# This test checks that external linking with --gc-sections does not strip version information.

[short] skip
[!cgo] skip
[GOOS:aix] skip  # no --gc-sections
[GOOS:darwin] skip  # no --gc-sections

go build -ldflags='-linkmode=external -extldflags=-Wl,--gc-sections'
go version hello$GOEXE
! stdout 'not a Go executable'
! stderr 'not a Go executable'

-- go.mod --
module hello
-- hello.go --
package main

/*
*/
import "C"

[short] skip
[!cgo] skip '-buildmode=c-shared requires external linking'
[!buildmode:c-shared] stop

env GO111MODULE=on

go get rsc.io/fortune
go build -buildmode=c-shared -o external.so rsc.io/fortune
go version external.so
stdout '^external.so: .+'
go version -m external.so
stdout '^\tpath\trsc.io/fortune'
stdout '^\tmod\trsc.io/fortune\tv1.0.0'

-- go.mod --
module m

-- empty.go --
package main

KEPs or supporting documentation, please reference a specific commit and avoid
linking directly to the master branch. This ensures that links reference a
specific point in time, rather than a document that may change over time.

See here for guidance on getting permanent links to files: https://help.github.com/en/articles/getting-permanent-links-to-files

Please use the following format for linking documentation:
- [KEP]: <link>
- [Usage]: <link>

		// TODO(mwhudson): We only set AttrVisibilityHidden in ldelf, i.e. when
		// internally linking. But STV_HIDDEN visibility only matters in object
		// files and shared libraries, and as we are a long way from implementing
		// internal linking for shared libraries and only create object files when
		// externally linking, I don't think this makes a lot of sense.
		other = int(elf.STV_HIDDEN)
	}

As far as configurations go, the main ones of interest are:

 * `implementation` - used for compilation, linking and runtime
 * `cppCompile__Variant__` - for dependencies that are necessary to compile your production code but shouldn’t be part of the linking or runtime process
 * `nativeLink__Variant__` - for dependencies that are necessary to link your code but shouldn’t be part of the compilation or runtime process

// There are various function pointers that should be set too,
// but those depend on dynamic linker magic to get initialized
// correctly, and sometimes they break. This variable is a
// backup: it depends only on old C style static linking rules.

package cgo

import _ "unsafe" // for go:linkname

//go:linkname _iscgo runtime.iscgo

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Test that a -B option is passed through when using both internal
// and external linking mode.

package main

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
)

func main() {
	test("internal")

		If not set, default value comes from running the compiler,
		which may be set by the -extld option.
		Set to "none" to use no support library.
	-linkmode mode
		Set link mode (internal, external, auto).
		This sets the linking mode as described in cmd/cgo/doc.go.
	-linkshared
		Link against installed Go shared libraries (experimental).
	-memprofile file
		Write memory profile to file.
	-memprofilerate rate

//go:build cmd_go_bootstrap

// This code is compiled only into the bootstrap 'go' binary.
// These stubs avoid importing packages with large dependency
// trees that potentially require C linking,
// like the use of "net/http" in vcs.go.

package web

import (
	"errors"
	urlpkg "net/url"
)

func get(security SecurityMode, url *urlpkg.URL) (*Response, error) {

		if withCgo && CanInternalLink(false) {
			t.Skipf("skipping test: internal linking on %s/%s is not supported with cgo", runtime.GOOS, runtime.GOARCH)
		}
		t.Skipf("skipping test: internal linking on %s/%s is not supported", runtime.GOOS, runtime.GOARCH)
	}
}

// MustInternalLinkPIE checks whether the current system can link PIE binary using
// internal linking.
// If not, MustInternalLinkPIE calls t.Skip with an explanation.