Golang constant.StringVal函数代码示例

// Comapres xv to yv using operator op
// Both xv and yv must be loaded and have a compatible type (as determined by negotiateType)
func compareOp(op token.Token, xv *Variable, yv *Variable) (bool, error) {
	switch xv.Kind {
	case reflect.Bool:
		fallthrough
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		fallthrough
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		fallthrough
	case reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
		return constantCompare(op, xv.Value, yv.Value)
	case reflect.String:
		if int64(len(constant.StringVal(xv.Value))) != xv.Len || int64(len(constant.StringVal(yv.Value))) != yv.Len {
			return false, fmt.Errorf("string too long for comparison")
		}
		return constantCompare(op, xv.Value, yv.Value)
	}

	if op != token.EQL && op != token.NEQ {
		return false, fmt.Errorf("operator %s not defined on %s", op.String(), xv.Kind.String())
	}

	var eql bool
	var err error

	switch xv.Kind {
	case reflect.Ptr:
		eql = xv.Children[0].Addr == yv.Children[0].Addr
	case reflect.Array:
		if int64(len(xv.Children)) != xv.Len || int64(len(yv.Children)) != yv.Len {
			return false, fmt.Errorf("array too long for comparison")
		}
		eql, err = equalChildren(xv, yv, true)
	case reflect.Struct:
		if len(xv.Children) != len(yv.Children) {
			return false, nil
		}
		if int64(len(xv.Children)) != xv.Len || int64(len(yv.Children)) != yv.Len {
			return false, fmt.Errorf("sturcture too deep for comparison")
		}
		eql, err = equalChildren(xv, yv, false)
	case reflect.Slice, reflect.Map, reflect.Func, reflect.Chan:
		if xv != nilVariable && yv != nilVariable {
			return false, fmt.Errorf("can not compare %s variables", xv.Kind.String())
		}

		eql = xv.base == yv.base
	default:
		return false, fmt.Errorf("unimplemented comparison of %s variables", xv.Kind.String())
	}

	if op == token.NEQ {
		return !eql, err
	}
	return eql, err
}

// goVal returns the Go value for val, or nil.
func goVal(val constant.Value) interface{} {
	// val should exist, but be conservative and check
	if val == nil {
		return nil
	}
	// Match implementation restriction of other compilers.
	// gc only checks duplicates for integer, floating-point
	// and string values, so only create Go values for these
	// types.
	switch val.Kind() {
	case constant.Int:
		if x, ok := constant.Int64Val(val); ok {
			return x
		}
		if x, ok := constant.Uint64Val(val); ok {
			return x
		}
	case constant.Float:
		if x, ok := constant.Float64Val(val); ok {
			return x
		}
	case constant.String:
		return constant.StringVal(val)
	}
	return nil
}

func (p *exporter) value(x constant.Value) {
	if trace {
		p.tracef("value { ")
		defer p.tracef("} ")
	}

	switch kind := x.Kind(); kind {
	case constant.Bool:
		tag := falseTag
		if constant.BoolVal(x) {
			tag = trueTag
		}
		p.int(tag)
	case constant.Int:
		if i, ok := constant.Int64Val(x); ok {
			p.int(int64Tag)
			p.int64(i)
			return
		}
		p.int(floatTag)
		p.float(x)
	case constant.Float:
		p.int(fractionTag)
		p.fraction(x)
	case constant.Complex:
		p.int(complexTag)
		p.fraction(constant.Real(x))
		p.fraction(constant.Imag(x))
	case constant.String:
		p.int(stringTag)
		p.string(constant.StringVal(x))
	default:
		panic(fmt.Sprintf("unexpected value kind %d", kind))
	}
}

func (dbp *Process) getGoInformation() (ver GoVersion, isextld bool, err error) {
	vv, err := dbp.EvalPackageVariable("runtime.buildVersion")
	if err != nil {
		err = fmt.Errorf("Could not determine version number: %v\n", err)
		return
	}
	if vv.Unreadable != nil {
		err = fmt.Errorf("Unreadable version number: %v\n", vv.Unreadable)
		return
	}

	ver, ok := parseVersionString(constant.StringVal(vv.Value))
	if !ok {
		err = fmt.Errorf("Could not parse version number: %v\n", vv.Value)
		return
	}

	rdr := dbp.DwarfReader()
	rdr.Seek(0)
	for entry, err := rdr.NextCompileUnit(); entry != nil; entry, err = rdr.NextCompileUnit() {
		if err != nil {
			return ver, isextld, err
		}
		if prod, ok := entry.Val(dwarf.AttrProducer).(string); ok && (strings.HasPrefix(prod, "GNU AS")) {
			isextld = true
			break
		}
	}
	return
}

func (gvar *Variable) parseG() (*G, error) {
	mem := gvar.mem
	dbp := gvar.dbp
	gaddr := uint64(gvar.Addr)
	_, deref := gvar.RealType.(*dwarf.PtrType)

	initialInstructions := make([]byte, dbp.arch.PtrSize()+1)
	initialInstructions[0] = op.DW_OP_addr
	binary.LittleEndian.PutUint64(initialInstructions[1:], gaddr)
	if deref {
		gaddrbytes, err := mem.readMemory(uintptr(gaddr), dbp.arch.PtrSize())
		if err != nil {
			return nil, fmt.Errorf("error derefing *G %s", err)
		}
		initialInstructions = append([]byte{op.DW_OP_addr}, gaddrbytes...)
		gaddr = binary.LittleEndian.Uint64(gaddrbytes)
		if gaddr == 0 {
			id := 0
			if thread, ok := mem.(*Thread); ok {
				id = thread.ID
			}
			return nil, NoGError{tid: id}
		}
	}
	if gaddr == 0 {
		return nil, NoGError{}
	}
	gvar.loadValue()
	if gvar.Unreadable != nil {
		return nil, gvar.Unreadable
	}
	schedVar := gvar.toFieldNamed("sched")
	pc, _ := constant.Int64Val(schedVar.toFieldNamed("pc").Value)
	sp, _ := constant.Int64Val(schedVar.toFieldNamed("sp").Value)
	id, _ := constant.Int64Val(gvar.toFieldNamed("goid").Value)
	gopc, _ := constant.Int64Val(gvar.toFieldNamed("gopc").Value)
	waitReason := constant.StringVal(gvar.toFieldNamed("waitreason").Value)
	d := gvar.toFieldNamed("_defer")
	deferPC := int64(0)
	fnvar := d.toFieldNamed("fn")
	if fnvar != nil {
		fnvalvar := fnvar.toFieldNamed("fn")
		deferPC, _ = constant.Int64Val(fnvalvar.Value)
	}
	status, _ := constant.Int64Val(gvar.toFieldNamed("atomicstatus").Value)
	f, l, fn := gvar.dbp.goSymTable.PCToLine(uint64(pc))
	g := &G{
		ID:         int(id),
		GoPC:       uint64(gopc),
		PC:         uint64(pc),
		SP:         uint64(sp),
		WaitReason: waitReason,
		DeferPC:    uint64(deferPC),
		Status:     uint64(status),
		CurrentLoc: Location{PC: uint64(pc), File: f, Line: l, Fn: fn},
		dbp:        gvar.dbp,
	}
	return g, nil
}

// checkPrintf checks a call to a formatted print routine such as Printf.
// call.Args[formatIndex] is (well, should be) the format argument.
func (f *File) checkPrintf(call *ast.CallExpr, name string, formatIndex int) {
	if formatIndex >= len(call.Args) {
		f.Bad(call.Pos(), "too few arguments in call to", name)
		return
	}
	lit := f.pkg.types[call.Args[formatIndex]].Value
	if lit == nil {
		if *verbose {
			f.Warn(call.Pos(), "can't check non-constant format in call to", name)
		}
		return
	}
	if lit.Kind() != constant.String {
		f.Badf(call.Pos(), "constant %v not a string in call to %s", lit, name)
		return
	}
	format := constant.StringVal(lit)
	firstArg := formatIndex + 1 // Arguments are immediately after format string.
	if !strings.Contains(format, "%") {
		if len(call.Args) > firstArg {
			f.Badf(call.Pos(), "no formatting directive in %s call", name)
		}
		return
	}
	// Hard part: check formats against args.
	argNum := firstArg
	indexed := false
	for i, w := 0, 0; i < len(format); i += w {
		w = 1
		if format[i] == '%' {
			state := f.parsePrintfVerb(call, name, format[i:], firstArg, argNum)
			if state == nil {
				return
			}
			w = len(state.format)
			if state.indexed {
				indexed = true
			}
			if !f.okPrintfArg(call, state) { // One error per format is enough.
				return
			}
			if len(state.argNums) > 0 {
				// Continue with the next sequential argument.
				argNum = state.argNums[len(state.argNums)-1] + 1
			}
		}
	}
	// Dotdotdot is hard.
	if call.Ellipsis.IsValid() && argNum >= len(call.Args)-1 {
		return
	}
	// If the arguments were direct indexed, we assume the programmer knows what's up.
	// Otherwise, there should be no leftover arguments.
	if !indexed && argNum != len(call.Args) {
		expect := argNum - firstArg
		numArgs := len(call.Args) - firstArg
		f.Badf(call.Pos(), "wrong number of args for format in %s call: %d needed but %d args", name, expect, numArgs)
	}
}

// stringConstantArg returns call's string constant argument at the index idx.
//
// ("", false) is returned if call's argument at the index idx isn't a string
// constant.
func stringConstantArg(f *File, call *ast.CallExpr, idx int) (string, bool) {
	if idx >= len(call.Args) {
		return "", false
	}
	arg := call.Args[idx]
	lit := f.pkg.types[arg].Value
	if lit != nil && lit.Kind() == constant.String {
		return constant.StringVal(lit), true
	}
	return "", false
}

// constValue returns the value of the constant with the
// dynamic type tag appropriate for c.Type().
func constValue(c *ssa.Const) value {
	if c.IsNil() {
		return zero(c.Type()) // typed nil
	}

	if t, ok := c.Type().Underlying().(*types.Basic); ok {
		// TODO(adonovan): eliminate untyped constants from SSA form.
		switch t.Kind() {
		case types.Bool, types.UntypedBool:
			return exact.BoolVal(c.Value)
		case types.Int, types.UntypedInt:
			// Assume sizeof(int) is same on host and target.
			return int(c.Int64())
		case types.Int8:
			return int8(c.Int64())
		case types.Int16:
			return int16(c.Int64())
		case types.Int32, types.UntypedRune:
			return int32(c.Int64())
		case types.Int64:
			return c.Int64()
		case types.Uint:
			// Assume sizeof(uint) is same on host and target.
			return uint(c.Uint64())
		case types.Uint8:
			return uint8(c.Uint64())
		case types.Uint16:
			return uint16(c.Uint64())
		case types.Uint32:
			return uint32(c.Uint64())
		case types.Uint64:
			return c.Uint64()
		case types.Uintptr:
			// Assume sizeof(uintptr) is same on host and target.
			return uintptr(c.Uint64())
		case types.Float32:
			return float32(c.Float64())
		case types.Float64, types.UntypedFloat:
			return c.Float64()
		case types.Complex64:
			return complex64(c.Complex128())
		case types.Complex128, types.UntypedComplex:
			return c.Complex128()
		case types.String, types.UntypedString:
			if c.Value.Kind() == exact.String {
				return exact.StringVal(c.Value)
			}
			return string(rune(c.Int64()))
		}
	}

	panic(fmt.Sprintf("constValue: %s", c))
}

func (c *funcContext) identifierConstant(expr ast.Expr) (string, bool) {
	val := c.p.Types[expr].Value
	if val == nil {
		return "", false
	}
	s := constant.StringVal(val)
	if len(s) == 0 {
		return "", false
	}
	for i, c := range s {
		if !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (i > 0 && c >= '0' && c <= '9') || c == '_' || c == '$') {
			return "", false
		}
	}
	return s, true
}

func (c *Const) RelString(from *types.Package) string {
	var s string
	if c.Value == nil {
		s = "nil"
	} else if c.Value.Kind() == exact.String {
		s = exact.StringVal(c.Value)
		const max = 20
		// TODO(adonovan): don't cut a rune in half.
		if len(s) > max {
			s = s[:max-3] + "..." // abbreviate
		}
		s = strconv.Quote(s)
	} else {
		s = c.Value.String()
	}
	return s + ":" + relType(c.Type(), from)
}

func newConstant(val constant.Value, mem memoryReadWriter) *Variable {
	v := &Variable{Value: val, mem: mem, loaded: true}
	switch val.Kind() {
	case constant.Int:
		v.Kind = reflect.Int
	case constant.Float:
		v.Kind = reflect.Float64
	case constant.Bool:
		v.Kind = reflect.Bool
	case constant.Complex:
		v.Kind = reflect.Complex128
	case constant.String:
		v.Kind = reflect.String
		v.Len = int64(len(constant.StringVal(val)))
	}
	return v
}

func (p *exporter) value(x constant.Value) {
	if trace {
		p.tracef("= ")
	}

	switch x.Kind() {
	case constant.Bool:
		tag := falseTag
		if constant.BoolVal(x) {
			tag = trueTag
		}
		p.tag(tag)

	case constant.Int:
		if v, exact := constant.Int64Val(x); exact {
			// common case: x fits into an int64 - use compact encoding
			p.tag(int64Tag)
			p.int64(v)
			return
		}
		// uncommon case: large x - use float encoding
		// (powers of 2 will be encoded efficiently with exponent)
		p.tag(floatTag)
		p.float(constant.ToFloat(x))

	case constant.Float:
		p.tag(floatTag)
		p.float(x)

	case constant.Complex:
		p.tag(complexTag)
		p.float(constant.Real(x))
		p.float(constant.Imag(x))

	case constant.String:
		p.tag(stringTag)
		p.string(constant.StringVal(x))

	case constant.Unknown:
		// package contains type errors
		p.tag(unknownTag)

	default:
		log.Fatalf("gcimporter: unexpected value %v (%T)", x, x)
	}
}

func ConvertVar(v *proc.Variable) *Variable {
	r := Variable{
		Addr: v.Addr,
		Name: v.Name,
		Kind: v.Kind,
		Len:  v.Len,
		Cap:  v.Cap,
	}

	if v.DwarfType != nil {
		r.Type = v.DwarfType.String()
	}

	if v.RealType != nil {
		r.RealType = v.RealType.String()
	}

	if v.Unreadable != nil {
		r.Unreadable = v.Unreadable.Error()
	}

	if v.Value != nil {
		switch v.Kind {
		case reflect.Float32:
			f, _ := constant.Float64Val(v.Value)
			r.Value = strconv.FormatFloat(f, 'f', -1, 32)
		case reflect.Float64:
			f, _ := constant.Float64Val(v.Value)
			r.Value = strconv.FormatFloat(f, 'f', -1, 64)
		case reflect.String, reflect.Func:
			r.Value = constant.StringVal(v.Value)
		default:
			r.Value = v.Value.String()
		}
	}

	r.Children = make([]Variable, len(v.Children))

	for i := range v.Children {
		r.Children[i] = *ConvertVar(&v.Children[i])
	}

	return &r
}

func (c *converter) convertConstantValue(v goconstant.Value) constant.Value {
	if v == nil {
		return nil
	}
	if v, ok := c.converted[v]; ok {
		return v.(constant.Value)
	}
	var ret constant.Value
	switch v.Kind() {
	case goconstant.Bool:
		ret = constant.MakeBool(goconstant.BoolVal(v))
	case goconstant.String:
		ret = constant.MakeString(goconstant.StringVal(v))
	case goconstant.Int:
		ret = constant.MakeFromLiteral(v.String(), token.INT, 0)
	case goconstant.Float:
		ret = constant.MakeFromLiteral(v.String(), token.FLOAT, 0)
	case goconstant.Complex:
		ret = constant.MakeFromLiteral(v.String(), token.IMAG, 0)
	}
	c.converted[v] = ret
	return ret
}

// stringVal returns the (unquoted) string value and true if
// tv is a string constant; otherwise it returns "" and false.
func stringVal(tv types.TypeAndValue) (string, bool) {
	if tv.IsValue() && tv.Value != nil && tv.Value.Kind() == constant.String {
		return constant.StringVal(tv.Value), true
	}
	return "", false
}