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[dev.unified] cmd/compile: plumb rtype through OSWITCH/OCASE clauses

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For (value) switch statements, we may generate OEQ comparisons between
values of interface and concrete type, which in turn may require
access to the concrete type's RType.

To plumb this through, this CL adds CaseClause.RTypes to hold the
rtype values, updates the GOEXPERIMENT=unified frontend to set it, and
updates walk to plumb rtypes through into generated OEQ nodes.

Change-Id: I6f1de2a1167ce54f5770147498a0a591efb3f012
Reviewed-on: https://go-review.googlesource.com/c/go/+/413361
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
This commit is contained in:
Matthew Dempsky 2022-06-21 02:30:21 -07:00
parent 3d432b6c4b
commit 61ae2b734c
4 changed files with 47 additions and 10 deletions
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23
src/cmd/compile/internal/noder/reader.go
View file

@ -1487,7 +1487,7 @@ func (r *reader) switchStmt(label *types.Sym) ir.Node {
r.openScope()
pos := r.pos()
var cases []ir.Node
var cases, rtypes []ir.Node
if iface != nil {
cases = make([]ir.Node, r.Len())
if len(cases) == 0 {
@ -1498,9 +1498,30 @@ func (r *reader) switchStmt(label *types.Sym) ir.Node {
}
} else {
cases = r.exprList()
tagType := types.Types[types.TBOOL]
if tag != nil {
tagType = tag.Type()
}
for i, cas := range cases {
if cas.Op() == ir.ONIL {
continue // never needs rtype
}
if tagType.IsInterface() != cas.Type().IsInterface() {
typ := tagType
if typ.IsInterface() {
typ = cas.Type()
}
for len(rtypes) < i {
rtypes = append(rtypes, nil)
}
rtypes = append(rtypes, reflectdata.TypePtr(typ))
}
}
}
clause := ir.NewCaseStmt(pos, cases, nil)
clause.RTypes = rtypes
if ident != nil {
pos := r.pos()