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cmd: remove GOEXPERIMENT=nounified knob

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This CL removes the GOEXPERIMENT=nounified knob, and any conditional
statements that depend on that knob. Further CLs to remove unreachable
code follow this one.

Updates #57410.

Change-Id: I39c147e1a83601c73f8316a001705778fee64a91
Reviewed-on: https://go-review.googlesource.com/c/go/+/458615
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
Matthew Dempsky 2022-12-01 16:14:11 -08:00
parent 3d49b683c6
commit 4f467f1082
32 changed files with 71 additions and 533 deletions
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90
src/cmd/compile/internal/devirtualize/devirtualize.go
View file

@ -57,58 +57,52 @@ func Call(call *ir.CallExpr) {
return
}
if base.Debug.Unified != 0 {
// N.B., stencil.go converts shape-typed values to interface type
// using OEFACE instead of OCONVIFACE, so devirtualization fails
// above instead. That's why this code is specific to unified IR.
// If typ is a shape type, then it was a type argument originally
// and we'd need an indirect call through the dictionary anyway.
// We're unable to devirtualize this call.
if typ.IsShape() {
return
}
// If typ is a shape type, then it was a type argument originally
// and we'd need an indirect call through the dictionary anyway.
// We're unable to devirtualize this call.
if typ.IsShape() {
return
// If typ *has* a shape type, then it's an shaped, instantiated
// type like T[go.shape.int], and its methods (may) have an extra
// dictionary parameter. We could devirtualize this call if we
// could derive an appropriate dictionary argument.
//
// TODO(mdempsky): If typ has has a promoted non-generic method,
// then that method won't require a dictionary argument. We could
// still devirtualize those calls.
//
// TODO(mdempsky): We have the *runtime.itab in recv.TypeWord. It
// should be possible to compute the represented type's runtime
// dictionary from this (e.g., by adding a pointer from T[int]'s
// *runtime._type to .dict.T[int]; or by recognizing static
// references to go:itab.T[int],iface and constructing a direct
// reference to .dict.T[int]).
if typ.HasShape() {
if base.Flag.LowerM != 0 {
base.WarnfAt(call.Pos(), "cannot devirtualize %v: shaped receiver %v", call, typ)
}
return
}
// If typ *has* a shape type, then it's an shaped, instantiated
// type like T[go.shape.int], and its methods (may) have an extra
// dictionary parameter. We could devirtualize this call if we
// could derive an appropriate dictionary argument.
//
// TODO(mdempsky): If typ has has a promoted non-generic method,
// then that method won't require a dictionary argument. We could
// still devirtualize those calls.
//
// TODO(mdempsky): We have the *runtime.itab in recv.TypeWord. It
// should be possible to compute the represented type's runtime
// dictionary from this (e.g., by adding a pointer from T[int]'s
// *runtime._type to .dict.T[int]; or by recognizing static
// references to go:itab.T[int],iface and constructing a direct
// reference to .dict.T[int]).
if typ.HasShape() {
if base.Flag.LowerM != 0 {
base.WarnfAt(call.Pos(), "cannot devirtualize %v: shaped receiver %v", call, typ)
}
return
}
// Further, if sel.X's type has a shape type, then it's a shaped
// interface type. In this case, the (non-dynamic) TypeAssertExpr
// we construct below would attempt to create an itab
// corresponding to this shaped interface type; but the actual
// itab pointer in the interface value will correspond to the
// original (non-shaped) interface type instead. These are
// functionally equivalent, but they have distinct pointer
// identities, which leads to the type assertion failing.
//
// TODO(mdempsky): We know the type assertion here is safe, so we
// could instead set a flag so that walk skips the itab check. For
// now, punting is easy and safe.
if sel.X.Type().HasShape() {
if base.Flag.LowerM != 0 {
base.WarnfAt(call.Pos(), "cannot devirtualize %v: shaped interface %v", call, sel.X.Type())
}
return
// Further, if sel.X's type has a shape type, then it's a shaped
// interface type. In this case, the (non-dynamic) TypeAssertExpr
// we construct below would attempt to create an itab
// corresponding to this shaped interface type; but the actual
// itab pointer in the interface value will correspond to the
// original (non-shaped) interface type instead. These are
// functionally equivalent, but they have distinct pointer
// identities, which leads to the type assertion failing.
//
// TODO(mdempsky): We know the type assertion here is safe, so we
// could instead set a flag so that walk skips the itab check. For
// now, punting is easy and safe.
if sel.X.Type().HasShape() {
if base.Flag.LowerM != 0 {
base.WarnfAt(call.Pos(), "cannot devirtualize %v: shaped interface %v", call, sel.X.Type())
}
return
}
dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil)