cmd/link: don't switch to gold on ARM Linux

The bug in GNU ld appears to have been fixed in GNU binutils 2.28 by
GNU binutils revision 5522f910cb539905d6adfdceab208ddfa5e84557.
(This may have been accidental as the ChangeLog for the fix makes
no reference to it; the fix is from
https://sourceware.org/bugzilla/show_bug.cgi?id=19962).

Continue using gold on arm64, at least for now, because as reported in
issue #22040 GNU ld still fails there.

For #15696
For #22040

Change-Id: I5534bb8b5680daf536a7941aba5c701e8a4138ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/468655
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>

src/cmd/link/internal/ld/lib.go

@@ -1551,15 +1551,12 @@ func (ctxt *Link) hostlink() {
 			altLinker = "lld"
 		}
 
-		if ctxt.Arch.InFamily(sys.ARM, sys.ARM64) && buildcfg.GOOS == "linux" {
-			// On ARM, the GNU linker will generate COPY relocations
-			// even with -znocopyreloc set.
+		if ctxt.Arch.InFamily(sys.ARM64) && buildcfg.GOOS == "linux" {
+			// On ARM64, the GNU linker will fail with
+			// -znocopyreloc if it thinks a COPY relocation is
+			// required. Switch to gold.
 			// https://sourceware.org/bugzilla/show_bug.cgi?id=19962
-			//
-			// On ARM64, the GNU linker will fail instead of
-			// generating COPY relocations.
-			//
-			// In both cases, switch to gold.
+			// https://go.dev/issue/22040
 			altLinker = "gold"
 
 			// If gold is not installed, gcc will silently switch
@@ -1570,7 +1567,7 @@ func (ctxt *Link) hostlink() {
 			cmd := exec.Command(name, args...)
 			if out, err := cmd.CombinedOutput(); err == nil {
 				if !bytes.Contains(out, []byte("GNU gold")) {
-					log.Fatalf("ARM external linker must be gold (issue #15696), but is not: %s", out)
+					log.Fatalf("ARM64 external linker must be gold (issue #15696, 22040), but is not: %s", out)
 				}
 			}
 		}