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[dev.regabi] cmd/compile: merge ascompatee, ascompatee1, and reorder3

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These functions are interelated and have arbitrarily overlapping
responsibilities. By joining them together, we simplify the code and
remove some redundancy.

Passes toolstash -cmp.

Change-Id: I7c42cb7171b3006bc790199be3fd0991e6e985f2
Reviewed-on: https://go-review.googlesource.com/c/go/+/280438
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Matthew Dempsky 2020-12-26 21:10:16 -08:00
parent 4c215c4fa9
commit c98548e110
1 changed files with 32 additions and 72 deletions
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104
src/cmd/compile/internal/walk/assign.go
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@ -297,54 +297,6 @@ func fncall(l ir.Node, rt *types.Type) bool {
return true
}
func ascompatee(op ir.Op, nl, nr []ir.Node, init *ir.Nodes) []ir.Node {
// check assign expression list to
// an expression list. called in
// expr-list = expr-list
// ensure order of evaluation for function calls
for i := range nl {
nl[i] = safeExpr(nl[i], init)
}
for i1 := range nr {
nr[i1] = safeExpr(nr[i1], init)
}
var nn []*ir.AssignStmt
i := 0
for ; i < len(nl); i++ {
if i >= len(nr) {
break
}
// Do not generate 'x = x' during return. See issue 4014.
if op == ir.ORETURN && ir.SameSafeExpr(nl[i], nr[i]) {
continue
}
nn = append(nn, ascompatee1(nl[i], nr[i], init))
}
// cannot happen: caller checked that lists had same length
if i < len(nl) || i < len(nr) {
var nln, nrn ir.Nodes
nln.Set(nl)
nrn.Set(nr)
base.Fatalf("error in shape across %+v %v %+v / %d %d [%s]", nln, op, nrn, len(nl), len(nr), ir.FuncName(ir.CurFunc))
}
return reorder3(nn)
}
func ascompatee1(l ir.Node, r ir.Node, init *ir.Nodes) *ir.AssignStmt {
// convas will turn map assigns into function calls,
// making it impossible for reorder3 to work.
n := ir.NewAssignStmt(base.Pos, l, r)
if l.Op() == ir.OINDEXMAP {
return n
}
return convas(n, init)
}
// check assign type list to
// an expression list. called in
// expr-list = func()
@ -387,14 +339,23 @@ func ascompatet(nl ir.Nodes, nr *types.Type) []ir.Node {
return append(nn, mm...)
}
// reorder3
// from ascompatee
// a,b = c,d
// simultaneous assignment. there cannot
// be later use of an earlier lvalue.
//
// function calls have been removed.
func reorder3(all []*ir.AssignStmt) []ir.Node {
// check assign expression list to
// an expression list. called in
// expr-list = expr-list
func ascompatee(op ir.Op, nl, nr []ir.Node, init *ir.Nodes) []ir.Node {
// cannot happen: should have been rejected during type checking
if len(nl) != len(nr) {
base.Fatalf("assignment operands mismatch: %+v / %+v", ir.Nodes(nl), ir.Nodes(nr))
}
// ensure order of evaluation for function calls
for i := range nl {
nl[i] = safeExpr(nl[i], init)
}
for i := range nr {
nr[i] = safeExpr(nr[i], init)
}
var assigned ir.NameSet
var memWrite bool
@ -425,9 +386,16 @@ func reorder3(all []*ir.AssignStmt) []ir.Node {
}
}
var mapinit ir.Nodes
for i, n := range all {
l := n.X
var late []ir.Node
for i, l := range nl {
r := nr[i]
// Do not generate 'x = x' during return. See issue 4014.
if op == ir.ORETURN && ir.SameSafeExpr(l, r) {
continue
}
as := ir.NewAssignStmt(base.Pos, l, r)
// Save subexpressions needed on left side.
// Drill through non-dereferences.
@ -454,19 +422,13 @@ func reorder3(all []*ir.AssignStmt) []ir.Node {
var name *ir.Name
switch l.Op() {
default:
base.Fatalf("reorder3 unexpected lvalue %v", l.Op())
base.Fatalf("unexpected lvalue %v", l.Op())
case ir.ONAME:
name = l.(*ir.Name)
case ir.OINDEX, ir.OINDEXMAP:
l := l.(*ir.IndexExpr)
save(&l.X)
save(&l.Index)
if l.Op() == ir.OINDEXMAP {
all[i] = convas(all[i], &mapinit)
}
case ir.ODEREF:
l := l.(*ir.StarExpr)
save(&l.X)
@ -476,7 +438,9 @@ func reorder3(all []*ir.AssignStmt) []ir.Node {
}
// Save expression on right side.
save(&all[i].Y)
save(&as.Y)
late = append(late, convas(as, init))
if name == nil || name.Addrtaken() || name.Class_ == ir.PEXTERN || name.Class_ == ir.PAUTOHEAP {
memWrite = true
@ -489,11 +453,7 @@ func reorder3(all []*ir.AssignStmt) []ir.Node {
assigned.Add(name)
}
early = append(mapinit, early...)
for _, as := range all {
early = append(early, as)
}
return early
return append(early, late...)
}
// readsMemory reports whether the evaluation n directly reads from