Current File : //usr/local/go119/src/cmd/compile/internal/noder/scopes.go
// Copyright 2021 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 noder
import (
"strings"
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/compile/internal/syntax"
"cmd/compile/internal/types2"
)
// recordScopes populates fn.Parents and fn.Marks based on the scoping
// information provided by types2.
func (g *irgen) recordScopes(fn *ir.Func, sig *syntax.FuncType) {
scope, ok := g.info.Scopes[sig]
if !ok {
base.FatalfAt(fn.Pos(), "missing scope for %v", fn)
}
for i, n := 0, scope.NumChildren(); i < n; i++ {
g.walkScope(scope.Child(i))
}
g.marker.WriteTo(fn)
}
func (g *irgen) walkScope(scope *types2.Scope) bool {
// types2 doesn't provide a proper API for determining the
// lexical element a scope represents, so we have to resort to
// string matching. Conveniently though, this allows us to
// skip both function types and function literals, neither of
// which are interesting to us here.
if strings.HasPrefix(scope.String(), "function scope ") {
return false
}
g.marker.Push(g.pos(scope))
haveVars := false
for _, name := range scope.Names() {
if obj, ok := scope.Lookup(name).(*types2.Var); ok && obj.Name() != "_" {
haveVars = true
break
}
}
for i, n := 0, scope.NumChildren(); i < n; i++ {
if g.walkScope(scope.Child(i)) {
haveVars = true
}
}
if haveVars {
g.marker.Pop(g.end(scope))
} else {
g.marker.Unpush()
}
return haveVars
}
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