parameter loading

gotypes/components.go

@@ -35,28 +35,30 @@ func (c componenterr) Index(int) Component      { return c }
 
 type component struct {
 	name   string
-	offset int
 	typ    types.Type
+	offset int
 	err    error
 }
 
-func NewComponentFromVar(v *types.Var) Component {
+func NewComponent(name string, t types.Type, offset int) Component {
 	return &component{
-		name: v.Name(),
+		name:   name,
+		typ:    t,
+		offset: offset,
 	}
 }
 
+func NewComponentFromVar(v *types.Var, offset int) Component {
+	return NewComponent(v.Name(), v.Type(), offset)
+}
+
 func (c *component) Resolve() (*Basic, error) {
-	b, ok := c.typ.(*types.Basic)
-	if !ok {
-		return nil, errors.New("not basic type")
-	}
-	if b.Kind() == types.String {
-		return nil, errors.New("string types are handled specially")
+	if !isprimitive(c.typ) {
+		return nil, errors.New("component is not primitive")
 	}
 	return &Basic{
 		Addr: operand.NewParamAddr(c.name, c.offset),
-		Type: b,
+		Type: c.typ.(*types.Basic),
 	}, nil
 }
 
@@ -134,51 +136,7 @@ func (c *component) sub(suffix string, offset int, t types.Type) *component {
 }
 
 // TODO(mbm): gotypes.Component handling for structs
-// TODO(mbm): gotypes.Component handling for complex
-
-type Signature struct {
-	sig *types.Signature
-}
-
-func newSignature(sig *types.Signature) *Signature {
-	return &Signature{
-		sig: sig,
-	}
-}
-
-func ParseSignature(expr string) (*Signature, error) {
-	tv, err := types.Eval(token.NewFileSet(), nil, token.NoPos, expr)
-	if err != nil {
-		return nil, err
-	}
-	if tv.Value != nil {
-		return nil, errors.New("signature expression should have nil value")
-	}
-	s, ok := tv.Type.(*types.Signature)
-	if !ok {
-		return nil, errors.New("provided type is not a function signature")
-	}
-	return newSignature(s), nil
-}
-
-func (s *Signature) Parameter(name string) Component {
-	p := s.param(name)
-	if p == nil {
-		return componenterr("unknown parameter")
-	}
-	return NewComponentFromVar(p)
-}
-
-func (s *Signature) param(name string) *types.Var {
-	t := s.sig.Params()
-	for i := 0; i < t.Len(); i++ {
-		p := t.At(i)
-		if p.Name() == name {
-			return p
-		}
-	}
-	return nil
-}
+// TODO(mbm): gotypes.Component handling for complex64/128
 
 func isslice(t types.Type) bool {
 	_, ok := t.(*types.Slice)
@@ -189,3 +147,9 @@ func isstring(t types.Type) bool {
 	b, ok := t.(*types.Basic)
 	return ok && b.Kind() == types.String
 }
+
+// isprimitive returns true if the type cannot be broken into components.
+func isprimitive(t types.Type) bool {
+	b, ok := t.(*types.Basic)
+	return ok && (b.Info()&(types.IsString|types.IsComplex)) == 0
+}

gotypes/signature.go

@@ -0,0 +1,101 @@
+package gotypes
+
+import (
+	"errors"
+	"go/token"
+	"go/types"
+	"strconv"
+)
+
+type Signature struct {
+	sig     *types.Signature
+	params  *Tuple
+	results *Tuple
+}
+
+func NewSignature(sig *types.Signature) *Signature {
+	s := &Signature{
+		sig: sig,
+	}
+	s.init()
+	return s
+}
+
+func ParseSignature(expr string) (*Signature, error) {
+	tv, err := types.Eval(token.NewFileSet(), nil, token.NoPos, expr)
+	if err != nil {
+		return nil, err
+	}
+	if tv.Value != nil {
+		return nil, errors.New("signature expression should have nil value")
+	}
+	s, ok := tv.Type.(*types.Signature)
+	if !ok {
+		return nil, errors.New("provided type is not a function signature")
+	}
+	return NewSignature(s), nil
+}
+
+func (s *Signature) Params() *Tuple { return s.params }
+
+func (s *Signature) Results() *Tuple { return s.results }
+
+func (s *Signature) Bytes() int { return s.Params().Bytes() + s.Results().Bytes() }
+
+func (s *Signature) init() {
+	p := s.sig.Params()
+	r := s.sig.Results()
+
+	// Compute offsets of parameters and return values.
+	vs := tuplevars(p)
+	vs = append(vs, tuplevars(r)...)
+	vs = append(vs, types.NewParam(token.NoPos, nil, "sentinel", types.Typ[types.Uint64]))
+	offsets := Sizes.Offsetsof(vs)
+
+	// Build components for them.
+	s.params = newTuple(p, offsets, "arg")
+	s.results = newTuple(r, offsets[p.Len():], "ret")
+}
+
+type Tuple struct {
+	components []Component
+	byname     map[string]Component
+	size       int
+}
+
+func newTuple(t *types.Tuple, offsets []int64, defaultprefix string) *Tuple {
+	tuple := &Tuple{
+		byname: map[string]Component{},
+		size:   int(offsets[t.Len()]),
+	}
+	for i := 0; i < t.Len(); i++ {
+		v := t.At(i)
+		name := v.Name()
+		if name == "" {
+			name = defaultprefix
+			if i > 0 {
+				name += strconv.Itoa(i)
+			}
+		}
+		c := NewComponent(name, v.Type(), int(offsets[i]))
+		tuple.components = append(tuple.components, c)
+		if v.Name() != "" {
+			tuple.byname[v.Name()] = c
+		}
+	}
+	return tuple
+}
+
+func (t *Tuple) Lookup(name string) Component { return t.byname[name] }
+
+func (t *Tuple) At(i int) Component { return t.components[i] }
+
+func (t *Tuple) Bytes() int { return t.size }
+
+func tuplevars(t *types.Tuple) []*types.Var {
+	vs := make([]*types.Var, t.Len())
+	for i := 0; i < t.Len(); i++ {
+		vs[i] = t.At(i)
+	}
+	return vs
+}

gotypes/signature_test.go

@@ -51,11 +51,11 @@ func TestParseSignature(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if !TypesTuplesEqual(s.Params(), c.ExpectParams) {
-			t.Errorf("parameter mismatch\ngot %#v\nexpect %#v\n", s.Params(), c.ExpectParams)
+		if !TypesTuplesEqual(s.sig.Params(), c.ExpectParams) {
+			t.Errorf("parameter mismatch\ngot %#v\nexpect %#v\n", s.sig.Params(), c.ExpectParams)
 		}
-		if !TypesTuplesEqual(s.Results(), c.ExpectReturn) {
-			t.Errorf("return value(s) mismatch\ngot %#v\nexpect %#v\n", s.Results(), c.ExpectReturn)
+		if !TypesTuplesEqual(s.sig.Results(), c.ExpectReturn) {
+			t.Errorf("return value(s) mismatch\ngot %#v\nexpect %#v\n", s.sig.Results(), c.ExpectReturn)
 		}
 	}
 }