diff options
Diffstat (limited to 'src/cmd/compile/internal/devirtualize/devirtualize.go')
| -rw-r--r-- | src/cmd/compile/internal/devirtualize/devirtualize.go | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/devirtualize/devirtualize.go b/src/cmd/compile/internal/devirtualize/devirtualize.go index 60ba208d08..f64ebc87d0 100644 --- a/src/cmd/compile/internal/devirtualize/devirtualize.go +++ b/src/cmd/compile/internal/devirtualize/devirtualize.go @@ -41,6 +41,41 @@ 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 *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 + } + } + dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil) dt.SetType(typ) x := typecheck.Callee(ir.NewSelectorExpr(sel.Pos(), ir.OXDOT, dt, sel.Sel)) |