1 files changed, 182 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/escape/call.go b/src/cmd/compile/internal/escape/call.go
new file mode 100644
index 0000000000..28a3b679a5
--- /dev/null
+++ b/src/cmd/compile/internal/escape/call.go
@@ -0,0 +1,182 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package escape
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+)
+
+// call evaluates a call expressions, including builtin calls. ks
+// should contain the holes representing where the function callee's
+// results flows; where is the OGO/ODEFER context of the call, if any.
+func (e *escape) call(ks []hole, call, where ir.Node) {
+	topLevelDefer := where != nil && where.Op() == ir.ODEFER && e.loopDepth == 1
+	if topLevelDefer {
+		// force stack allocation of defer record, unless
+		// open-coded defers are used (see ssa.go)
+		where.SetEsc(ir.EscNever)
+	}
+
+	argument := func(k hole, arg ir.Node) {
+		if topLevelDefer {
+			// Top level defers arguments don't escape to
+			// heap, but they do need to last until end of
+			// function.
+			k = e.later(k)
+		} else if where != nil {
+			k = e.heapHole()
+		}
+
+		e.expr(k.note(call, "call parameter"), arg)
+	}
+
+	switch call.Op() {
+	default:
+		ir.Dump("esc", call)
+		base.Fatalf("unexpected call op: %v", call.Op())
+
+	case ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER:
+		call := call.(*ir.CallExpr)
+		typecheck.FixVariadicCall(call)
+
+		// Pick out the function callee, if statically known.
+		var fn *ir.Name
+		switch call.Op() {
+		case ir.OCALLFUNC:
+			switch v := ir.StaticValue(call.X); {
+			case v.Op() == ir.ONAME && v.(*ir.Name).Class == ir.PFUNC:
+				fn = v.(*ir.Name)
+			case v.Op() == ir.OCLOSURE:
+				fn = v.(*ir.ClosureExpr).Func.Nname
+			}
+		case ir.OCALLMETH:
+			fn = ir.MethodExprName(call.X)
+		}
+
+		fntype := call.X.Type()
+		if fn != nil {
+			fntype = fn.Type()
+		}
+
+		if ks != nil && fn != nil && e.inMutualBatch(fn) {
+			for i, result := range fn.Type().Results().FieldSlice() {
+				e.expr(ks[i], ir.AsNode(result.Nname))
+			}
+		}
+
+		if r := fntype.Recv(); r != nil {
+			argument(e.tagHole(ks, fn, r), call.X.(*ir.SelectorExpr).X)
+		} else {
+			// Evaluate callee function expression.
+			argument(e.discardHole(), call.X)
+		}
+
+		args := call.Args
+		for i, param := range fntype.Params().FieldSlice() {
+			argument(e.tagHole(ks, fn, param), args[i])
+		}
+
+	case ir.OAPPEND:
+		call := call.(*ir.CallExpr)
+		args := call.Args
+
+		// Appendee slice may flow directly to the result, if
+		// it has enough capacity. Alternatively, a new heap
+		// slice might be allocated, and all slice elements
+		// might flow to heap.
+		appendeeK := ks[0]
+		if args[0].Type().Elem().HasPointers() {
+			appendeeK = e.teeHole(appendeeK, e.heapHole().deref(call, "appendee slice"))
+		}
+		argument(appendeeK, args[0])
+
+		if call.IsDDD {
+			appendedK := e.discardHole()
+			if args[1].Type().IsSlice() && args[1].Type().Elem().HasPointers() {
+				appendedK = e.heapHole().deref(call, "appended slice...")
+			}
+			argument(appendedK, args[1])
+		} else {
+			for _, arg := range args[1:] {
+				argument(e.heapHole(), arg)
+			}
+		}
+
+	case ir.OCOPY:
+		call := call.(*ir.BinaryExpr)
+		argument(e.discardHole(), call.X)
+
+		copiedK := e.discardHole()
+		if call.Y.Type().IsSlice() && call.Y.Type().Elem().HasPointers() {
+			copiedK = e.heapHole().deref(call, "copied slice")
+		}
+		argument(copiedK, call.Y)
+
+	case ir.OPANIC:
+		call := call.(*ir.UnaryExpr)
+		argument(e.heapHole(), call.X)
+
+	case ir.OCOMPLEX:
+		call := call.(*ir.BinaryExpr)
+		argument(e.discardHole(), call.X)
+		argument(e.discardHole(), call.Y)
+	case ir.ODELETE, ir.OPRINT, ir.OPRINTN, ir.ORECOVER:
+		call := call.(*ir.CallExpr)
+		for _, arg := range call.Args {
+			argument(e.discardHole(), arg)
+		}
+	case ir.OLEN, ir.OCAP, ir.OREAL, ir.OIMAG, ir.OCLOSE:
+		call := call.(*ir.UnaryExpr)
+		argument(e.discardHole(), call.X)
+
+	case ir.OUNSAFEADD, ir.OUNSAFESLICE:
+		call := call.(*ir.BinaryExpr)
+		argument(ks[0], call.X)
+		argument(e.discardHole(), call.Y)
+	}
+}
+
+// tagHole returns a hole for evaluating an argument passed to param.
+// ks should contain the holes representing where the function
+// callee's results flows. fn is the statically-known callee function,
+// if any.
+func (e *escape) tagHole(ks []hole, fn *ir.Name, param *types.Field) hole {
+	// If this is a dynamic call, we can't rely on param.Note.
+	if fn == nil {
+		return e.heapHole()
+	}
+
+	if e.inMutualBatch(fn) {
+		return e.addr(ir.AsNode(param.Nname))
+	}
+
+	// Call to previously tagged function.
+
+	if fn.Func != nil && fn.Func.Pragma&ir.UintptrEscapes != 0 && (param.Type.IsUintptr() || param.IsDDD() && param.Type.Elem().IsUintptr()) {
+		k := e.heapHole()
+		k.uintptrEscapesHack = true
+		return k
+	}
+
+	var tagKs []hole
+
+	esc := parseLeaks(param.Note)
+	if x := esc.Heap(); x >= 0 {
+		tagKs = append(tagKs, e.heapHole().shift(x))
+	}
+
+	if ks != nil {
+		for i := 0; i < numEscResults; i++ {
+			if x := esc.Result(i); x >= 0 {
+				tagKs = append(tagKs, ks[i].shift(x))
+			}
+		}
+	}
+
+	return e.teeHole(tagKs...)
+}