[dev.regabi] cmd/compile: use ClosureVars for method value wrappers

Similar to with regular closures, we can change method value wrappers
to use ClosureVars and allow SSA construction to take care of wiring
it up appropriately.

Change-Id: I05c0b1bcec4e24305324755df35b7bc5b8a6ce7a
Reviewed-on: https://go-review.googlesource.com/c/go/+/281353
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go
index 5df82d8cdc5648bd6eb5ad743ab8b81724cd3d80..9b9b8f6a5870c0b4144c94a3bf753afdc65a55e3 100644 (file)
--- a/src/cmd/compile/internal/escape/escape.go
+++ b/src/cmd/compile/internal/escape/escape.go
@@ -583,6 +583,9 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
                if n.Class == ir.PFUNC || n.Class == ir.PEXTERN {
                        return
                }
+               if n.IsClosureVar() && n.Defn == nil {
+                       return // ".this" from method value wrapper
+               }
                e.flow(k, e.oldLoc(n))
 
        case ir.ONAMEOFFSET:

diff --git a/src/cmd/compile/internal/ir/name.go b/src/cmd/compile/internal/ir/name.go
index a51cf79929e466a75975bc91f205bd11d15cac65..cfb481e31cd1f5dafab5a53e7f4a16c1cd963aba 100644 (file)
--- a/src/cmd/compile/internal/ir/name.go
+++ b/src/cmd/compile/internal/ir/name.go
@@ -264,7 +264,7 @@ const (
        nameNeedzero              // if it contains pointers, needs to be zeroed on function entry
        nameAutoTemp              // is the variable a temporary (implies no dwarf info. reset if escapes to heap)
        nameUsed                  // for variable declared and not used error
-       nameIsClosureVar          // PAUTOHEAP closure pseudo-variable; original at n.Name.Defn
+       nameIsClosureVar          // PAUTOHEAP closure pseudo-variable; original (if any) at n.Defn
        nameIsOutputParamHeapAddr // pointer to a result parameter's heap copy
        nameAddrtaken             // address taken, even if not moved to heap
        nameInlFormal             // PAUTO created by inliner, derived from callee formal
@@ -332,7 +332,7 @@ func (n *Name) SetVal(v constant.Value) {
 // it appears in the function that immediately contains the
 // declaration. Otherwise, Canonical simply returns n itself.
 func (n *Name) Canonical() *Name {
-       if n.IsClosureVar() {
+       if n.IsClosureVar() && n.Defn != nil {
                n = n.Defn.(*Name)
        }
        return n

diff --git a/src/cmd/compile/internal/typecheck/func.go b/src/cmd/compile/internal/typecheck/func.go
index 8789395ffbd981a03f90702f307cdcd533da1fc1..12762f7ee8f55b2224a15cf3505a58b39c640a71 100644 (file)
--- a/src/cmd/compile/internal/typecheck/func.go
+++ b/src/cmd/compile/internal/typecheck/func.go
@@ -246,29 +246,26 @@ func MethodValueWrapper(dot *ir.SelectorExpr) *ir.Func {
        fn.SetWrapper(true)
 
        // Declare and initialize variable holding receiver.
-       cr := ir.NewClosureRead(rcvrtype, types.Rnd(int64(types.PtrSize), int64(rcvrtype.Align)))
-       var ptr *ir.Name
-       var body []ir.Node
-       if rcvrtype.IsPtr() || rcvrtype.IsInterface() {
-               ptr = Temp(rcvrtype)
-               body = append(body, ir.NewAssignStmt(base.Pos, ptr, cr))
-       } else {
-               ptr = Temp(types.NewPtr(rcvrtype))
-               body = append(body, ir.NewAssignStmt(base.Pos, ptr, NodAddr(cr)))
-       }
+       ptr := ir.NewNameAt(base.Pos, Lookup(".this"))
+       ptr.Class = ir.PAUTOHEAP
+       ptr.SetType(rcvrtype)
+       ptr.Curfn = fn
+       ptr.SetIsClosureVar(true)
+       ptr.SetByval(true)
+       fn.ClosureVars = append(fn.ClosureVars, ptr)
 
        call := ir.NewCallExpr(base.Pos, ir.OCALL, ir.NewSelectorExpr(base.Pos, ir.OXDOT, ptr, meth), nil)
        call.Args = ir.ParamNames(tfn.Type())
        call.IsDDD = tfn.Type().IsVariadic()
+
+       var body ir.Node = call
        if t0.NumResults() != 0 {
                ret := ir.NewReturnStmt(base.Pos, nil)
                ret.Results = []ir.Node{call}
-               body = append(body, ret)
-       } else {
-               body = append(body, call)
+               body = ret
        }
 
-       fn.Body = body
+       fn.Body = []ir.Node{body}
        FinishFuncBody()
 
        Func(fn)