diff --git a/cl/_testlibgo/_atomic/in.go b/cl/_testlibgo/atomic/in.go
similarity index 67%
rename from cl/_testlibgo/_atomic/in.go
rename to cl/_testlibgo/atomic/in.go
index be7974ac..c6879d7e 100644
--- a/cl/_testlibgo/_atomic/in.go
+++ b/cl/_testlibgo/atomic/in.go
@@ -6,6 +6,5 @@ import (
 
 func main() {
 	var v int64 = 100
-	atomic.AddInt64(&v, 1)
-	println(v)
+	println(atomic.AddInt64(&v, 1))
 }
diff --git a/cl/_testlibgo/atomic/out.ll b/cl/_testlibgo/atomic/out.ll
new file mode 100644
index 00000000..2155a116
--- /dev/null
+++ b/cl/_testlibgo/atomic/out.ll
@@ -0,0 +1,46 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+@"main.init$guard" = global i1 false, align 1
+@__llgo_argc = global i32 0, align 4
+@__llgo_argv = global ptr null, align 8
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  call void @"sync/atomic.init"()
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define i32 @main(i32 %0, ptr %1) {
+_llgo_0:
+  store i32 %0, ptr @__llgo_argc, align 4
+  store ptr %1, ptr @__llgo_argv, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  %2 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 8)
+  store i64 100, ptr %2, align 4
+  %3 = call i64 @"sync/atomic.AddInt64"(ptr %2, i64 1)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintInt"(i64 %3)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  ret i32 0
+}
+
+declare void @"sync/atomic.init"()
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64)
+
+declare i64 @"sync/atomic.AddInt64"(ptr, i64)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintInt"(i64)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8)
diff --git a/cl/_testrt/_gotypes/in.go b/cl/_testrt/gotypes/in.go
similarity index 100%
rename from cl/_testrt/_gotypes/in.go
rename to cl/_testrt/gotypes/in.go
diff --git a/cl/_testrt/_gotypes/out.ll b/cl/_testrt/gotypes/out.ll
similarity index 88%
rename from cl/_testrt/_gotypes/out.ll
rename to cl/_testrt/gotypes/out.ll
index ae8de993..571235f3 100644
--- a/cl/_testrt/_gotypes/out.ll
+++ b/cl/_testrt/gotypes/out.ll
@@ -3,9 +3,9 @@ source_filename = "main"
 
 %"github.com/goplus/llgo/internal/runtime.iface" = type { ptr, ptr }
 
-@"main.init$guard" = global ptr null
-@__llgo_argc = global ptr null
-@__llgo_argv = global ptr null
+@"main.init$guard" = global i1 false, align 1
+@__llgo_argc = global i32 0, align 4
+@__llgo_argv = global ptr null, align 8
 
 define void @main.foo(%"github.com/goplus/llgo/internal/runtime.iface" %0) {
 _llgo_0:
diff --git a/cl/builtin_test.go b/cl/builtin_test.go
index 9d3ee83d..bf5e12df 100644
--- a/cl/builtin_test.go
+++ b/cl/builtin_test.go
@@ -209,7 +209,7 @@ func TestIntVal(t *testing.T) {
 }
 
 func TestIgnoreName(t *testing.T) {
-	if !ignoreName("runtime.foo") || !ignoreName("runtime/foo") || !ignoreName("internal/abi") {
+	if !ignoreName("runtime/foo") || !ignoreName("internal/abi") {
 		t.Fatal("ignoreName failed")
 	}
 }
diff --git a/cl/compile.go b/cl/compile.go
index 3b631e69..b73e96ce 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -96,22 +96,12 @@ func ignoreName(name string) bool {
 		return true
 	}
 	*/
-	if strings.HasPrefix(name, "internal/") || strings.HasPrefix(name, "crypto/") ||
+	return strings.HasPrefix(name, "internal/") || strings.HasPrefix(name, "crypto/") ||
 		strings.HasPrefix(name, "arena.") || strings.HasPrefix(name, "maps.") ||
 		strings.HasPrefix(name, "time.") || strings.HasPrefix(name, "syscall.") ||
 		strings.HasPrefix(name, "os.") || strings.HasPrefix(name, "plugin.") ||
-		strings.HasPrefix(name, "reflect.") || strings.HasPrefix(name, "errors.") {
-		return true // TODO(xsw)
-	}
-	return inPkg(name, "runtime") || inPkg(name, "sync")
-}
-
-func inPkg(name, pkg string) bool {
-	if len(name) > len(pkg) && strings.HasPrefix(name, pkg) {
-		c := name[len(pkg)]
-		return c == '.' || c == '/'
-	}
-	return false
+		strings.HasPrefix(name, "reflect.") || strings.HasPrefix(name, "errors.") ||
+		strings.HasPrefix(name, "runtime/")
 }
 
 // -----------------------------------------------------------------------------
@@ -157,6 +147,8 @@ type context struct {
 
 	inits []func()
 	phis  []func()
+
+	skipall bool
 }
 
 func (p *context) inMain(instr ssa.Instruction) bool {
@@ -1048,7 +1040,9 @@ func NewPackageEx(prog llssa.Program, pkg, alt *ssa.Package, files []*ast.File)
 		processPkg(ctx, ret, alt)
 		ctx.skips = skips
 	}
-	processPkg(ctx, ret, pkg)
+	if !ctx.skipall {
+		processPkg(ctx, ret, pkg)
+	}
 	for len(ctx.inits) > 0 {
 		inits := ctx.inits
 		ctx.inits = nil
diff --git a/cl/import.go b/cl/import.go
index c1217778..72addadd 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -193,10 +193,12 @@ func (p *context) initFiles(pkgPath string, files []*ast.File) {
 	}
 }
 
+// llgo:skip symbol1 symbol2 ...
+// llgo:skipall
 func (p *context) collectSkipNames(line string) {
 	const (
-		skip  = "//llgo:skip "
-		skip2 = "// llgo:skip "
+		skip  = "//llgo:skip"
+		skip2 = "// llgo:skip"
 	)
 	if strings.HasPrefix(line, skip2) {
 		p.collectSkip(line, len(skip2))
@@ -206,7 +208,15 @@ func (p *context) collectSkipNames(line string) {
 }
 
 func (p *context) collectSkip(line string, prefix int) {
-	names := strings.Split(line[prefix:], " ")
+	line = line[prefix:]
+	if line == "all" {
+		p.skipall = true
+		return
+	}
+	if len(line) == 0 || line[0] != ' ' {
+		return
+	}
+	names := strings.Split(line[1:], " ")
 	for _, name := range names {
 		if name != "" {
 			p.skips[name] = none{}
diff --git a/internal/build/build.go b/internal/build/build.go
index 2fba905e..4dc353c5 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -22,6 +22,7 @@ import (
 	"go/token"
 	"go/types"
 	"io"
+	"log"
 	"os"
 	"os/exec"
 	"path"
@@ -155,15 +156,20 @@ func Do(args []string, conf *Config) {
 		return nil
 	}
 
-	pkgs := buildAllPkgs(prog, imp, initial, nil, mode, verbose)
+	progSSA := ssa.NewProgram(initial[0].Fset, ssaBuildMode)
+	pkgs := buildAllPkgs(prog, progSSA, imp, initial, nil, mode, verbose)
 
 	var runtimeFiles []string
 	if needRt {
+		// TODO(xsw): maybe we need trace runtime sometimes
+		llssa.SetDebug(0)
+		cl.SetDebug(0)
+
 		skip := make(map[string]bool)
 		for _, v := range pkgs {
 			skip[v.PkgPath] = true
 		}
-		dpkg := buildAllPkgs(prog, imp, rt[:1], skip, mode, verbose)
+		dpkg := buildAllPkgs(prog, progSSA, imp, rt[:1], skip, mode, verbose)
 		for _, pkg := range dpkg {
 			if !strings.HasSuffix(pkg.ExportFile, ".ll") {
 				continue
@@ -206,10 +212,9 @@ const (
 	ssaBuildMode = ssa.SanityCheckFunctions
 )
 
-func buildAllPkgs(prog llssa.Program, imp importer, initial []*packages.Package, skip map[string]bool, mode Mode, verbose bool) (pkgs []*aPackage) {
+func buildAllPkgs(prog llssa.Program, progSSA *ssa.Program, imp importer, initial []*packages.Package, skip map[string]bool, mode Mode, verbose bool) (pkgs []*aPackage) {
 	// Create SSA-form program representation.
-	ssaProg, pkgs, errPkgs := allPkgs(imp, initial, ssaBuildMode)
-	ssaProg.Build()
+	pkgs, errPkgs := allPkgs(progSSA, imp, initial, verbose)
 	for _, errPkg := range errPkgs {
 		for _, err := range errPkg.Errors {
 			fmt.Fprintln(os.Stderr, err)
@@ -399,7 +404,7 @@ func buildPkg(prog llssa.Program, aPkg *aPackage, mode Mode, verbose bool) {
 
 func canSkipToBuild(pkgPath string) bool {
 	switch pkgPath {
-	case "unsafe", "runtime", "errors", "sync", "sync/atomic":
+	case "unsafe", "errors":
 		return true
 	default:
 		return strings.HasPrefix(pkgPath, "internal/") ||
@@ -418,25 +423,25 @@ type aPackage struct {
 type none struct{}
 
 var hasAltPkg = map[string]none{
-	"math": {},
+	"math":        {},
+	"sync":        {},
+	"sync/atomic": {},
+	"runtime":     {},
 }
 
 type importer = func(pkgPath string) *packages.Package
 
-func allPkgs(imp importer, initial []*packages.Package, mode ssa.BuilderMode) (prog *ssa.Program, all []*aPackage, errs []*packages.Package) {
-	var fset *token.FileSet
-	if len(initial) > 0 {
-		fset = initial[0].Fset
-	}
-
-	prog = ssa.NewProgram(fset, mode)
+func allPkgs(prog *ssa.Program, imp importer, initial []*packages.Package, verbose bool) (all []*aPackage, errs []*packages.Package) {
 	packages.Visit(initial, nil, func(p *packages.Package) {
 		if p.Types != nil && !p.IllTyped {
 			var altPkg *packages.Package
 			var altSSA *ssa.Package
-			var ssaPkg = prog.CreatePackage(p.Types, p.Syntax, p.TypesInfo, true)
+			var ssaPkg = createSSAPkg(prog, p)
 			if imp != nil {
 				if _, ok := hasAltPkg[p.PkgPath]; ok {
+					if verbose {
+						log.Println("==> Patching", p.PkgPath)
+					}
 					altPkgPath := "github.com/goplus/llgo/internal/lib/" + p.PkgPath
 					if altPkg = imp(altPkgPath); altPkg != nil { // TODO(xsw): how to minimize import times
 						altSSA = createAltSSAPkg(prog, altPkg)
@@ -452,22 +457,27 @@ func allPkgs(imp importer, initial []*packages.Package, mode ssa.BuilderMode) (p
 }
 
 func createAltSSAPkg(prog *ssa.Program, alt *packages.Package) *ssa.Package {
-	altPath := alt.Types.Path()
-	altSSA := prog.ImportedPackage(altPath)
+	altSSA := prog.ImportedPackage(alt.PkgPath)
 	if altSSA == nil {
 		packages.Visit([]*packages.Package{alt}, nil, func(p *packages.Package) {
-			pkgTypes := p.Types
-			if pkgTypes != nil && !p.IllTyped {
-				if prog.ImportedPackage(pkgTypes.Path()) == nil {
-					prog.CreatePackage(pkgTypes, p.Syntax, p.TypesInfo, true)
-				}
+			if p.Types != nil && !p.IllTyped {
+				createSSAPkg(prog, p)
 			}
 		})
-		altSSA = prog.ImportedPackage(altPath)
+		altSSA = prog.ImportedPackage(alt.PkgPath)
 	}
 	return altSSA
 }
 
+func createSSAPkg(prog *ssa.Program, p *packages.Package) *ssa.Package {
+	pkgSSA := prog.ImportedPackage(p.PkgPath)
+	if pkgSSA == nil {
+		pkgSSA = prog.CreatePackage(p.Types, p.Syntax, p.TypesInfo, true)
+		pkgSSA.Build() // TODO(xsw): build concurrently
+	}
+	return pkgSSA
+}
+
 var (
 	// TODO(xsw): complete build flags
 	buildFlags = map[string]bool{
diff --git a/internal/lib/runtime/runtime.go b/internal/lib/runtime/runtime.go
new file mode 100644
index 00000000..e8492442
--- /dev/null
+++ b/internal/lib/runtime/runtime.go
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package runtime
+
+// llgo:skipall
+import (
+	_ "unsafe"
+)
diff --git a/internal/lib/sync/atomic/atomic.go b/internal/lib/sync/atomic/atomic.go
new file mode 100644
index 00000000..24c3ecb1
--- /dev/null
+++ b/internal/lib/sync/atomic/atomic.go
@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package atomic
+
+import (
+	_ "unsafe"
+)
+
+const (
+	LLGoPackage = true
+)
+
+//go:linkname cAddInt64 llgo.atomicAdd
+func cAddInt64(addr *int64, delta int64) (old int64)
+
+func AddInt64(addr *int64, delta int64) (new int64) {
+	return cAddInt64(addr, delta) + delta
+}
diff --git a/internal/lib/sync/sync.go b/internal/lib/sync/sync.go
new file mode 100644
index 00000000..56822964
--- /dev/null
+++ b/internal/lib/sync/sync.go
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sync
+
+// llgo:skipall
+import (
+	_ "unsafe"
+)