func buildCast(b *builder, expr *ast.CallExpr, t types.T) tast.Expr {
pos := expr.Lparen.Pos
args := buildExprList(b, expr.Args)
if args == nil {
return nil
}
ref := args.R()
if !ref.IsSingle() {
b.Errorf(pos, "cannot convert %s to %s", ref, t)
return nil
}
srcType := ref.T
if c, ok := srcType.(*types.Const); ok {
if v, ok := types.NumConst(srcType); ok && types.IsInteger(t) {
return constCast(b, pos, v, args, t)
}
srcType = c.Type // using the underlying type
}
if types.IsInteger(t) && types.IsInteger(srcType) {
return tast.NewCast(args, t)
}
if regSizeCastable(t, srcType) {
return tast.NewCast(args, t)
}
b.Errorf(pos, "cannot convert from %s to %s", srcType, t)
return nil
}
func canShift(b *builder, atyp, btyp types.T, pos *lex8.Pos, op string) bool {
if !types.IsInteger(atyp) {
b.Errorf(pos, "%q on %s", op, atyp)
return false
} else if !types.IsInteger(btyp) {
b.Errorf(pos, "%q with %s", op, btyp)
return false
} else if !types.IsUnsigned(btyp) {
b.Errorf(pos, "%q with %s; must be unsigned", op, btyp)
return false
}
return true
}
func buildUnaryOpExpr(b *builder, expr *ast.OpExpr) tast.Expr {
opTok := expr.Op
op := opTok.Lit
opPos := opTok.Pos
B := b.buildExpr(expr.B)
if B == nil {
return nil
}
bref := B.R()
if !bref.IsSingle() {
b.Errorf(opPos, "%q on %s", op, bref)
return nil
}
btyp := bref.T
if op == "&" {
return refAddress(b, opTok, B)
} else if types.IsConst(btyp) {
return unaryOpConst(b, opTok, B)
} else if types.IsInteger(btyp) {
return unaryOpInt(b, opTok, B)
} else if types.IsBasic(btyp, types.Bool) {
return unaryOpBool(b, opTok, B)
}
b.Errorf(opPos, "invalid unary operator %q", op)
return nil
}
func buildIncStmt(b *builder, stmt *ast.IncStmt) tast.Stmt {
op := stmt.Op.Lit
expr := b.buildExpr(stmt.Expr)
if expr == nil {
return nil
}
ref := expr.R()
if !ref.IsSingle() {
b.Errorf(stmt.Op.Pos, "%s on expression list", op)
return nil
}
t := ref.Type()
if !types.IsInteger(t) {
b.Errorf(stmt.Op.Pos, "%s on %s", op, t)
return nil
}
if !ref.Addressable {
b.Errorf(stmt.Op.Pos, "%s on non-addressable", op)
return nil
}
switch stmt.Op.Lit {
case "++", "--":
return &tast.IncStmt{expr, stmt.Op}
default:
b.Errorf(stmt.Op.Pos, "invalid inc op %s", op)
return nil
}
}
func constCast(
b *builder, pos *lex8.Pos, v int64, from tast.Expr, to types.T,
) tast.Expr {
if types.IsInteger(to) && types.InRange(v, to) {
return tast.NewCast(from, to)
}
b.Errorf(pos, "cannot cast %d to %s", v, to)
return nil
}
func checkArrayIndex(b *builder, index tast.Expr, pos *lex8.Pos) tast.Expr {
t := index.R().T
if v, ok := types.NumConst(t); ok {
if v < 0 {
b.Errorf(pos, "array index is negative: %d", v)
return nil
}
return constCastInt(b, pos, v, index)
}
if !types.IsInteger(t) {
b.Errorf(pos, "index must be an integer")
return nil
}
return index
}
func buildCast(b *builder, from *ref, t types.T) *ref {
srcType := from.Type()
ret := b.newTemp(t)
if types.IsNil(srcType) {
size := t.Size()
if size == arch8.RegSize {
return newRef(t, ir.Num(0))
}
if _, ok := t.(*types.Slice); !ok {
panic("bug")
}
ret := b.newTemp(t)
b.b.Zero(ret.IR())
return ret
}
if c, ok := srcType.(*types.Const); ok {
if v, ok := types.NumConst(srcType); ok && types.IsInteger(t) {
return newRef(t, constNumIr(v, t))
}
// TODO: we do not support typed const right?
// so why need this line?
srcType = c.Type // using the underlying type
}
if types.IsInteger(t) && types.IsInteger(srcType) {
b.b.Arith(ret.IR(), nil, "cast", from.IR())
return ret
}
if regSizeCastable(t, srcType) {
b.b.Arith(ret.IR(), nil, "", from.IR())
return ret
}
panic("bug")
}
func buildUnaryOpExpr(b *builder, expr *tast.OpExpr) *ref {
op := expr.Op.Lit
B := b.buildExpr(expr.B)
btyp := B.Type()
if op == "&" {
ret := b.newTemp(&types.Pointer{btyp})
b.b.Arith(ret.IR(), nil, op, B.IR())
return ret
} else if types.IsConst(btyp) {
panic("bug")
} else if types.IsInteger(btyp) {
return unaryOpInt(b, op, B)
} else if types.IsBasic(btyp, types.Bool) {
return unaryOpBool(b, op, B)
}
panic("bug")
}
func buildBinaryOpExpr(b *builder, expr *ast.OpExpr) tast.Expr {
opTok := expr.Op
op := opTok.Lit
opPos := opTok.Pos
A := b.buildExpr(expr.A)
if A == nil {
return nil
}
aref := A.R()
if !aref.IsSingle() {
b.Errorf(opPos, "%q on %s", op, aref)
return nil
}
atyp := aref.T
B := b.buildExpr(expr.B)
if B == nil {
return nil
}
bref := B.R()
if !bref.IsSingle() {
b.Errorf(opPos, "%q on %s", op, bref)
return nil
}
btyp := bref.T
if types.IsConst(atyp) && types.IsConst(btyp) {
return binaryOpConst(b, opTok, A, B)
}
if op == ">>" || op == "<<" {
if v, ok := types.NumConst(btyp); ok {
B = constCast(b, opPos, v, B, types.Uint)
if B == nil {
return nil
}
btyp = types.Uint
}
if v, ok := types.NumConst(atyp); ok {
A = constCast(b, opPos, v, A, types.Int)
if A == nil {
return nil
}
atyp = types.Int
}
if !canShift(b, atyp, btyp, opPos, op) {
return nil
}
r := tast.NewRef(atyp)
return &tast.OpExpr{A, opTok, B, r}
}
if v, ok := types.NumConst(atyp); ok {
A = constCast(b, opPos, v, A, btyp)
if A == nil {
return nil
}
atyp = btyp
} else if c, ok := atyp.(*types.Const); ok {
atyp = c.Type
}
if v, ok := types.NumConst(btyp); ok {
B = constCast(b, opPos, v, B, atyp)
if B == nil {
return nil
}
btyp = atyp
} else if c, ok := btyp.(*types.Const); ok {
btyp = c.Type
}
if ok, t := types.SameBasic(atyp, btyp); ok {
switch t {
case types.Int, types.Int8, types.Uint, types.Uint8:
return binaryOpInt(b, opTok, A, B, t)
case types.Bool:
return binaryOpBool(b, opTok, A, B)
case types.Float32:
b.Errorf(opPos, "floating point operations not implemented")
return nil
}
}
if types.IsNil(atyp) && types.IsNil(btyp) {
return binaryOpNil(b, opTok, A, B)
} else if types.BothPointer(atyp, btyp) {
return binaryOpPtr(b, opTok, A, B)
} else if types.BothFuncPointer(atyp, btyp) {
return binaryOpPtr(b, opTok, A, B)
} else if types.BothSlice(atyp, btyp) {
return binaryOpSlice(b, opTok, A, B)
}
b.Errorf(opPos, "invalid operation of %s %s %s", atyp, op, btyp)
if types.IsInteger(atyp) && types.IsInteger(btyp) {
switch op {
case "+", "-", "*", "&", "|", "^", "%", "/",
"==", "!=", ">", "<", ">=", "<=":
b.Errorf(
opPos,
"operation %s needs the same type on both sides",
op,
)
}
}
return nil
}
func buildArrayLit(b *builder, lit *ast.ArrayLiteral) tast.Expr {
hold := b.lhsSwap(false)
defer b.lhsRestore(hold)
if lit.Type.Len != nil {
b.Errorf(
ast.ExprPos(lit),
"array literal with length not supported yet",
)
return nil
}
buf := new(bytes.Buffer)
t := buildType(b, lit.Type.Type)
if t == nil {
return nil
}
if !types.IsInteger(t) {
pos := ast.ExprPos(lit.Type.Type)
b.Errorf(pos, "array literal must be integer type")
return nil
}
bt := t.(types.Basic)
if lit.Exprs != nil {
for _, expr := range lit.Exprs.Exprs {
n := b.buildConstExpr(expr)
if n == nil {
return nil
}
ntype := n.R().T
if _, ok := ntype.(*types.Const); !ok {
b.Errorf(ast.ExprPos(expr), "array literal not a constant")
return nil
}
if v, ok := types.NumConst(ntype); ok {
if !types.InRange(v, t) {
b.Errorf(
ast.ExprPos(expr),
"constant out of range of %s",
t,
)
return nil
}
switch bt {
case types.Int, types.Uint:
var bs [4]byte
binary.LittleEndian.PutUint32(bs[:], uint32(v))
buf.Write(bs[:])
case types.Int8, types.Uint8:
buf.Write([]byte{byte(v)})
default:
panic("not integer")
}
}
}
}
ref := tast.NewConstRef(&types.Slice{bt}, buf.Bytes())
return &tast.Const{ref}
}