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// 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.
func (e *escape) call(ks []hole, call ir.Node) {
e.callCommon(ks, call, nil)
}
func (e *escape) callCommon(ks []hole, call ir.Node, where *ir.GoDeferStmt) {
argument := func(k hole, argp *ir.Node) {
if where != nil {
if where.Esc() == ir.EscNever {
// Top-level defers arguments don't escape to heap,
// but they do need to last until end of function.
k = e.later(k)
} else {
k = e.heapHole()
}
}
e.expr(k.note(call, "call parameter"), *argp)
}
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 i := 1; i < len(args); i++ {
argument(e.heapHole(), &args[i])
}
}
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)
fixRecoverCall(call)
for i := range call.Args {
argument(e.discardHole(), &call.Args[i])
}
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)
}
}
func (e *escape) goDeferStmt(n *ir.GoDeferStmt) {
topLevelDefer := n.Op() == ir.ODEFER && e.loopDepth == 1
if topLevelDefer {
// force stack allocation of defer record, unless
// open-coded defers are used (see ssa.go)
n.SetEsc(ir.EscNever)
}
e.stmts(n.Call.Init())
e.callCommon(nil, n.Call, n)
}
// 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...)
}
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