func buildBinaryOpExpr(b *builder, expr *tast.OpExpr) *ref {
op := expr.Op.Lit
A := b.buildExpr(expr.A)
atyp := A.Type()
if types.IsBasic(atyp, types.Bool) && (op == "&&" || op == "||") {
switch op {
case "&&":
return buildLogicAnd(b, A, expr.B)
case "||":
return buildLogicOr(b, A, expr.B)
}
panic("unreachable")
}
B := b.buildExpr(expr.B)
btyp := B.Type()
if types.IsConst(atyp) && types.IsConst(btyp) {
return binaryOpConst(b, op, A, B)
}
if op == ">>" || op == "<<" {
ret := b.newTemp(atyp)
buildShift(b, ret, A, B, op)
return ret
}
if ok, t := types.SameBasic(atyp, btyp); ok {
switch t {
case types.Int, types.Int8:
return binaryOpInt(b, op, A, B, t)
case types.Uint, types.Uint8:
return binaryOpUint(b, op, A, B, t)
case types.Bool:
return binaryOpBool(b, op, A, B)
}
panic("bug")
}
if types.IsNil(atyp) && types.IsNil(btyp) {
return binaryOpNil(b, op, A, B)
} else if types.BothPointer(atyp, btyp) {
return binaryOpPtr(b, op, A, B)
} else if types.BothFuncPointer(atyp, btyp) {
return binaryOpPtr(b, op, A, B)
} else if types.BothSlice(atyp, btyp) {
return binaryOpSlice(b, op, A, B)
}
panic("bug")
}
// allocPrepare checks if the provided types are all allocable, and insert
// implicit type casts if needed. Only literay expression list needs alloc
// prepare.
func allocPrepare(
b *builder, toks []*lex8.Token, lst *tast.ExprList,
) *tast.ExprList {
ret := tast.NewExprList()
for i, tok := range toks {
e := lst.Exprs[i]
t := e.Type()
if types.IsNil(t) {
b.Errorf(tok.Pos, "cannot infer type from nil for %q", tok.Lit)
return nil
}
if v, ok := types.NumConst(t); ok {
e = constCastInt(b, tok.Pos, v, e)
if e == nil {
return nil
}
}
if !types.IsAllocable(t) {
b.Errorf(tok.Pos, "cannot allocate for %s", t)
return nil
}
ret.Append(e)
}
return ret
}
func binaryOpPtr(b *builder, op string, A, B *ref) *ref {
atyp := A.Type()
btyp := B.Type()
switch op {
case "==", "!=":
// replace nil with a typed zero
if types.IsNil(atyp) {
A = newRef(btyp, ir.Num(0))
} else if types.IsNil(btyp) {
B = newRef(atyp, ir.Num(0))
}
ret := b.newTemp(types.Bool)
b.b.Arith(ret.IR(), A.IR(), op, B.IR())
return ret
}
panic("bug")
}
func binaryOpPtr(b *builder, opTok *lex8.Token, A, B tast.Expr) tast.Expr {
op := opTok.Lit
atyp := A.R().T
btyp := B.R().T
switch op {
case "==", "!=":
if types.IsNil(atyp) {
A = tast.NewCast(A, btyp)
} else if types.IsNil(btyp) {
B = tast.NewCast(B, atyp)
}
return &tast.OpExpr{A, opTok, B, tast.NewRef(types.Bool)}
}
b.Errorf(opTok.Pos, "%q on pointers", op)
return nil
}
func binaryOpSlice(b *builder, op string, A, B *ref) *ref {
atyp := A.Type()
btyp := B.Type()
switch op {
case "==", "!=":
if types.IsNil(atyp) {
return testNilSlice(b, B, op == "==")
} else if types.IsNil(btyp) {
return testNilSlice(b, A, op == "==")
}
addrA := b.newPtr()
addrB := b.newPtr()
b.b.Arith(addrA, nil, "&", A.IR())
b.b.Arith(addrB, nil, "&", B.IR())
baseA := ir.NewAddrRef(addrA, 4, 0, false, true)
sizeA := ir.NewAddrRef(addrA, 4, 4, false, true)
baseB := ir.NewAddrRef(addrB, 4, 0, false, true)
sizeB := ir.NewAddrRef(addrB, 4, 4, false, true)
ptrEq := b.newCond()
sizeEq := b.newCond()
b.b.Arith(ptrEq, baseA, "==", baseB)
b.b.Arith(sizeEq, sizeA, "==", sizeB)
ret := b.newCond()
b.b.Arith(ret, ptrEq, "&", sizeEq)
if op == "!=" {
b.b.Arith(ret, nil, "!", ret)
}
return newRef(types.Bool, ret)
}
panic("bug")
}
func assign(b *builder, dest, src tast.Expr, op *lex8.Token) tast.Stmt {
destRef := dest.R()
srcRef := src.R()
ndest := destRef.Len()
nsrc := srcRef.Len()
if ndest != nsrc {
b.Errorf(op.Pos, "cannot assign %s to %s", nsrc, ndest)
return nil
}
for i := 0; i < ndest; i++ {
r := destRef.At(i)
if !r.Addressable {
b.Errorf(op.Pos, "assigning to non-addressable")
return nil
}
destType := r.Type()
srcType := srcRef.At(i).Type()
if !types.CanAssign(destType, srcType) {
b.Errorf(op.Pos, "cannot assign %s to %s", srcType, destType)
return nil
}
}
// insert casting if needed
if srcList, ok := tast.MakeExprList(src); ok {
newList := tast.NewExprList()
for i, e := range srcList.Exprs {
t := e.Type()
if types.IsNil(t) {
e = tast.NewCast(e, destRef.At(i).Type())
} else if v, ok := types.NumConst(t); ok {
e = constCast(b, nil, v, e, destRef.At(i).Type())
if e == nil {
panic("bug")
}
}
newList.Append(e)
}
src = newList
}
return &tast.AssignStmt{dest, op, src}
}
func varDeclPrepare(
b *builder, toks []*lex8.Token, lst *tast.ExprList, t types.T,
) *tast.ExprList {
ret := tast.NewExprList()
for i, tok := range toks {
e := lst.Exprs[i]
etype := e.Type()
if types.IsNil(etype) {
e = tast.NewCast(e, t)
} else if v, ok := types.NumConst(etype); ok {
e = constCast(b, tok.Pos, v, e, t)
if e == nil {
return nil
}
}
ret.Append(e)
}
return ret
}
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 buildReturnStmt(b *builder, stmt *ast.ReturnStmt) tast.Stmt {
pos := stmt.Kw.Pos
if stmt.Exprs == nil {
if b.retType == nil || b.retNamed {
return &tast.ReturnStmt{}
}
b.Errorf(pos, "expects return %s", fmt8.Join(b.retType, ","))
return nil
}
if b.retType == nil {
b.Errorf(pos, "function expects no return value")
return nil
}
src := b.buildExpr(stmt.Exprs)
if src == nil {
return nil
}
srcRef := src.R()
nret := len(b.retType)
nsrc := srcRef.Len()
if nret != nsrc {
b.Errorf(pos, "expect (%s), returning (%s)",
fmt8.Join(b.retType, ","), srcRef,
)
return nil
}
for i := 0; i < nret; i++ {
t := b.retType[i]
srcType := srcRef.At(i).Type()
if !types.CanAssign(t, srcType) {
b.Errorf(pos, "expect (%s), returning (%s)",
fmt8.Join(b.retType, ","), srcRef,
)
return nil
}
}
// insert implicit type casts
if srcList, ok := tast.MakeExprList(src); ok {
newList := tast.NewExprList()
for i, e := range srcList.Exprs {
t := e.Type()
if types.IsNil(t) {
e = tast.NewCast(e, b.retType[i])
} else if v, ok := types.NumConst(t); ok {
e = constCast(b, nil, v, e, b.retType[i])
if e == nil {
panic("bug")
}
}
newList.Append(e)
}
src = newList
}
return &tast.ReturnStmt{src}
}
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 (r *ref) IsNil() bool {
if !r.IsSingle() {
return false
}
return types.IsNil(r.Type())
}
func buildCallExpr(b *builder, expr *ast.CallExpr) tast.Expr {
f := b.buildExpr(expr.Func)
if f == nil {
return nil
}
pos := ast.ExprPos(expr.Func)
fref := f.R()
if !fref.IsSingle() {
b.Errorf(pos, "%s is not callable", fref)
return nil
}
if t, ok := fref.T.(*types.Type); ok {
return buildCast(b, expr, t.T)
}
builtin, ok := fref.T.(*types.BuiltInFunc)
if ok {
switch builtin.Name {
case "len":
return buildCallLen(b, expr, f)
case "make":
return buildCallMake(b, expr, f)
}
b.Errorf(pos, "builtin %s() not implemented", builtin.Name)
return nil
}
funcType, ok := fref.T.(*types.Func)
if !ok {
b.Errorf(pos, "function call on non-callable: %s", fref)
return nil
}
args := buildExprList(b, expr.Args)
if args == nil {
return nil
}
argsRef := args.R()
nargs := argsRef.Len()
if nargs != len(funcType.Args) {
b.Errorf(ast.ExprPos(expr), "argument expects (%s), got (%s)",
fmt8.Join(funcType.Args, ","), args,
)
return nil
}
// type check on each argument
for i := 0; i < nargs; i++ {
argType := argsRef.At(i).Type()
expect := funcType.Args[i].T
if !types.CanAssign(expect, argType) {
pos := ast.ExprPos(expr.Args.Exprs[i])
b.Errorf(pos, "argument %d expects %s, got %s",
i+1, expect, argType,
)
return nil
}
}
// insert casting when it is a literal expression list.
callArgs, ok := tast.MakeExprList(args)
if ok {
castedArgs := tast.NewExprList()
for i := 0; i < nargs; i++ {
argExpr := callArgs.Exprs[i]
argType := argExpr.Type()
expect := funcType.Args[i].T
// insert auto casts for consts
if types.IsNil(argType) {
castedArgs.Append(tast.NewCast(argExpr, expect))
} else if _, ok := types.NumConst(argType); ok {
castedArgs.Append(tast.NewCast(argExpr, expect))
} else {
castedArgs.Append(argExpr)
}
}
args = castedArgs
}
retRef := tast.Void
for _, t := range funcType.RetTypes {
retRef = tast.AppendRef(retRef, tast.NewRef(t))
}
return &tast.CallExpr{f, args, retRef}
}