[dev.link] all: merge branch 'master' into dev.link

Change-Id: I644cfc9dfd6e024a0d62bbd226db8639e4a87dc7

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

@@ -123,12 +123,14 @@ type ArchSyms struct {
 // mkArchSym is a helper for setArchSyms, to set up a special symbol.
 func (ctxt *Link) mkArchSym(name string, ver int, ls *loader.Sym) {
 	*ls = ctxt.loader.LookupOrCreateSym(name, ver)
+	ctxt.loader.SetAttrReachable(*ls, true)
 }
 
 // mkArchVecSym is similar to  setArchSyms, but operates on elements within
 // a slice, where each element corresponds to some symbol version.
 func (ctxt *Link) mkArchSymVec(name string, ver int, ls []loader.Sym) {
 	ls[ver] = ctxt.loader.LookupOrCreateSym(name, ver)
+	ctxt.loader.SetAttrReachable(ls[ver], true)
 }
 
 // setArchSyms sets up the ArchSyms structure, and must be called before
@@ -1999,7 +2001,9 @@ func ldshlibsyms(ctxt *Link, shlib string) {
 		Errorf(nil, "cannot open shared library: %s", libpath)
 		return
 	}
-	defer f.Close()
+	// Keep the file open as decodetypeGcprog needs to read from it.
+	// TODO: fix. Maybe mmap the file.
+	//defer f.Close()
 
 	hash, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GOABIHASH_TAG)
 	if err != nil {