Golang Type.Obj方法代码示例

func describeType(o *Oracle, qpos *QueryPos, path []ast.Node) (*describeTypeResult, error) {
	var description string
	var t types.Type
	switch n := path[0].(type) {
	case *ast.Ident:
		t = qpos.info.TypeOf(n)
		switch t := t.(type) {
		case *types.Basic:
			description = "reference to built-in type " + t.String()

		case *types.Named:
			isDef := t.Obj().Pos() == n.Pos() // see caveats at isDef above
			if isDef {
				description = "definition of type " + t.String()
			} else {
				description = "reference to type " + t.String()
			}
		}

	case ast.Expr:
		t = qpos.info.TypeOf(n)
		description = "type " + t.String()

	default:
		// Unreachable?
		return nil, fmt.Errorf("unexpected AST for type: %T", n)
	}

	return &describeTypeResult{
		node:        path[0],
		description: description,
		typ:         t,
		methods:     accessibleMethods(t, qpos.info.Pkg),
	}, nil
}

// promoteMethod promotes a named type's method to another type
// which has embedded the named type.
func (c *compiler) promoteMethod(m *types.Func, recv types.Type, indices []int) types.Object {
	var pkg *types.Package
	if recv, ok := recv.(*types.Named); ok {
		pkg = c.objectdata[recv.Obj()].Package
	}
	recvvar := types.NewVar(pkg, "", recv)
	sig := m.Type().(*types.Signature)
	sig = types.NewSignature(recvvar, sig.Params(), sig.Results(), sig.IsVariadic())
	f := &synthFunc{pkg: pkg, name: m.Name(), typ: sig}
	ident := ast.NewIdent(f.Name())

	var isptr bool
	if ptr, ok := recv.(*types.Pointer); ok {
		isptr = true
		recv = ptr.Elem()
	}

	c.objects[ident] = f
	c.objectdata[f] = &ObjectData{Ident: ident, Package: pkg}

	if pkg == nil || pkg == c.pkg {
		if currblock := c.builder.GetInsertBlock(); !currblock.IsNil() {
			defer c.builder.SetInsertPointAtEnd(currblock)
		}
		llvmfn := c.Resolve(ident).LLVMValue()
		llvmfn = c.builder.CreateExtractValue(llvmfn, 0, "")
		llvmfn.SetLinkage(llvm.LinkOnceODRLinkage)
		entry := llvm.AddBasicBlock(llvmfn, "entry")
		c.builder.SetInsertPointAtEnd(entry)

		realfn := c.Resolve(c.objectdata[m].Ident).LLVMValue()
		realfn = c.builder.CreateExtractValue(realfn, 0, "")

		args := llvmfn.Params()
		recvarg := args[0]
		if !isptr {
			ptr := c.builder.CreateAlloca(recvarg.Type(), "")
			c.builder.CreateStore(recvarg, ptr)
			recvarg = ptr
		}
		for _, i := range indices {
			if i == -1 {
				recvarg = c.builder.CreateLoad(recvarg, "")
			} else {
				recvarg = c.builder.CreateStructGEP(recvarg, i, "")
			}
		}

		args[0] = recvarg
		result := c.builder.CreateCall(realfn, args, "")
		if sig.Results().Len() == 0 {
			c.builder.CreateRetVoid()
		} else {
			c.builder.CreateRet(result)
		}
	}
	return f
}

// hashFor computes the hash of t.
func (h Hasher) hashFor(t types.Type) uint32 {
	// See IsIdentical for rationale.
	switch t := t.(type) {
	case *types.Basic:
		return uint32(t.Kind())

	case *types.Array:
		return 9043 + 2*uint32(t.Len()) + 3*h.Hash(t.Elem())

	case *types.Slice:
		return 9049 + 2*h.Hash(t.Elem())

	case *types.Struct:
		var hash uint32 = 9059
		for i, n := 0, t.NumFields(); i < n; i++ {
			f := t.Field(i)
			if f.Anonymous() {
				hash += 8861
			}
			hash += hashString(t.Tag(i))
			hash += hashString(f.Name()) // (ignore f.Pkg)
			hash += h.Hash(f.Type())
		}
		return hash

	case *types.Pointer:
		return 9067 + 2*h.Hash(t.Elem())

	case *types.Signature:
		var hash uint32 = 9091
		if t.IsVariadic() {
			hash *= 8863
		}
		return hash + 3*h.hashTuple(t.Params()) + 5*h.hashTuple(t.Results())

	case *types.Interface:
		var hash uint32 = 9103
		for i, n := 0, t.NumMethods(); i < n; i++ {
			// See go/types.identicalMethods for rationale.
			// Method order is not significant.
			// Ignore m.Pkg().
			m := t.Method(i)
			hash += 3*hashString(m.Name()) + 5*h.Hash(m.Type())
		}
		return hash

	case *types.Map:
		return 9109 + 2*h.Hash(t.Key()) + 3*h.Hash(t.Elem())

	case *types.Chan:
		return 9127 + 2*uint32(t.Dir()) + 3*h.Hash(t.Elem())

	case *types.Named:
		// Not safe with a copying GC; objects may move.
		return uint32(uintptr(unsafe.Pointer(t.Obj())))
	}
	panic("unexpected type")
}

// CanHaveDynamicTypes reports whether the type T can "hold" dynamic types,
// i.e. is an interface (incl. reflect.Type) or a reflect.Value.
//
func CanHaveDynamicTypes(T types.Type) bool {
	switch T := T.(type) {
	case *types.Named:
		if obj := T.Obj(); obj.Name() == "Value" && obj.Pkg().Path() == "reflect" {
			return true // reflect.Value
		}
		return CanHaveDynamicTypes(T.Underlying())
	case *types.Interface:
		return true
	}
	return false
}

// CanPoint reports whether the type T is pointerlike,
// for the purposes of this analysis.
func CanPoint(T types.Type) bool {
	switch T := T.(type) {
	case *types.Named:
		if obj := T.Obj(); obj.Name() == "Value" && obj.Pkg().Path() == "reflect" {
			return true // treat reflect.Value like interface{}
		}
		return CanPoint(T.Underlying())

	case *types.Pointer, *types.Interface, *types.Map, *types.Chan, *types.Signature, *types.Slice:
		return true
	}

	return false // array struct tuple builtin basic
}

func describeType(o *Oracle, qpos *QueryPos, path []ast.Node) (*describeTypeResult, error) {
	var description string
	var t types.Type
	switch n := path[0].(type) {
	case *ast.Ident:
		t = qpos.info.TypeOf(n)
		switch t := t.(type) {
		case *types.Basic:
			description = "reference to built-in "

		case *types.Named:
			isDef := t.Obj().Pos() == n.Pos() // see caveats at isDef above
			if isDef {
				description = "definition of "
			} else {
				description = "reference to "
			}
		}

	case ast.Expr:
		t = qpos.info.TypeOf(n)

	default:
		// Unreachable?
		return nil, fmt.Errorf("unexpected AST for type: %T", n)
	}

	description = description + "type " + qpos.TypeString(t)

	// Show sizes for structs and named types (it's fairly obvious for others).
	switch t.(type) {
	case *types.Named, *types.Struct:
		// TODO(adonovan): use o.imp.Config().TypeChecker.Sizes when
		// we add the Config() method (needs some thought).
		szs := types.StdSizes{8, 8}
		description = fmt.Sprintf("%s (size %d, align %d)", description,
			szs.Sizeof(t), szs.Alignof(t))
	}

	return &describeTypeResult{
		qpos:        qpos,
		node:        path[0],
		description: description,
		typ:         t,
		methods:     accessibleMethods(t, qpos.info.Pkg),
	}, nil
}

// promoteInterfaceMethod promotes an interface method to a type
// which has embedded the interface.
//
// TODO consolidate this and promoteMethod.
func (c *compiler) promoteInterfaceMethod(iface *types.Interface, methodIndex int, recv types.Type, indices []int) types.Object {
	m := iface.Method(methodIndex)
	var pkg *types.Package
	if recv, ok := recv.(*types.Named); ok {
		pkg = c.objectdata[recv.Obj()].Package
	}
	recvvar := types.NewVar(pkg, "", recv)
	sig := m.Type().(*types.Signature)
	sig = types.NewSignature(recvvar, sig.Params(), sig.Results(), sig.IsVariadic())
	f := &synthFunc{pkg: pkg, name: m.Name(), typ: sig}
	ident := ast.NewIdent(f.Name())

	var isptr bool
	if ptr, ok := recv.(*types.Pointer); ok {
		isptr = true
		recv = ptr.Elem()
	}

	c.objects[ident] = f
	c.objectdata[f] = &ObjectData{Ident: ident, Package: pkg}

	if pkg == nil || pkg == c.pkg {
		if currblock := c.builder.GetInsertBlock(); !currblock.IsNil() {
			defer c.builder.SetInsertPointAtEnd(currblock)
		}
		llvmfn := c.Resolve(ident).LLVMValue()
		llvmfn = c.builder.CreateExtractValue(llvmfn, 0, "")
		llvmfn.SetLinkage(llvm.LinkOnceODRLinkage)
		entry := llvm.AddBasicBlock(llvmfn, "entry")
		c.builder.SetInsertPointAtEnd(entry)

		args := llvmfn.Params()
		ifaceval := args[0]
		if !isptr {
			ptr := c.builder.CreateAlloca(ifaceval.Type(), "")
			c.builder.CreateStore(ifaceval, ptr)
			ifaceval = ptr
		}
		for _, i := range indices {
			if i == -1 {
				ifaceval = c.builder.CreateLoad(ifaceval, "")
			} else {
				ifaceval = c.builder.CreateStructGEP(ifaceval, i, "")
			}
		}

		recvarg := c.builder.CreateExtractValue(ifaceval, 0, "")
		ifn := c.builder.CreateExtractValue(ifaceval, methodIndex+2, "")

		// Add the receiver argument type.
		fntyp := ifn.Type().ElementType()
		returnType := fntyp.ReturnType()
		paramTypes := fntyp.ParamTypes()
		paramTypes = append([]llvm.Type{recvarg.Type()}, paramTypes...)
		vararg := fntyp.IsFunctionVarArg()
		fntyp = llvm.FunctionType(returnType, paramTypes, vararg)
		fnptrtyp := llvm.PointerType(fntyp, 0)
		ifn = c.builder.CreateBitCast(ifn, fnptrtyp, "")

		args[0] = recvarg
		result := c.builder.CreateCall(ifn, args, "")
		if sig.Results().Len() == 0 {
			c.builder.CreateRetVoid()
		} else {
			c.builder.CreateRet(result)
		}
	}

	return f
}

func (w *Walker) writeType(buf *bytes.Buffer, typ types.Type) {
	switch typ := typ.(type) {
	case *types.Basic:
		s := typ.Name()
		switch typ.Kind() {
		case types.UnsafePointer:
			s = "unsafe.Pointer"
		case types.UntypedBool:
			s = "ideal-bool"
		case types.UntypedInt:
			s = "ideal-int"
		case types.UntypedRune:
			// "ideal-char" for compatibility with old tool
			// TODO(gri) change to "ideal-rune"
			s = "ideal-char"
		case types.UntypedFloat:
			s = "ideal-float"
		case types.UntypedComplex:
			s = "ideal-complex"
		case types.UntypedString:
			s = "ideal-string"
		case types.UntypedNil:
			panic("should never see untyped nil type")
		default:
			switch s {
			case "byte":
				s = "uint8"
			case "rune":
				s = "int32"
			}
		}
		buf.WriteString(s)

	case *types.Array:
		fmt.Fprintf(buf, "[%d]", typ.Len())
		w.writeType(buf, typ.Elem())

	case *types.Slice:
		buf.WriteString("[]")
		w.writeType(buf, typ.Elem())

	case *types.Struct:
		buf.WriteString("struct")

	case *types.Pointer:
		buf.WriteByte('*')
		w.writeType(buf, typ.Elem())

	case *types.Tuple:
		panic("should never see a tuple type")

	case *types.Signature:
		buf.WriteString("func")
		w.writeSignature(buf, typ)

	case *types.Interface:
		buf.WriteString("interface{")
		if typ.NumMethods() > 0 {
			buf.WriteByte(' ')
			buf.WriteString(strings.Join(sortedMethodNames(typ), ", "))
			buf.WriteByte(' ')
		}
		buf.WriteString("}")

	case *types.Map:
		buf.WriteString("map[")
		w.writeType(buf, typ.Key())
		buf.WriteByte(']')
		w.writeType(buf, typ.Elem())

	case *types.Chan:
		var s string
		switch typ.Dir() {
		case ast.SEND:
			s = "chan<- "
		case ast.RECV:
			s = "<-chan "
		default:
			s = "chan "
		}
		buf.WriteString(s)
		w.writeType(buf, typ.Elem())

	case *types.Named:
		obj := typ.Obj()
		pkg := obj.Pkg()
		if pkg != nil && pkg != w.current {
			buf.WriteString(pkg.Name())
			buf.WriteByte('.')
		}
		buf.WriteString(typ.Obj().Name())

	default:
		panic(fmt.Sprintf("unknown type %T", typ))
	}
}