cmd/link/internal/ld: move more of mustLinkExternal into internal/platform

internal/platform.MustLinkExternal is used in various places to
determine whether external linking is required. It should always
match what the linker actually requires, but today does not match
because the linker imposes additional constraints.

Updates #31544.

Change-Id: I0cc6ad587e95c607329dea5d60d29a5fb2a9e722
Reviewed-on: https://go-review.googlesource.com/c/go/+/472515
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/internal/testenv/testenv.go b/src/internal/testenv/testenv.go
index 65a82fd5f7..816a1a100f 100644
--- a/src/internal/testenv/testenv.go
+++ b/src/internal/testenv/testenv.go
@@ -288,15 +288,18 @@ func MustHaveCGO(t testing.TB) {
 
 // CanInternalLink reports whether the current system can link programs with
 // internal linking.
-func CanInternalLink() bool {
-	return !platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH)
+func CanInternalLink(withCgo bool) bool {
+	return !platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, withCgo)
 }
 
 // MustInternalLink checks that the current system can link programs with internal
 // linking.
 // If not, MustInternalLink calls t.Skip with an explanation.
-func MustInternalLink(t testing.TB) {
-	if !CanInternalLink() {
+func MustInternalLink(t testing.TB, withCgo bool) {
+	if !CanInternalLink(withCgo) {
+		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)
 	}
 }