diff --git a/ssa/decl.go b/ssa/decl.go
index a42f9cb6..83b3bbb2 100644
--- a/ssa/decl.go
+++ b/ssa/decl.go
@@ -17,6 +17,8 @@
 package ssa
 
 import (
+	"go/types"
+
 	"github.com/goplus/llvm"
 )
 
@@ -105,11 +107,32 @@ type aFunction struct {
 	Type
 
 	prog Program
+
+	params []Type
 }
 
 type Function = *aFunction
 
-func (p *aFunction) MakeBody(label string) Builder {
+func newFunction(fn llvm.Value, t Type, prog Program) Function {
+	ret := &aFunction{fn, t, prog, newParams(t, prog)}
+	return ret
+}
+
+func newParams(fn Type, prog Program) []Type {
+	in := fn.t.(*types.Signature).Params()
+	n := in.Len()
+	ret := make([]Type, n)
+	for i := 0; i < n; i++ {
+		ret[i] = prog.llvmType(in.At(i).Type())
+	}
+	return ret
+}
+
+func (p Function) Param(i int) Expr {
+	return Expr{p.impl.Param(i), p.params[i]}
+}
+
+func (p Function) MakeBody(label string) Builder {
 	body := llvm.AddBasicBlock(p.impl, label)
 	prog := p.prog
 	b := prog.ctx.NewBuilder()
diff --git a/ssa/package.go b/ssa/package.go
index f38e4565..2ebb9015 100644
--- a/ssa/package.go
+++ b/ssa/package.go
@@ -114,7 +114,7 @@ func (p Package) NewVar(name string, typ types.Type) Global {
 func (p Package) NewFunc(name string, sig *types.Signature) Function {
 	t := p.prog.llvmSignature(sig)
 	fn := llvm.AddFunction(p.mod, name, t.ll)
-	return &aFunction{fn, t, p.prog}
+	return newFunction(fn, t, p.prog)
 }
 
 func (p Package) String() string {
diff --git a/ssa/ssa_test.go b/ssa/ssa_test.go
index 49adf334..97e91028 100644
--- a/ssa/ssa_test.go
+++ b/ssa/ssa_test.go
@@ -95,15 +95,37 @@ declare void @fn(i64)
 func TestBasicFunc(t *testing.T) {
 	prog := NewProgram(nil)
 	pkg := prog.NewPackage("bar", "foo/bar")
-	rets := types.NewTuple(types.NewVar(0, nil, "a", types.Typ[types.Int]))
-	sig := types.NewSignatureType(nil, nil, nil, nil, rets, false)
-	b := pkg.NewFunc("fn", sig).MakeBody("")
-	b.Return(prog.Val(1))
+	params := types.NewTuple(
+		types.NewVar(0, nil, "a", types.Typ[types.Int]),
+		types.NewVar(0, nil, "b", types.Typ[types.Float64]))
+	rets := types.NewTuple(types.NewVar(0, nil, "", types.Typ[types.Int]))
+	sig := types.NewSignatureType(nil, nil, nil, params, rets, false)
+	pkg.NewFunc("fn", sig).MakeBody("").
+		Return(prog.Val(1))
 	assertPkg(t, pkg, `; ModuleID = 'foo/bar'
 source_filename = "foo/bar"
 
-define i64 @fn() {
+define i64 @fn(i64 %0, double %1) {
   ret i64 1
 }
 `)
 }
+
+func TestFuncParam(t *testing.T) {
+	prog := NewProgram(nil)
+	pkg := prog.NewPackage("bar", "foo/bar")
+	params := types.NewTuple(
+		types.NewVar(0, nil, "a", types.Typ[types.Int]),
+		types.NewVar(0, nil, "b", types.Typ[types.Float64]))
+	rets := types.NewTuple(types.NewVar(0, nil, "", types.Typ[types.Int]))
+	sig := types.NewSignatureType(nil, nil, nil, params, rets, false)
+	fn := pkg.NewFunc("fn", sig)
+	fn.MakeBody("").Return(fn.Param(1))
+	assertPkg(t, pkg, `; ModuleID = 'foo/bar'
+source_filename = "foo/bar"
+
+define i64 @fn(i64 %0, double %1) {
+  ret double %1
+}
+`)
+}