cmd/compile: provide types for all order-allocated temporaries

Ensure that we correctly type the stack temps for regular closures,
method function closures, and slice literals.

Then we don't need to override the dummy types later.
Furthermore, this allows order to reuse temporaries of these types.

OARRAYLIT doesn't need a temporary as far as I can tell, so I
removed that case from order.

Change-Id: Ic58520fa50c90639393ff78f33d3c831d5c4acb9
Reviewed-on: https://go-review.googlesource.com/c/140306
Reviewed-by: Cherry Zhang <cherryyz@google.com>

2 files changed, 53 insertions, 38 deletions

diff --git a/src/cmd/compile/internal/gc/closure.go b/src/cmd/compile/internal/gc/closure.go
index 834cdc41eb..dcea567a14 100644
--- a/src/cmd/compile/internal/gc/closure.go
+++ b/src/cmd/compile/internal/gc/closure.go
@@ -337,18 +337,10 @@ func closuredebugruntimecheck(clo *Node) {
 	}
 }
 
-func walkclosure(clo *Node, init *Nodes) *Node {
-	xfunc := clo.Func.Closure
-
-	// If no closure vars, don't bother wrapping.
-	if hasemptycvars(clo) {
-		if Debug_closure > 0 {
-			Warnl(clo.Pos, "closure converted to global")
-		}
-		return xfunc.Func.Nname
-	}
-	closuredebugruntimecheck(clo)
-
+// closureType returns the struct type used to hold all the information
+// needed in the closure for clo (clo must be a OCLOSURE node).
+// The address of a variable of the returned type can be cast to a func.
+func closureType(clo *Node) *types.Type {
 	// Create closure in the form of a composite literal.
 	// supposing the closure captures an int i and a string s
 	// and has one float64 argument and no results,
@@ -362,11 +354,10 @@ func walkclosure(clo *Node, init *Nodes) *Node {
 	// The information appears in the binary in the form of type descriptors;
 	// the struct is unnamed so that closures in multiple packages with the
 	// same struct type can share the descriptor.
-
 	fields := []*Node{
 		namedfield(".F", types.Types[TUINTPTR]),
 	}
-	for _, v := range xfunc.Func.Cvars.Slice() {
+	for _, v := range clo.Func.Closure.Func.Cvars.Slice() {
 		typ := v.Type
 		if !v.Name.Byval() {
 			typ = types.NewPtr(typ)
@@ -375,6 +366,22 @@ func walkclosure(clo *Node, init *Nodes) *Node {
 	}
 	typ := tostruct(fields)
 	typ.SetNoalg(true)
+	return typ
+}
+
+func walkclosure(clo *Node, init *Nodes) *Node {
+	xfunc := clo.Func.Closure
+
+	// If no closure vars, don't bother wrapping.
+	if hasemptycvars(clo) {
+		if Debug_closure > 0 {
+			Warnl(clo.Pos, "closure converted to global")
+		}
+		return xfunc.Func.Nname
+	}
+	closuredebugruntimecheck(clo)
+
+	typ := closureType(clo)
 
 	clos := nod(OCOMPLIT, nil, nod(OIND, typenod(typ), nil))
 	clos.Esc = clo.Esc
@@ -389,10 +396,10 @@ func walkclosure(clo *Node, init *Nodes) *Node {
 	clos.Left.Esc = clo.Esc
 
 	// non-escaping temp to use, if any.
-	// orderexpr did not compute the type; fill it in now.
 	if x := prealloc[clo]; x != nil {
-		x.Type = clos.Left.Left.Type
-		x.Orig.Type = x.Type
+		if !eqtype(typ, x.Type) {
+			panic("closure type does not match order's assigned type")
+		}
 		clos.Left.Right = x
 		delete(prealloc, clo)
 	}
@@ -479,6 +486,18 @@ func makepartialcall(fn *Node, t0 *types.Type, meth *types.Sym) *Node {
 	return xfunc
 }
 
+// partialCallType returns the struct type used to hold all the information
+// needed in the closure for n (n must be a OCALLPART node).
+// The address of a variable of the returned type can be cast to a func.
+func partialCallType(n *Node) *types.Type {
+	t := tostruct([]*Node{
+		namedfield("F", types.Types[TUINTPTR]),
+		namedfield("R", n.Left.Type),
+	})
+	t.SetNoalg(true)
+	return t
+}
+
 func walkpartialcall(n *Node, init *Nodes) *Node {
 	// Create closure in the form of a composite literal.
 	// For x.M with receiver (x) type T, the generated code looks like:
@@ -495,30 +514,25 @@ func walkpartialcall(n *Node, init *Nodes) *Node {
 		checknil(n.Left, init)
 	}
 
-	typ := tostruct([]*Node{
-		namedfield("F", types.Types[TUINTPTR]),
-		namedfield("R", n.Left.Type),
-	})
-	typ.SetNoalg(true)
+	typ := partialCallType(n)
 
 	clos := nod(OCOMPLIT, nil, nod(OIND, typenod(typ), nil))
 	clos.Esc = n.Esc
 	clos.Right.SetImplicit(true)
-	clos.List.Set1(nod(OCFUNC, n.Func.Nname, nil))
-	clos.List.Append(n.Left)
+	clos.List.Set2(nod(OCFUNC, n.Func.Nname, nil), n.Left)
 
 	// Force type conversion from *struct to the func type.
 	clos = convnop(clos, n.Type)
 
-	// typecheck will insert a PTRLIT node under CONVNOP,
-	// tag it with escape analysis result.
+	// The typecheck inside convnop will insert a PTRLIT node under CONVNOP.
+	// Tag it with escape analysis result.
 	clos.Left.Esc = n.Esc
 
 	// non-escaping temp to use, if any.
-	// orderexpr did not compute the type; fill it in now.
 	if x := prealloc[n]; x != nil {
-		x.Type = clos.Left.Left.Type
-		x.Orig.Type = x.Type
+		if !eqtype(typ, x.Type) {
+			panic("partial call type does not match order's assigned type")
+		}
 		clos.Left.Right = x
 		delete(prealloc, n)
 	}
diff --git a/src/cmd/compile/internal/gc/order.go b/src/cmd/compile/internal/gc/order.go
index f33689298f..694f8fbd34 100644
--- a/src/cmd/compile/internal/gc/order.go
+++ b/src/cmd/compile/internal/gc/order.go
@@ -244,12 +244,6 @@ func (o *Order) markTemp() ordermarker {
 // which must have been returned by marktemp.
 func (o *Order) popTemp(mark ordermarker) {
 	for _, n := range o.temp[mark:] {
-		if n.Type.Etype == types.TUINT8 {
-			// Don't recycle temps of this type. TUINT8 is used
-			// as a placeholder for a type to be determined later.
-			// TODO: fix
-			continue
-		}
 		key := n.Type.LongString()
 		o.free[key] = append(o.free[key], n)
 	}
@@ -1170,16 +1164,23 @@ func (o *Order) expr(n, lhs *Node) *Node {
 
 	case OCLOSURE:
 		if n.Noescape() && n.Func.Closure.Func.Cvars.Len() > 0 {
-			prealloc[n] = o.newTemp(types.Types[TUINT8], false) // walk will fill in correct type
+			prealloc[n] = o.newTemp(closureType(n), false)
 		}
 
-	case OARRAYLIT, OSLICELIT, OCALLPART:
+	case OSLICELIT, OCALLPART:
 		n.Left = o.expr(n.Left, nil)
 		n.Right = o.expr(n.Right, nil)
 		o.exprList(n.List)
 		o.exprList(n.Rlist)
 		if n.Noescape() {
-			prealloc[n] = o.newTemp(types.Types[TUINT8], false) // walk will fill in correct type
+			var t *types.Type
+			switch n.Op {
+			case OSLICELIT:
+				t = types.NewArray(n.Type.Elem(), n.Right.Int64())
+			case OCALLPART:
+				t = partialCallType(n)
+			}
+			prealloc[n] = o.newTemp(t, false)
 		}
 
 	case ODDDARG: