cmd/compile/internal/gc: update cgo_import_dynamic for AIX

On AIX, cmd/link needs two information in order to generate a dynamic
import, the library and its object needed. Currently, cmd/link isn't
able to retrieve this object only with the name of the library.
Therefore, the library pattern in cgo_import_dynamic must be
"lib.a/obj.o".

Change-Id: Ib8b8aaa9807c9fa6af46ece4e312d58073ed6ec1
Reviewed-on: https://go-review.googlesource.com/c/146957
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/cgo/doc.go

@@ -827,6 +827,10 @@ The directives are:
 	possibly version in the dynamic library, and the optional "<library>"
 	names the specific library where the symbol should be found.
 
+	On AIX, the library pattern is slightly different. It must be
+	"lib.a/obj.o" with obj.o the member of this library exporting
+	this symbol.
+
 	In the <remote>, # or @ can be used to introduce a symbol version.
 
 	Examples:

src/cmd/compile/internal/gc/lex.go

@@ -114,6 +114,14 @@ func (p *noder) pragcgo(pos syntax.Pos, text string) {
 		case len(f) == 3 && !isQuoted(f[1]) && !isQuoted(f[2]):
 		case len(f) == 4 && !isQuoted(f[1]) && !isQuoted(f[2]) && isQuoted(f[3]):
 			f[3] = strings.Trim(f[3], `"`)
+			if objabi.GOOS == "aix" && f[3] != "" {
+				// On Aix, library pattern must be "lib.a/object.o"
+				n := strings.Split(f[3], "/")
+				if len(n) != 2 || !strings.HasSuffix(n[0], ".a") || !strings.HasSuffix(n[1], ".o") {
+					p.error(syntax.Error{Pos: pos, Msg: `usage: //go:cgo_import_dynamic local [remote ["lib.a/object.o"]]`})
+					return
+				}
+			}
 		default:
 			p.error(syntax.Error{Pos: pos, Msg: `usage: //go:cgo_import_dynamic local [remote ["library"]]`})
 			return

src/cmd/compile/internal/gc/lex_test.go

@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/syntax"
 	"reflect"
+	"runtime"
 	"testing"
 )
 
@@ -49,10 +50,12 @@ func TestPragmaFields(t *testing.T) {
 }
 
 func TestPragcgo(t *testing.T) {
-	var tests = []struct {
+	type testStruct struct {
 		in   string
 		want []string
-	}{
+	}
+
+	var tests = []testStruct{
 		{`go:cgo_export_dynamic local`, []string{`cgo_export_dynamic`, `local`}},
 		{`go:cgo_export_dynamic local remote`, []string{`cgo_export_dynamic`, `local`, `remote`}},
 		{`go:cgo_export_dynamic local' remote'`, []string{`cgo_export_dynamic`, `local'`, `remote'`}},
@@ -61,8 +64,6 @@ func TestPragcgo(t *testing.T) {
 		{`go:cgo_export_static local' remote'`, []string{`cgo_export_static`, `local'`, `remote'`}},
 		{`go:cgo_import_dynamic local`, []string{`cgo_import_dynamic`, `local`}},
 		{`go:cgo_import_dynamic local remote`, []string{`cgo_import_dynamic`, `local`, `remote`}},
-		{`go:cgo_import_dynamic local remote "library"`, []string{`cgo_import_dynamic`, `local`, `remote`, `library`}},
-		{`go:cgo_import_dynamic local' remote' "lib rary"`, []string{`cgo_import_dynamic`, `local'`, `remote'`, `lib rary`}},
 		{`go:cgo_import_static local`, []string{`cgo_import_static`, `local`}},
 		{`go:cgo_import_static local'`, []string{`cgo_import_static`, `local'`}},
 		{`go:cgo_dynamic_linker "/path/"`, []string{`cgo_dynamic_linker`, `/path/`}},
@@ -71,17 +72,50 @@ func TestPragcgo(t *testing.T) {
 		{`go:cgo_ldflag "a rg"`, []string{`cgo_ldflag`, `a rg`}},
 	}
 
+	if runtime.GOOS != "aix" {
+		tests = append(tests, []testStruct{
+			{`go:cgo_import_dynamic local remote "library"`, []string{`cgo_import_dynamic`, `local`, `remote`, `library`}},
+			{`go:cgo_import_dynamic local' remote' "lib rary"`, []string{`cgo_import_dynamic`, `local'`, `remote'`, `lib rary`}},
+		}...)
+	} else {
+		// cgo_import_dynamic with a library is slightly different on AIX
+		// as the library field must follow the pattern [libc.a/object.o].
+		tests = append(tests, []testStruct{
+			{`go:cgo_import_dynamic local remote "lib.a/obj.o"`, []string{`cgo_import_dynamic`, `local`, `remote`, `lib.a/obj.o`}},
+			// This test must fail.
+			{`go:cgo_import_dynamic local' remote' "library"`, []string{`<unknown position>: usage: //go:cgo_import_dynamic local [remote ["lib.a/object.o"]]`}},
+		}...)
+
+	}
+
 	var p noder
 	var nopos syntax.Pos
 	for _, tt := range tests {
-		p.pragcgobuf = nil
-		p.pragcgo(nopos, tt.in)
 
-		got := p.pragcgobuf
-		want := [][]string{tt.want}
-		if !reflect.DeepEqual(got, want) {
-			t.Errorf("pragcgo(%q) = %q; want %q", tt.in, got, want)
-			continue
+		p.err = make(chan syntax.Error)
+		gotch := make(chan [][]string)
+		go func() {
+			p.pragcgobuf = nil
+			p.pragcgo(nopos, tt.in)
+			if p.pragcgobuf != nil {
+				gotch <- p.pragcgobuf
+			}
+		}()
+
+		select {
+		case e := <-p.err:
+			want := tt.want[0]
+			if e.Error() != want {
+				t.Errorf("pragcgo(%q) = %q; want %q", tt.in, e, want)
+				continue
+			}
+		case got := <-gotch:
+			want := [][]string{tt.want}
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("pragcgo(%q) = %q; want %q", tt.in, got, want)
+				continue
+			}
 		}
+
 	}
 }