diff --git a/cl/compile.go b/cl/compile.go
index 4239cd76..60c2ceba 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -201,7 +201,7 @@ func (p *context) compileGlobal(pkg llssa.Package, gbl *ssa.Global) {
 	}
 	g := pkg.NewVar(name, typ, llssa.Background(vtype))
 	if vtype == goVar {
-		g.Init(p.prog.Null(g.Type))
+		g.Init(p.prog.Nil(g.Type))
 	}
 }
 
@@ -338,6 +338,8 @@ func (p *context) funcOf(fn *ssa.Function) (aFn llssa.Function, pyFn llssa.PyObj
 			ftype = llgoSigsetjmp
 		case "siglongjmp":
 			ftype = llgoSiglongjmp
+		case "deferData":
+			ftype = llgoDeferData
 		case "unreachable":
 			ftype = llgoUnreachable
 		default:
@@ -378,8 +380,8 @@ func (p *context) compileBlock(b llssa.Builder, block *ssa.BasicBlock, n int, do
 		fn := p.fn
 		argc := pkg.NewVar("__llgo_argc", types.NewPointer(types.Typ[types.Int32]), llssa.InC)
 		argv := pkg.NewVar("__llgo_argv", types.NewPointer(argvTy), llssa.InC)
-		argc.Init(prog.Null(argc.Type))
-		argv.Init(prog.Null(argv.Type))
+		argc.Init(prog.Nil(argc.Type))
+		argv.Init(prog.Nil(argv.Type))
 		b.Store(argc.Expr, fn.Param(0))
 		b.Store(argv.Expr, fn.Param(1))
 		callRuntimeInit(b, pkg)
@@ -395,7 +397,7 @@ func (p *context) compileBlock(b llssa.Builder, block *ssa.BasicBlock, n int, do
 		modName := pysymPrefix + modPath
 		modPtr := pkg.PyNewModVar(modName, true).Expr
 		mod := b.Load(modPtr)
-		cond := b.BinOp(token.NEQ, mod, prog.Null(mod.Type))
+		cond := b.BinOp(token.NEQ, mod, prog.Nil(mod.Type))
 		newBlk := p.fn.MakeBlock()
 		b.If(cond, jumpTo, newBlk)
 		b.SetBlockEx(newBlk, llssa.AtEnd, false)
@@ -431,8 +433,11 @@ func intVal(v ssa.Value) int64 {
 }
 
 func (p *context) isVArgs(vx ssa.Value) (ret []llssa.Expr, ok bool) {
-	if va, vok := vx.(*ssa.Alloc); vok {
-		ret, ok = p.vargs[va] // varargs: this is a varargs index
+	switch vx := vx.(type) {
+	case *ssa.Alloc:
+		ret, ok = p.vargs[vx] // varargs: this is a varargs index
+	case *ssa.Const:
+		ok = vx.Value == nil
 	}
 	return
 }
@@ -642,6 +647,8 @@ func (p *context) call(b llssa.Builder, act llssa.DoAction, call *ssa.CallCommon
 			p.siglongjmp(b, args)
 		case llgoSigjmpbuf: // func sigjmpbuf()
 			ret = b.AllocaSigjmpBuf()
+		case llgoDeferData: // func deferData() *Defer
+			ret = b.DeferData()
 		case llgoUnreachable: // func unreachable()
 			b.Unreachable()
 		default:
diff --git a/cl/import.go b/cl/import.go
index 7cd23813..473226c0 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -312,6 +312,7 @@ const (
 	llgoSigjmpbuf   = llgoInstrBase + 10
 	llgoSigsetjmp   = llgoInstrBase + 11
 	llgoSiglongjmp  = llgoInstrBase + 12
+	llgoDeferData   = llgoInstrBase + 13
 )
 
 func (p *context) funcName(fn *ssa.Function, ignore bool) (*types.Package, string, int) {
diff --git a/internal/runtime/c/c.go b/internal/runtime/c/c.go
index 63ace390..4183c832 100644
--- a/internal/runtime/c/c.go
+++ b/internal/runtime/c/c.go
@@ -42,15 +42,30 @@ func Alloca(size uintptr) Pointer
 //go:linkname AllocaCStr llgo.allocaCStr
 func AllocaCStr(s string) *Char
 
+//go:linkname GoDeferData llgo.deferData
+func GoDeferData() Pointer
+
 //go:linkname Unreachable llgo.unreachable
 func Unreachable()
 
+//go:linkname AllocaSigjmpBuf llgo.sigjmpbuf
+func AllocaSigjmpBuf() Pointer
+
+//go:linkname Sigsetjmp llgo.sigsetjmp
+func Sigsetjmp(jb Pointer, savemask Int) Int
+
+//go:linkname Siglongjmp llgo.siglongjmp
+func Siglongjmp(jb Pointer, retval Int)
+
 //go:linkname Rand C.rand
 func Rand() Int
 
 //go:linkname Malloc C.malloc
 func Malloc(size uintptr) Pointer
 
+//go:linkname Free C.free
+func Free(ptr Pointer)
+
 //go:linkname Memcpy C.memcpy
 func Memcpy(dst, src Pointer, n uintptr) Pointer
 
diff --git a/internal/runtime/z_rt.go b/internal/runtime/z_rt.go
index 3b5b29b7..69fa4584 100644
--- a/internal/runtime/z_rt.go
+++ b/internal/runtime/z_rt.go
@@ -19,6 +19,7 @@ package runtime
 import (
 	"unsafe"
 
+	"github.com/goplus/llgo/c/pthread"
 	"github.com/goplus/llgo/internal/abi"
 	"github.com/goplus/llgo/internal/runtime/c"
 )
@@ -27,19 +28,43 @@ import (
 
 // Defer presents defer statements in a function.
 type Defer struct {
-	Addr unsafe.Pointer
+	Addr unsafe.Pointer // sigjmpbuf
 	Bits uintptr
 	Link *Defer
 	Rund int // index of RunDefers
 }
 
-// -----------------------------------------------------------------------------
+// Panic panics with a value.
+func Panic(v Eface) {
+	ptr := c.Malloc(unsafe.Sizeof(v))
+	*(*Eface)(ptr) = v
+	excepKey.Set(ptr)
 
-// Zeroinit initializes memory to zero.
-func Zeroinit(p unsafe.Pointer, size uintptr) unsafe.Pointer {
-	return c.Memset(p, 0, size)
+	Rethrow((*Defer)(c.GoDeferData()))
 }
 
+// Rethrow rethrows a panic.
+func Rethrow(link *Defer) {
+	if link == nil {
+		ptr := excepKey.Get()
+		TracePanic(*(*Eface)(ptr))
+		c.Free(ptr)
+		c.Unreachable()
+	} else {
+		c.Siglongjmp(link.Addr, 1)
+	}
+}
+
+var (
+	excepKey pthread.Key
+)
+
+func init() {
+	excepKey.Create(nil)
+}
+
+// -----------------------------------------------------------------------------
+
 // TracePanic prints panic message.
 func TracePanic(v Eface) {
 	kind := v._type.Kind()
@@ -56,3 +81,10 @@ func stringTracef(fp c.FilePtr, format *c.Char, s String) {
 }
 
 // -----------------------------------------------------------------------------
+
+// Zeroinit initializes memory to zero.
+func Zeroinit(p unsafe.Pointer, size uintptr) unsafe.Pointer {
+	return c.Memset(p, 0, size)
+}
+
+// -----------------------------------------------------------------------------
diff --git a/ssa/abitype.go b/ssa/abitype.go
index e41fda58..2fa2ec71 100644
--- a/ssa/abitype.go
+++ b/ssa/abitype.go
@@ -303,7 +303,7 @@ func (p Package) abiTypeInit(g Global, t types.Type, pub bool) {
 	var eq Expr
 	var blks []BasicBlock
 	if pub {
-		eq = b.BinOp(token.EQL, b.Load(expr), b.Prog.Null(expr.Type))
+		eq = b.BinOp(token.EQL, b.Load(expr), b.Prog.Nil(expr.Type))
 		blks = b.Func.MakeBlocks(2)
 		b.If(eq, blks[0], blks[1])
 		b.SetBlockEx(blks[0], AtEnd, false)
@@ -343,7 +343,7 @@ func (b Builder) abiType(t types.Type) Expr {
 	if g == nil {
 		prog := b.Prog
 		g = pkg.doNewVar(name, prog.AbiTypePtrPtr())
-		g.Init(prog.Null(g.Type))
+		g.Init(prog.Nil(g.Type))
 		if pub {
 			g.impl.SetLinkage(llvm.LinkOnceAnyLinkage)
 		}
diff --git a/ssa/eh.go b/ssa/eh.go
index 0dac60e8..d883fdf2 100644
--- a/ssa/eh.go
+++ b/ssa/eh.go
@@ -22,7 +22,6 @@ import "C"
 import (
 	"go/token"
 	"go/types"
-	"log"
 	"unsafe"
 
 	"github.com/goplus/llvm"
@@ -77,6 +76,7 @@ func (b Builder) Siglongjmp(jb, retval Expr) {
 
 const (
 	deferKey = "__llgo_defer"
+	excepKey = "__llgo_ex"
 )
 
 func (p Function) deferInitBuilder() (b Builder, next BasicBlock) {
@@ -96,29 +96,33 @@ type aDefer struct {
 	stmts    []func(bits Expr)
 }
 
-func (p Package) deferInit() {
-	keyVar := p.VarOf(deferKey)
+func (p Package) keyInit(name string) {
+	keyVar := p.VarOf(name)
 	if keyVar == nil {
 		return
 	}
 	prog := p.Prog
-	keyNil := prog.Null(prog.DeferPtrPtr())
+	keyNil := prog.Nil(prog.CIntPtr())
 	keyVar.Init(keyNil)
 	keyVar.impl.SetLinkage(llvm.LinkOnceAnyLinkage)
 
 	b := p.afterBuilder()
-	eq := b.BinOp(token.EQL, b.Load(keyVar.Expr), keyNil)
+	eq := b.BinOp(token.EQL, b.Load(keyVar.Expr), prog.IntVal(0, prog.CInt()))
 	b.IfThen(eq, func() {
-		b.pthreadKeyCreate(keyVar.Expr, prog.Null(prog.VoidPtr()))
+		b.pthreadKeyCreate(keyVar.Expr, prog.Nil(prog.VoidPtr()))
 	})
 }
 
-func (p Package) newDeferKey() Global {
-	return p.NewVarEx(deferKey, p.Prog.DeferPtrPtr())
+func (p Package) newKey(name string) Global {
+	return p.NewVarEx(name, p.Prog.CIntPtr())
 }
 
 func (b Builder) deferKey() Expr {
-	return b.Load(b.Pkg.newDeferKey().Expr)
+	return b.Load(b.Pkg.newKey(deferKey).Expr)
+}
+
+func (b Builder) excepKey() Expr {
+	return b.Load(b.Pkg.newKey(excepKey).Expr)
 }
 
 func (b Builder) getDefer(kind DoAction) *aDefer {
@@ -148,7 +152,7 @@ func (b Builder) getDefer(kind DoAction) *aDefer {
 		deferData := Expr{ptr, prog.DeferPtr()}
 		b.pthreadSetspecific(key, deferData)
 		blks := self.MakeBlocks(2)
-		procBlk, throwBlk := blks[0], blks[1]
+		procBlk, rethrowBlk := blks[0], blks[1]
 		bitsPtr := b.FieldAddr(deferData, deferBits)
 		rundPtr := b.FieldAddr(deferData, deferRund)
 		self.defer_ = &aDefer{
@@ -157,7 +161,7 @@ func (b Builder) getDefer(kind DoAction) *aDefer {
 			bitsPtr:  bitsPtr,
 			rundPtr:  rundPtr,
 			procBlk:  procBlk,
-			runsNext: []BasicBlock{throwBlk},
+			runsNext: []BasicBlock{rethrowBlk},
 		}
 		czero := prog.IntVal(0, prog.CInt())
 		retval := b.Sigsetjmp(jb, czero)
@@ -168,12 +172,14 @@ func (b Builder) getDefer(kind DoAction) *aDefer {
 			next, rundBlk = blks[0], blks[1]
 		}
 		b.If(b.BinOp(token.EQL, retval, czero), next, rundBlk)
-		b.SetBlockEx(rundBlk, AtEnd, false) // exec runDefers and throw
+		b.SetBlockEx(rundBlk, AtEnd, false) // exec runDefers and rethrow
 		b.Store(rundPtr, prog.Val(0))
 		b.Jump(procBlk)
-		b.SetBlockEx(throwBlk, AtEnd, false) // throw
-		linkJBPtr := b.FieldAddr(link, deferSigjmpbuf)
-		b.Siglongjmp(b.Load(linkJBPtr), prog.IntVal(1, prog.CInt()))
+
+		b.SetBlockEx(rethrowBlk, AtEnd, false) // rethrow
+		b.Call(b.Pkg.rtFunc("Rethrow"), b.Load(link))
+		b.Unreachable() // TODO: func supports noreturn attribute
+
 		if kind == DeferAlways {
 			b.SetBlockEx(next, AtEnd, false)
 			b.blk.last = next.last
@@ -182,6 +188,12 @@ func (b Builder) getDefer(kind DoAction) *aDefer {
 	return self.defer_
 }
 
+// DeferData returns the defer data (*runtime.Defer).
+func (b Builder) DeferData() Expr {
+	key := b.deferKey()
+	return Expr{b.pthreadGetspecific(key).impl, b.Prog.DeferPtr()}
+}
+
 // Defer emits a defer instruction.
 func (b Builder) Defer(kind DoAction, fn Expr, args ...Expr) {
 	if debugInstr {
@@ -249,13 +261,16 @@ func (p Function) endDefer(b Builder) {
 
 	link := b.getField(b.Load(self.data), 2)
 	b.pthreadSetspecific(self.key, link)
-
-	// rund := b.Load(self.rundPtr)
 	b.IndirectJump(self.rundPtr, nexts)
 }
 
 // -----------------------------------------------------------------------------
 
+// Unreachable emits an unreachable instruction.
+func (b Builder) Unreachable() {
+	b.impl.CreateUnreachable()
+}
+
 /*
 // Recover emits a recover instruction.
 func (b Builder) Recover() (v Expr) {
@@ -263,22 +278,34 @@ func (b Builder) Recover() (v Expr) {
 		log.Println("Recover")
 	}
 	prog := b.Prog
-	return prog.Zero(prog.Eface())
+	return prog.Zero(prog.Any())
 }
 */
 
 // Panic emits a panic instruction.
 func (b Builder) Panic(v Expr) {
+	b.Call(b.Pkg.rtFunc("Panic"), v)
+	b.Unreachable() // TODO: func supports noreturn attribute
+}
+
+/*
+// Panic emits a panic instruction.
+func (b Builder) Panic(v Expr) {
+	vimpl := v.impl
 	if debugInstr {
-		log.Printf("Panic %v\n", v.impl)
+		log.Printf("Panic %v\n", vimpl)
 	}
+	if v.kind != vkEface {
+		panic("Panic only accepts an any expression")
+	}
+	ptr := b.dupMalloc(v)
+	b.pthreadSetspecific(b.excepKey(), ptr)
+}
+
+func (b Builder) doPanic(v Expr) {
 	b.Call(b.Pkg.rtFunc("TracePanic"), v)
 	b.impl.CreateUnreachable()
 }
-
-// Unreachable emits an unreachable instruction.
-func (b Builder) Unreachable() {
-	b.impl.CreateUnreachable()
-}
+*/
 
 // -----------------------------------------------------------------------------
diff --git a/ssa/expr.go b/ssa/expr.go
index 960f1cde..ac7733a6 100644
--- a/ssa/expr.go
+++ b/ssa/expr.go
@@ -83,6 +83,7 @@ func pyVarExpr(mod Expr, name string) Expr {
 
 // -----------------------------------------------------------------------------
 
+// Zero returns a zero constant expression.
 func (p Program) Zero(t Type) Expr {
 	var ret llvm.Value
 	switch u := t.raw.Type.Underlying().(type) {
@@ -127,16 +128,11 @@ func (p Program) Zero(t Type) Expr {
 	return Expr{ret, t}
 }
 
-// Null returns a null constant expression.
-func (p Program) Null(t Type) Expr {
+// Nil returns a null constant expression. t should be a pointer type.
+func (p Program) Nil(t Type) Expr {
 	return Expr{llvm.ConstNull(t.ll), t}
 }
 
-// PyNull returns a null *PyObject constant expression.
-func (p Program) PyNull() Expr {
-	return p.Null(p.PyObjectPtr())
-}
-
 // BoolVal returns a boolean constant expression.
 func (p Program) BoolVal(v bool) Expr {
 	t := p.Bool()
@@ -180,7 +176,7 @@ func (p Program) Val(v interface{}) Expr {
 func (b Builder) Const(v constant.Value, typ Type) Expr {
 	prog := b.Prog
 	if v == nil {
-		return prog.Null(typ)
+		return prog.Nil(typ)
 	}
 	raw := typ.raw.Type
 	switch t := raw.Underlying().(type) {
diff --git a/ssa/goroutine.go b/ssa/goroutine.go
index 389ae8df..d2bf3787 100644
--- a/ssa/goroutine.go
+++ b/ssa/goroutine.go
@@ -86,7 +86,7 @@ func (b Builder) Go(fn Expr, args ...Expr) {
 	data := Expr{b.aggregateMalloc(t, flds...), voidPtr}
 	size := prog.SizeOf(voidPtr)
 	pthd := b.Alloca(prog.IntVal(uint64(size), prog.Uintptr()))
-	b.pthreadCreate(pthd, prog.Null(voidPtr), pkg.routine(t, len(args)), data)
+	b.pthreadCreate(pthd, prog.Nil(voidPtr), pkg.routine(t, len(args)), data)
 }
 
 func (p Package) routineName() string {
@@ -107,7 +107,7 @@ func (p Package) routine(t Type, n int) Expr {
 	}
 	b.Call(fn, args...)
 	b.free(param)
-	b.Return(prog.Null(prog.VoidPtr()))
+	b.Return(prog.Nil(prog.VoidPtr()))
 	return routine.Expr
 }
 
diff --git a/ssa/memory.go b/ssa/memory.go
index 94cfc7f3..d63df457 100644
--- a/ssa/memory.go
+++ b/ssa/memory.go
@@ -107,6 +107,17 @@ func aggregateInit(b llvm.Builder, ptr llvm.Value, tll llvm.Type, flds ...llvm.V
 	}
 }
 
+/*
+func (b Builder) dupMalloc(v Expr) Expr {
+	prog := b.Prog
+	n := prog.SizeOf(v.Type)
+	tptr := prog.Pointer(v.Type)
+	ptr := b.malloc(prog.Val(uintptr(n))).impl
+	b.Store(Expr{ptr, tptr}, v)
+	return Expr{ptr, tptr}
+}
+*/
+
 // -----------------------------------------------------------------------------
 
 // The Alloc instruction reserves space for a variable of the given type,
diff --git a/ssa/package.go b/ssa/package.go
index 24171164..2d0f3e09 100644
--- a/ssa/package.go
+++ b/ssa/package.go
@@ -131,14 +131,16 @@ type aProgram struct {
 	rtSliceTy  llvm.Type
 	rtMapTy    llvm.Type
 
-	anyTy    Type
-	voidTy   Type
-	voidPtr  Type
-	voidPPtr Type
-	boolTy   Type
-	cstrTy   Type
-	cintTy   Type
-	//cintPtr Type
+	anyTy Type
+	//anyPtr  Type
+	//anyPPtr Type
+	voidTy    Type
+	voidPtr   Type
+	voidPPtr  Type
+	boolTy    Type
+	cstrTy    Type
+	cintTy    Type
+	cintPtr   Type
 	stringTy  Type
 	uintptrTy Type
 	intTy     Type
@@ -158,7 +160,6 @@ type aProgram struct {
 	abiTyPPtr Type
 	deferTy   Type
 	deferPtr  Type
-	deferPPtr Type
 
 	pyImpTy      *types.Signature
 	pyNewList    *types.Signature
@@ -328,14 +329,6 @@ func (p Program) DeferPtr() Type {
 	return p.deferPtr
 }
 
-// DeferPtrPtr returns **runtime.Defer type.
-func (p Program) DeferPtrPtr() Type {
-	if p.deferPPtr == nil {
-		p.deferPPtr = p.Pointer(p.DeferPtr())
-	}
-	return p.deferPPtr
-}
-
 // AbiTypePtr returns *abi.Type type.
 func (p Program) AbiTypePtr() Type {
 	if p.abiTyPtr == nil {
@@ -360,6 +353,7 @@ func (p Program) Void() Type {
 	return p.voidTy
 }
 
+// VoidPtr returns *void type.
 func (p Program) VoidPtr() Type {
 	if p.voidPtr == nil {
 		p.voidPtr = p.rawType(types.Typ[types.UnsafePointer])
@@ -367,6 +361,7 @@ func (p Program) VoidPtr() Type {
 	return p.voidPtr
 }
 
+// VoidPtrPtr returns **void type.
 func (p Program) VoidPtrPtr() Type {
 	if p.voidPPtr == nil {
 		p.voidPPtr = p.rawType(types.NewPointer(types.Typ[types.UnsafePointer]))
@@ -382,6 +377,7 @@ func (p Program) Bool() Type {
 	return p.boolTy
 }
 
+// CStr returns *int8 type.
 func (p Program) CStr() Type {
 	if p.cstrTy == nil { // *int8
 		p.cstrTy = p.rawType(types.NewPointer(types.Typ[types.Int8]))
@@ -389,6 +385,7 @@ func (p Program) CStr() Type {
 	return p.cstrTy
 }
 
+// String returns string type.
 func (p Program) String() Type {
 	if p.stringTy == nil {
 		p.stringTy = p.rawType(types.Typ[types.String])
@@ -396,6 +393,24 @@ func (p Program) String() Type {
 	return p.stringTy
 }
 
+/*
+// AnyPtrPtr returns **any type.
+func (p Program) AnyPtrPtr() Type {
+	if p.anyPPtr == nil {
+		p.anyPPtr = p.Pointer(p.AnyPtr())
+	}
+	return p.anyPPtr
+}
+
+// AnyPtr returns *any type.
+func (p Program) AnyPtr() Type {
+	if p.anyPtr == nil {
+		p.anyPtr = p.Pointer(p.Any())
+	}
+	return p.anyPtr
+}
+*/
+
 // Any returns the any (empty interface) type.
 func (p Program) Any() Type {
 	if p.anyTy == nil {
@@ -410,6 +425,7 @@ func (p Program) Any() Type {
 func (p Program) Eface() Type {
 	return p.Any()
 }
+*/
 
 // CIntPtr returns *c.Int type.
 func (p Program) CIntPtr() Type {
@@ -418,7 +434,6 @@ func (p Program) CIntPtr() Type {
 	}
 	return p.cintPtr
 }
-*/
 
 // CInt returns c.Int type.
 func (p Program) CInt() Type {
@@ -550,7 +565,7 @@ func (p Package) cFunc(fullName string, sig *types.Signature) Expr {
 func (p Package) closureStub(b Builder, t *types.Struct, v Expr) Expr {
 	name := v.impl.Name()
 	prog := b.Prog
-	nilVal := prog.Null(prog.VoidPtr()).impl
+	nilVal := prog.Nil(prog.VoidPtr()).impl
 	if fn, ok := p.stubs[name]; ok {
 		v = fn.Expr
 	} else {
@@ -605,7 +620,8 @@ func (p Package) afterBuilder() Builder {
 
 // AfterInit is called after the package is initialized (init all packages that depends on).
 func (p Package) AfterInit(b Builder, ret BasicBlock) {
-	p.deferInit()
+	p.keyInit(deferKey)
+	p.keyInit(excepKey)
 	doAfterb := p.afterb != nil
 	doPyLoadModSyms := p.pyHasModSyms()
 	if doAfterb || doPyLoadModSyms {
diff --git a/ssa/python.go b/ssa/python.go
index 2ff344a4..b9520bee 100644
--- a/ssa/python.go
+++ b/ssa/python.go
@@ -217,7 +217,7 @@ func (p Package) PyNewModVar(name string, doInit bool) Global {
 	objPtr := prog.PyObjectPtrPtr().raw.Type
 	g := p.NewVar(name, objPtr, InC)
 	if doInit {
-		g.Init(prog.Null(g.Type))
+		g.Init(prog.Nil(g.Type))
 		g.impl.SetLinkage(llvm.LinkOnceAnyLinkage)
 	}
 	p.pymods[name] = g
@@ -246,7 +246,7 @@ func (b Builder) PyLoadModSyms(modName string, objs ...PyObjRef) Expr {
 		args = append(args, o.Expr)
 	}
 	prog := b.Prog
-	args = append(args, prog.Null(prog.CStr()))
+	args = append(args, prog.Nil(prog.CStr()))
 	return b.Call(fnLoad, args...)
 }
 
@@ -273,7 +273,7 @@ func (b Builder) pyCall(fn Expr, args []Expr) (ret Expr) {
 		callargs := make([]Expr, n+2)
 		callargs[0] = fn
 		copy(callargs[1:], args)
-		callargs[n+1] = prog.PyNull()
+		callargs[n+1] = prog.Nil(prog.PyObjectPtr())
 		ret = b.Call(call, callargs...)
 	}
 	return
@@ -372,7 +372,7 @@ func (p Package) PyNewFunc(name string, sig *types.Signature, doInit bool) PyObj
 	obj := p.NewVar(name, prog.PyObjectPtrPtr().RawType(), InC)
 	if doInit {
 		prog.NeedPyInit = true
-		obj.Init(prog.Null(obj.Type))
+		obj.Init(prog.Nil(obj.Type))
 		obj.impl.SetLinkage(llvm.LinkOnceAnyLinkage)
 	}
 	ty := &aType{obj.ll, rawType{types.NewPointer(sig)}, vkPyFuncRef}