build: skip PkgDeclOnly

cl/builtin_test.go

@@ -36,10 +36,10 @@ func TestPkgNoInit(t *testing.T) {
 }
 
 func TestPkgKind(t *testing.T) {
-	if v := pkgKind("noinit"); v != pkgNoInit {
+	if v := pkgKind("noinit"); v != PkgNoInit {
 		t.Fatal("pkgKind:", v)
 	}
-	if v := pkgKind(""); v != pkgNormal {
+	if v := pkgKind(""); v != PkgLLGo {
 		t.Fatal("pkgKind:", v)
 	}
 }

cl/compile.go

@@ -82,7 +82,7 @@ func (p *context) funcKind(vfn ssa.Value) int {
 func (p *context) pkgNoInit(pkg *types.Package) bool {
 	p.ensureLoaded(pkg)
 	if i, ok := p.loaded[pkg]; ok {
-		return i.kind != pkgNormal
+		return i.kind >= PkgNoInit
 	}
 	return false
 }
@@ -119,9 +119,10 @@ type instrOrValue interface {
 }
 
 const (
-	pkgNormal   = iota
-	pkgNoInit   // noinit: a package that don't need to be initialized
-	pkgDeclOnly // decl: a package that only have declarations
+	PkgNormal = iota
+	PkgLLGo
+	PkgNoInit   // noinit: a package that don't need to be initialized
+	PkgDeclOnly // decl: a package that only have declarations
 )
 
 type pkgInfo struct {
@@ -494,7 +495,7 @@ func NewPackage(prog llssa.Program, pkg *ssa.Package, files []*ast.File) (ret ll
 		link:   make(map[string]string),
 		vargs:  make(map[*ssa.Alloc][]llssa.Expr),
 		loaded: map[*types.Package]*pkgInfo{
-			types.Unsafe: {kind: pkgNoInit}, // TODO(xsw): pkgNoInit or pkgDeclOnly?
+			types.Unsafe: {kind: PkgDeclOnly}, // TODO(xsw): PkgNoInit or PkgDeclOnly?
 		},
 	}
 	ctx.initFiles(pkgPath, files)

cl/import.go

@@ -44,27 +44,45 @@ func contentOf(m contentMap, file string) (lines contentLines, err error) {
 	return
 }
 
+// PkgKindOf returns the kind of a package.
+func PkgKindOf(pkg *types.Package) int {
+	scope := pkg.Scope()
+	kind := pkgKindByScope(scope)
+	if kind == PkgNormal {
+		kind = pkgKindByPath(pkg.Path())
+	}
+	return kind
+}
+
 // decl: a package that only contains declarations
 // noinit: a package that does not need to be initialized
 func pkgKind(v string) int {
 	switch v {
 	case "decl":
-		return pkgDeclOnly
+		return PkgDeclOnly
 	case "noinit":
-		return pkgNoInit
+		return PkgNoInit
 	}
-	return pkgNormal
+	return PkgLLGo
+}
+
+func pkgKindByScope(scope *types.Scope) int {
+	if v, ok := scope.Lookup("LLGoPackage").(*types.Const); ok {
+		if v := v.Val(); v.Kind() == constant.String {
+			return pkgKind(constant.StringVal(v))
+		}
+		return PkgLLGo
+	}
+	return PkgNormal
 }
 
 func (p *context) importPkg(pkg *types.Package, i *pkgInfo) {
 	scope := pkg.Scope()
-	llpkg, ok := scope.Lookup("LLGoPackage").(*types.Const)
-	if !ok {
+	kind := pkgKindByScope(scope)
+	if kind == PkgNormal {
 		return
 	}
-	if v := llpkg.Val(); v.Kind() == constant.String {
-		i.kind = pkgKind(constant.StringVal(v))
-	}
+	i.kind = kind
 	fset := p.fset
 	names := scope.Names()
 	contents := make(contentMap)
@@ -199,8 +217,8 @@ func (p *context) ensureLoaded(pkgTypes *types.Package) *types.Package {
 
 func pkgKindByPath(pkgPath string) int {
 	switch pkgPath {
-	case "syscall", "runtime/cgo":
-		return pkgNoInit
+	case "syscall", "runtime/cgo", "unsafe":
+		return PkgDeclOnly
 	}
-	return pkgNormal
+	return PkgNormal
 }

internal/build/build.go

@@ -183,7 +183,7 @@ func linkMainPkg(pkg *packages.Package, runtimeFiles []string, conf *Config, mod
 	args[2] = "-Wno-override-module"
 	needRuntime := false
 	packages.Visit([]*packages.Package{pkg}, nil, func(p *packages.Package) {
-		if p.PkgPath != "unsafe" { // TODO(xsw): maybe can remove this special case
+		if p.ExportFile != "" { // skip packages that only contain declarations
 			args = append(args, p.ExportFile+".ll")
 			if !needRuntime {
 				needRuntime = isNeedRuntime(p)
@@ -220,6 +220,12 @@ func linkMainPkg(pkg *packages.Package, runtimeFiles []string, conf *Config, mod
 
 func buildPkg(prog llssa.Program, aPkg aPackage, mode Mode, verbose bool) {
 	pkg := aPkg.Package
+	if cl.PkgKindOf(pkg.Types) == cl.PkgDeclOnly {
+		// skip packages that only contain declarations
+		// and set no export file
+		pkg.ExportFile = ""
+		return
+	}
 	pkgPath := pkg.PkgPath
 	if verbose {
 		fmt.Fprintln(os.Stderr, pkgPath)
@@ -320,7 +326,7 @@ func allLinkFiles(rt []*packages.Package) (outFiles []string) {
 	outFiles = make([]string, 0, len(rt))
 	root := rootLLGo(rt[0])
 	packages.Visit(rt, nil, func(p *packages.Package) {
-		if isPkgInLLGo(p.PkgPath) {
+		if hasLinkFile(p) {
 			outFile := filepath.Join(root+p.PkgPath[len(llgoModPath):], "llgo_autogen.ll")
 			outFiles = append(outFiles, outFile)
 		}
@@ -328,6 +334,13 @@ func allLinkFiles(rt []*packages.Package) (outFiles []string) {
 	return
 }
 
+func hasLinkFile(pkg *packages.Package) bool {
+	if isPkgInLLGo(pkg.PkgPath) {
+		return cl.PkgKindOf(pkg.Types) != cl.PkgDeclOnly
+	}
+	return false
+}
+
 // TODO(xsw): llgo root dir
 func rootLLGo(runtime *packages.Package) string {
 	return runtime.Module.Dir