Golang types.NewSlice函数代码示例

func (p *importer) param(named bool) (*types.Var, bool) {
	t := p.typ(nil)
	td, isddd := t.(*dddSlice)
	if isddd {
		t = types.NewSlice(td.elem)
	}

	var pkg *types.Package
	var name string
	if named {
		name = p.string()
		if name == "" {
			panic("expected named parameter")
		}
		if name != "_" {
			pkg = p.pkg()
		}
		if i := strings.Index(name, "·"); i > 0 {
			name = name[:i] // cut off gc-specific parameter numbering
		}
	}

	// read and discard compiler-specific info
	p.string()

	return types.NewVar(token.NoPos, pkg, name, t), isddd
}

// generate generates offline constraints for the entire program.
func (a *analysis) generate() {
	start("Constraint generation")
	if a.log != nil {
		fmt.Fprintln(a.log, "==== Generating constraints")
	}

	// Create a dummy node since we use the nodeid 0 for
	// non-pointerlike variables.
	a.addNodes(tInvalid, "(zero)")

	// Create the global node for panic values.
	a.panicNode = a.addNodes(tEface, "panic")

	// Create nodes and constraints for all methods of reflect.rtype.
	// (Shared contours are used by dynamic calls to reflect.Type
	// methods---typically just String().)
	if rtype := a.reflectRtypePtr; rtype != nil {
		a.genMethodsOf(rtype)
	}

	root := a.genRootCalls()

	if a.config.BuildCallGraph {
		a.result.CallGraph = callgraph.New(root.fn)
	}

	// Create nodes and constraints for all methods of all types
	// that are dynamically accessible via reflection or interfaces.
	for _, T := range a.prog.RuntimeTypes() {
		a.genMethodsOf(T)
	}

	// Generate constraints for functions as they become reachable
	// from the roots.  (No constraints are generated for functions
	// that are dead in this analysis scope.)
	for len(a.genq) > 0 {
		cgn := a.genq[0]
		a.genq = a.genq[1:]
		a.genFunc(cgn)
	}

	// The runtime magically allocates os.Args; so should we.
	if os := a.prog.ImportedPackage("os"); os != nil {
		// In effect:  os.Args = new([1]string)[:]
		T := types.NewSlice(types.Typ[types.String])
		obj := a.addNodes(sliceToArray(T), "<command-line args>")
		a.endObject(obj, nil, "<command-line args>")
		a.addressOf(T, a.objectNode(nil, os.Var("Args")), obj)
	}

	// Discard generation state, to avoid confusion after node renumbering.
	a.panicNode = 0
	a.globalval = nil
	a.localval = nil
	a.localobj = nil

	stop("Constraint generation")
}

// createParams creates parameters for wrapper method fn based on its
// Signature.Params, which do not include the receiver.
// start is the index of the first regular parameter to use.
//
func createParams(fn *Function, start int) {
	var last *Parameter
	tparams := fn.Signature.Params()
	for i, n := start, tparams.Len(); i < n; i++ {
		last = fn.addParamObj(tparams.At(i))
	}
	if fn.Signature.Variadic() {
		last.typ = types.NewSlice(last.typ)
	}
}

// ArrayOrSliceType = "[" [ int ] "]" Type .
func (p *parser) parseArrayOrSliceType(pkg *types.Package) types.Type {
	p.expect('[')
	if p.tok == ']' {
		p.next()
		return types.NewSlice(p.parseType(pkg))
	}

	n := p.parseInt()
	p.expect(']')
	return types.NewArray(p.parseType(pkg), n)
}

// Param = Name ["..."] Type .
func (p *parser) parseParam(pkg *types.Package) (param *types.Var, isVariadic bool) {
	name := p.parseName()
	if p.tok == '.' {
		p.next()
		p.expect('.')
		p.expect('.')
		isVariadic = true
	}
	typ := p.parseType(pkg)
	if isVariadic {
		typ = types.NewSlice(typ)
	}
	param = types.NewParam(token.NoPos, pkg, name, typ)
	return
}

// Type =
//	BasicType | TypeName | ArrayType | SliceType | StructType |
//      PointerType | FuncType | InterfaceType | MapType | ChanType |
//      "(" Type ")" .
//
// BasicType   = ident .
// TypeName    = ExportedName .
// SliceType   = "[" "]" Type .
// PointerType = "*" Type .
// FuncType    = "func" Signature .
//
func (p *parser) parseType(parent *types.Package) types.Type {
	switch p.tok {
	case scanner.Ident:
		switch p.lit {
		default:
			return p.parseBasicType()
		case "struct":
			return p.parseStructType(parent)
		case "func":
			// FuncType
			p.next()
			return p.parseSignature(nil)
		case "interface":
			return p.parseInterfaceType(parent)
		case "map":
			return p.parseMapType(parent)
		case "chan":
			return p.parseChanType(parent)
		}
	case '@':
		// TypeName
		pkg, name := p.parseExportedName()
		return declTypeName(pkg, name).Type()
	case '[':
		p.next() // look ahead
		if p.tok == ']' {
			// SliceType
			p.next()
			return types.NewSlice(p.parseType(parent))
		}
		return p.parseArrayType(parent)
	case '*':
		// PointerType
		p.next()
		return types.NewPointer(p.parseType(parent))
	case '<':
		return p.parseChanType(parent)
	case '(':
		// "(" Type ")"
		p.next()
		typ := p.parseType(parent)
		p.expect(')')
		return typ
	}
	p.errorf("expected type, got %s (%q)", scanner.TokenString(p.tok), p.lit)
	return nil
}

func (p *importer) param(named bool) (*types.Var, bool) {
	t := p.typ(nil)
	td, isddd := t.(*dddSlice)
	if isddd {
		t = types.NewSlice(td.elem)
	}

	var name string
	if named {
		name = p.string()
		if name == "" {
			panic("expected named parameter")
		}
	}

	// read and discard compiler-specific info
	p.string()

	return types.NewVar(token.NoPos, nil, name, t), isddd
}

// Parameter = ( identifier | "?" ) [ "..." ] Type [ string_lit ] .
//
func (p *parser) parseParameter() (par *types.Var, isVariadic bool) {
	_, name := p.parseName(nil, false)
	// remove gc-specific parameter numbering
	if i := strings.Index(name, "·"); i >= 0 {
		name = name[:i]
	}
	if p.tok == '.' {
		p.expectSpecial("...")
		isVariadic = true
	}
	typ := p.parseType(nil)
	if isVariadic {
		typ = types.NewSlice(typ)
	}
	// ignore argument tag (e.g. "noescape")
	if p.tok == scanner.String {
		p.next()
	}
	// TODO(gri) should we provide a package?
	par = types.NewVar(token.NoPos, nil, name, typ)
	return
}

func (c *funcContext) translateConversion(expr ast.Expr, desiredType types.Type) *expression {
	exprType := c.p.TypeOf(expr)
	if types.Identical(exprType, desiredType) {
		return c.translateExpr(expr)
	}

	if c.p.Pkg.Path() == "reflect" {
		if call, isCall := expr.(*ast.CallExpr); isCall && types.Identical(c.p.TypeOf(call.Fun), types.Typ[types.UnsafePointer]) {
			if ptr, isPtr := desiredType.(*types.Pointer); isPtr {
				if named, isNamed := ptr.Elem().(*types.Named); isNamed {
					switch named.Obj().Name() {
					case "arrayType", "chanType", "funcType", "interfaceType", "mapType", "ptrType", "sliceType", "structType":
						return c.formatExpr("%e.kindType", call.Args[0]) // unsafe conversion
					default:
						return c.translateExpr(expr)
					}
				}
			}
		}
	}

	switch t := desiredType.Underlying().(type) {
	case *types.Basic:
		switch {
		case isInteger(t):
			basicExprType := exprType.Underlying().(*types.Basic)
			switch {
			case is64Bit(t):
				if !is64Bit(basicExprType) {
					if basicExprType.Kind() == types.Uintptr { // this might be an Object returned from reflect.Value.Pointer()
						return c.formatExpr("new %1s(0, %2e.constructor === Number ? %2e : 1)", c.typeName(desiredType), expr)
					}
					return c.formatExpr("new %s(0, %e)", c.typeName(desiredType), expr)
				}
				return c.formatExpr("new %1s(%2h, %2l)", c.typeName(desiredType), expr)
			case is64Bit(basicExprType):
				if !isUnsigned(t) && !isUnsigned(basicExprType) {
					return c.fixNumber(c.formatParenExpr("%1l + ((%1h >> 31) * 4294967296)", expr), t)
				}
				return c.fixNumber(c.formatExpr("%s.$low", c.translateExpr(expr)), t)
			case isFloat(basicExprType):
				return c.formatParenExpr("%e >> 0", expr)
			case types.Identical(exprType, types.Typ[types.UnsafePointer]):
				return c.translateExpr(expr)
			default:
				return c.fixNumber(c.translateExpr(expr), t)
			}
		case isFloat(t):
			if t.Kind() == types.Float32 && exprType.Underlying().(*types.Basic).Kind() == types.Float64 {
				return c.formatExpr("$fround(%e)", expr)
			}
			return c.formatExpr("%f", expr)
		case isComplex(t):
			return c.formatExpr("new %1s(%2r, %2i)", c.typeName(desiredType), expr)
		case isString(t):
			value := c.translateExpr(expr)
			switch et := exprType.Underlying().(type) {
			case *types.Basic:
				if is64Bit(et) {
					value = c.formatExpr("%s.$low", value)
				}
				if isNumeric(et) {
					return c.formatExpr("$encodeRune(%s)", value)
				}
				return value
			case *types.Slice:
				if types.Identical(et.Elem().Underlying(), types.Typ[types.Rune]) {
					return c.formatExpr("$runesToString(%s)", value)
				}
				return c.formatExpr("$bytesToString(%s)", value)
			default:
				panic(fmt.Sprintf("Unhandled conversion: %v\n", et))
			}
		case t.Kind() == types.UnsafePointer:
			if unary, isUnary := expr.(*ast.UnaryExpr); isUnary && unary.Op == token.AND {
				if indexExpr, isIndexExpr := unary.X.(*ast.IndexExpr); isIndexExpr {
					return c.formatExpr("$sliceToArray(%s)", c.translateConversionToSlice(indexExpr.X, types.NewSlice(types.Typ[types.Uint8])))
				}
				if ident, isIdent := unary.X.(*ast.Ident); isIdent && ident.Name == "_zero" {
					return c.formatExpr("new Uint8Array(0)")
				}
			}
			if ptr, isPtr := c.p.TypeOf(expr).(*types.Pointer); c.p.Pkg.Path() == "syscall" && isPtr {
				if s, isStruct := ptr.Elem().Underlying().(*types.Struct); isStruct {
					array := c.newVariable("_array")
					target := c.newVariable("_struct")
					c.Printf("%s = new Uint8Array(%d);", array, sizes32.Sizeof(s))
					c.Delayed(func() {
						c.Printf("%s = %s, %s;", target, c.translateExpr(expr), c.loadStruct(array, target, s))
					})
					return c.formatExpr("%s", array)
				}
			}
			if call, ok := expr.(*ast.CallExpr); ok {
				if id, ok := call.Fun.(*ast.Ident); ok && id.Name == "new" {
					return c.formatExpr("new Uint8Array(%d)", int(sizes32.Sizeof(c.p.TypeOf(call.Args[0]))))
				}
			}
		}

//.........这里部分代码省略.........

func ext۰reflect۰SliceOf(fr *frame, args []value) value {
	// Signature: func (t reflect.rtype) Type
	return makeReflectType(rtype{types.NewSlice(args[0].(iface).v.(rtype).t)})
}