build: PkgLinkExtern

cl/builtin_test.go

@@ -140,16 +140,19 @@ func TestPkgNoInit(t *testing.T) {
 }
 
 func TestPkgKind(t *testing.T) {
-	if v := pkgKind("noinit"); v != PkgNoInit {
+	if v, _ := pkgKind("link: hello.a"); v != PkgLinkExtern {
 		t.Fatal("pkgKind:", v)
 	}
-	if v := pkgKind(""); v != PkgLLGo {
+	if v, _ := pkgKind("noinit"); v != PkgNoInit {
+		t.Fatal("pkgKind:", v)
+	}
+	if v, _ := pkgKind(""); v != PkgLLGo {
 		t.Fatal("pkgKind:", v)
 	}
 }
 
 func TestPkgKindOf(t *testing.T) {
-	if v := PkgKindOf(types.Unsafe); v != PkgDeclOnly {
+	if v, _ := PkgKindOf(types.Unsafe); v != PkgDeclOnly {
 		t.Fatal("PkgKindOf unsafe:", v)
 	}
 	pkg := types.NewPackage("foo", "foo")
@@ -158,7 +161,7 @@ func TestPkgKindOf(t *testing.T) {
 			0, pkg, "LLGoPackage", types.Typ[types.String],
 			constant.MakeString("noinit")),
 	)
-	if v := PkgKindOf(pkg); v != PkgNoInit {
+	if v, _ := PkgKindOf(pkg); v != PkgNoInit {
 		t.Fatal("PkgKindOf foo:", v)
 	}
 }

cl/compile.go

@@ -126,6 +126,7 @@ const (
 	PkgNoInit     // noinit: a package that don't need to be initialized
 	PkgDeclOnly   // decl: a package that only have declarations
 	PkgLinkIR     // link llvm ir (.ll)
+	PkgLinkExtern // link external object (.a/.so/.dll/.dylib/etc.)
 	// PkgLinkBitCode // link bitcode (.bc)
 )
 

cl/import.go

@@ -77,44 +77,48 @@ func (p *pkgSymInfo) initLinknames(ctx *context) {
 }
 
 // PkgKindOf returns the kind of a package.
-func PkgKindOf(pkg *types.Package) int {
+func PkgKindOf(pkg *types.Package) (int, string) {
 	scope := pkg.Scope()
-	kind := pkgKindByScope(scope)
+	kind, param := pkgKindByScope(scope)
 	if kind == PkgNormal {
 		kind = pkgKindByPath(pkg.Path())
 	}
-	return kind
+	return kind, param
 }
 
 // decl: a package that only contains declarations
 // noinit: a package that does not need to be initialized
-func pkgKind(v string) int {
+func pkgKind(v string) (int, string) {
 	switch v {
 	case "link":
-		return PkgLinkIR
+		return PkgLinkIR, ""
+	case "decl":
+		return PkgDeclOnly, ""
+	case "noinit":
+		return PkgNoInit, ""
+	default:
 		// case "link:bc":
 		//	return PkgLinkBitCode
-	case "decl":
-		return PkgDeclOnly
-	case "noinit":
-		return PkgNoInit
+		if strings.HasPrefix(v, "link:") { // "link: <libpath>"
+			return PkgLinkExtern, v[5:]
 		}
-	return PkgLLGo
+	}
+	return PkgLLGo, ""
 }
 
-func pkgKindByScope(scope *types.Scope) int {
+func pkgKindByScope(scope *types.Scope) (int, string) {
 	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 PkgLLGo, ""
 	}
-	return PkgNormal
+	return PkgNormal, ""
 }
 
 func (p *context) importPkg(pkg *types.Package, i *pkgInfo) {
 	scope := pkg.Scope()
-	kind := pkgKindByScope(scope)
+	kind, _ := pkgKindByScope(scope)
 	if kind == PkgNormal {
 		return
 	}

internal/build/build.go

@@ -167,12 +167,12 @@ func buildAllPkgs(prog llssa.Program, initial []*packages.Package, mode Mode, ve
 	}
 	for _, aPkg := range pkgs {
 		pkg := aPkg.Package
-		switch kind := cl.PkgKindOf(pkg.Types); kind {
+		switch kind, param := cl.PkgKindOf(pkg.Types); kind {
 		case cl.PkgDeclOnly:
 			// skip packages that only contain declarations
 			// and set no export file
 			pkg.ExportFile = ""
-		case cl.PkgLinkIR: // cl.PkgLinkBitCode:
+		case cl.PkgLinkIR:
 			// skip packages that don't need to be compiled but need to be linked
 			pkgPath := pkg.PkgPath
 			if isPkgInLLGo(pkgPath) {
@@ -180,6 +180,15 @@ func buildAllPkgs(prog llssa.Program, initial []*packages.Package, mode Mode, ve
 			} else {
 				panic("todo")
 			}
+		case cl.PkgLinkExtern:
+			// skip packages that don't need to be compiled but need to be linked with external library
+			linkFile := os.ExpandEnv(strings.TrimSpace(param))
+			dir, lib := filepath.Split(linkFile)
+			command := " -l " + lib
+			if dir != "" {
+				command += " -L " + dir
+			}
+			pkg.ExportFile = command
 		default:
 			buildPkg(prog, aPkg, mode, verbose)
 			if prog.NeedRuntime() {