cmd/compile: drop legacy code for generating iface wrappers

Originally, scalar values were directly stored within interface values
as long as they fit into a pointer-sized slot of memory. And since
interface method calls always pass the full pointer-sized value as the
receiver argument, value-narrowing wrappers were necessary to adapt to
the calling convention for methods with smaller receiver types.

However, for precise garbage collection, we now only store actual
pointers within interface values, so these wrappers are no longer
necessary.

Passes toolstash-check.

Change-Id: I5303bfeb8d0f11db619b5a5d06b37ac898588670
Reviewed-on: https://go-review.googlesource.com/104875
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index 39f7cd45c6f0ba1d76ca652876a6033ab3e2d15f..d2ea5a602edfeaee3149dc1a90d976048863e20c 100644 (file)
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -829,7 +829,7 @@ func functypefield0(t *types.Type, this *types.Field, in, out []*types.Field) {
 
 var methodsym_toppkg *types.Pkg
 
-func methodsym(nsym *types.Sym, t0 *types.Type, iface bool) *types.Sym {
+func methodsym(nsym *types.Sym, t0 *types.Type) *types.Sym {
        if t0 == nil {
                Fatalf("methodsym: nil receiver type")
        }
@@ -850,14 +850,6 @@ func methodsym(nsym *types.Sym, t0 *types.Type, iface bool) *types.Sym {
                t0 = types.NewPtr(t)
        }
 
-       suffix := ""
-       if iface {
-               dowidth(t0)
-               if t0.Width < int64(Widthptr) {
-                       suffix = "·i"
-               }
-       }
-
        var spkg *types.Pkg
        if s != nil {
                spkg = s.Pkg
@@ -868,9 +860,9 @@ func methodsym(nsym *types.Sym, t0 *types.Type, iface bool) *types.Sym {
        }
        var p string
        if t0.Sym == nil && t0.IsPtr() {
-               p = fmt.Sprintf("(%-S)%s.%s%s", t0, pkgprefix, nsym.Name, suffix)
+               p = fmt.Sprintf("(%-S)%s.%s", t0, pkgprefix, nsym.Name)
        } else {
-               p = fmt.Sprintf("%-S%s.%s%s", t0, pkgprefix, nsym.Name, suffix)
+               p = fmt.Sprintf("%-S%s.%s", t0, pkgprefix, nsym.Name)
        }
 
        if spkg == nil {

diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index 579e10f9852fdf2dff9abcd9b6de09cc3907c4b9..6375a996fe5fbc3e0efaa888ec448bca8a4c10af 100644 (file)
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -427,16 +427,16 @@ func methods(t *types.Type) []*Sig {
                        sig.pkg = method.Pkg
                }
 
-               sig.isym = methodsym(method, it, true)
-               sig.tsym = methodsym(method, t, false)
+               sig.isym = methodsym(method, it)
+               sig.tsym = methodsym(method, t)
                sig.type_ = methodfunc(f.Type, t)
                sig.mtype = methodfunc(f.Type, nil)
 
                if !sig.isym.Siggen() {
                        sig.isym.SetSiggen(true)
-                       if !eqtype(this, it) || this.Width < int64(Widthptr) {
+                       if !eqtype(this, it) {
                                compiling_wrappers = true
-                               genwrapper(it, f, sig.isym, true)
+                               genwrapper(it, f, sig.isym)
                                compiling_wrappers = false
                        }
                }
@@ -445,7 +445,7 @@ func methods(t *types.Type) []*Sig {
                        sig.tsym.SetSiggen(true)
                        if !eqtype(this, t) {
                                compiling_wrappers = true
-                               genwrapper(t, f, sig.tsym, false)
+                               genwrapper(t, f, sig.tsym)
                                compiling_wrappers = false
                        }
                }
@@ -493,10 +493,10 @@ func imethods(t *types.Type) []*Sig {
                // IfaceType.Method is not in the reflect data.
                // Generate the method body, so that compiled
                // code can refer to it.
-               isym := methodsym(method, t, false)
+               isym := methodsym(method, t)
                if !isym.Siggen() {
                        isym.SetSiggen(true)
-                       genwrapper(t, f, isym, false)
+                       genwrapper(t, f, isym)
                }
        }
 

diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index ef68d677e64f7d7dc8bd3487691962c77ecee859..9b8103f22ee250dff0e3ec9020ff2a58871c43bc 100644 (file)
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -1654,7 +1654,7 @@ func structargs(tl *types.Type, mustname bool) []*Node {
 //     rcvr - U
 //     method - M func (t T)(), a TFIELD type struct
 //     newnam - the eventual mangled name of this function
-func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym, iface bool) {
+func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
        if false && Debug['r'] != 0 {
                fmt.Printf("genwrapper rcvrtype=%v method=%v newnam=%v\n", rcvr, method, newnam)
        }
@@ -1676,19 +1676,7 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym, iface
        out := structargs(method.Type.Results(), false)
 
        t := nod(OTFUNC, nil, nil)
-       l := []*Node{this}
-       if iface && rcvr.Width < int64(Widthptr) {
-               // Building method for interface table and receiver
-               // is smaller than the single pointer-sized word
-               // that the interface call will pass in.
-               // Add a dummy padding argument after the
-               // receiver to make up the difference.
-               tpad := types.NewArray(types.Types[TUINT8], int64(Widthptr)-rcvr.Width)
-               pad := namedfield(".pad", tpad)
-               l = append(l, pad)
-       }
-
-       t.List.Set(append(l, in...))
+       t.List.Set(append([]*Node{this}, in...))
        t.Rlist.Set(out)
 
        newnam.SetOnExportList(true) // prevent export; see closure.go
@@ -1735,7 +1723,7 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym, iface
                as := nod(OAS, this.Left, nod(OCONVNOP, dot, nil))
                as.Right.Type = rcvr
                fn.Nbody.Append(as)
-               fn.Nbody.Append(nodSym(ORETJMP, nil, methodsym(method.Sym, methodrcvr, false)))
+               fn.Nbody.Append(nodSym(ORETJMP, nil, methodsym(method.Sym, methodrcvr)))
        } else {
                fn.Func.SetWrapper(true) // ignore frame for panic+recover matching
                call := nod(OCALL, dot, nil)

diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 0b01d803ea45c4b33aa4f49c76163e524bb3a781..867979c2fe241a749810508158b5710d2a34ee56 100644 (file)
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -2352,7 +2352,7 @@ func looktypedot(n *Node, t *types.Type, dostrcmp int) bool {
                        return false
                }
 
-               n.Sym = methodsym(n.Sym, t, false)
+               n.Sym = methodsym(n.Sym, t)
                n.Xoffset = f1.Offset
                n.Type = f1.Type
                n.Op = ODOTINTER
@@ -2378,7 +2378,7 @@ func looktypedot(n *Node, t *types.Type, dostrcmp int) bool {
                return false
        }
 
-       n.Sym = methodsym(n.Sym, t, false)
+       n.Sym = methodsym(n.Sym, t)
        n.Xoffset = f2.Offset
        n.Type = f2.Type
        n.Op = ODOTMETH
@@ -2495,7 +2495,7 @@ func lookdot(n *Node, t *types.Type, dostrcmp int) *types.Field {
                        return nil
                }
 
-               n.Sym = methodsym(n.Sym, n.Left.Type, false)
+               n.Sym = methodsym(n.Sym, n.Left.Type)
                n.Xoffset = f2.Offset
                n.Type = f2.Type