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[dev.regabi] cmd/compile: use []*CaseStmt in {Select,Switch}Stmt

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Select and switch statements only ever contain case statements, so
change their Cases fields from Nodes to []*CaseStmt. This allows
removing a bunch of type assertions throughout the compiler.

CaseStmt should be renamed to CaseClause, and SelectStmt should
probably have its own CommClause type instead (like in go/ast and
cmd/compile/internal/syntax), but this is a good start.

Passes toolstash -cmp.

Change-Id: I2d41d616d44512c2be421e1e2ff13d0ee8b238ad
Reviewed-on: https://go-review.googlesource.com/c/go/+/280442
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Matthew Dempsky 2020-12-26 22:23:45 -08:00
parent fbc4458c06
commit a59d26603f
13 changed files with 73 additions and 53 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
src/cmd/compile/internal/escape/escape.go
View file

@ -369,7 +369,6 @@ func (e *escape) stmt(n ir.Node) {
var ks []hole
for _, cas := range n.Cases { // cases
cas := cas.(*ir.CaseStmt)
if typesw && n.Tag.(*ir.TypeSwitchGuard).Tag != nil {
cv := cas.Var
k := e.dcl(cv) // type switch variables have no ODCL.
@ -391,7 +390,6 @@ func (e *escape) stmt(n ir.Node) {
case ir.OSELECT:
n := n.(*ir.SelectStmt)
for _, cas := range n.Cases {
cas := cas.(*ir.CaseStmt)
e.stmt(cas.Comm)
e.block(cas.Body)
}

7
src/cmd/compile/internal/ir/mknode.go
View file

@ -37,6 +37,7 @@ func main() {
nodeType := lookup("Node")
ntypeType := lookup("Ntype")
nodesType := lookup("Nodes")
slicePtrCaseStmtType := types.NewSlice(types.NewPointer(lookup("CaseStmt")))
ptrFieldType := types.NewPointer(lookup("Field"))
slicePtrFieldType := types.NewSlice(ptrFieldType)
ptrIdentType := types.NewPointer(lookup("Ident"))
@ -76,6 +77,8 @@ func main() {
switch {
case is(nodesType):
fmt.Fprintf(&buf, "c.%s = c.%s.Copy()\n", name, name)
case is(slicePtrCaseStmtType):
fmt.Fprintf(&buf, "c.%s = copyCases(c.%s)\n", name, name)
case is(ptrFieldType):
fmt.Fprintf(&buf, "if c.%s != nil { c.%s = c.%s.copy() }\n", name, name, name)
case is(slicePtrFieldType):
@ -94,6 +97,8 @@ func main() {
fmt.Fprintf(&buf, "err = maybeDo(n.%s, err, do)\n", name)
case is(nodesType):
fmt.Fprintf(&buf, "err = maybeDoList(n.%s, err, do)\n", name)
case is(slicePtrCaseStmtType):
fmt.Fprintf(&buf, "err = maybeDoCases(n.%s, err, do)\n", name)
case is(ptrFieldType):
fmt.Fprintf(&buf, "err = maybeDoField(n.%s, err, do)\n", name)
case is(slicePtrFieldType):
@ -113,6 +118,8 @@ func main() {
fmt.Fprintf(&buf, "n.%s = toNtype(maybeEdit(n.%s, edit))\n", name, name)
case is(nodesType):
fmt.Fprintf(&buf, "editList(n.%s, edit)\n", name)
case is(slicePtrCaseStmtType):
fmt.Fprintf(&buf, "editCases(n.%s, edit)\n", name)
case is(ptrFieldType):
fmt.Fprintf(&buf, "editField(n.%s, edit)\n", name)
case is(slicePtrFieldType):

12
src/cmd/compile/internal/ir/node_gen.go
View file

@ -781,20 +781,20 @@ func (n *SelectStmt) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
func (n *SelectStmt) copy() Node {
c := *n
c.init = c.init.Copy()
c.Cases = c.Cases.Copy()
c.Cases = copyCases(c.Cases)
c.Compiled = c.Compiled.Copy()
return &c
}
func (n *SelectStmt) doChildren(do func(Node) error) error {
var err error
err = maybeDoList(n.init, err, do)
err = maybeDoList(n.Cases, err, do)
err = maybeDoCases(n.Cases, err, do)
err = maybeDoList(n.Compiled, err, do)
return err
}
func (n *SelectStmt) editChildren(edit func(Node) Node) {
editList(n.init, edit)
editList(n.Cases, edit)
editCases(n.Cases, edit)
editList(n.Compiled, edit)
}
@ -945,7 +945,7 @@ func (n *SwitchStmt) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
func (n *SwitchStmt) copy() Node {
c := *n
c.init = c.init.Copy()
c.Cases = c.Cases.Copy()
c.Cases = copyCases(c.Cases)
c.Compiled = c.Compiled.Copy()
return &c
}
@ -953,14 +953,14 @@ func (n *SwitchStmt) doChildren(do func(Node) error) error {
var err error
err = maybeDoList(n.init, err, do)
err = maybeDo(n.Tag, err, do)
err = maybeDoList(n.Cases, err, do)
err = maybeDoCases(n.Cases, err, do)
err = maybeDoList(n.Compiled, err, do)
return err
}
func (n *SwitchStmt) editChildren(edit func(Node) Node) {
editList(n.init, edit)
n.Tag = maybeEdit(n.Tag, edit)
editList(n.Cases, edit)
editCases(n.Cases, edit)
editList(n.Compiled, edit)
}

43
src/cmd/compile/internal/ir/stmt.go
View file

@ -191,6 +191,37 @@ func NewCaseStmt(pos src.XPos, list, body []Node) *CaseStmt {
return n
}
func copyCases(list []*CaseStmt) []*CaseStmt {
if list == nil {
return nil
}
c := make([]*CaseStmt, len(list))
copy(c, list)
return c
}
func maybeDoCases(list []*CaseStmt, err error, do func(Node) error) error {
if err != nil {
return err
}
for _, x := range list {
if x != nil {
if err := do(x); err != nil {
return err
}
}
}
return nil
}
func editCases(list []*CaseStmt, edit func(Node) Node) {
for i, x := range list {
if x != nil {
list[i] = edit(x).(*CaseStmt)
}
}
}
// A ForStmt is a non-range for loop: for Init; Cond; Post { Body }
// Op can be OFOR or OFORUNTIL (!Cond).
type ForStmt struct {
@ -334,18 +365,18 @@ func (n *ReturnStmt) SetOrig(x Node) { n.orig = x }
type SelectStmt struct {
miniStmt
Label *types.Sym
Cases Nodes
Cases []*CaseStmt
HasBreak bool
// TODO(rsc): Instead of recording here, replace with a block?
Compiled Nodes // compiled form, after walkswitch
}
func NewSelectStmt(pos src.XPos, cases []Node) *SelectStmt {
func NewSelectStmt(pos src.XPos, cases []*CaseStmt) *SelectStmt {
n := &SelectStmt{}
n.pos = pos
n.op = OSELECT
n.Cases.Set(cases)
n.Cases = cases
return n
}
@ -367,7 +398,7 @@ func NewSendStmt(pos src.XPos, ch, value Node) *SendStmt {
type SwitchStmt struct {
miniStmt
Tag Node
Cases Nodes // list of *CaseStmt
Cases []*CaseStmt
Label *types.Sym
HasBreak bool
@ -375,11 +406,11 @@ type SwitchStmt struct {
Compiled Nodes // compiled form, after walkswitch
}
func NewSwitchStmt(pos src.XPos, tag Node, cases []Node) *SwitchStmt {
func NewSwitchStmt(pos src.XPos, tag Node, cases []*CaseStmt) *SwitchStmt {
n := &SwitchStmt{Tag: tag}
n.pos = pos
n.op = OSWITCH
n.Cases.Set(cases)
n.Cases = cases
return n
}

3
src/cmd/compile/internal/ir/visit.go
View file

@ -217,10 +217,9 @@ func EditChildren(n Node, edit func(Node) Node) {
// Note that editList only calls edit on the nodes in the list, not their children.
// If x's children should be processed, edit(x) must call EditChildren(x, edit) itself.
func editList(list Nodes, edit func(Node) Node) {
s := list
for i, x := range list {
if x != nil {
s[i] = edit(x)
list[i] = edit(x)
}
}
}

10
src/cmd/compile/internal/noder/noder.go
View file

@ -1202,14 +1202,14 @@ func (p *noder) switchStmt(stmt *syntax.SwitchStmt) ir.Node {
if l := n.Tag; l != nil && l.Op() == ir.OTYPESW {
tswitch = l.(*ir.TypeSwitchGuard)
}
n.Cases.Set(p.caseClauses(stmt.Body, tswitch, stmt.Rbrace))
n.Cases = p.caseClauses(stmt.Body, tswitch, stmt.Rbrace)
p.closeScope(stmt.Rbrace)
return n
}
func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitchGuard, rbrace syntax.Pos) []ir.Node {
nodes := make([]ir.Node, 0, len(clauses))
func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitchGuard, rbrace syntax.Pos) []*ir.CaseStmt {
nodes := make([]*ir.CaseStmt, 0, len(clauses))
for i, clause := range clauses {
p.setlineno(clause)
if i > 0 {
@ -1266,8 +1266,8 @@ func (p *noder) simpleStmt(stmt syntax.SimpleStmt) []ir.Node {
return []ir.Node{p.stmt(stmt)}
}
func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []ir.Node {
nodes := make([]ir.Node, len(clauses))
func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []*ir.CaseStmt {
nodes := make([]*ir.CaseStmt, len(clauses))
for i, clause := range clauses {
p.setlineno(clause)
if i > 0 {

3
src/cmd/compile/internal/typecheck/iexport.go
View file

@ -1181,10 +1181,9 @@ func isNamedTypeSwitch(x ir.Node) bool {
return ok && guard.Tag != nil
}
func (w *exportWriter) caseList(cases []ir.Node, namedTypeSwitch bool) {
func (w *exportWriter) caseList(cases []*ir.CaseStmt, namedTypeSwitch bool) {
w.uint64(uint64(len(cases)))
for _, cas := range cases {
cas := cas.(*ir.CaseStmt)
w.pos(cas.Pos())
w.stmtList(cas.List)
if namedTypeSwitch {

4
src/cmd/compile/internal/typecheck/iimport.go
View file

@ -767,10 +767,10 @@ func (r *importReader) stmtList() []ir.Node {
return list
}
func (r *importReader) caseList(switchExpr ir.Node) []ir.Node {
func (r *importReader) caseList(switchExpr ir.Node) []*ir.CaseStmt {
namedTypeSwitch := isNamedTypeSwitch(switchExpr)
cases := make([]ir.Node, r.uint64())
cases := make([]*ir.CaseStmt, r.uint64())
for i := range cases {
cas := ir.NewCaseStmt(r.pos(), nil, nil)
cas.List.Set(r.stmtList())

4
src/cmd/compile/internal/typecheck/stmt.go
View file

@ -364,8 +364,6 @@ func tcSelect(sel *ir.SelectStmt) {
lno := ir.SetPos(sel)
Stmts(sel.Init())
for _, ncase := range sel.Cases {
ncase := ncase.(*ir.CaseStmt)
if len(ncase.List) == 0 {
// default
if def != nil {
@ -508,7 +506,6 @@ func tcSwitchExpr(n *ir.SwitchStmt) {
var defCase ir.Node
var cs constSet
for _, ncase := range n.Cases {
ncase := ncase.(*ir.CaseStmt)
ls := ncase.List
if len(ls) == 0 { // default:
if defCase != nil {
@ -577,7 +574,6 @@ func tcSwitchType(n *ir.SwitchStmt) {
var defCase, nilCase ir.Node
var ts typeSet
for _, ncase := range n.Cases {
ncase := ncase.(*ir.CaseStmt)
ls := ncase.List
if len(ls) == 0 { // default:
if defCase != nil {

13
src/cmd/compile/internal/typecheck/typecheck.go
View file

@ -2103,7 +2103,6 @@ func isTermNode(n ir.Node) bool {
}
def := false
for _, cas := range n.Cases {
cas := cas.(*ir.CaseStmt)
if !isTermNodes(cas.Body) {
return false
}
@ -2119,7 +2118,6 @@ func isTermNode(n ir.Node) bool {
return false
}
for _, cas := range n.Cases {
cas := cas.(*ir.CaseStmt)
if !isTermNodes(cas.Body) {
return false
}
@ -2218,9 +2216,6 @@ func deadcodeslice(nn *ir.Nodes) {
case ir.OBLOCK:
n := n.(*ir.BlockStmt)
deadcodeslice(&n.List)
case ir.OCASE:
n := n.(*ir.CaseStmt)
deadcodeslice(&n.Body)
case ir.OFOR:
n := n.(*ir.ForStmt)
deadcodeslice(&n.Body)
@ -2233,10 +2228,14 @@ func deadcodeslice(nn *ir.Nodes) {
deadcodeslice(&n.Body)
case ir.OSELECT:
n := n.(*ir.SelectStmt)
deadcodeslice(&n.Cases)
for _, cas := range n.Cases {
deadcodeslice(&cas.Body)
}
case ir.OSWITCH:
n := n.(*ir.SwitchStmt)
deadcodeslice(&n.Cases)
for _, cas := range n.Cases {
deadcodeslice(&cas.Body)
}
}
if cut {

6
src/cmd/compile/internal/walk/order.go
View file

@ -914,7 +914,6 @@ func (o *orderState) stmt(n ir.Node) {
n := n.(*ir.SelectStmt)
t := o.markTemp()
for _, ncas := range n.Cases {
ncas := ncas.(*ir.CaseStmt)
r := ncas.Comm
ir.SetPos(ncas)
@ -996,7 +995,6 @@ func (o *orderState) stmt(n ir.Node) {
// Also insert any ninit queued during the previous loop.
// (The temporary cleaning must follow that ninit work.)
for _, cas := range n.Cases {
cas := cas.(*ir.CaseStmt)
orderBlock(&cas.Body, o.free)
cas.Body.Prepend(o.cleanTempNoPop(t)...)
@ -1036,13 +1034,12 @@ func (o *orderState) stmt(n ir.Node) {
n := n.(*ir.SwitchStmt)
if base.Debug.Libfuzzer != 0 && !hasDefaultCase(n) {
// Add empty "default:" case for instrumentation.
n.Cases.Append(ir.NewCaseStmt(base.Pos, nil, nil))
n.Cases = append(n.Cases, ir.NewCaseStmt(base.Pos, nil, nil))
}
t := o.markTemp()
n.Tag = o.expr(n.Tag, nil)
for _, ncas := range n.Cases {
ncas := ncas.(*ir.CaseStmt)
o.exprListInPlace(ncas.List)
orderBlock(&ncas.Body, o.free)
}
@ -1056,7 +1053,6 @@ func (o *orderState) stmt(n ir.Node) {
func hasDefaultCase(n *ir.SwitchStmt) bool {
for _, ncas := range n.Cases {
ncas := ncas.(*ir.CaseStmt)
if len(ncas.List) == 0 {
return true
}

12
src/cmd/compile/internal/walk/select.go
View file

@ -21,7 +21,7 @@ func walkSelect(sel *ir.SelectStmt) {
sel.PtrInit().Set(nil)
init = append(init, walkSelectCases(sel.Cases)...)
sel.Cases = ir.Nodes{}
sel.Cases = nil
sel.Compiled.Set(init)
walkStmtList(sel.Compiled)
@ -29,7 +29,7 @@ func walkSelect(sel *ir.SelectStmt) {
base.Pos = lno
}
func walkSelectCases(cases ir.Nodes) []ir.Node {
func walkSelectCases(cases []*ir.CaseStmt) []ir.Node {
ncas := len(cases)
sellineno := base.Pos
@ -40,7 +40,7 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {
// optimization: one-case select: single op.
if ncas == 1 {
cas := cases[0].(*ir.CaseStmt)
cas := cases[0]
ir.SetPos(cas)
l := cas.Init()
if cas.Comm != nil { // not default:
@ -75,7 +75,6 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {
// this rewrite is used by both the general code and the next optimization.
var dflt *ir.CaseStmt
for _, cas := range cases {
cas := cas.(*ir.CaseStmt)
ir.SetPos(cas)
n := cas.Comm
if n == nil {
@ -99,9 +98,9 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {
// optimization: two-case select but one is default: single non-blocking op.
if ncas == 2 && dflt != nil {
cas := cases[0].(*ir.CaseStmt)
cas := cases[0]
if cas == dflt {
cas = cases[1].(*ir.CaseStmt)
cas = cases[1]
}
n := cas.Comm
@ -170,7 +169,6 @@ func walkSelectCases(cases ir.Nodes) []ir.Node {
// register cases
for _, cas := range cases {
cas := cas.(*ir.CaseStmt)
ir.SetPos(cas)
init = append(init, cas.Init()...)

7
src/cmd/compile/internal/walk/switch.go
View file

@ -71,7 +71,6 @@ func walkSwitchExpr(sw *ir.SwitchStmt) {
var defaultGoto ir.Node
var body ir.Nodes
for _, ncase := range sw.Cases {
ncase := ncase.(*ir.CaseStmt)
label := typecheck.AutoLabel(".s")
jmp := ir.NewBranchStmt(ncase.Pos(), ir.OGOTO, label)
@ -96,7 +95,7 @@ func walkSwitchExpr(sw *ir.SwitchStmt) {
body.Append(br)
}
}
sw.Cases.Set(nil)
sw.Cases = nil
if defaultGoto == nil {
br := ir.NewBranchStmt(base.Pos, ir.OBREAK, nil)
@ -259,7 +258,6 @@ func allCaseExprsAreSideEffectFree(sw *ir.SwitchStmt) bool {
// enough.
for _, ncase := range sw.Cases {
ncase := ncase.(*ir.CaseStmt)
for _, v := range ncase.List {
if v.Op() != ir.OLITERAL {
return false
@ -325,7 +323,6 @@ func walkSwitchType(sw *ir.SwitchStmt) {
var defaultGoto, nilGoto ir.Node
var body ir.Nodes
for _, ncase := range sw.Cases {
ncase := ncase.(*ir.CaseStmt)
caseVar := ncase.Var
// For single-type cases with an interface type,
@ -384,7 +381,7 @@ func walkSwitchType(sw *ir.SwitchStmt) {
body.Append(ncase.Body...)
body.Append(br)
}
sw.Cases.Set(nil)
sw.Cases = nil
if defaultGoto == nil {
defaultGoto = br