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[dev.unified] cmd/compile/internal/noder: push exprBlank up into assignment handling

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Blanks can only appear on the LHS of an assignment. Instead of
handling them as an arbitrary expression, handle them as part of
assignee expression lists.

Change-Id: Iaeb0a5c471ffa1abd2bbbd9c95f7876533e5a607
Reviewed-on: https://go-review.googlesource.com/c/go/+/410100
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Matthew Dempsky 2022-06-03 13:21:09 -07:00
parent 55fc07e164
commit b39ac80871
5 changed files with 97 additions and 67 deletions
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12
src/cmd/compile/internal/noder/codes.go
View file

@ -42,7 +42,6 @@ const (
exprType // type expression
exprLocal // local variable
exprGlobal // global variable or function
exprBlank
exprCompLit
exprFuncLit
exprSelector
@ -55,6 +54,17 @@ const (
exprConvert
)
type codeAssign int
func (c codeAssign) Marker() pkgbits.SyncMarker { return pkgbits.SyncAssign }
func (c codeAssign) Value() int { return int(c) }
const (
assignBlank codeAssign = iota
assignDef
assignExpr
)
type codeDecl int
func (c codeDecl) Marker() pkgbits.SyncMarker { return pkgbits.SyncDecl }

47
src/cmd/compile/internal/noder/reader.go
View file

@ -1323,25 +1323,41 @@ func (r *reader) assignList() ([]*ir.Name, []ir.Node) {
var names []*ir.Name
for i := range lhs {
if r.Bool() {
pos := r.pos()
_, sym := r.localIdent()
typ := r.typ()
name := ir.NewNameAt(pos, sym)
lhs[i] = name
names = append(names, name)
setType(name, typ)
r.addLocal(name, ir.PAUTO)
continue
expr, def := r.assign()
lhs[i] = expr
if def {
names = append(names, expr.(*ir.Name))
}
lhs[i] = r.expr()
}
return names, lhs
}
// assign returns an assignee expression. It also reports whether the
// returned expression is a newly declared variable.
func (r *reader) assign() (ir.Node, bool) {
switch tag := codeAssign(r.Code(pkgbits.SyncAssign)); tag {
default:
panic("unhandled assignee expression")
case assignBlank:
return typecheck.AssignExpr(ir.BlankNode), false
case assignDef:
pos := r.pos()
_, sym := r.localIdent()
typ := r.typ()
name := ir.NewNameAt(pos, sym)
setType(name, typ)
r.addLocal(name, ir.PAUTO)
return name, true
case assignExpr:
return r.expr(), false
}
}
func (r *reader) blockStmt() []ir.Node {
r.Sync(pkgbits.SyncBlockStmt)
r.openScope()
@ -1551,11 +1567,6 @@ func (r *reader) expr() (res ir.Node) {
default:
panic("unhandled expression")
case exprBlank:
// blank only allowed in LHS of assignments
// TODO(mdempsky): Handle directly in assignList instead?
return typecheck.AssignExpr(ir.BlankNode)
case exprLocal:
return typecheck.Expr(r.useLocal())

43
src/cmd/compile/internal/noder/writer.go
View file

@ -1023,25 +1023,36 @@ func (w *writer) assignList(expr syntax.Expr) {
w.Len(len(exprs))
for _, expr := range exprs {
if name, ok := expr.(*syntax.Name); ok && name.Value != "_" {
if obj, ok := w.p.info.Defs[name]; ok {
obj := obj.(*types2.Var)
w.assign(expr)
}
}
w.Bool(true)
w.pos(obj)
w.localIdent(obj)
w.typ(obj.Type())
func (w *writer) assign(expr syntax.Expr) {
expr = unparen(expr)
// TODO(mdempsky): Minimize locals index size by deferring
// this until the variables actually come into scope.
w.addLocal(obj)
continue
}
if name, ok := expr.(*syntax.Name); ok {
if name.Value == "_" {
w.Code(assignBlank)
return
}
w.Bool(false)
w.expr(expr)
if obj, ok := w.p.info.Defs[name]; ok {
obj := obj.(*types2.Var)
w.Code(assignDef)
w.pos(obj)
w.localIdent(obj)
w.typ(obj.Type())
// TODO(mdempsky): Minimize locals index size by deferring
// this until the variables actually come into scope.
w.addLocal(obj)
return
}
}
w.Code(assignExpr)
w.expr(expr)
}
func (w *writer) declStmt(decl syntax.Decl) {
@ -1256,10 +1267,6 @@ func (w *writer) expr(expr syntax.Expr) {
default:
w.p.unexpected("expression", expr)
case *syntax.Name:
assert(expr.Value == "_")
w.Code(exprBlank)
case *syntax.CompositeLit:
w.Code(exprCompLit)
w.compLit(expr)

1
src/internal/pkgbits/sync.go
View file

@ -90,6 +90,7 @@ const (
SyncExprs
SyncExpr
SyncExprType
SyncAssign
SyncOp
SyncFuncLit
SyncCompLit

61
src/internal/pkgbits/syncmarker_string.go
View file

@ -45,39 +45,40 @@ func _() {
_ = x[SyncExprs-35]
_ = x[SyncExpr-36]
_ = x[SyncExprType-37]
_ = x[SyncOp-38]
_ = x[SyncFuncLit-39]
_ = x[SyncCompLit-40]
_ = x[SyncDecl-41]
_ = x[SyncFuncBody-42]
_ = x[SyncOpenScope-43]
_ = x[SyncCloseScope-44]
_ = x[SyncCloseAnotherScope-45]
_ = x[SyncDeclNames-46]
_ = x[SyncDeclName-47]
_ = x[SyncStmts-48]
_ = x[SyncBlockStmt-49]
_ = x[SyncIfStmt-50]
_ = x[SyncForStmt-51]
_ = x[SyncSwitchStmt-52]
_ = x[SyncRangeStmt-53]
_ = x[SyncCaseClause-54]
_ = x[SyncCommClause-55]
_ = x[SyncSelectStmt-56]
_ = x[SyncDecls-57]
_ = x[SyncLabeledStmt-58]
_ = x[SyncUseObjLocal-59]
_ = x[SyncAddLocal-60]
_ = x[SyncLinkname-61]
_ = x[SyncStmt1-62]
_ = x[SyncStmtsEnd-63]
_ = x[SyncLabel-64]
_ = x[SyncOptLabel-65]
_ = x[SyncAssign-38]
_ = x[SyncOp-39]
_ = x[SyncFuncLit-40]
_ = x[SyncCompLit-41]
_ = x[SyncDecl-42]
_ = x[SyncFuncBody-43]
_ = x[SyncOpenScope-44]
_ = x[SyncCloseScope-45]
_ = x[SyncCloseAnotherScope-46]
_ = x[SyncDeclNames-47]
_ = x[SyncDeclName-48]
_ = x[SyncStmts-49]
_ = x[SyncBlockStmt-50]
_ = x[SyncIfStmt-51]
_ = x[SyncForStmt-52]
_ = x[SyncSwitchStmt-53]
_ = x[SyncRangeStmt-54]
_ = x[SyncCaseClause-55]
_ = x[SyncCommClause-56]
_ = x[SyncSelectStmt-57]
_ = x[SyncDecls-58]
_ = x[SyncLabeledStmt-59]
_ = x[SyncUseObjLocal-60]
_ = x[SyncAddLocal-61]
_ = x[SyncLinkname-62]
_ = x[SyncStmt1-63]
_ = x[SyncStmtsEnd-64]
_ = x[SyncLabel-65]
_ = x[SyncOptLabel-66]
}
const _SyncMarker_name = "EOFBoolInt64Uint64StringValueValRelocsRelocUseRelocPublicPosPosBaseObjectObject1PkgPkgDefMethodTypeTypeIdxTypeParamNamesSignatureParamsParamCodeObjSymLocalIdentSelectorPrivateFuncExtVarExtTypeExtPragmaExprListExprsExprAssertTypeOpFuncLitCompLitDeclFuncBodyOpenScopeCloseScopeCloseAnotherScopeDeclNamesDeclNameStmtsBlockStmtIfStmtForStmtSwitchStmtRangeStmtCaseClauseCommClauseSelectStmtDeclsLabeledStmtUseObjLocalAddLocalLinknameStmt1StmtsEndLabelOptLabel"
const _SyncMarker_name = "EOFBoolInt64Uint64StringValueValRelocsRelocUseRelocPublicPosPosBaseObjectObject1PkgPkgDefMethodTypeTypeIdxTypeParamNamesSignatureParamsParamCodeObjSymLocalIdentSelectorPrivateFuncExtVarExtTypeExtPragmaExprListExprsExprExprTypeAssignOpFuncLitCompLitDeclFuncBodyOpenScopeCloseScopeCloseAnotherScopeDeclNamesDeclNameStmtsBlockStmtIfStmtForStmtSwitchStmtRangeStmtCaseClauseCommClauseSelectStmtDeclsLabeledStmtUseObjLocalAddLocalLinknameStmt1StmtsEndLabelOptLabel"
var _SyncMarker_index = [...]uint16{0, 3, 7, 12, 18, 24, 29, 32, 38, 43, 51, 57, 60, 67, 73, 80, 83, 89, 95, 99, 106, 120, 129, 135, 140, 147, 150, 160, 168, 175, 182, 188, 195, 201, 209, 214, 218, 228, 230, 237, 244, 248, 256, 265, 275, 292, 301, 309, 314, 323, 329, 336, 346, 355, 365, 375, 385, 390, 401, 412, 420, 428, 433, 441, 446, 454}
var _SyncMarker_index = [...]uint16{0, 3, 7, 12, 18, 24, 29, 32, 38, 43, 51, 57, 60, 67, 73, 80, 83, 89, 95, 99, 106, 120, 129, 135, 140, 147, 150, 160, 168, 175, 182, 188, 195, 201, 209, 214, 218, 226, 232, 234, 241, 248, 252, 260, 269, 279, 296, 305, 313, 318, 327, 333, 340, 350, 359, 369, 379, 389, 394, 405, 416, 424, 432, 437, 445, 450, 458}
func (i SyncMarker) String() string {
i -= 1