gollvm: multiple definition of 'runtime.nanotime..f'

[johnnyyu029]

As shown in the sample code, since Nanotime is declared in both package main and packagea(using: //go:linkname Nanotime runtime.nanotime), and package packagea is imported to package main.
gofrontend creates the function descriptor with the same name "runtime.nanotime..f" for Nanotime in both packages main and packagea, resulting in a multiple definition error during the link phase.

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

gollvm master

$ go version
go version unknown linux/amd64

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?

The issue may be reproduced with the following sample:

go build linkname.go

File linkname.go

package main
  
import (
    "fmt"
    "linkname/packagea"
    _ "unsafe"
)

//go:linkname Nanotime runtime.nanotime
func Nanotime() int64

func main() {
    fmt.Println(Nanotime())
    fmt.Println(packagea.Nanotime)
}

File packagea/a.go

package packagea
  
import (
        _ "unsafe"
)

//go:linkname Nanotime runtime.nanotime
func Nanotime() int64

What did you expect to see?

No error, successful build.

What did you see instead?

[root@kwephis525702 test]# go build linkname.go 
# command-line-arguments
/usr/bin/ld.gold: error: /root/.cache/go-build/72/72a31748b9a7e4660f3fbe9b02046db2b83d204da0b133c508593d4b82ac82b3-d(_go_.o): multiple definition of 'runtime.nanotime..f'
/usr/bin/ld.gold: $WORK/b001/_pkg_.a(_go_.o): previous definition here

[mknyszek]

CC @thanm @cherrymui

[cherrymui]

As shown in the sample code, since Nanotime is declared in both package main and packagea(using: //go:linkname Nanotime runtime.nanotime)

Do not do this. Using linkname to access runtime internal functions is not supported. Thanks.

[johnnyyu029]

@cherrymui
As shown in the sample code, using linkname on non-runtime function GetTime defined in "linkname/a.go" has the same problem:

[root@kwephis525702 test]# go build linkname.go 
# command-line-arguments
/usr/bin/ld.gold: error: $WORK/b003/_pkg_.a(_go_.o): multiple definition of 'linkname_1packagea.GetTime..f'
/usr/bin/ld.gold: $WORK/b001/_pkg_.a(_go_.o): previous definition here

File linkname.go

package main

import (
    "fmt"
    _ "linkname/packagea"
    _ "unsafe"
)

//go:linkname GetTime linkname_1packagea.GetTime
func GetTime() int64

func main() {
    fmt.Println(GetTime())
    fmt.Println(GetTime)
}  

File linkname/a.go

package packagea                                                                                                                                                                                                                               

import (
    _ "unsafe"
)

func GetTime() int64 {
    return 0
}

[ianlancetaylor]

Thanks, I think there is a bug here. But in general go:linkname is not well supported. Patches welcome.