cmd/compile: don't cater to race detector in write barriers

The new lower-level barriers work fine and don't need special handling,
because they appear to the race detector as (visible) ordinary assignments.

Change-Id: I7477d73a3deecbebf68716580678c595cc4151e3
Reviewed-on: https://go-review.googlesource.com/10316
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/compile/internal/gc/racewalk.go b/src/cmd/compile/internal/gc/racewalk.go
index 446ec038c8e004642c3f2e638494551e31ec1082..6e384682fd10bcea0648ffabd00b1e696a294a97 100644 (file)
--- a/src/cmd/compile/internal/gc/racewalk.go
+++ b/src/cmd/compile/internal/gc/racewalk.go
@@ -186,31 +186,6 @@ func racewalknode(np **Node, init **NodeList, wr int, skip int) {
        // as we do not instrument runtime code.
        // typedslicecopy is instrumented in runtime.
        case OCALLFUNC:
-               if n.Left.Sym != nil && n.Left.Sym.Pkg == Runtimepkg && (strings.HasPrefix(n.Left.Sym.Name, "writebarrier") || n.Left.Sym.Name == "typedmemmove") {
-                       // Find the dst argument.
-                       // The list can be reordered, so it's not necessary just the first or the second element.
-                       var l *NodeList
-                       for l = n.List; l != nil; l = l.Next {
-                               if n.Left.Sym.Name == "typedmemmove" {
-                                       if l.N.Left.Xoffset == int64(Widthptr) {
-                                               break
-                                       }
-                               } else {
-                                       if l.N.Left.Xoffset == 0 {
-                                               break
-                                       }
-                               }
-                       }
-
-                       if l == nil {
-                               Fatal("racewalk: writebarrier no arg")
-                       }
-                       if l.N.Right.Op != OADDR {
-                               Fatal("racewalk: writebarrier bad arg")
-                       }
-                       callinstr(&l.N.Right.Left, init, 1, 0)
-               }
-
                racewalknode(&n.Left, init, 0, 0)
                goto ret
 

diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 11117666c74e71a0e0a464c9f06ffa66c9d6cca5..04f0491c15a1257dd09ed6803bd13911e57bfbf7 100644 (file)
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -2226,65 +2226,11 @@ var applywritebarrier_bv Bvec
 
 func applywritebarrier(n *Node, init **NodeList) *Node {
        if n.Left != nil && n.Right != nil && needwritebarrier(n.Left, n.Right) {
-               if flag_race == 0 {
-                       if Debug_wb > 1 {
-                               Warnl(int(n.Lineno), "marking %v for barrier", Nconv(n.Left, 0))
-                       }
-                       n.Op = OASWB
-                       return n
-               }
-               // Use slow path always for race detector.
-               if Curfn != nil && Curfn.Func.Nowritebarrier {
-                       Yyerror("write barrier prohibited")
-               }
-               if Debug_wb > 0 {
-                       Warnl(int(n.Lineno), "write barrier")
-               }
-               t := n.Left.Type
-               l := Nod(OADDR, n.Left, nil)
-               l.Etype = 1 // addr does not escape
-               if t.Width == int64(Widthptr) {
-                       n = mkcall1(writebarrierfn("writebarrierptr", t, n.Right.Type), nil, init, l, n.Right)
-               } else if t.Etype == TSTRING {
-                       n = mkcall1(writebarrierfn("writebarrierstring", t, n.Right.Type), nil, init, l, n.Right)
-               } else if Isslice(t) {
-                       n = mkcall1(writebarrierfn("writebarrierslice", t, n.Right.Type), nil, init, l, n.Right)
-               } else if Isinter(t) {
-                       n = mkcall1(writebarrierfn("writebarrieriface", t, n.Right.Type), nil, init, l, n.Right)
-               } else if t.Width <= int64(4*Widthptr) {
-                       x := int64(0)
-                       if applywritebarrier_bv.b == nil {
-                               applywritebarrier_bv = bvalloc(4)
-                       }
-                       bvresetall(applywritebarrier_bv)
-                       onebitwalktype1(t, &x, applywritebarrier_bv)
-                       var name string
-                       switch t.Width / int64(Widthptr) {
-                       default:
-                               Fatal("found writebarrierfat for %d-byte object of type %v", int(t.Width), t)
-
-                       case 2:
-                               name = fmt.Sprintf("writebarrierfat%d%d", bvget(applywritebarrier_bv, 0), bvget(applywritebarrier_bv, 1))
-
-                       case 3:
-                               name = fmt.Sprintf("writebarrierfat%d%d%d", bvget(applywritebarrier_bv, 0), bvget(applywritebarrier_bv, 1), bvget(applywritebarrier_bv, 2))
-
-                       case 4:
-                               name = fmt.Sprintf("writebarrierfat%d%d%d%d", bvget(applywritebarrier_bv, 0), bvget(applywritebarrier_bv, 1), bvget(applywritebarrier_bv, 2), bvget(applywritebarrier_bv, 3))
-                       }
-
-                       n = mkcall1(writebarrierfn(name, t, n.Right.Type), nil, init, l, Nodintconst(0), n.Right)
-               } else {
-                       r := n.Right
-                       for r.Op == OCONVNOP {
-                               r = r.Left
-                       }
-                       r = Nod(OADDR, r, nil)
-                       r.Etype = 1 // addr does not escape
-
-                       //warnl(n->lineno, "typedmemmove %T %N", t, r);
-                       n = mkcall1(writebarrierfn("typedmemmove", t, r.Left.Type), nil, init, typename(t), l, r)
+               if Debug_wb > 1 {
+                       Warnl(int(n.Lineno), "marking %v for barrier", Nconv(n.Left, 0))
                }
+               n.Op = OASWB
+               return n
        }
        return n
 }