cmd/link: allow buildmode c-archive for aix/ppc64

Change-Id: Ia268b0d64dc89866aa09bfffcaa109741088a904
Reviewed-on: https://go-review.googlesource.com/c/go/+/169119
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

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

@@ -51,7 +51,7 @@ func (mode *BuildMode) Set(s string) error {
 		*mode = BuildModePIE
 	case "c-archive":
 		switch objabi.GOOS {
-		case "darwin", "linux":
+		case "aix", "darwin", "linux":
 		case "freebsd":
 			switch objabi.GOARCH {
 			case "amd64":

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

@@ -1000,7 +1000,7 @@ func dosymtype(ctxt *Link) {
 		for _, s := range ctxt.Syms.Allsym {
 			// Create a new entry in the .init_array section that points to the
 			// library initializer function.
-			if s.Name == *flagEntrySymbol {
+			if s.Name == *flagEntrySymbol && ctxt.HeadType != objabi.Haix {
 				addinitarrdata(ctxt, s)
 			}
 		}
@@ -1380,6 +1380,13 @@ func (ctxt *Link) dodata() {
 	case BuildModeCArchive, BuildModeCShared, BuildModeShared, BuildModePlugin:
 		hasinitarr = true
 	}
+
+	if ctxt.HeadType == objabi.Haix {
+		if len(data[sym.SINITARR]) > 0 {
+			Errorf(nil, "XCOFF format doesn't allow .init_array section")
+		}
+	}
+
 	if hasinitarr && len(data[sym.SINITARR]) > 0 {
 		sect := addsection(ctxt.Arch, &Segdata, ".init_array", 06)
 		sect.Align = dataMaxAlign[sym.SINITARR]

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

@@ -1102,7 +1102,11 @@ func (ctxt *Link) archive() {
 	}
 	ctxt.Out.f = nil
 
-	argv := []string{*flagExtar, "-q", "-c", "-s", *flagOutfile}
+	argv := []string{*flagExtar, "-q", "-c", "-s"}
+	if ctxt.HeadType == objabi.Haix {
+		argv = append(argv, "-X64")
+	}
+	argv = append(argv, *flagOutfile)
 	argv = append(argv, filepath.Join(*flagTmpdir, "go.o"))
 	argv = append(argv, hostobjCopy()...)