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[dev.regabi] cmd/compile: address some ir TODOs

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Previously, ODOTTYPE/ODOTTYPE2 were forced to reuse some available
Node fields for storing pointers to runtime type descriptors. This
resulted in awkward field types for TypeAssertExpr and AddrExpr.

This CL gives TypeAssertExpr proper fields for the runtime type
descriptors, and also tightens the field types as
possible/appropriate.

Passes toolstash -cmp.

Change-Id: I521ee7a1462affc5459de33a0de6c68a7d6416ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/280637
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 17:06:43 -08:00
parent 4629f6a51d
commit 6acbae4fcc
5 changed files with 18 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
src/cmd/compile/internal/ir/expr.go
View File

@ -109,7 +109,7 @@ func NewAddStringExpr(pos src.XPos, list []Node) *AddStringExpr {
type AddrExpr struct {
miniExpr
X Node
Alloc Node // preallocated storage if any
Alloc *Name // preallocated storage if any
}
func NewAddrExpr(pos src.XPos, x Node) *AddrExpr {
@ -660,8 +660,13 @@ func (n *StarExpr) SetOTYPE(t *types.Type) {
type TypeAssertExpr struct {
miniExpr
X Node
Ntype Node // TODO: Should be Ntype, but reused as address of type structure
Itab Nodes // Itab[0] is itab
Ntype Ntype
// Runtime type information provided by walkDotType.
// Caution: These aren't always populated; see walkDotType.
SrcType *AddrExpr // *runtime._type for X's type
DstType *AddrExpr // *runtime._type for Type
Itab *AddrExpr // *runtime.itab for Type implementing X's type
}
func NewTypeAssertExpr(pos src.XPos, x Node, typ Ntype) *TypeAssertExpr {

7
src/cmd/compile/internal/ir/node_gen.go
View File

@ -32,13 +32,11 @@ func (n *AddrExpr) doChildren(do func(Node) error) error {
var err error
err = maybeDoList(n.init, err, do)
err = maybeDo(n.X, err, do)
err = maybeDo(n.Alloc, err, do)
return err
}
func (n *AddrExpr) editChildren(edit func(Node) Node) {
editList(n.init, edit)
n.X = maybeEdit(n.X, edit)
n.Alloc = maybeEdit(n.Alloc, edit)
}
func (n *ArrayType) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
@ -954,7 +952,6 @@ func (n *TypeAssertExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
func (n *TypeAssertExpr) copy() Node {
c := *n
c.init = c.init.Copy()
c.Itab = c.Itab.Copy()
return &c
}
func (n *TypeAssertExpr) doChildren(do func(Node) error) error {
@ -962,14 +959,12 @@ func (n *TypeAssertExpr) doChildren(do func(Node) error) error {
err = maybeDoList(n.init, err, do)
err = maybeDo(n.X, err, do)
err = maybeDo(n.Ntype, err, do)
err = maybeDoList(n.Itab, err, do)
return err
}
func (n *TypeAssertExpr) editChildren(edit func(Node) Node) {
editList(n.init, edit)
n.X = maybeEdit(n.X, edit)
n.Ntype = maybeEdit(n.Ntype, edit)
editList(n.Itab, edit)
n.Ntype = toNtype(maybeEdit(n.Ntype, edit))
}
func (n *TypeSwitchGuard) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }

8
src/cmd/compile/internal/ssagen/ssa.go
View File

@ -5978,8 +5978,8 @@ func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *
// commaok indicates whether to panic or return a bool.
// If commaok is false, resok will be nil.
func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
iface := s.expr(n.X) // input interface
target := s.expr(n.Ntype) // target type
iface := s.expr(n.X) // input interface
target := s.expr(n.DstType) // target type
byteptr := s.f.Config.Types.BytePtr
if n.Type().IsInterface() {
@ -6086,7 +6086,7 @@ func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Val
targetITab = target
} else {
// Looking for pointer to itab for target type and source interface.
targetITab = s.expr(n.Itab[0])
targetITab = s.expr(n.Itab)
}
var tmp ir.Node // temporary for use with large types
@ -6113,7 +6113,7 @@ func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Val
if !commaok {
// on failure, panic by calling panicdottype
s.startBlock(bFail)
taddr := s.expr(n.Ntype.(*ir.AddrExpr).Alloc)
taddr := s.expr(n.SrcType)
if n.X.Type().IsEmptyInterface() {
s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
} else {

2
src/cmd/compile/internal/typecheck/expr.go
View File

@ -649,7 +649,7 @@ func tcDotType(n *ir.TypeAssertExpr) ir.Node {
}
if n.Ntype != nil {
n.Ntype = typecheck(n.Ntype, ctxType)
n.Ntype = typecheckNtype(n.Ntype)
n.SetType(n.Ntype.Type())
n.Ntype = nil
if n.Type() == nil {

7
src/cmd/compile/internal/walk/expr.go
View File

@ -639,12 +639,13 @@ func walkDot(n *ir.SelectorExpr, init *ir.Nodes) ir.Node {
func walkDotType(n *ir.TypeAssertExpr, init *ir.Nodes) ir.Node {
n.X = walkExpr(n.X, init)
// Set up interface type addresses for back end.
n.Ntype = reflectdata.TypePtr(n.Type())
n.DstType = reflectdata.TypePtr(n.Type())
if n.Op() == ir.ODOTTYPE {
n.Ntype.(*ir.AddrExpr).Alloc = reflectdata.TypePtr(n.X.Type())
n.SrcType = reflectdata.TypePtr(n.X.Type())
}
if !n.Type().IsInterface() && !n.X.Type().IsEmptyInterface() {
n.Itab = []ir.Node{reflectdata.ITabAddr(n.Type(), n.X.Type())}
n.Itab = reflectdata.ITabAddr(n.Type(), n.X.Type())
}
return n
}