// Copyright 2009 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package typecheck import ( "fmt" "go/constant" "go/token" "strings" "cmd/compile/internal/base" "cmd/compile/internal/ir" "cmd/compile/internal/types" "cmd/internal/src" ) func AssignExpr(n ir.Node) ir.Node { return typecheck(n, ctxExpr|ctxAssign) } func Expr(n ir.Node) ir.Node { return typecheck(n, ctxExpr) } func Stmt(n ir.Node) ir.Node { return typecheck(n, ctxStmt) } func Exprs(exprs []ir.Node) { typecheckslice(exprs, ctxExpr) } func Stmts(stmts []ir.Node) { typecheckslice(stmts, ctxStmt) } func Call(pos src.XPos, callee ir.Node, args []ir.Node, dots bool) ir.Node { call := ir.NewCallExpr(pos, ir.OCALL, callee, args) call.IsDDD = dots return typecheck(call, ctxStmt|ctxExpr) } func Callee(n ir.Node) ir.Node { return typecheck(n, ctxExpr|ctxCallee) } var traceIndent []byte func tracePrint(title string, n ir.Node) func(np *ir.Node) { indent := traceIndent // guard against nil var pos, op string var tc uint8 if n != nil { pos = base.FmtPos(n.Pos()) op = n.Op().String() tc = n.Typecheck() } types.SkipSizeForTracing = true defer func() { types.SkipSizeForTracing = false }() fmt.Printf("%s: %s%s %p %s %v tc=%d\n", pos, indent, title, n, op, n, tc) traceIndent = append(traceIndent, ". "...) return func(np *ir.Node) { traceIndent = traceIndent[:len(traceIndent)-2] // if we have a result, use that if np != nil { n = *np } // guard against nil // use outer pos, op so we don't get empty pos/op if n == nil (nicer output) var tc uint8 var typ *types.Type if n != nil { pos = base.FmtPos(n.Pos()) op = n.Op().String() tc = n.Typecheck() typ = n.Type() } types.SkipSizeForTracing = true defer func() { types.SkipSizeForTracing = false }() fmt.Printf("%s: %s=> %p %s %v tc=%d type=%L\n", pos, indent, n, op, n, tc, typ) } } const ( ctxStmt = 1 << iota // evaluated at statement level ctxExpr // evaluated in value context ctxType // evaluated in type context ctxCallee // call-only expressions are ok ctxMultiOK // multivalue function returns are ok ctxAssign // assigning to expression ) // type checks the whole tree of an expression. // calculates expression types. // evaluates compile time constants. // marks variables that escape the local frame. // rewrites n.Op to be more specific in some cases. func typecheckslice(l []ir.Node, top int) { for i := range l { l[i] = typecheck(l[i], top) } } var _typekind = []string{ types.TINT: "int", types.TUINT: "uint", types.TINT8: "int8", types.TUINT8: "uint8", types.TINT16: "int16", types.TUINT16: "uint16", types.TINT32: "int32", types.TUINT32: "uint32", types.TINT64: "int64", types.TUINT64: "uint64", types.TUINTPTR: "uintptr", types.TCOMPLEX64: "complex64", types.TCOMPLEX128: "complex128", types.TFLOAT32: "float32", types.TFLOAT64: "float64", types.TBOOL: "bool", types.TSTRING: "string", types.TPTR: "pointer", types.TUNSAFEPTR: "unsafe.Pointer", types.TSTRUCT: "struct", types.TINTER: "interface", types.TCHAN: "chan", types.TMAP: "map", types.TARRAY: "array", types.TSLICE: "slice", types.TFUNC: "func", types.TNIL: "nil", types.TIDEAL: "untyped number", } func typekind(t *types.Type) string { if t.IsUntyped() { return fmt.Sprintf("%v", t) } et := t.Kind() if int(et) < len(_typekind) { s := _typekind[et] if s != "" { return s } } return fmt.Sprintf("etype=%d", et) } // typecheck type checks node n. // The result of typecheck MUST be assigned back to n, e.g. // // n.Left = typecheck(n.Left, top) func typecheck(n ir.Node, top int) (res ir.Node) { if n == nil { return nil } // only trace if there's work to do if base.EnableTrace && base.Flag.LowerT { defer tracePrint("typecheck", n)(&res) } lno := ir.SetPos(n) defer func() { base.Pos = lno }() // Skip over parens. for n.Op() == ir.OPAREN { n = n.(*ir.ParenExpr).X } // Skip typecheck if already done. // But re-typecheck ONAME/OTYPE/OLITERAL/OPACK node in case context has changed. if n.Typecheck() == 1 || n.Typecheck() == 3 { switch n.Op() { case ir.ONAME: break default: return n } } if n.Typecheck() == 2 { base.FatalfAt(n.Pos(), "typechecking loop") } n.SetTypecheck(2) n = typecheck1(n, top) n.SetTypecheck(1) t := n.Type() if t != nil && !t.IsFuncArgStruct() && n.Op() != ir.OTYPE { switch t.Kind() { case types.TFUNC, // might have TANY; wait until it's called types.TANY, types.TFORW, types.TIDEAL, types.TNIL, types.TBLANK: break default: types.CheckSize(t) } } return n } // indexlit implements typechecking of untyped values as // array/slice indexes. It is almost equivalent to DefaultLit // but also accepts untyped numeric values representable as // value of type int (see also checkmake for comparison). // The result of indexlit MUST be assigned back to n, e.g. // // n.Left = indexlit(n.Left) func indexlit(n ir.Node) ir.Node { if n != nil && n.Type() != nil && n.Type().Kind() == types.TIDEAL { return DefaultLit(n, types.Types[types.TINT]) } return n } // typecheck1 should ONLY be called from typecheck. func typecheck1(n ir.Node, top int) ir.Node { switch n.Op() { default: ir.Dump("typecheck", n) base.Fatalf("typecheck %v", n.Op()) panic("unreachable") case ir.ONAME: n := n.(*ir.Name) if n.BuiltinOp != 0 { if top&ctxCallee == 0 { base.Errorf("use of builtin %v not in function call", n.Sym()) n.SetType(nil) return n } return n } if top&ctxAssign == 0 { // not a write to the variable if ir.IsBlank(n) { base.Errorf("cannot use _ as value") n.SetType(nil) return n } n.SetUsed(true) } return n // type or expr case ir.ODEREF: n := n.(*ir.StarExpr) return tcStar(n, top) // x op= y case ir.OASOP: n := n.(*ir.AssignOpStmt) n.X, n.Y = Expr(n.X), Expr(n.Y) checkassign(n.X) if n.IncDec && !okforarith[n.X.Type().Kind()] { base.Errorf("invalid operation: %v (non-numeric type %v)", n, n.X.Type()) return n } switch n.AsOp { case ir.OLSH, ir.ORSH: n.X, n.Y, _ = tcShift(n, n.X, n.Y) case ir.OADD, ir.OAND, ir.OANDNOT, ir.ODIV, ir.OMOD, ir.OMUL, ir.OOR, ir.OSUB, ir.OXOR: n.X, n.Y, _ = tcArith(n, n.AsOp, n.X, n.Y) default: base.Fatalf("invalid assign op: %v", n.AsOp) } return n // logical operators case ir.OANDAND, ir.OOROR: n := n.(*ir.LogicalExpr) n.X, n.Y = Expr(n.X), Expr(n.Y) if n.X.Type() == nil || n.Y.Type() == nil { n.SetType(nil) return n } // For "x == x && len(s)", it's better to report that "len(s)" (type int) // can't be used with "&&" than to report that "x == x" (type untyped bool) // can't be converted to int (see issue #41500). if !n.X.Type().IsBoolean() { base.Errorf("invalid operation: %v (operator %v not defined on %s)", n, n.Op(), typekind(n.X.Type())) n.SetType(nil) return n } if !n.Y.Type().IsBoolean() { base.Errorf("invalid operation: %v (operator %v not defined on %s)", n, n.Op(), typekind(n.Y.Type())) n.SetType(nil) return n } l, r, t := tcArith(n, n.Op(), n.X, n.Y) n.X, n.Y = l, r n.SetType(t) return n // shift operators case ir.OLSH, ir.ORSH: n := n.(*ir.BinaryExpr) n.X, n.Y = Expr(n.X), Expr(n.Y) l, r, t := tcShift(n, n.X, n.Y) n.X, n.Y = l, r n.SetType(t) return n // comparison operators case ir.OEQ, ir.OGE, ir.OGT, ir.OLE, ir.OLT, ir.ONE: n := n.(*ir.BinaryExpr) n.X, n.Y = Expr(n.X), Expr(n.Y) l, r, t := tcArith(n, n.Op(), n.X, n.Y) if t != nil { n.X, n.Y = l, r n.SetType(types.UntypedBool) n.X, n.Y = defaultlit2(l, r, true) } return n // binary operators case ir.OADD, ir.OAND, ir.OANDNOT, ir.ODIV, ir.OMOD, ir.OMUL, ir.OOR, ir.OSUB, ir.OXOR: n := n.(*ir.BinaryExpr) n.X, n.Y = Expr(n.X), Expr(n.Y) l, r, t := tcArith(n, n.Op(), n.X, n.Y) if t != nil && t.Kind() == types.TSTRING && n.Op() == ir.OADD { // create or update OADDSTR node with list of strings in x + y + z + (w + v) + ... var add *ir.AddStringExpr if l.Op() == ir.OADDSTR { add = l.(*ir.AddStringExpr) add.SetPos(n.Pos()) } else { add = ir.NewAddStringExpr(n.Pos(), []ir.Node{l}) } if r.Op() == ir.OADDSTR { r := r.(*ir.AddStringExpr) add.List.Append(r.List.Take()...) } else { add.List.Append(r) } add.SetType(t) return add } n.X, n.Y = l, r n.SetType(t) return n case ir.OBITNOT, ir.ONEG, ir.ONOT, ir.OPLUS: n := n.(*ir.UnaryExpr) return tcUnaryArith(n) // exprs case ir.OCOMPLIT: return tcCompLit(n.(*ir.CompLitExpr)) case ir.OXDOT, ir.ODOT: n := n.(*ir.SelectorExpr) return tcDot(n, top) case ir.ODOTTYPE: n := n.(*ir.TypeAssertExpr) return tcDotType(n) case ir.OINDEX: n := n.(*ir.IndexExpr) return tcIndex(n) case ir.ORECV: n := n.(*ir.UnaryExpr) return tcRecv(n) case ir.OSEND: n := n.(*ir.SendStmt) return tcSend(n) case ir.OSLICEHEADER: n := n.(*ir.SliceHeaderExpr) return tcSliceHeader(n) case ir.OSTRINGHEADER: n := n.(*ir.StringHeaderExpr) return tcStringHeader(n) case ir.OMAKESLICECOPY: n := n.(*ir.MakeExpr) return tcMakeSliceCopy(n) case ir.OSLICE, ir.OSLICE3: n := n.(*ir.SliceExpr) return tcSlice(n) // call and call like case ir.OCALL: n := n.(*ir.CallExpr) return tcCall(n, top) case ir.OCAP, ir.OLEN: n := n.(*ir.UnaryExpr) return tcLenCap(n) case ir.OMIN, ir.OMAX: n := n.(*ir.CallExpr) return tcMinMax(n) case ir.OREAL, ir.OIMAG: n := n.(*ir.UnaryExpr) return tcRealImag(n) case ir.OCOMPLEX: n := n.(*ir.BinaryExpr) return tcComplex(n) case ir.OCLEAR: n := n.(*ir.UnaryExpr) return tcClear(n) case ir.OCLOSE: n := n.(*ir.UnaryExpr) return tcClose(n) case ir.ODELETE: n := n.(*ir.CallExpr) return tcDelete(n) case ir.OAPPEND: n := n.(*ir.CallExpr) return tcAppend(n) case ir.OCOPY: n := n.(*ir.BinaryExpr) return tcCopy(n) case ir.OCONV: n := n.(*ir.ConvExpr) return tcConv(n) case ir.OMAKE: n := n.(*ir.CallExpr) return tcMake(n) case ir.ONEW: n := n.(*ir.UnaryExpr) return tcNew(n) case ir.OPRINT, ir.OPRINTLN: n := n.(*ir.CallExpr) return tcPrint(n) case ir.OPANIC: n := n.(*ir.UnaryExpr) return tcPanic(n) case ir.ORECOVER: n := n.(*ir.CallExpr) return tcRecover(n) case ir.OUNSAFEADD: n := n.(*ir.BinaryExpr) return tcUnsafeAdd(n) case ir.OUNSAFESLICE: n := n.(*ir.BinaryExpr) return tcUnsafeSlice(n) case ir.OUNSAFESLICEDATA: n := n.(*ir.UnaryExpr) return tcUnsafeData(n) case ir.OUNSAFESTRING: n := n.(*ir.BinaryExpr) return tcUnsafeString(n) case ir.OUNSAFESTRINGDATA: n := n.(*ir.UnaryExpr) return tcUnsafeData(n) case ir.OITAB: n := n.(*ir.UnaryExpr) return tcITab(n) case ir.OIDATA: // Whoever creates the OIDATA node must know a priori the concrete type at that moment, // usually by just having checked the OITAB. n := n.(*ir.UnaryExpr) base.Fatalf("cannot typecheck interface data %v", n) panic("unreachable") case ir.OSPTR: n := n.(*ir.UnaryExpr) return tcSPtr(n) case ir.OCFUNC: n := n.(*ir.UnaryExpr) n.X = Expr(n.X) n.SetType(types.Types[types.TUINTPTR]) return n case ir.OGETCALLERPC, ir.OGETCALLERSP: n := n.(*ir.CallExpr) if len(n.Args) != 0 { base.FatalfAt(n.Pos(), "unexpected arguments: %v", n) } n.SetType(types.Types[types.TUINTPTR]) return n case ir.OCONVNOP: n := n.(*ir.ConvExpr) n.X = Expr(n.X) return n // statements case ir.OAS: n := n.(*ir.AssignStmt) tcAssign(n) // Code that creates temps does not bother to set defn, so do it here. if n.X.Op() == ir.ONAME && ir.IsAutoTmp(n.X) { n.X.Name().Defn = n } return n case ir.OAS2: tcAssignList(n.(*ir.AssignListStmt)) return n case ir.OBREAK, ir.OCONTINUE, ir.ODCL, ir.OGOTO, ir.OFALL: return n case ir.OBLOCK: n := n.(*ir.BlockStmt) Stmts(n.List) return n case ir.OLABEL: if n.Sym().IsBlank() { // Empty identifier is valid but useless. // Eliminate now to simplify life later. // See issues 7538, 11589, 11593. n = ir.NewBlockStmt(n.Pos(), nil) } return n case ir.ODEFER, ir.OGO: n := n.(*ir.GoDeferStmt) n.Call = typecheck(n.Call, ctxStmt|ctxExpr) tcGoDefer(n) return n case ir.OFOR: n := n.(*ir.ForStmt) return tcFor(n) case ir.OIF: n := n.(*ir.IfStmt) return tcIf(n) case ir.ORETURN: n := n.(*ir.ReturnStmt) return tcReturn(n) case ir.OTAILCALL: n := n.(*ir.TailCallStmt) n.Call = typecheck(n.Call, ctxStmt|ctxExpr).(*ir.CallExpr) return n case ir.OCHECKNIL: n := n.(*ir.UnaryExpr) return tcCheckNil(n) case ir.OSELECT: tcSelect(n.(*ir.SelectStmt)) return n case ir.OSWITCH: tcSwitch(n.(*ir.SwitchStmt)) return n case ir.ORANGE: tcRange(n.(*ir.RangeStmt)) return n case ir.OTYPESW: n := n.(*ir.TypeSwitchGuard) base.Fatalf("use of .(type) outside type switch") return n case ir.ODCLFUNC: tcFunc(n.(*ir.Func)) return n } // No return n here! // Individual cases can type-assert n, introducing a new one. // Each must execute its own return n. } func typecheckargs(n ir.InitNode) { var list []ir.Node switch n := n.(type) { default: base.Fatalf("typecheckargs %+v", n.Op()) case *ir.CallExpr: list = n.Args if n.IsDDD { Exprs(list) return } case *ir.ReturnStmt: list = n.Results } if len(list) != 1 { Exprs(list) return } typecheckslice(list, ctxExpr|ctxMultiOK) t := list[0].Type() if t == nil || !t.IsFuncArgStruct() { return } // Rewrite f(g()) into t1, t2, ... = g(); f(t1, t2, ...). RewriteMultiValueCall(n, list[0]) } // RewriteNonNameCall replaces non-Name call expressions with temps, // rewriting f()(...) to t0 := f(); t0(...). func RewriteNonNameCall(n *ir.CallExpr) { np := &n.Fun if dot, ok := (*np).(*ir.SelectorExpr); ok && (dot.Op() == ir.ODOTMETH || dot.Op() == ir.ODOTINTER || dot.Op() == ir.OMETHVALUE) { np = &dot.X // peel away method selector } // Check for side effects in the callee expression. // We explicitly special case new(T) though, because it doesn't have // observable side effects, and keeping it in place allows better escape analysis. if !ir.Any(*np, func(n ir.Node) bool { return n.Op() != ir.ONEW && callOrChan(n) }) { return } tmp := TempAt(base.Pos, ir.CurFunc, (*np).Type()) as := ir.NewAssignStmt(base.Pos, tmp, *np) as.PtrInit().Append(Stmt(ir.NewDecl(n.Pos(), ir.ODCL, tmp))) *np = tmp n.PtrInit().Append(Stmt(as)) } // RewriteMultiValueCall rewrites multi-valued f() to use temporaries, // so the backend wouldn't need to worry about tuple-valued expressions. func RewriteMultiValueCall(n ir.InitNode, call ir.Node) { as := ir.NewAssignListStmt(base.Pos, ir.OAS2, nil, []ir.Node{call}) results := call.Type().Fields() list := make([]ir.Node, len(results)) for i, result := range results { tmp := TempAt(base.Pos, ir.CurFunc, result.Type) as.PtrInit().Append(ir.NewDecl(base.Pos, ir.ODCL, tmp)) as.Lhs.Append(tmp) list[i] = tmp } n.PtrInit().Append(Stmt(as)) switch n := n.(type) { default: base.Fatalf("rewriteMultiValueCall %+v", n.Op()) case *ir.CallExpr: n.Args = list case *ir.ReturnStmt: n.Results = list case *ir.AssignListStmt: if n.Op() != ir.OAS2FUNC { base.Fatalf("rewriteMultiValueCall: invalid op %v", n.Op()) } as.SetOp(ir.OAS2FUNC) n.SetOp(ir.OAS2) n.Rhs = make([]ir.Node, len(list)) for i, tmp := range list { n.Rhs[i] = AssignConv(tmp, n.Lhs[i].Type(), "assignment") } } } func checksliceindex(l ir.Node, r ir.Node, tp *types.Type) bool { t := r.Type() if t == nil { return false } if !t.IsInteger() { base.Errorf("invalid slice index %v (type %v)", r, t) return false } if r.Op() == ir.OLITERAL { x := r.Val() if constant.Sign(x) < 0 { base.Errorf("invalid slice index %v (index must be non-negative)", r) return false } else if tp != nil && tp.NumElem() >= 0 && constant.Compare(x, token.GTR, constant.MakeInt64(tp.NumElem())) { base.Errorf("invalid slice index %v (out of bounds for %d-element array)", r, tp.NumElem()) return false } else if ir.IsConst(l, constant.String) && constant.Compare(x, token.GTR, constant.MakeInt64(int64(len(ir.StringVal(l))))) { base.Errorf("invalid slice index %v (out of bounds for %d-byte string)", r, len(ir.StringVal(l))) return false } else if ir.ConstOverflow(x, types.Types[types.TINT]) { base.Errorf("invalid slice index %v (index too large)", r) return false } } return true } func checksliceconst(lo ir.Node, hi ir.Node) bool { if lo != nil && hi != nil && lo.Op() == ir.OLITERAL && hi.Op() == ir.OLITERAL && constant.Compare(lo.Val(), token.GTR, hi.Val()) { base.Errorf("invalid slice index: %v > %v", lo, hi) return false } return true } // The result of implicitstar MUST be assigned back to n, e.g. // // n.Left = implicitstar(n.Left) func implicitstar(n ir.Node) ir.Node { // insert implicit * if needed for fixed array t := n.Type() if t == nil || !t.IsPtr() { return n } t = t.Elem() if t == nil { return n } if !t.IsArray() { return n } star := ir.NewStarExpr(base.Pos, n) star.SetImplicit(true) return Expr(star) } func needOneArg(n *ir.CallExpr, f string, args ...interface{}) (ir.Node, bool) { if len(n.Args) == 0 { p := fmt.Sprintf(f, args...) base.Errorf("missing argument to %s: %v", p, n) return nil, false } if len(n.Args) > 1 { p := fmt.Sprintf(f, args...) base.Errorf("too many arguments to %s: %v", p, n) return n.Args[0], false } return n.Args[0], true } func needTwoArgs(n *ir.CallExpr) (ir.Node, ir.Node, bool) { if len(n.Args) != 2 { if len(n.Args) < 2 { base.Errorf("not enough arguments in call to %v", n) } else { base.Errorf("too many arguments in call to %v", n) } return nil, nil, false } return n.Args[0], n.Args[1], true } // Lookdot1 looks up the specified method s in the list fs of methods, returning // the matching field or nil. If dostrcmp is 0, it matches the symbols. If // dostrcmp is 1, it matches by name exactly. If dostrcmp is 2, it matches names // with case folding. func Lookdot1(errnode ir.Node, s *types.Sym, t *types.Type, fs []*types.Field, dostrcmp int) *types.Field { var r *types.Field for _, f := range fs { if dostrcmp != 0 && f.Sym.Name == s.Name { return f } if dostrcmp == 2 && strings.EqualFold(f.Sym.Name, s.Name) { return f } if f.Sym != s { continue } if r != nil { if errnode != nil { base.Errorf("ambiguous selector %v", errnode) } else if t.IsPtr() { base.Errorf("ambiguous selector (%v).%v", t, s) } else { base.Errorf("ambiguous selector %v.%v", t, s) } break } r = f } return r } // NewMethodExpr returns an OMETHEXPR node representing method // expression "recv.sym". func NewMethodExpr(pos src.XPos, recv *types.Type, sym *types.Sym) *ir.SelectorExpr { // Compute the method set for recv. var ms []*types.Field if recv.IsInterface() { ms = recv.AllMethods() } else { mt := types.ReceiverBaseType(recv) if mt == nil { base.FatalfAt(pos, "type %v has no receiver base type", recv) } CalcMethods(mt) ms = mt.AllMethods() } m := Lookdot1(nil, sym, recv, ms, 0) if m == nil { base.FatalfAt(pos, "type %v has no method %v", recv, sym) } if !types.IsMethodApplicable(recv, m) { base.FatalfAt(pos, "invalid method expression %v.%v (needs pointer receiver)", recv, sym) } n := ir.NewSelectorExpr(pos, ir.OMETHEXPR, ir.TypeNode(recv), sym) n.Selection = m n.SetType(NewMethodType(m.Type, recv)) n.SetTypecheck(1) return n } func derefall(t *types.Type) *types.Type { for t != nil && t.IsPtr() { t = t.Elem() } return t } // Lookdot looks up field or method n.Sel in the type t and returns the matching // field. It transforms the op of node n to ODOTINTER or ODOTMETH, if appropriate. // It also may add a StarExpr node to n.X as needed for access to non-pointer // methods. If dostrcmp is 0, it matches the field/method with the exact symbol // as n.Sel (appropriate for exported fields). If dostrcmp is 1, it matches by name // exactly. If dostrcmp is 2, it matches names with case folding. func Lookdot(n *ir.SelectorExpr, t *types.Type, dostrcmp int) *types.Field { s := n.Sel types.CalcSize(t) var f1 *types.Field if t.IsStruct() { f1 = Lookdot1(n, s, t, t.Fields(), dostrcmp) } else if t.IsInterface() { f1 = Lookdot1(n, s, t, t.AllMethods(), dostrcmp) } var f2 *types.Field if n.X.Type() == t || n.X.Type().Sym() == nil { mt := types.ReceiverBaseType(t) if mt != nil { f2 = Lookdot1(n, s, mt, mt.Methods(), dostrcmp) } } if f1 != nil { if dostrcmp > 1 { // Already in the process of diagnosing an error. return f1 } if f2 != nil { base.Errorf("%v is both field and method", n.Sel) } if f1.Offset == types.BADWIDTH { base.Fatalf("Lookdot badwidth t=%v, f1=%v@%p", t, f1, f1) } n.Selection = f1 n.SetType(f1.Type) if t.IsInterface() { if n.X.Type().IsPtr() { star := ir.NewStarExpr(base.Pos, n.X) star.SetImplicit(true) n.X = Expr(star) } n.SetOp(ir.ODOTINTER) } return f1 } if f2 != nil { if dostrcmp > 1 { // Already in the process of diagnosing an error. return f2 } orig := n.X tt := n.X.Type() types.CalcSize(tt) rcvr := f2.Type.Recv().Type if !types.Identical(rcvr, tt) { if rcvr.IsPtr() && types.Identical(rcvr.Elem(), tt) { checklvalue(n.X, "call pointer method on") addr := NodAddr(n.X) addr.SetImplicit(true) n.X = typecheck(addr, ctxType|ctxExpr) } else if tt.IsPtr() && (!rcvr.IsPtr() || rcvr.IsPtr() && rcvr.Elem().NotInHeap()) && types.Identical(tt.Elem(), rcvr) { star := ir.NewStarExpr(base.Pos, n.X) star.SetImplicit(true) n.X = typecheck(star, ctxType|ctxExpr) } else if tt.IsPtr() && tt.Elem().IsPtr() && types.Identical(derefall(tt), derefall(rcvr)) { base.Errorf("calling method %v with receiver %L requires explicit dereference", n.Sel, n.X) for tt.IsPtr() { // Stop one level early for method with pointer receiver. if rcvr.IsPtr() && !tt.Elem().IsPtr() { break } star := ir.NewStarExpr(base.Pos, n.X) star.SetImplicit(true) n.X = typecheck(star, ctxType|ctxExpr) tt = tt.Elem() } } else { base.Fatalf("method mismatch: %v for %v", rcvr, tt) } } // Check that we haven't implicitly dereferenced any defined pointer types. for x := n.X; ; { var inner ir.Node implicit := false switch x := x.(type) { case *ir.AddrExpr: inner, implicit = x.X, x.Implicit() case *ir.SelectorExpr: inner, implicit = x.X, x.Implicit() case *ir.StarExpr: inner, implicit = x.X, x.Implicit() } if !implicit { break } if inner.Type().Sym() != nil && (x.Op() == ir.ODEREF || x.Op() == ir.ODOTPTR) { // Found an implicit dereference of a defined pointer type. // Restore n.X for better error message. n.X = orig return nil } x = inner } n.Selection = f2 n.SetType(f2.Type) n.SetOp(ir.ODOTMETH) return f2 } return nil } func nokeys(l ir.Nodes) bool { for _, n := range l { if n.Op() == ir.OKEY || n.Op() == ir.OSTRUCTKEY { return false } } return true } func hasddd(params []*types.Field) bool { // TODO(mdempsky): Simply check the last param. for _, tl := range params { if tl.IsDDD() { return true } } return false } // typecheck assignment: type list = expression list func typecheckaste(op ir.Op, call ir.Node, isddd bool, params []*types.Field, nl ir.Nodes, desc func() string) { var t *types.Type var i int lno := base.Pos defer func() { base.Pos = lno }() var n ir.Node if len(nl) == 1 { n = nl[0] } n1 := len(params) n2 := len(nl) if !hasddd(params) { if isddd { goto invalidddd } if n2 > n1 { goto toomany } if n2 < n1 { goto notenough } } else { if !isddd { if n2 < n1-1 { goto notenough } } else { if n2 > n1 { goto toomany } if n2 < n1 { goto notenough } } } i = 0 for _, tl := range params { t = tl.Type if tl.IsDDD() { if isddd { if i >= len(nl) { goto notenough } if len(nl)-i > 1 { goto toomany } n = nl[i] ir.SetPos(n) if n.Type() != nil { nl[i] = assignconvfn(n, t, desc) } return } // TODO(mdempsky): Make into ... call with implicit slice. for ; i < len(nl); i++ { n = nl[i] ir.SetPos(n) if n.Type() != nil { nl[i] = assignconvfn(n, t.Elem(), desc) } } return } if i >= len(nl) { goto notenough } n = nl[i] ir.SetPos(n) if n.Type() != nil { nl[i] = assignconvfn(n, t, desc) } i++ } if i < len(nl) { goto toomany } invalidddd: if isddd { if call != nil { base.Errorf("invalid use of ... in call to %v", call) } else { base.Errorf("invalid use of ... in %v", op) } } return notenough: if n == nil || n.Type() != nil { base.Fatalf("not enough arguments to %v", op) } return toomany: base.Fatalf("too many arguments to %v", op) } // type check composite. func fielddup(name string, hash map[string]bool) { if hash[name] { base.Errorf("duplicate field name in struct literal: %s", name) return } hash[name] = true } // typecheckarraylit type-checks a sequence of slice/array literal elements. func typecheckarraylit(elemType *types.Type, bound int64, elts []ir.Node, ctx string) int64 { // If there are key/value pairs, create a map to keep seen // keys so we can check for duplicate indices. var indices map[int64]bool for _, elt := range elts { if elt.Op() == ir.OKEY { indices = make(map[int64]bool) break } } var key, length int64 for i, elt := range elts { ir.SetPos(elt) r := elts[i] var kv *ir.KeyExpr if elt.Op() == ir.OKEY { elt := elt.(*ir.KeyExpr) elt.Key = Expr(elt.Key) key = IndexConst(elt.Key) if key < 0 { base.Fatalf("invalid index: %v", elt.Key) } kv = elt r = elt.Value } r = Expr(r) r = AssignConv(r, elemType, ctx) if kv != nil { kv.Value = r } else { elts[i] = r } if key >= 0 { if indices != nil { if indices[key] { base.Errorf("duplicate index in %s: %d", ctx, key) } else { indices[key] = true } } if bound >= 0 && key >= bound { base.Errorf("array index %d out of bounds [0:%d]", key, bound) bound = -1 } } key++ if key > length { length = key } } return length } // visible reports whether sym is exported or locally defined. func visible(sym *types.Sym) bool { return sym != nil && (types.IsExported(sym.Name) || sym.Pkg == types.LocalPkg) } // nonexported reports whether sym is an unexported field. func nonexported(sym *types.Sym) bool { return sym != nil && !types.IsExported(sym.Name) } func checklvalue(n ir.Node, verb string) { if !ir.IsAddressable(n) { base.Errorf("cannot %s %v", verb, n) } } func checkassign(n ir.Node) { // have already complained about n being invalid if n.Type() == nil { if base.Errors() == 0 { base.Fatalf("expected an error about %v", n) } return } if ir.IsAddressable(n) { return } if n.Op() == ir.OINDEXMAP { n := n.(*ir.IndexExpr) n.Assigned = true return } defer n.SetType(nil) switch { case n.Op() == ir.ODOT && n.(*ir.SelectorExpr).X.Op() == ir.OINDEXMAP: base.Errorf("cannot assign to struct field %v in map", n) case (n.Op() == ir.OINDEX && n.(*ir.IndexExpr).X.Type().IsString()) || n.Op() == ir.OSLICESTR: base.Errorf("cannot assign to %v (strings are immutable)", n) case n.Op() == ir.OLITERAL && n.Sym() != nil && ir.IsConstNode(n): base.Errorf("cannot assign to %v (declared const)", n) default: base.Errorf("cannot assign to %v", n) } } func checkassignto(src *types.Type, dst ir.Node) { // TODO(mdempsky): Handle all untyped types correctly. if src == types.UntypedBool && dst.Type().IsBoolean() { return } if op, why := assignOp(src, dst.Type()); op == ir.OXXX { base.Errorf("cannot assign %v to %L in multiple assignment%s", src, dst, why) return } } // The result of stringtoruneslit MUST be assigned back to n, e.g. // // n.Left = stringtoruneslit(n.Left) func stringtoruneslit(n *ir.ConvExpr) ir.Node { if n.X.Op() != ir.OLITERAL || n.X.Val().Kind() != constant.String { base.Fatalf("stringtoarraylit %v", n) } var l []ir.Node i := 0 for _, r := range ir.StringVal(n.X) { l = append(l, ir.NewKeyExpr(base.Pos, ir.NewInt(base.Pos, int64(i)), ir.NewInt(base.Pos, int64(r)))) i++ } return Expr(ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, n.Type(), l)) } func checkmake(t *types.Type, arg string, np *ir.Node) bool { n := *np if !n.Type().IsInteger() && n.Type().Kind() != types.TIDEAL { base.Errorf("non-integer %s argument in make(%v) - %v", arg, t, n.Type()) return false } // Do range checks for constants before DefaultLit // to avoid redundant "constant NNN overflows int" errors. if n.Op() == ir.OLITERAL { v := toint(n.Val()) if constant.Sign(v) < 0 { base.Errorf("negative %s argument in make(%v)", arg, t) return false } if ir.ConstOverflow(v, types.Types[types.TINT]) { base.Errorf("%s argument too large in make(%v)", arg, t) return false } } // DefaultLit is necessary for non-constants too: n might be 1.1<