func fixGoTypesExpr(fn *cc.Decl, x *cc.Expr, targ *cc.Type) (ret *cc.Type) {
if x == nil {
return nil
}
defer func() {
x.XType = ret
}()
if x.Op == cc.Paren {
return fixGoTypesExpr(fn, x.Left, targ)
}
// Make explicit C's implicit conversions from boolean to non-boolean and vice versa.
switch x.Op {
case cc.AndAnd, cc.OrOr, cc.Not, cc.EqEq, cc.Lt, cc.LtEq, cc.Gt, cc.GtEq, cc.NotEq:
if targ != nil && targ.Kind != Bool {
old := copyExpr(x)
if targ.Kind == Int {
x.Op = cc.Call
x.Left = &cc.Expr{Op: cc.Name, Text: "bool2int"}
x.List = []*cc.Expr{old}
x.Right = nil
} else {
x.Op = cc.Cast
x.Left = &cc.Expr{Op: cc.Call, Left: &cc.Expr{Op: cc.Name, Text: "bool2int"}, List: []*cc.Expr{old}}
x.Type = targ
}
fixGoTypesExpr(fn, old, boolType)
return targ
}
default:
if targ != nil && targ.Kind == Bool {
old := copyExpr(x)
left := fixGoTypesExpr(fn, old, nil)
if left != nil && left.Kind == Bool {
return targ
}
if old.Op == cc.Number {
switch old.Text {
case "1":
x.Op = cc.Name
x.Text = "true"
return targ
case "0":
x.Op = cc.Name
x.Text = "false"
return targ
}
}
x.Op = cc.NotEq
x.Left = old
x.Right = zeroFor(left)
fixSpecialCompare(fn, x)
return targ
}
}
fixArray(fn, x)
switch x.Op {
default:
panic(fmt.Sprintf("unexpected construct %v in fixGoTypesExpr - %v - %v", GoString(x), x.Op, x.Span))
case ExprType:
// inserted by a rewrite
return nil
case ExprSlice:
// inserted by rewriteLen
left := fixGoTypesExpr(fn, x.List[0], targ)
fixGoTypesExpr(fn, x.List[1], nil)
fixGoTypesExpr(fn, x.List[2], nil)
return left
case cc.Comma:
for i, y := range x.List {
t := targ
if i+1 < len(x.List) {
t = nil
}
fixGoTypesExpr(fn, y, t)
}
return nil
case ExprBlock:
for _, stmt := range x.Block {
fixGoTypesStmt(nil, fn, stmt)
}
return nil
case cc.Add, cc.And, cc.Div, cc.Mod, cc.Mul, cc.Or, cc.Sub, cc.Xor:
if x.Op == cc.Sub && isPtrSliceOrArray(x.Left.XType) && isPtrSliceOrArray(x.Right.XType) {
left := fixGoTypesExpr(fn, x.Left, nil)
right := fixGoTypesExpr(fn, x.Right, nil)
if left != nil && right != nil && left.Kind != right.Kind {
if left.Kind == Slice {
forceConvert(fn, x.Right, right, left)
} else {
forceConvert(fn, x.Left, left, right)
}
}
x.Left = &cc.Expr{Op: cc.Minus, Left: &cc.Expr{Op: cc.Call, Left: &cc.Expr{Op: cc.Name, Text: "cap"}, List: []*cc.Expr{x.Left}}}
x.Right = &cc.Expr{Op: cc.Call, Left: &cc.Expr{Op: cc.Name, Text: "cap"}, List: []*cc.Expr{x.Right}}
x.Op = cc.Add
return intType
}
left := fixGoTypesExpr(fn, x.Left, targ)
if x.Op == cc.And && x.Right.Op == cc.Twid {
x.Op = AndNot
x.Right = x.Right.Left
}
if x.Op == cc.Add && isSliceStringOrArray(left) {
fixGoTypesExpr(fn, x.Right, nil)
x.Op = ExprSlice
x.List = []*cc.Expr{x.Left, x.Right, nil}
x.Left = nil
x.Right = nil
if left.Kind == cc.Array {
left = &cc.Type{Kind: Slice, Base: left.Base}
}
return left
}
right := fixGoTypesExpr(fn, x.Right, targ)
return fixBinary(fn, x, left, right, targ)
case cc.AddEq, cc.AndEq, cc.DivEq, cc.Eq, cc.ModEq, cc.MulEq, cc.OrEq, cc.SubEq, cc.XorEq:
left := fixGoTypesExpr(fn, x.Left, nil)
if x.Op == cc.AndEq && x.Right.Op == cc.Twid {
x.Op = AndNotEq
x.Right = x.Right.Left
}
if x.Op == cc.AddEq && isSliceOrString(left) {
fixGoTypesExpr(fn, x.Right, nil)
old := copyExpr(x.Left)
x.Op = cc.Eq
x.Right = &cc.Expr{Op: ExprSlice, List: []*cc.Expr{old, x.Right, nil}}
return left
}
if x.Op == cc.Eq && x.Left.Op == cc.Index && sameType(x.Left.Left.XType, stringType) && GoString(x.Left.Right) == "0" && GoString(x.Right) == "0" {
x.Left = x.Left.Left
x.Right = &cc.Expr{Op: cc.Name, Text: `""`}
return x.Left.XType
}
forceGoType(fn, x.Right, left)
if x.Op == cc.Eq && x.Left != nil && x.Right != nil && x.Right.XType != nil && isCall(x.Right, "make") && x.Left.XDecl != nil && x.Left.XDecl.Type != nil && x.Left.XDecl.Type.Kind == cc.Ptr && sameType(x.Left.XDecl.Type.Base, x.Right.XType.Base) {
x.Left.XDecl.Type = x.Right.XType
x.Left.XType = x.Right.XType
left = x.Right.XType
}
return left
case ColonEq:
left := fixGoTypesExpr(fn, x.Right, nil)
x.Left.XType = left
x.Left.XDecl.Type = left
return left
case cc.Addr:
left := fixGoTypesExpr(fn, x.Left, nil)
if left == nil {
return nil
}
if targ != nil && targ.Kind == Slice && sameType(targ.Base, left) {
l := x.Left
l.Op = ExprSlice
l.List = []*cc.Expr{l.Left, l.Right, nil}
l.Left = nil
l.Right = nil
fixMerge(x, l)
return targ
}
return &cc.Type{Kind: cc.Ptr, Base: left}
case cc.AndAnd, cc.OrOr, cc.Not:
fixGoTypesExpr(fn, x.Left, boolType)
if x.Right != nil {
fixGoTypesExpr(fn, x.Right, boolType)
}
return boolType
case cc.Arrow, cc.Dot:
left := fixGoTypesExpr(fn, x.Left, nil)
if x.Op == cc.Arrow && isSliceOrString(left) {
x.Left = &cc.Expr{Op: cc.Index, Left: x.Left, Right: &cc.Expr{Op: cc.Number, Text: "0"}}
}
return x.XDecl.Type
case cc.Call:
if fixPrintf(fn, x) {
return x.XType
}
if fixSpecialCall(fn, x, targ) {
return x.XType
}
left := fixGoTypesExpr(fn, x.Left, nil)
if left != nil && left.Kind == cc.Ptr && left.Base.Kind == cc.Func {
left = left.Base
}
for i, y := range x.List {
if left != nil && left.Kind == cc.Func && i < len(left.Decls) {
forceGoType(fn, y, left.Decls[i].Type)
} else {
fixGoTypesExpr(fn, y, nil)
}
}
if left != nil && left.Kind == cc.Func {
return left.Base
}
return nil
case cc.Cast:
fixGoTypesExpr(fn, x.Left, nil)
if isEmptyInterface(x.Left.XType) {
x.Op = TypeAssert
}
return x.Type
case cc.CastInit:
fixGoTypesInit(nil, x.Init)
return x.Type
case cc.EqEq, cc.Gt, cc.GtEq, cc.Lt, cc.LtEq, cc.NotEq:
if fixSpecialCompare(fn, x) {
return boolType
}
left := fixGoTypesExpr(fn, x.Left, nil)
if x.Right.Op == cc.Number && x.Right.Text == "0" || x.Right.Op == cc.Name && x.Right.Text == "nil" {
if isSliceOrPtr(left) {
x.Right.Op = cc.Name
x.Right.Text = "nil"
return boolType
}
if left != nil && left.Kind == String {
x.Right.Op = cc.String
x.Right.Texts = []string{`""`}
return boolType
}
}
right := fixGoTypesExpr(fn, x.Right, nil)
if isSliceOrArray(x.Left.XType) && isSliceOrArray(x.Right.XType) {
x.Left = &cc.Expr{Op: cc.Minus, Left: &cc.Expr{Op: cc.Call, Left: &cc.Expr{Op: cc.Name, Text: "cap"}, List: []*cc.Expr{x.Left}}}
x.Right = &cc.Expr{Op: cc.Minus, Left: &cc.Expr{Op: cc.Call, Left: &cc.Expr{Op: cc.Name, Text: "cap"}, List: []*cc.Expr{x.Right}}}
return boolType
}
fixBinary(fn, x, left, right, nil)
return boolType
case cc.Index, cc.Indir:
left := fixGoTypesExpr(fn, x.Left, nil)
if x.Right != nil {
fixGoTypesExpr(fn, x.Right, nil)
}
if left == nil {
return nil
}
if isSliceOrString(left) && x.Op == cc.Indir {
x.Op = cc.Index
x.Right = &cc.Expr{Op: cc.Number, Text: "0"}
}
switch left.Kind {
case cc.Ptr, Slice, cc.Array:
if x.Op == cc.Indir && left.Kind == cc.Ptr && left.Base.Kind == cc.Func {
*x = *x.Left
}
return left.Base
case String:
return byteType
}
return nil
case cc.Lsh, cc.Rsh:
left := fixGoTypesExpr(fn, x.Left, targ)
if left != nil && targ != nil && Int8 <= left.Kind && left.Kind <= Float64 && targ.Kind > left.Kind {
forceConvert(fn, x.Left, left, targ)
left = targ
}
fixShiftCount(fn, x.Right)
return left
case cc.LshEq, cc.RshEq:
left := fixGoTypesExpr(fn, x.Left, nil)
fixShiftCount(fn, x.Right)
return left
case cc.Name:
if x.Text == "nelem" {
}
switch x.Text {
case "T", "S", "N", "L", "P", "C":
x.Text = "nil"
x.XDecl = nil
return nil
case "nelem":
x.Text = "len"
x.XDecl = nil
fallthrough
case "len":
return &cc.Type{Kind: cc.Func, Base: intType}
}
if x.XDecl == nil {
if x.Text == "true" || x.Text == "false" {
return x.XType
}
return nil
}
return x.XDecl.Type
case cc.Number:
return idealType
case cc.Minus, cc.Plus, cc.Twid:
return fixGoTypesExpr(fn, x.Left, targ)
case cc.Offsetof:
// TODO
return nil
case cc.Paren:
return fixGoTypesExpr(fn, x.Left, targ)
case cc.PostDec, cc.PostInc:
left := fixGoTypesExpr(fn, x.Left, nil)
if x.Op == cc.PostInc && isSliceOrString(left) {
old := copyExpr(x.Left)
x.Op = cc.Eq
x.Right = &cc.Expr{Op: ExprSlice, List: []*cc.Expr{old, &cc.Expr{Op: cc.Number, Text: "1"}, nil}}
}
return nil
case cc.SizeofExpr:
left := fixGoTypesExpr(fn, x.Left, nil)
if left != nil && (left.Kind == cc.Array || left.Kind == Slice) && left.Base.Def().Is(Uint8) {
x.Op = cc.Call
x.List = []*cc.Expr{x.Left}
x.Left = &cc.Expr{Op: cc.Name, Text: "len"}
return intType
}
return nil
case cc.SizeofType:
return nil
case cc.String:
return &cc.Type{Kind: String}
case cc.VaArg:
// TODO
return nil
}
}
func forceConvert(fn *cc.Decl, x *cc.Expr, actual, targ *cc.Type) {
if isEmptyInterface(targ) {
return
}
if isEmptyInterface(actual) {
old := copyExpr(x)
x.Op = TypeAssert
x.Left = old
x.Right = nil
x.List = nil
x.Type = targ
x.XType = targ
return
}
if isNumericConst(x) && targ != nil {
switch targ.Kind {
case cc.Ptr, Slice:
if x.Op == cc.Number && x.Text == "0" {
x.Op = cc.Name
x.Text = "nil"
x.XType = targ
}
case String:
if x.Op == cc.Number && x.Text == "0" {
x.Op = cc.Name
x.Text = `""`
x.XType = targ
}
}
return
}
if x.Op == cc.Name && x.Text == "nil" && targ != nil {
switch targ.Kind {
case cc.Func, cc.Ptr, Slice:
return
case String:
x.Text = `""`
x.XType = targ
x.XDecl = nil
return
}
}
if actual == nil || targ == nil {
return
}
if actual.Kind == Ideal && Int8 <= targ.Kind && targ.Kind <= Float64 {
return
}
if x != nil && x.Op == cc.Name && x.Text == "nil" {
if targ.Kind == cc.Func || targ.Kind == cc.Ptr || targ.Kind == Slice {
return
}
}
// Func conversions are never useful.
// If the func types are different, the conversion will fail;
// if not, the conversion is unnecessary.
// Either way the conversion is an eyesore.
if targ.Kind == cc.Func || targ.Kind == cc.Ptr && targ.Base.Kind == cc.Func {
return
}
if actual.Kind == Bool && Int8 <= targ.Kind && targ.Kind <= Float64 {
old := copyExpr(x)
if targ.Kind == Int {
x.Op = cc.Call
x.Left = &cc.Expr{Op: cc.Name, Text: "bool2int"}
x.List = []*cc.Expr{old}
x.Right = nil
} else {
x.Op = cc.Cast
x.Left = &cc.Expr{Op: cc.Call, Left: &cc.Expr{Op: cc.Name, Text: "bool2int"}, List: []*cc.Expr{old}}
x.Type = targ
}
return
}
if actual.Kind == cc.Array && targ.Kind == Slice && sameType(actual.Base, targ.Base) {
old := copyExpr(x)
x.Op = ExprSlice
x.List = []*cc.Expr{old, nil, nil}
x.Left = nil
x.Right = nil
return
}
if actual.Kind == Slice && targ.Kind == cc.Ptr && sameType(actual.Base, targ.Base) {
if isCall(x, "make") {
return
}
old := copyExpr(x)
x.Op = cc.Addr
x.Left = &cc.Expr{Op: cc.Index, Left: old, Right: &cc.Expr{Op: cc.Number, Text: "0"}}
return
}
if !sameType(actual, targ) {
if x.Op == cc.Twid {
forceConvert(fn, x.Left, actual, targ)
x.XType = targ
return
}
old := copyExpr(x)
// for debugging:
// old = &cc.Expr{Op: cc.Cast, Left: old, Type: actual, XType: actual}
x.Op = cc.Cast
x.Left = old
x.Right = nil
x.List = nil
x.Type = targ
x.XType = targ
if actual.Kind == cc.Array && targ.Kind == Slice {
x.Op = ExprSlice
x.List = []*cc.Expr{old, nil, nil}
x.Left = nil
x.Type = nil
}
}
}
func doSideEffects(x *cc.Expr, before, after *[]*cc.Stmt, mode int) {
if x == nil {
return
}
// Cannot hoist side effects from conditionally evaluated expressions
// into unconditionally evaluated statement lists.
// For now, detect but do not handle.
switch x.Op {
case cc.Cond:
doSideEffects(x.List[0], before, after, mode&^sideStmt|sideNoAfter)
checkNoSideEffects(x.List[1], 0)
checkNoSideEffects(x.List[2], 0)
case cc.AndAnd, cc.OrOr:
doSideEffects(x.Left, before, after, mode&^sideStmt|sideNoAfter)
checkNoSideEffects(x.Right, 0)
case cc.Comma:
var leftover []*cc.Expr
for i, y := range x.List {
m := mode | sideNoAfter
if i+1 < len(x.List) {
m |= sideStmt
}
doSideEffects(y, before, after, m)
switch y.Op {
case cc.PostInc, cc.PostDec, cc.Eq, cc.AddEq, cc.SubEq, cc.MulEq, cc.DivEq, cc.ModEq, cc.XorEq, cc.OrEq, cc.AndEq, cc.LshEq, cc.RshEq:
*before = append(*before, &cc.Stmt{Op: cc.StmtExpr, Expr: y})
default:
leftover = append(leftover, y)
}
}
x.List = leftover
default:
doSideEffects(x.Left, before, after, mode&^sideStmt)
doSideEffects(x.Right, before, after, mode&^sideStmt)
for _, y := range x.List {
doSideEffects(y, before, after, mode&^sideStmt)
}
}
if mode&sideStmt != 0 {
// Expression as statement.
// Can leave x++ alone, can rewrite ++x to x++, can leave x [op]= y alone.
switch x.Op {
case cc.PreInc:
x.Op = cc.PostInc
return
case cc.PreDec:
x.Op = cc.PostDec
return
case cc.PostInc, cc.PostDec:
return
case cc.Eq, cc.AddEq, cc.SubEq, cc.MulEq, cc.DivEq, cc.ModEq, cc.XorEq, cc.OrEq, cc.AndEq, cc.LshEq, cc.RshEq:
return
case cc.Call:
return
}
}
switch x.Op {
case cc.Eq, cc.AddEq, cc.SubEq, cc.MulEq, cc.DivEq, cc.ModEq, cc.XorEq, cc.OrEq, cc.AndEq, cc.LshEq, cc.RshEq:
x.Left = forceCheap(before, x.Left)
old := copyExpr(x)
*before = append(*before, &cc.Stmt{Op: cc.StmtExpr, Expr: old})
fixMerge(x, x.Left)
case cc.PreInc, cc.PreDec:
x.Left = forceCheap(before, x.Left)
old := copyExpr(x)
old.SyntaxInfo = cc.SyntaxInfo{}
if old.Op == cc.PreInc {
old.Op = cc.PostInc
} else {
old.Op = cc.PostDec
}
*before = append(*before, &cc.Stmt{Op: cc.StmtExpr, Expr: old})
fixMerge(x, x.Left)
case cc.PostInc, cc.PostDec:
x.Left = forceCheap(before, x.Left)
if mode&sideNoAfter != 0 {
// Not allowed to generate fixups afterward.
d := &cc.Decl{
Name: fmt.Sprintf("tmp%d", <-tmpGen),
Type: x.Left.XType,
}
eq := &cc.Expr{
Op: ColonEq,
Left: &cc.Expr{Op: cc.Name, Text: d.Name, XDecl: d},
Right: x.Left,
}
old := copyExpr(x.Left)
old.SyntaxInfo = cc.SyntaxInfo{}
*before = append(*before,
&cc.Stmt{Op: cc.StmtExpr, Expr: eq},
&cc.Stmt{Op: cc.StmtExpr, Expr: &cc.Expr{Op: x.Op, Left: old}},
)
x.Op = cc.Name
x.Text = d.Name
x.XDecl = d
x.Left = nil
break
}
old := copyExpr(x)
old.SyntaxInfo = cc.SyntaxInfo{}
*after = append(*after, &cc.Stmt{Op: cc.StmtExpr, Expr: old})
fixMerge(x, x.Left)
case cc.Cond:
// Rewrite c ? y : z into tmp with initialization:
// var tmp typeof(c?y:z)
// if c {
// tmp = y
// } else {
// tmp = z
// }
d := &cc.Decl{
Name: "tmp",
Type: x.XType,
}
*before = append(*before,
&cc.Stmt{Op: cc.StmtDecl, Decl: d},
&cc.Stmt{Op: cc.If, Expr: x.List[0],
Body: &cc.Stmt{
Op: cc.StmtExpr,
Expr: &cc.Expr{
Op: cc.Eq,
Left: &cc.Expr{Op: cc.Name, Text: d.Name, XDecl: d},
Right: x.List[1],
},
},
Else: &cc.Stmt{
Op: cc.StmtExpr,
Expr: &cc.Expr{
Op: cc.Eq,
Left: &cc.Expr{Op: cc.Name, Text: d.Name, XDecl: d},
Right: x.List[2],
},
},
},
)
x.Op = cc.Name
x.Text = d.Name
x.XDecl = d
x.List = nil
case cc.Call:
if x.Left.Text == "fmtstrcpy" || x.Left.Text == "fmtprint" {
old := copyExpr(x)
old.SyntaxInfo = cc.SyntaxInfo{}
*before = append(*before, &cc.Stmt{Op: cc.StmtExpr, Expr: old})
x.Op = cc.Number
x.Text = "0"
x.XDecl = nil
x.Left = nil
x.List = nil
}
}
}