Static linking on arm but dynamic on x86

[jhiemstrawisc]

I noticed recently that compiling your libc example has different behavior on arm64 than it does on x86 -- on arm, it produces a static binary, but on x86 it's dynamically linked, even with CGO_ENABLED=0.

Is this intended? I initially observed similar behavior after using purego in another project, where my x86 go binaries broke because they switched from static to dynamic.

[TotallyGamerJet]

Which OS, go version, purego version are you using?

Amd64, and arm64 should be dynamically linked. How are you determining they are static?

[TotallyGamerJet]

@jhiemstrawisc is this still an issue? If not, I'd like to close it.

[TotallyGamerJet]

Closing as there hasn't been a response and this doesn't appear to actually be an issue.

[zhangyongding]

I also noticed this issue. Using the ldd command, it can be seen that dynamic libraries are linked in amd64, while this situation does not exist in arm64

[TotallyGamerJet]

Can you provide a minimal reproducible code? Both architectures should be dynamically linked.

[zhangyongding]

I am cross compiling linux/arm64 on linux/amd64, do I don‘t know if it is related to this?

[zhangyongding]

main.go

package main

import (
	"github.com/ebitengine/purego"
)

func openLibrary(name string) (uintptr, error) {
	return purego.Dlopen(name, purego.RTLD_NOW|purego.RTLD_GLOBAL)
}

// CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o puts_amd64 main.go
// CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -o puts_arm64 main.go
func main() {
	libc, err := openLibrary("libc.so.6")
	if err != nil {
		panic(err)
	}
	var puts func(string)
	purego.RegisterLibFunc(&puts, libc, "puts")
	puts("Calling C from Go without Cgo!")
}

go build

CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o puts_amd64 main.go
CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -o puts_arm64 main.go

result

puts_amd64:
        linux-vdso.so.1 (0x00007ffc642cd000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f629ad48000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f629a957000)
        libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f629a738000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f629af4c000)
puts_arm64:
        not a dynamic executable

[TotallyGamerJet]

I don't have an amd64 computer but on my arm64 linux it was amd64 that gave a not a dynamic executable. I think it's a limitation of the natively installed version of ldd that only supports whatever architecture the system is.

desktop:~/purego/examples/libc$ CGO_ENABLED=0 GOARCH=arm64 go build -o libc_arm64
desktop:~/purego/examples/libc$ CGO_ENABLED=0 GOARCH=amd64 go build -o libc_amd64
desktop:~/purego/examples/libc$ ldd libc_arm64
	linux-vdso.so.1 (0x0000ffffa0d00000)
	libdl.so.2 => /lib/aarch64-linux-gnu/libdl.so.2 (0x0000ffffa0ca0000)
	libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000ffffa0af0000)
	libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000ffffa0ad0000)
	/lib/ld-linux-aarch64.so.1 (0x0000ffffa0cc7000)
desktop:~/purego/examples/libc$ ldd libc_amd64
	not a dynamic executable