diff options
| -rw-r--r-- | src/cmd/compile/internal/gc/main.go | 15 | ||||
| -rw-r--r-- | src/cmd/compile/internal/walk/closure.go | 99 | ||||
| -rw-r--r-- | src/cmd/compile/internal/walk/expr.go | 23 |
3 files changed, 61 insertions, 76 deletions
diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go index 2903d64ff8..9ecdd510b1 100644 --- a/src/cmd/compile/internal/gc/main.go +++ b/src/cmd/compile/internal/gc/main.go @@ -22,7 +22,6 @@ import ( "cmd/compile/internal/ssagen" "cmd/compile/internal/typecheck" "cmd/compile/internal/types" - "cmd/compile/internal/walk" "cmd/internal/dwarf" "cmd/internal/obj" "cmd/internal/objabi" @@ -269,20 +268,6 @@ func Main(archInit func(*ssagen.ArchInfo)) { ssagen.EnableNoWriteBarrierRecCheck() } - // Transform closure bodies to properly reference captured variables. - // This needs to happen before walk, because closures must be transformed - // before walk reaches a call of a closure. - base.Timer.Start("fe", "xclosures") - for _, n := range typecheck.Target.Decls { - if n.Op() == ir.ODCLFUNC { - n := n.(*ir.Func) - if n.OClosure != nil { - ir.CurFunc = n - walk.Closure(n) - } - } - } - // Prepare for SSA compilation. // This must be before peekitabs, because peekitabs // can trigger function compilation. diff --git a/src/cmd/compile/internal/walk/closure.go b/src/cmd/compile/internal/walk/closure.go index 7fa63ea9c7..e9b3698080 100644 --- a/src/cmd/compile/internal/walk/closure.go +++ b/src/cmd/compile/internal/walk/closure.go @@ -12,50 +12,43 @@ import ( "cmd/internal/src" ) -// Closure is called in a separate phase after escape analysis. -// It transform closure bodies to properly reference captured variables. -func Closure(fn *ir.Func) { - if len(fn.ClosureVars) == 0 { - return - } +// directClosureCall rewrites a direct call of a function literal into +// a normal function call with closure variables passed as arguments. +// This avoids allocation of a closure object. +// +// For illustration, the following call: +// +// func(a int) { +// println(byval) +// byref++ +// }(42) +// +// becomes: +// +// func(byval int, &byref *int, a int) { +// println(byval) +// (*&byref)++ +// }(byval, &byref, 42) +func directClosureCall(n *ir.CallExpr) { + clo := n.X.(*ir.ClosureExpr) + clofn := clo.Func - if !fn.ClosureCalled() { - // The closure is not directly called, so it is going to stay as closure. - fn.SetNeedctxt(true) - return + if ir.IsTrivialClosure(clo) { + return // leave for walkClosure to handle } - lno := base.Pos - base.Pos = fn.Pos() - - // If the closure is directly called, we transform it to a plain function call - // with variables passed as args. This avoids allocation of a closure object. - // Here we do only a part of the transformation. Walk of OCALLFUNC(OCLOSURE) - // will complete the transformation later. - // For illustration, the following closure: - // func(a int) { - // println(byval) - // byref++ - // }(42) - // becomes: - // func(byval int, &byref *int, a int) { - // println(byval) - // (*&byref)++ - // }(byval, &byref, 42) - - // f is ONAME of the actual function. - f := fn.Nname - // We are going to insert captured variables before input args. var params []*types.Field var decls []*ir.Name - for _, v := range fn.ClosureVars { + for _, v := range clofn.ClosureVars { if !v.Byval() { // If v of type T is captured by reference, // we introduce function param &v *T // and v remains PAUTOHEAP with &v heapaddr // (accesses will implicitly deref &v). - addr := typecheck.NewName(typecheck.Lookup("&" + v.Sym().Name)) + + addr := ir.NewNameAt(clofn.Pos(), typecheck.Lookup("&"+v.Sym().Name)) + addr.Curfn = clofn addr.SetType(types.NewPtr(v.Type())) v.Heapaddr = addr v = addr @@ -69,32 +62,58 @@ func Closure(fn *ir.Func) { params = append(params, fld) } + // f is ONAME of the actual function. + f := clofn.Nname + // Prepend params and decls. - f.Type().Params().SetFields(append(params, f.Type().Params().FieldSlice()...)) - fn.Dcl = append(decls, fn.Dcl...) + typ := f.Type() + typ.Params().SetFields(append(params, typ.Params().FieldSlice()...)) + clofn.Dcl = append(decls, clofn.Dcl...) + + // Rewrite call. + n.X = f + n.Args.Prepend(closureArgs(clo)...) + + // Update the call expression's type. We need to do this + // because typecheck gave it the result type of the OCLOSURE + // node, but we only rewrote the ONAME node's type. Logically, + // they're the same, but the stack offsets probably changed. + // + // TODO(mdempsky): Reuse a single type for both. + if typ.NumResults() == 1 { + n.SetType(typ.Results().Field(0).Type) + } else { + n.SetType(typ.Results()) + } - base.Pos = lno + // Add to Closures for enqueueFunc. It's no longer a proper + // closure, but we may have already skipped over it in the + // functions list as a non-trivial closure, so this just + // ensures it's compiled. + ir.CurFunc.Closures = append(ir.CurFunc.Closures, clofn) } func walkClosure(clo *ir.ClosureExpr, init *ir.Nodes) ir.Node { - fn := clo.Func + clofn := clo.Func // If no closure vars, don't bother wrapping. if ir.IsTrivialClosure(clo) { if base.Debug.Closure > 0 { base.WarnfAt(clo.Pos(), "closure converted to global") } - return fn.Nname + return clofn.Nname } - ir.CurFunc.Closures = append(ir.CurFunc.Closures, fn) + // The closure is not trivial or directly called, so it's going to stay a closure. ir.ClosureDebugRuntimeCheck(clo) + clofn.SetNeedctxt(true) + ir.CurFunc.Closures = append(ir.CurFunc.Closures, clofn) typ := typecheck.ClosureType(clo) clos := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(typ), nil) clos.SetEsc(clo.Esc()) - clos.List = append([]ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, fn.Nname)}, closureArgs(clo)...) + clos.List = append([]ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, clofn.Nname)}, closureArgs(clo)...) addr := typecheck.NodAddr(clos) addr.SetEsc(clo.Esc()) diff --git a/src/cmd/compile/internal/walk/expr.go b/src/cmd/compile/internal/walk/expr.go index 508cdd1d06..893a95f403 100644 --- a/src/cmd/compile/internal/walk/expr.go +++ b/src/cmd/compile/internal/walk/expr.go @@ -488,27 +488,8 @@ func walkCall(n *ir.CallExpr, init *ir.Nodes) ir.Node { reflectdata.MarkUsedIfaceMethod(n) } - if n.Op() == ir.OCALLFUNC && n.X.Op() == ir.OCLOSURE && !ir.IsTrivialClosure(n.X.(*ir.ClosureExpr)) { - // Transform direct call of a closure to call of a normal function. - // transformclosure already did all preparation work. - // We leave trivial closures for walkClosure to handle. - - clo := n.X.(*ir.ClosureExpr) - ir.CurFunc.Closures = append(ir.CurFunc.Closures, clo.Func) - - // Prepend captured variables to argument list. - n.Args.Prepend(closureArgs(clo)...) - - // Replace OCLOSURE with ONAME/PFUNC. - n.X = clo.Func.Nname - - // Update type of OCALLFUNC node. - // Output arguments had not changed, but their offsets could. - if n.X.Type().NumResults() == 1 { - n.SetType(n.X.Type().Results().Field(0).Type) - } else { - n.SetType(n.X.Type().Results()) - } + if n.Op() == ir.OCALLFUNC && n.X.Op() == ir.OCLOSURE { + directClosureCall(n) } walkCall1(n, init) |