --wide output:

18: 00000000     0 NOTYPE  LOCAL  DEFAULT   17 
19: 00000045     0 NOTYPE  LOCAL  DEFAULT   17 
20: 00000073     0 NOTYPE  LOCAL  DEFAULT   17 

If you feel like it, you should report this as an LLVM bug.

Could you please see if the problem is fixed by https://golang.org/cl/16667 ? Thanks.

[gopherbot]

CL https://golang.org/cl/16667 mentions this issue.

[paulzhol]

# cmd/go
panic: runtime error: index out of range

goroutine 1 [running]:
bootstrap/link/internal/ld.genasmsym(0x2369cc)
        /tmp/goexp2/src/cmd/link/internal/ld/lib.go:1810 +0x19c
bootstrap/link/internal/ld.Asmelfsym()
        /tmp/goexp2/src/cmd/link/internal/ld/symtab.go:213 +0x78
bootstrap/link/internal/arm.asmb()
        /tmp/goexp2/src/cmd/link/internal/arm/asm.go:643 +0x1548
bootstrap/link/internal/ld.Ldmain()
        /tmp/goexp2/src/cmd/link/internal/ld/pobj.go:125 +0x2cc0
bootstrap/link/internal/arm.Main()
        /tmp/goexp2/src/cmd/link/internal/arm/obj.go:44 +0x20
main.main()
        /tmp/goexp2/src/cmd/link/main.go:28 +0x304

...

# cmd/trace
panic: runtime error: index out of range

goroutine 1 [running]:
bootstrap/link/internal/ld.genasmsym(0x2369cc)
        /tmp/goexp2/src/cmd/link/internal/ld/lib.go:1810 +0x19c
bootstrap/link/internal/ld.Asmelfsym()
        /tmp/goexp2/src/cmd/link/internal/ld/symtab.go:213 +0x78
bootstrap/link/internal/arm.asmb()
        /tmp/goexp2/src/cmd/link/internal/arm/asm.go:643 +0x1548
bootstrap/link/internal/ld.Ldmain()
        /tmp/goexp2/src/cmd/link/internal/ld/pobj.go:125 +0x2cc0
bootstrap/link/internal/arm.Main()
        /tmp/goexp2/src/cmd/link/internal/arm/obj.go:44 +0x20
main.main()
        /tmp/goexp2/src/cmd/link/main.go:28 +0x304
cmd/pprof/internal/symbolizer
cmd/pprof/internal/symbolz
cmd/vet/whitelist
cmd/pprof
cmd/vet
# cmd/pprof
panic: runtime error: index out of range

goroutine 1 [running]:
bootstrap/link/internal/ld.genasmsym(0x2369cc)
        /tmp/goexp2/src/cmd/link/internal/ld/lib.go:1810 +0x19c
bootstrap/link/internal/ld.Asmelfsym()
        /tmp/goexp2/src/cmd/link/internal/ld/symtab.go:213 +0x78
bootstrap/link/internal/arm.asmb()
        /tmp/goexp2/src/cmd/link/internal/arm/asm.go:643 +0x1548
bootstrap/link/internal/ld.Ldmain()
        /tmp/goexp2/src/cmd/link/internal/ld/pobj.go:125 +0x2cc0
bootstrap/link/internal/arm.Main()
        /tmp/goexp2/src/cmd/link/internal/arm/obj.go:44 +0x20
main.main()
        /tmp/goexp2/src/cmd/link/main.go:28 +0x304

/tmp/goexp2/src/cmd/link/internal/ld/lib.go:1810 tries to access s.Name[0], but it's an empty string.
if s.Hide != 0 || (s.Name[0] == '.' && s.Version == 0 && s.Name != ".rathole") {

[ianlancetaylor]

Thanks for testing it. I've updated the CL to avoid that problem. Can you try it again?

[paulzhol]

It works! Thanks!