cmd/link: disable plugin support if cgo is disabled

Functional plugin support requires cgo to be enabled. Disable
it if the environment has disabled cgo.

This prevents unexpected linker failures when linking large
binaries with cgo disabled which use the plugin package.

Fixes #45564

Change-Id: Ib71f0e089f7373b7b3e3cd53da3612291e7bc473
Reviewed-on: https://go-review.googlesource.com/c/go/+/314449
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Lynn Boger <laboger@linux.vnet.ibm.com>

diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index adf1669cf269acdeec24e4d6cf4060c496da6afa..043bf5a35ed6c33d3e0bf37460b47f8048c724e0 100644 (file)
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -539,7 +539,10 @@ func (ctxt *Link) loadlib() {
        // up symbol by name may not get expected result.
 
        iscgo = ctxt.LibraryByPkg["runtime/cgo"] != nil
-       ctxt.canUsePlugins = ctxt.LibraryByPkg["plugin"] != nil
+
+       // Plugins a require cgo support to function. Similarly, plugins may require additional
+       // internal linker support on some platforms which may not be implemented.
+       ctxt.canUsePlugins = ctxt.LibraryByPkg["plugin"] != nil && iscgo
 
        // We now have enough information to determine the link mode.
        determineLinkMode(ctxt)