cmd/link: refactor addlib

* extract pkgname() and findlib() from the function for #18190.
* rename const pkgname to const pkgdef to avoid confliction.

Change-Id: Ie62509bfbddcf19cf92b5b12b598679a069e6e74
Reviewed-on: https://go-review.googlesource.com/59417Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

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

@@ -86,19 +86,18 @@ func (ctxt *Link) readImportCfg(file string) {
 	}
 }
 
-func addlib(ctxt *Link, src string, obj string, pathname string) *Library {
-	name := path.Clean(pathname)
-
+func pkgname(lib string) string {
+	name := path.Clean(lib)
 	// runtime.a -> runtime, runtime.6 -> runtime
 	pkg := name
 	if len(pkg) >= 2 && pkg[len(pkg)-2] == '.' {
 		pkg = pkg[:len(pkg)-2]
 	}
+	return pkg
+}
 
-	// already loaded?
-	if l := ctxt.LibraryByPkg[pkg]; l != nil {
-		return l
-	}
+func findlib(ctxt *Link, lib string) (string, bool) {
+	name := path.Clean(lib)
 
 	var pname string
 	isshlib := false
@@ -110,12 +109,13 @@ func addlib(ctxt *Link, src string, obj string, pathname string) *Library {
 		pname = ctxt.PackageFile[name]
 		if pname == "" {
 			ctxt.Logf("cannot find package %s (using -importcfg)\n", name)
-			return nil
+			return "", false
 		}
 	} else {
 		if filepath.IsAbs(name) {
 			pname = name
 		} else {
+			pkg := pkgname(lib)
 			// try dot, -L "libdir", and then goroot.
 			for _, dir := range ctxt.Libdir {
 				if *FlagLinkshared {
@@ -134,6 +134,19 @@ func addlib(ctxt *Link, src string, obj string, pathname string) *Library {
 		pname = path.Clean(pname)
 	}
 
+	return pname, isshlib
+}
+
+func addlib(ctxt *Link, src string, obj string, lib string) *Library {
+	pkg := pkgname(lib)
+
+	// already loaded?
+	if l := ctxt.LibraryByPkg[pkg]; l != nil {
+		return l
+	}
+
+	pname, isshlib := findlib(ctxt, lib)
+
 	if ctxt.Debugvlog > 1 {
 		ctxt.Logf("%5.2f addlib: %s %s pulls in %s isshlib %v\n", elapsed(), obj, src, pname, isshlib)
 	}

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

@@ -242,7 +242,7 @@ func (w *outBuf) Offset() int64 {
 
 var coutbuf outBuf
 
-const pkgname = "__.PKGDEF"
+const pkgdef = "__.PKGDEF"
 
 var (
 	// Set if we see an object compiled by the host compiler that is not
@@ -811,7 +811,7 @@ func objfile(ctxt *Link, lib *Library) {
 		goto out
 	}
 
-	if !strings.HasPrefix(arhdr.name, pkgname) {
+	if !strings.HasPrefix(arhdr.name, pkgdef) {
 		Errorf(nil, "%s: cannot find package header", lib.File)
 		goto out
 	}