Golang exact.Int64Val函數代碼示例

func writeFloat(w *bytes.Buffer, ev exact.Value, k types.BasicKind) {
	v, _ := exact.Int64Val(exact.Num(ev))
	w.WriteString(strconv.FormatInt(v, 10))
	v, _ = exact.Int64Val(exact.Denom(ev))
	if v != 1 {
		w.WriteByte('/')
		w.WriteString(strconv.FormatInt(v, 10))
	}
	w.WriteByte('.')
	if k == types.Float32 {
		w.WriteByte('F')
	}
}

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

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

// IntVal is a utility function returns an int64 constant value from an exact.Value, split into high and low int32.
func IntVal(eVal exact.Value, posStr string) (high, low int32) {
	iVal, isExact := exact.Int64Val(eVal)
	if !isExact {
		LogWarning(posStr, "inexact", fmt.Errorf("constant value %d cannot be accurately represented in int64", iVal))
	}
	return int32(iVal >> 32), int32(iVal & 0xFFFFFFFF)
}

// Conversion type-checks the conversion T(x).
// The result is in x.
func (check *Checker) conversion(x *operand, T Type) {
	constArg := x.mode == constant

	var ok bool
	switch {
	case constArg && isConstType(T):
		// constant conversion
		switch t := T.Underlying().(*Basic); {
		case representableConst(x.val, check.conf, t.kind, &x.val):
			ok = true
		case x.isInteger() && isString(t):
			codepoint := int64(-1)
			if i, ok := exact.Int64Val(x.val); ok {
				codepoint = i
			}
			// If codepoint < 0 the absolute value is too large (or unknown) for
			// conversion. This is the same as converting any other out-of-range
			// value - let string(codepoint) do the work.
			x.val = exact.MakeString(string(codepoint))
			ok = true
		}
	case x.convertibleTo(check.conf, T):
		// non-constant conversion
		x.mode = value
		ok = true
	}

	if !ok {
		check.errorf(x.pos(), "cannot convert %s to %s", x, T)
		x.mode = invalid
		return
	}

	// The conversion argument types are final. For untyped values the
	// conversion provides the type, per the spec: "A constant may be
	// given a type explicitly by a constant declaration or conversion,...".
	final := x.typ
	if isUntyped(x.typ) {
		final = T
		// - For conversions to interfaces, use the argument's default type.
		// - For conversions of untyped constants to non-constant types, also
		//   use the default type (e.g., []byte("foo") should report string
		//   not []byte as type for the constant "foo").
		// - Keep untyped nil for untyped nil arguments.
		if isInterface(T) || constArg && !isConstType(T) {
			final = defaultType(x.typ)
		}
		check.updateExprType(x.expr, final, true)
	}

	x.typ = T
}

// Int64 returns the numeric value of this literal truncated to fit
// a signed 64-bit integer.
//
func (l *Literal) Int64() int64 {
	switch x := l.Value; x.Kind() {
	case exact.Int:
		if i, ok := exact.Int64Val(x); ok {
			return i
		}
		return 0
	case exact.Float:
		f, _ := exact.Float64Val(x)
		return int64(f)
	}
	panic(fmt.Sprintf("unexpected literal value: %T", l.Value))
}

// Int64 returns the numeric value of this constant truncated to fit
// a signed 64-bit integer.
//
func (c *Const) Int64() int64 {
	switch x := c.Value; x.Kind() {
	case exact.Int:
		if i, ok := exact.Int64Val(x); ok {
			return i
		}
		return 0
	case exact.Float:
		f, _ := exact.Float64Val(x)
		return int64(f)
	}
	panic(fmt.Sprintf("unexpected constant value: %T", c.Value))
}

func doOp(x exact.Value, op token.Token, y exact.Value) (z exact.Value) {
	defer panicHandler(&z)

	if x == nil {
		return exact.UnaryOp(op, y, -1)
	}

	switch op {
	case token.EQL, token.NEQ, token.LSS, token.LEQ, token.GTR, token.GEQ:
		return exact.MakeBool(exact.Compare(x, op, y))
	case token.SHL, token.SHR:
		s, _ := exact.Int64Val(y)
		return exact.Shift(x, op, uint(s))
	default:
		return exact.BinaryOp(x, op, y)
	}
}

func ext۰reflect۰rtype۰InOut(a *analysis, cgn *cgnode, out bool) {
	// If we have access to the callsite,
	// and the argument is an int constant,
	// return only that parameter.
	index := -1
	if site := cgn.callersite; site != nil {
		if c, ok := site.instr.Common().Args[0].(*ssa.Const); ok {
			v, _ := exact.Int64Val(c.Value)
			index = int(v)
		}
	}
	a.addConstraint(&rtypeInOutConstraint{
		cgn:    cgn,
		t:      a.funcParams(cgn.obj),
		result: a.funcResults(cgn.obj),
		out:    out,
		i:      index,
	})
}

func (check *Checker) arrayLength(e ast.Expr) int64 {
	var x operand
	check.expr(&x, e)
	if x.mode != constant {
		if x.mode != invalid {
			check.errorf(x.pos(), "array length %s must be constant", &x)
		}
		return 0
	}
	if !x.isInteger() {
		check.errorf(x.pos(), "array length %s must be integer", &x)
		return 0
	}
	n, ok := exact.Int64Val(x.val)
	if !ok || n < 0 {
		check.errorf(x.pos(), "invalid array length %s", &x)
		return 0
	}
	return n
}

// checkLongShift checks if shift or shift-assign operations shift by more than
// the length of the underlying variable.
func checkLongShift(f *File, node ast.Node, x, y ast.Expr) {
	v := f.pkg.types[y].Value
	if v == nil {
		return
	}
	amt, ok := exact.Int64Val(v)
	if !ok {
		return
	}
	t := f.pkg.types[x].Type
	if t == nil {
		return
	}
	b, ok := t.Underlying().(*types.Basic)
	if !ok {
		return
	}
	var size int64
	var msg string
	switch b.Kind() {
	case types.Uint8, types.Int8:
		size = 8
	case types.Uint16, types.Int16:
		size = 16
	case types.Uint32, types.Int32:
		size = 32
	case types.Uint64, types.Int64:
		size = 64
	case types.Int, types.Uint, types.Uintptr:
		// These types may be as small as 32 bits, but no smaller.
		size = 32
		msg = "might be "
	default:
		return
	}
	if amt >= size {
		ident := f.gofmt(x)
		f.Badf(node.Pos(), "%s %stoo small for shift of %d", ident, msg, amt)
	}
}

func evalAction(n ast.Node) exact.Value {
	switch e := n.(type) {
	case *ast.BasicLit:
		return val(e.Value)
	case *ast.BinaryExpr:
		x := evalAction(e.X)
		if x == nil {
			return nil
		}
		y := evalAction(e.Y)
		if y == nil {
			return nil
		}
		switch e.Op {
		case token.EQL, token.NEQ, token.LSS, token.LEQ, token.GTR, token.GEQ:
			return exact.MakeBool(exact.Compare(x, e.Op, y))
		case token.SHL, token.SHR:
			s, _ := exact.Int64Val(y)
			return exact.Shift(x, e.Op, uint(s))
		default:
			return exact.BinaryOp(x, e.Op, y)
		}
	case *ast.UnaryExpr:
		return exact.UnaryOp(e.Op, evalAction(e.X), -1)
	case *ast.CallExpr:
		fmt.Printf("Can't handle call (%s) yet at pos %d\n", e.Fun, e.Pos())
		return nil
	case *ast.Ident:
		fmt.Printf("Can't handle Ident %s here at pos %d\n", e.Name, e.Pos())
		return nil
	case *ast.ParenExpr:
		return evalAction(e.X)
	default:
		fmt.Println("Can't handle")
		fmt.Printf("n: %s, e: %s\n", n, e)
		return nil
	}
}

// index checks an index expression for validity.
// If max >= 0, it is the upper bound for index.
// If index is valid and the result i >= 0, then i is the constant value of index.
func (check *Checker) index(index ast.Expr, max int64) (i int64, valid bool) {
	var x operand
	check.expr(&x, index)
	if x.mode == invalid {
		return
	}

	// an untyped constant must be representable as Int
	check.convertUntyped(&x, Typ[Int])
	if x.mode == invalid {
		return
	}

	// the index must be of integer type
	if !isInteger(x.typ) {
		check.invalidArg(x.pos(), "index %s must be integer", &x)
		return
	}

	// a constant index i must be in bounds
	if x.mode == constant {
		if exact.Sign(x.val) < 0 {
			check.invalidArg(x.pos(), "index %s must not be negative", &x)
			return
		}
		i, valid = exact.Int64Val(x.val)
		if !valid || max >= 0 && i >= max {
			check.errorf(x.pos(), "index %s is out of bounds", &x)
			return i, false
		}
		// 0 <= i [ && i < max ]
		return i, true
	}

	return -1, true
}

func (c *compiler) NewConstValue(v exact.Value, typ types.Type) *LLVMValue {
	switch {
	case v.Kind() == exact.Unknown:
		// TODO nil literals should be represented more appropriately once the exact-package supports it.
		llvmtyp := c.types.ToLLVM(typ)
		return c.NewValue(llvm.ConstNull(llvmtyp), typ)

	case isString(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.String]
		}
		llvmtyp := c.types.ToLLVM(typ)
		strval := exact.StringVal(v)
		strlen := len(strval)
		i8ptr := llvm.PointerType(llvm.Int8Type(), 0)
		var ptr llvm.Value
		if strlen > 0 {
			init := llvm.ConstString(strval, false)
			ptr = llvm.AddGlobal(c.module.Module, init.Type(), "")
			ptr.SetInitializer(init)
			ptr = llvm.ConstBitCast(ptr, i8ptr)
		} else {
			ptr = llvm.ConstNull(i8ptr)
		}
		len_ := llvm.ConstInt(c.types.inttype, uint64(strlen), false)
		llvmvalue := llvm.Undef(llvmtyp)
		llvmvalue = llvm.ConstInsertValue(llvmvalue, ptr, []uint32{0})
		llvmvalue = llvm.ConstInsertValue(llvmvalue, len_, []uint32{1})
		return c.NewValue(llvmvalue, typ)

	case isInteger(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Int]
		}
		llvmtyp := c.types.ToLLVM(typ)
		var llvmvalue llvm.Value
		if isUnsigned(typ) {
			v, _ := exact.Uint64Val(v)
			llvmvalue = llvm.ConstInt(llvmtyp, v, false)
		} else {
			v, _ := exact.Int64Val(v)
			llvmvalue = llvm.ConstInt(llvmtyp, uint64(v), true)
		}
		return c.NewValue(llvmvalue, typ)

	case isBoolean(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Bool]
		}
		var llvmvalue llvm.Value
		if exact.BoolVal(v) {
			llvmvalue = llvm.ConstAllOnes(llvm.Int1Type())
		} else {
			llvmvalue = llvm.ConstNull(llvm.Int1Type())
		}
		return c.NewValue(llvmvalue, typ)

	case isFloat(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Float64]
		}
		llvmtyp := c.types.ToLLVM(typ)
		floatval, _ := exact.Float64Val(v)
		llvmvalue := llvm.ConstFloat(llvmtyp, floatval)
		return c.NewValue(llvmvalue, typ)

	case typ == types.Typ[types.UnsafePointer]:
		llvmtyp := c.types.ToLLVM(typ)
		v, _ := exact.Uint64Val(v)
		llvmvalue := llvm.ConstInt(llvmtyp, v, false)
		return c.NewValue(llvmvalue, typ)

	case isComplex(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Complex128]
		}
		llvmtyp := c.types.ToLLVM(typ)
		floattyp := llvmtyp.StructElementTypes()[0]
		llvmvalue := llvm.ConstNull(llvmtyp)
		realv := exact.Real(v)
		imagv := exact.Imag(v)
		realfloatval, _ := exact.Float64Val(realv)
		imagfloatval, _ := exact.Float64Val(imagv)
		llvmre := llvm.ConstFloat(floattyp, realfloatval)
		llvmim := llvm.ConstFloat(floattyp, imagfloatval)
		llvmvalue = llvm.ConstInsertValue(llvmvalue, llvmre, []uint32{0})
		llvmvalue = llvm.ConstInsertValue(llvmvalue, llvmim, []uint32{1})
		return c.NewValue(llvmvalue, typ)
	}

	// Special case for string -> [](byte|rune)
	if u, ok := typ.Underlying().(*types.Slice); ok && isInteger(u.Elem()) {
		if v.Kind() == exact.String {
			strval := c.NewConstValue(v, types.Typ[types.String])
			return strval.Convert(typ).(*LLVMValue)
		}
	}

	panic(fmt.Sprintf("unhandled: t=%s(%T), v=%v(%T)", c.types.TypeString(typ), typ, v, v))
}

func Write(pkg *types.Package, out io.Writer, sizes types.Sizes) {
	fmt.Fprintf(out, "package %s\n", pkg.Name())

	e := &exporter{pkg: pkg, imports: make(map[*types.Package]bool), out: out}

	for _, imp := range pkg.Imports() {
		e.addImport(imp)
	}

	for _, name := range pkg.Scope().Names() {
		obj := pkg.Scope().Lookup(name)

		_, isTypeName := obj.(*types.TypeName)
		if obj.Exported() || isTypeName {
			e.toExport = append(e.toExport, obj)
		}
	}

	for i := 0; i < len(e.toExport); i++ {
		switch o := e.toExport[i].(type) {
		case *types.TypeName:
			fmt.Fprintf(out, "type %s %s\n", e.makeName(o), e.makeType(o.Type().Underlying()))
			if _, isInterface := o.Type().Underlying().(*types.Interface); !isInterface {
				writeMethods := func(t types.Type) {
					methods := types.NewMethodSet(t)
					for i := 0; i < methods.Len(); i++ {
						m := methods.At(i)
						if len(m.Index()) > 1 {
							continue // method of embedded field
						}
						out.Write([]byte("func (? " + e.makeType(m.Recv()) + ") " + e.makeName(m.Obj()) + e.makeSignature(m.Type()) + "\n"))
					}
				}
				writeMethods(o.Type())
				writeMethods(types.NewPointer(o.Type()))
			}
		case *types.Func:
			out.Write([]byte("func " + e.makeName(o) + e.makeSignature(o.Type()) + "\n"))
		case *types.Const:
			optType := ""
			basic, isBasic := o.Type().(*types.Basic)
			if !isBasic || basic.Info()&types.IsUntyped == 0 {
				optType = " " + e.makeType(o.Type())
			}

			basic = o.Type().Underlying().(*types.Basic)
			var val string
			switch {
			case basic.Info()&types.IsBoolean != 0:
				val = strconv.FormatBool(exact.BoolVal(o.Val()))
			case basic.Info()&types.IsInteger != 0:
				if basic.Kind() == types.Uint64 {
					d, _ := exact.Uint64Val(o.Val())
					val = fmt.Sprintf("%#x", d)
					break
				}
				d, _ := exact.Int64Val(o.Val())
				if basic.Kind() == types.UntypedRune {
					switch {
					case d < 0 || d > unicode.MaxRune:
						val = fmt.Sprintf("('\\x00' + %d)", d)
					case d > 0xffff:
						val = fmt.Sprintf("'\\U%08x'", d)
					default:
						val = fmt.Sprintf("'\\u%04x'", d)
					}
					break
				}
				val = fmt.Sprintf("%#x", d)
			case basic.Info()&types.IsFloat != 0:
				f, _ := exact.Float64Val(o.Val())
				val = strconv.FormatFloat(f, 'b', -1, 64)
			case basic.Info()&types.IsComplex != 0:
				r, _ := exact.Float64Val(exact.Real(o.Val()))
				i, _ := exact.Float64Val(exact.Imag(o.Val()))
				val = fmt.Sprintf("(%s+%si)", strconv.FormatFloat(r, 'b', -1, 64), strconv.FormatFloat(i, 'b', -1, 64))
			case basic.Info()&types.IsString != 0:
				val = fmt.Sprintf("%#v", exact.StringVal(o.Val()))
			default:
				panic("Unhandled constant type: " + basic.String())
			}
			out.Write([]byte("const " + e.makeName(o) + optType + " = " + val + "\n"))
		case *types.Var:
			out.Write([]byte("var " + e.makeName(o) + " " + e.makeType(o.Type()) + "\n"))
		default:
			panic(fmt.Sprintf("Unhandled object: %T\n", o))
		}
	}

	fmt.Fprintf(out, "$$\n")
}

func (c *funcContext) translateExpr(expr ast.Expr) *expression {
	exprType := c.p.info.Types[expr].Type
	if value := c.p.info.Types[expr].Value; value != nil {
		basic := types.Typ[types.String]
		if value.Kind() != exact.String { // workaround for bug in go/types
			basic = exprType.Underlying().(*types.Basic)
		}
		switch {
		case basic.Info()&types.IsBoolean != 0:
			return c.formatExpr("%s", strconv.FormatBool(exact.BoolVal(value)))
		case basic.Info()&types.IsInteger != 0:
			if is64Bit(basic) {
				d, _ := exact.Uint64Val(value)
				if basic.Kind() == types.Int64 {
					return c.formatExpr("new %s(%s, %s)", c.typeName(exprType), strconv.FormatInt(int64(d)>>32, 10), strconv.FormatUint(d&(1<<32-1), 10))
				}
				return c.formatExpr("new %s(%s, %s)", c.typeName(exprType), strconv.FormatUint(d>>32, 10), strconv.FormatUint(d&(1<<32-1), 10))
			}
			d, _ := exact.Int64Val(value)
			return c.formatExpr("%s", strconv.FormatInt(d, 10))
		case basic.Info()&types.IsFloat != 0:
			f, _ := exact.Float64Val(value)
			return c.formatExpr("%s", strconv.FormatFloat(f, 'g', -1, 64))
		case basic.Info()&types.IsComplex != 0:
			r, _ := exact.Float64Val(exact.Real(value))
			i, _ := exact.Float64Val(exact.Imag(value))
			if basic.Kind() == types.UntypedComplex {
				exprType = types.Typ[types.Complex128]
			}
			return c.formatExpr("new %s(%s, %s)", c.typeName(exprType), strconv.FormatFloat(r, 'g', -1, 64), strconv.FormatFloat(i, 'g', -1, 64))
		case basic.Info()&types.IsString != 0:
			return c.formatExpr("%s", encodeString(exact.StringVal(value)))
		default:
			panic("Unhandled constant type: " + basic.String())
		}
	}

	switch e := expr.(type) {
	case *ast.CompositeLit:
		if ptrType, isPointer := exprType.(*types.Pointer); isPointer {
			exprType = ptrType.Elem()
		}

		collectIndexedElements := func(elementType types.Type) []string {
			elements := make([]string, 0)
			i := 0
			zero := c.zeroValue(elementType)
			for _, element := range e.Elts {
				if kve, isKve := element.(*ast.KeyValueExpr); isKve {
					key, _ := exact.Int64Val(c.p.info.Types[kve.Key].Value)
					i = int(key)
					element = kve.Value
				}
				for len(elements) <= i {
					elements = append(elements, zero)
				}
				elements[i] = c.translateImplicitConversionWithCloning(element, elementType).String()
				i++
			}
			return elements
		}

		switch t := exprType.Underlying().(type) {
		case *types.Array:
			elements := collectIndexedElements(t.Elem())
			if len(elements) == 0 {
				return c.formatExpr("%s", c.zeroValue(t))
			}
			zero := c.zeroValue(t.Elem())
			for len(elements) < int(t.Len()) {
				elements = append(elements, zero)
			}
			return c.formatExpr(`$toNativeArray("%s", [%s])`, typeKind(t.Elem()), strings.Join(elements, ", "))
		case *types.Slice:
			return c.formatExpr("new %s([%s])", c.typeName(exprType), strings.Join(collectIndexedElements(t.Elem()), ", "))
		case *types.Map:
			mapVar := c.newVariable("_map")
			keyVar := c.newVariable("_key")
			assignments := ""
			for _, element := range e.Elts {
				kve := element.(*ast.KeyValueExpr)
				assignments += c.formatExpr(`%s = %s, %s[%s] = { k: %s, v: %s }, `, keyVar, c.translateImplicitConversion(kve.Key, t.Key()), mapVar, c.makeKey(c.newIdent(keyVar, t.Key()), t.Key()), keyVar, c.translateImplicitConversion(kve.Value, t.Elem())).String()
			}
			return c.formatExpr("(%s = new $Map(), %s%s)", mapVar, assignments, mapVar)
		case *types.Struct:
			elements := make([]string, t.NumFields())
			isKeyValue := true
			if len(e.Elts) != 0 {
				_, isKeyValue = e.Elts[0].(*ast.KeyValueExpr)
			}
			if !isKeyValue {
				for i, element := range e.Elts {
					elements[i] = c.translateImplicitConversion(element, t.Field(i).Type()).String()
				}
			}
			if isKeyValue {
				for i := range elements {
					elements[i] = c.zeroValue(t.Field(i).Type())
				}
				for _, element := range e.Elts {
//.........這裏部分代碼省略.........