Revert "cmd/compile: stop interface conversions for generic method calls from allocating"

This reverts commit e550c3054586a224d949cc8fa030bac0887bee51.

Reason for revert: Method bound calls are no longer implemented using interface calls, so it is no longer necessary. Leaving the test, though.

Change-Id: I80f1e4cd921063cd27ca8f07998316ca282e075b
Reviewed-on: https://go-review.googlesource.com/c/go/+/395594
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 3 insertions, 10 deletions

diff --git a/src/cmd/compile/internal/noder/stencil.go b/src/cmd/compile/internal/noder/stencil.go
index 477259f734..eeac8d8de7 100644
--- a/src/cmd/compile/internal/noder/stencil.go
+++ b/src/cmd/compile/internal/noder/stencil.go
@@ -1279,11 +1279,7 @@ func (g *genInst) dictPass(info *instInfo) {
 						// we do a type assert to the type bound.
 						mse.X = assertToBound(info, info.dictParam, m.Pos(), mse.X, dst)
 					} else {
-						mse.X = convertUsingDictionary(info, info.dictParam, m.Pos(), mse.X, m, dst, true)
-						// Note: we set nonEscaping==true, because we can assume the backing store for the
-						// interface conversion doesn't escape. The method call will immediately go to
-						// a wrapper function which copies all the data out of the interface value.
-						// (It only matters for non-pointer-shaped interface conversions. See issue 50182.)
+						mse.X = convertUsingDictionary(info, info.dictParam, m.Pos(), mse.X, m, dst)
 					}
 				}
 				transformDot(mse, false)
@@ -1329,7 +1325,7 @@ func (g *genInst) dictPass(info *instInfo) {
 			// Note: x's argument is still typed as a type parameter.
 			// m's argument now has an instantiated type.
 			if mce.X.Type().HasShape() || (mce.X.Type().IsInterface() && m.Type().HasShape()) {
-				m = convertUsingDictionary(info, info.dictParam, m.Pos(), m.(*ir.ConvExpr).X, m, m.Type(), false)
+				m = convertUsingDictionary(info, info.dictParam, m.Pos(), m.(*ir.ConvExpr).X, m, m.Type())
 			}
 		case ir.ODOTTYPE, ir.ODOTTYPE2:
 			if !m.Type().HasShape() {
@@ -1422,9 +1418,7 @@ func findDictType(info *instInfo, t *types.Type) int {
 // type dst, by returning a new set of nodes that make use of a dictionary entry. in is the
 // instantiated node of the CONVIFACE node or XDOT node (for a bound method call) that is causing the
 // conversion.
-// If nonEscaping is true, the caller guarantees that the backing store needed for the interface data
-// word will not escape.
-func convertUsingDictionary(info *instInfo, dictParam *ir.Name, pos src.XPos, v ir.Node, in ir.Node, dst *types.Type, nonEscaping bool) ir.Node {
+func convertUsingDictionary(info *instInfo, dictParam *ir.Name, pos src.XPos, v ir.Node, in ir.Node, dst *types.Type) ir.Node {
 	assert(v.Type().HasShape() || v.Type().IsInterface() && in.Type().HasShape())
 	assert(dst.IsInterface())
 
@@ -1494,7 +1488,6 @@ func convertUsingDictionary(info *instInfo, dictParam *ir.Name, pos src.XPos, v
 	// Figure out what the data field of the interface will be.
 	data := ir.NewConvExpr(pos, ir.OCONVIDATA, nil, v)
 	typed(types.Types[types.TUNSAFEPTR], data)
-	data.NonEscaping = nonEscaping
 
 	// Build an interface from the type and data parts.
 	var i ir.Node = ir.NewBinaryExpr(pos, ir.OEFACE, rt, data)