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[dev.regabi] cmd/compile: merge {Selector,CallPart,Method}Expr

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These three expression nodes all represent the same syntax, and so
they're represented the same within types2. And also they're not
handled that meaningfully differently throughout the rest of the
compiler to merit unique representations.

Method expressions are somewhat unique today that they're very
frequently turned into plain function names. But eventually that can
be handled by a post-typecheck desugaring phase that reduces the
number of redundant AST forms.

Passes toolstash -cmp.

Change-Id: I20df91bbd0d885c1f18ec67feb61ae1558670719
Reviewed-on: https://go-review.googlesource.com/c/go/+/280636
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
This commit is contained in:
Matthew Dempsky 2020-12-28 16:14:11 -08:00
parent e563715b30
commit 4629f6a51d
14 changed files with 58 additions and 154 deletions
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8
src/cmd/compile/internal/escape/escape.go
View File

@ -612,10 +612,10 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
// Flow the receiver argument to both the closure and
// to the receiver parameter.
n := n.(*ir.CallPartExpr)
n := n.(*ir.SelectorExpr)
closureK := e.spill(k, n)
m := n.Method
m := n.Selection
// We don't know how the method value will be called
// later, so conservatively assume the result
@ -1542,7 +1542,7 @@ func (e *escape) finish(fns []*ir.Func) {
n := n.(*ir.ClosureExpr)
n.SetTransient(true)
case ir.OCALLPART:
n := n.(*ir.CallPartExpr)
n := n.(*ir.SelectorExpr)
n.SetTransient(true)
case ir.OSLICELIT:
n := n.(*ir.CompLitExpr)
@ -1863,7 +1863,7 @@ func HeapAllocReason(n ir.Node) string {
if n.Op() == ir.OCLOSURE && typecheck.ClosureType(n.(*ir.ClosureExpr)).Size() >= ir.MaxImplicitStackVarSize {
return "too large for stack"
}
if n.Op() == ir.OCALLPART && typecheck.PartialCallType(n.(*ir.CallPartExpr)).Size() >= ir.MaxImplicitStackVarSize {
if n.Op() == ir.OCALLPART && typecheck.PartialCallType(n.(*ir.SelectorExpr)).Size() >= ir.MaxImplicitStackVarSize {
return "too large for stack"
}

11
src/cmd/compile/internal/inline/inl.go
View File

@ -419,6 +419,9 @@ func (v *hairyVisitor) doNode(n ir.Node) error {
case ir.OCALLPART, ir.OSLICELIT:
v.budget-- // Hack for toolstash -cmp.
case ir.OMETHEXPR:
v.budget++ // Hack for toolstash -cmp.
}
v.budget--
@ -613,12 +616,12 @@ func inlCallee(fn ir.Node) *ir.Func {
fn = ir.StaticValue(fn)
switch fn.Op() {
case ir.OMETHEXPR:
fn := fn.(*ir.MethodExpr)
fn := fn.(*ir.SelectorExpr)
n := ir.MethodExprName(fn)
// Check that receiver type matches fn.Left.
// Check that receiver type matches fn.X.
// TODO(mdempsky): Handle implicit dereference
// of pointer receiver argument?
if n == nil || !types.Identical(n.Type().Recv().Type, fn.T) {
if n == nil || !types.Identical(n.Type().Recv().Type, fn.X.Type()) {
return nil
}
return n.Func
@ -1098,7 +1101,7 @@ func (subst *inlsubst) node(n ir.Node) ir.Node {
return n
case ir.OMETHEXPR:
n := n.(*ir.MethodExpr)
n := n.(*ir.SelectorExpr)
return n
case ir.OLITERAL, ir.ONIL, ir.OTYPE:

60
src/cmd/compile/internal/ir/expr.go
View File

@ -225,26 +225,6 @@ func (n *CallExpr) SetOp(op Op) {
}
}
// A CallPartExpr is a method expression X.Method (uncalled).
type CallPartExpr struct {
miniExpr
Func *Func
X Node
Method *types.Field
Prealloc *Name
}
func NewCallPartExpr(pos src.XPos, x Node, method *types.Field, fn *Func) *CallPartExpr {
n := &CallPartExpr{Func: fn, X: x, Method: method}
n.op = OCALLPART
n.pos = pos
n.typ = fn.Type()
n.Func = fn
return n
}
func (n *CallPartExpr) Sym() *types.Sym { return n.Method.Sym }
// A ClosureExpr is a function literal expression.
type ClosureExpr struct {
miniExpr
@ -476,24 +456,6 @@ func (n *MakeExpr) SetOp(op Op) {
}
}
// A MethodExpr is a method expression T.M (where T is a type).
type MethodExpr struct {
miniExpr
T *types.Type
Method *types.Field
FuncName_ *Name
}
func NewMethodExpr(pos src.XPos, t *types.Type, method *types.Field) *MethodExpr {
n := &MethodExpr{T: t, Method: method}
n.pos = pos
n.op = OMETHEXPR
return n
}
func (n *MethodExpr) FuncName() *Name { return n.FuncName_ }
func (n *MethodExpr) Sym() *types.Sym { panic("MethodExpr.Sym") }
// A NilExpr represents the predefined untyped constant nil.
// (It may be copied and assigned a type, though.)
type NilExpr struct {
@ -567,12 +529,13 @@ func NewNameOffsetExpr(pos src.XPos, name *Name, offset int64, typ *types.Type)
return n
}
// A SelectorExpr is a selector expression X.Sym.
// A SelectorExpr is a selector expression X.Sel.
type SelectorExpr struct {
miniExpr
X Node
Sel *types.Sym
Selection *types.Field
Prealloc *Name // preallocated storage for OCALLPART, if any
}
func NewSelectorExpr(pos src.XPos, op Op, x Node, sel *types.Sym) *SelectorExpr {
@ -586,7 +549,7 @@ func (n *SelectorExpr) SetOp(op Op) {
switch op {
default:
panic(n.no("SetOp " + op.String()))
case ODOT, ODOTPTR, ODOTMETH, ODOTINTER, OXDOT:
case OXDOT, ODOT, ODOTPTR, ODOTMETH, ODOTINTER, OCALLPART, OMETHEXPR:
n.op = op
}
}
@ -596,6 +559,16 @@ func (n *SelectorExpr) Implicit() bool { return n.flags&miniExprImplicit !=
func (n *SelectorExpr) SetImplicit(b bool) { n.flags.set(miniExprImplicit, b) }
func (n *SelectorExpr) Offset() int64 { return n.Selection.Offset }
func (n *SelectorExpr) FuncName() *Name {
if n.Op() != OMETHEXPR {
panic(n.no("FuncName"))
}
fn := NewNameAt(n.Selection.Pos, MethodSym(n.X.Type(), n.Sel))
fn.Class_ = PFUNC
fn.SetType(n.Type())
return fn
}
// Before type-checking, bytes.Buffer is a SelectorExpr.
// After type-checking it becomes a Name.
func (*SelectorExpr) CanBeNtype() {}
@ -1089,13 +1062,8 @@ func MethodExprName(n Node) *Name {
// MethodFunc is like MethodName, but returns the types.Field instead.
func MethodExprFunc(n Node) *types.Field {
switch n.Op() {
case ODOTMETH:
case ODOTMETH, OMETHEXPR, OCALLPART:
return n.(*SelectorExpr).Selection
case OMETHEXPR:
return n.(*MethodExpr).Method
case OCALLPART:
n := n.(*CallPartExpr)
return n.Method
}
base.Fatalf("unexpected node: %v (%v)", n, n.Op())
panic("unreachable")

21
src/cmd/compile/internal/ir/fmt.go
View File

@ -630,10 +630,6 @@ func exprFmt(n Node, s fmt.State, prec int) {
case OPACK, ONONAME:
fmt.Fprint(s, n.Sym())
case OMETHEXPR:
n := n.(*MethodExpr)
fmt.Fprint(s, n.FuncName().Sym())
case ONAMEOFFSET:
n := n.(*NameOffsetExpr)
fmt.Fprintf(s, "(%v)(%v@%d)", n.Type(), n.Name_, n.Offset_)
@ -749,16 +745,7 @@ func exprFmt(n Node, s fmt.State, prec int) {
n := n.(*StructKeyExpr)
fmt.Fprintf(s, "%v:%v", n.Field, n.Value)
case OCALLPART:
n := n.(*CallPartExpr)
exprFmt(n.X, s, nprec)
if n.Method.Sym == nil {
fmt.Fprint(s, ".<nil>")
return
}
fmt.Fprintf(s, ".%s", n.Method.Sym.Name)
case OXDOT, ODOT, ODOTPTR, ODOTINTER, ODOTMETH:
case OXDOT, ODOT, ODOTPTR, ODOTINTER, ODOTMETH, OCALLPART, OMETHEXPR:
n := n.(*SelectorExpr)
exprFmt(n.X, s, nprec)
if n.Sel == nil {
@ -1160,12 +1147,6 @@ func dumpNode(w io.Writer, n Node, depth int) {
}
return
case OMETHEXPR:
n := n.(*MethodExpr)
fmt.Fprintf(w, "%+v-%+v", n.Op(), n.FuncName().Sym())
dumpNodeHeader(w, n)
return
case OASOP:
n := n.(*AssignOpStmt)
fmt.Fprintf(w, "%+v-%+v", n.Op(), n.AsOp)

32
src/cmd/compile/internal/ir/node_gen.go
View File

@ -209,23 +209,6 @@ func (n *CallExpr) editChildren(edit func(Node) Node) {
editList(n.Body, edit)
}
func (n *CallPartExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
func (n *CallPartExpr) copy() Node {
c := *n
c.init = c.init.Copy()
return &c
}
func (n *CallPartExpr) doChildren(do func(Node) error) error {
var err error
err = maybeDoList(n.init, err, do)
err = maybeDo(n.X, err, do)
return err
}
func (n *CallPartExpr) editChildren(edit func(Node) Node) {
editList(n.init, edit)
n.X = maybeEdit(n.X, edit)
}
func (n *CaseClause) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
func (n *CaseClause) copy() Node {
c := *n
@ -655,21 +638,6 @@ func (n *MapType) editChildren(edit func(Node) Node) {
n.Elem = maybeEdit(n.Elem, edit)
}
func (n *MethodExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
func (n *MethodExpr) copy() Node {
c := *n
c.init = c.init.Copy()
return &c
}
func (n *MethodExpr) doChildren(do func(Node) error) error {
var err error
err = maybeDoList(n.init, err, do)
return err
}
func (n *MethodExpr) editChildren(edit func(Node) Node) {
editList(n.init, edit)
}
func (n *Name) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
func (n *Name) copy() Node { panic("Name.copy") }
func (n *Name) doChildren(do func(Node) error) error {

8
src/cmd/compile/internal/staticinit/sched.go
View File

@ -104,7 +104,7 @@ func (s *Schedule) staticcopy(l *ir.Name, loff int64, rn *ir.Name, typ *types.Ty
switch r.Op() {
case ir.OMETHEXPR:
r = r.(*ir.MethodExpr).FuncName()
r = r.(*ir.SelectorExpr).FuncName()
fallthrough
case ir.ONAME:
r := r.(*ir.Name)
@ -165,7 +165,7 @@ func (s *Schedule) staticcopy(l *ir.Name, loff int64, rn *ir.Name, typ *types.Ty
}
x := e.Expr
if x.Op() == ir.OMETHEXPR {
x = x.(*ir.MethodExpr).FuncName()
x = x.(*ir.SelectorExpr).FuncName()
}
if x.Op() == ir.ONAME && s.staticcopy(l, loff+e.Xoffset, x.(*ir.Name), typ) {
continue
@ -195,7 +195,7 @@ func (s *Schedule) StaticAssign(l *ir.Name, loff int64, r ir.Node, typ *types.Ty
return s.staticcopy(l, loff, r, typ)
case ir.OMETHEXPR:
r := r.(*ir.MethodExpr)
r := r.(*ir.SelectorExpr)
return s.staticcopy(l, loff, r.FuncName(), typ)
case ir.ONIL:
@ -461,7 +461,7 @@ func StaticLoc(n ir.Node) (name *ir.Name, offset int64, ok bool) {
return n, 0, true
case ir.OMETHEXPR:
n := n.(*ir.MethodExpr)
n := n.(*ir.SelectorExpr)
return StaticLoc(n.FuncName())
case ir.ODOT:

6
src/cmd/compile/internal/typecheck/expr.go
View File

@ -626,10 +626,8 @@ func tcDot(n *ir.SelectorExpr, top int) ir.Node {
}
if (n.Op() == ir.ODOTINTER || n.Op() == ir.ODOTMETH) && top&ctxCallee == 0 {
// Create top-level function.
fn := makepartialcall(n)
return ir.NewCallPartExpr(n.Pos(), n.X, n.Selection, fn)
n.SetOp(ir.OCALLPART)
n.SetType(MethodValueWrapper(n).Type())
}
return n
}

16
src/cmd/compile/internal/typecheck/func.go
View File

@ -91,7 +91,7 @@ func ClosureType(clo *ir.ClosureExpr) *types.Type {
// PartialCallType returns the struct type used to hold all the information
// needed in the closure for n (n must be a OCALLPART node).
// The address of a variable of the returned type can be cast to a func.
func PartialCallType(n *ir.CallPartExpr) *types.Type {
func PartialCallType(n *ir.SelectorExpr) *types.Type {
t := types.NewStruct(types.NoPkg, []*types.Field{
types.NewField(base.Pos, Lookup("F"), types.Types[types.TUINTPTR]),
types.NewField(base.Pos, Lookup("R"), n.X.Type()),
@ -247,9 +247,17 @@ func closurename(outerfunc *ir.Func) *types.Sym {
// globClosgen is like Func.Closgen, but for the global scope.
var globClosgen int32
// makepartialcall returns a DCLFUNC node representing the wrapper function (*-fm) needed
// for partial calls.
func makepartialcall(dot *ir.SelectorExpr) *ir.Func {
// MethodValueWrapper returns the DCLFUNC node representing the
// wrapper function (*-fm) needed for the given method value. If the
// wrapper function hasn't already been created yet, it's created and
// added to Target.Decls.
//
// TODO(mdempsky): Move into walk. This isn't part of type checking.
func MethodValueWrapper(dot *ir.SelectorExpr) *ir.Func {
if dot.Op() != ir.OCALLPART {
base.Fatalf("MethodValueWrapper: unexpected %v (%v)", dot, dot.Op())
}
t0 := dot.Type()
meth := dot.Sel
rcvrtype := dot.X.Type()

21
src/cmd/compile/internal/typecheck/iexport.go
View File

@ -1252,17 +1252,6 @@ func (w *exportWriter) expr(n ir.Node) {
w.pos(n.Pos())
w.value(n.Type(), n.Val())
case ir.OMETHEXPR:
// Special case: explicit name of func (*T) method(...) is turned into pkg.(*T).method,
// but for export, this should be rendered as (*pkg.T).meth.
// These nodes have the special property that they are names with a left OTYPE and a right ONAME.
n := n.(*ir.MethodExpr)
w.op(ir.OXDOT)
w.pos(n.Pos())
w.op(ir.OTYPE)
w.typ(n.T) // n.Left.Op == OTYPE
w.selector(n.Method.Sym)
case ir.ONAME:
// Package scope name.
n := n.(*ir.Name)
@ -1336,15 +1325,7 @@ func (w *exportWriter) expr(n ir.Node) {
// case OSTRUCTKEY:
// unreachable - handled in case OSTRUCTLIT by elemList
case ir.OCALLPART:
// An OCALLPART is an OXDOT before type checking.
n := n.(*ir.CallPartExpr)
w.op(ir.OXDOT)
w.pos(n.Pos())
w.expr(n.X)
w.selector(n.Method.Sym)
case ir.OXDOT, ir.ODOT, ir.ODOTPTR, ir.ODOTINTER, ir.ODOTMETH:
case ir.OXDOT, ir.ODOT, ir.ODOTPTR, ir.ODOTINTER, ir.ODOTMETH, ir.OCALLPART, ir.OMETHEXPR:
n := n.(*ir.SelectorExpr)
w.op(ir.OXDOT)
w.pos(n.Pos())

15
src/cmd/compile/internal/typecheck/typecheck.go
View File

@ -1176,19 +1176,16 @@ func typecheckMethodExpr(n *ir.SelectorExpr) (res ir.Node) {
return n
}
me := ir.NewMethodExpr(n.Pos(), n.X.Type(), m)
me.SetType(NewMethodType(m.Type, n.X.Type()))
f := NewName(ir.MethodSym(t, m.Sym))
f.Class_ = ir.PFUNC
f.SetType(me.Type())
me.FuncName_ = f
n.SetOp(ir.OMETHEXPR)
n.Selection = m
n.SetType(NewMethodType(m.Type, n.X.Type()))
// Issue 25065. Make sure that we emit the symbol for a local method.
if base.Ctxt.Flag_dynlink && !inimport && (t.Sym() == nil || t.Sym().Pkg == types.LocalPkg) {
NeedFuncSym(me.FuncName_.Sym())
NeedFuncSym(n.FuncName().Sym())
}
return me
return n
}
func derefall(t *types.Type) *types.Type {
@ -1422,7 +1419,7 @@ notenough:
// Method expressions have the form T.M, and the compiler has
// rewritten those to ONAME nodes but left T in Left.
if call.Op() == ir.OMETHEXPR {
call := call.(*ir.MethodExpr)
call := call.(*ir.SelectorExpr)
base.Errorf("not enough arguments in call to method expression %v%s", call, details)
} else {
base.Errorf("not enough arguments in call to %v%s", call, details)

4
src/cmd/compile/internal/walk/closure.go
View File

@ -151,7 +151,7 @@ func walkClosure(clo *ir.ClosureExpr, init *ir.Nodes) ir.Node {
return walkExpr(cfn, init)
}
func walkCallPart(n *ir.CallPartExpr, init *ir.Nodes) ir.Node {
func walkCallPart(n *ir.SelectorExpr, init *ir.Nodes) ir.Node {
// Create closure in the form of a composite literal.
// For x.M with receiver (x) type T, the generated code looks like:
//
@ -176,7 +176,7 @@ func walkCallPart(n *ir.CallPartExpr, init *ir.Nodes) ir.Node {
clos := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(typ).(ir.Ntype), nil)
clos.SetEsc(n.Esc())
clos.List = []ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, n.Func.Nname), n.X}
clos.List = []ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, typecheck.MethodValueWrapper(n).Nname), n.X}
addr := typecheck.NodAddr(clos)
addr.SetEsc(n.Esc())

4
src/cmd/compile/internal/walk/complit.go
View File

@ -539,7 +539,7 @@ func anylit(n ir.Node, var_ ir.Node, init *ir.Nodes) {
appendWalkStmt(init, ir.NewAssignStmt(base.Pos, var_, n))
case ir.OMETHEXPR:
n := n.(*ir.MethodExpr)
n := n.(*ir.SelectorExpr)
anylit(n.FuncName(), var_, init)
case ir.OPTRLIT:
@ -666,7 +666,7 @@ func genAsStatic(as *ir.AssignStmt) {
staticdata.InitConst(name, offset, r, int(r.Type().Width))
return
case ir.OMETHEXPR:
r := r.(*ir.MethodExpr)
r := r.(*ir.SelectorExpr)
staticdata.InitFunc(name, offset, r.FuncName())
return
case ir.ONAME:

4
src/cmd/compile/internal/walk/expr.go
View File

@ -100,7 +100,7 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
case ir.OMETHEXPR:
// TODO(mdempsky): Do this right after type checking.
n := n.(*ir.MethodExpr)
n := n.(*ir.SelectorExpr)
return n.FuncName()
case ir.ONOT, ir.ONEG, ir.OPLUS, ir.OBITNOT, ir.OREAL, ir.OIMAG, ir.OSPTR, ir.OITAB, ir.OIDATA:
@ -306,7 +306,7 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
return walkClosure(n.(*ir.ClosureExpr), init)
case ir.OCALLPART:
return walkCallPart(n.(*ir.CallPartExpr), init)
return walkCallPart(n.(*ir.SelectorExpr), init)
}
// No return! Each case must return (or panic),

2
src/cmd/compile/internal/walk/order.go
View File

@ -1310,7 +1310,7 @@ func (o *orderState) expr1(n, lhs ir.Node) ir.Node {
return n
case ir.OCALLPART:
n := n.(*ir.CallPartExpr)
n := n.(*ir.SelectorExpr)
n.X = o.expr(n.X, nil)
if n.Transient() {
t := typecheck.PartialCallType(n)