[dev.regabi] cmd/compile: cleanup import/export code

Now that we have concrete AST node types and better constructor APIs,
we can more cleanup a lot of the import code and some export code too.

Passes toolstash -cmp.

Change-Id: Ie3425d9dac11ac4245e5da675dd298984a926df4
Reviewed-on: https://go-review.googlesource.com/c/go/+/279954
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>

1 files changed, 43 insertions, 71 deletions

diff --git a/src/cmd/compile/internal/typecheck/iimport.go b/src/cmd/compile/internal/typecheck/iimport.go
index ab43d4f71b..3c7dde5506 100644
--- a/src/cmd/compile/internal/typecheck/iimport.go
+++ b/src/cmd/compile/internal/typecheck/iimport.go
@@ -767,8 +767,8 @@ func (r *importReader) stmtList() []ir.Node {
 	return list
 }
 
-func (r *importReader) caseList(sw ir.Node) []ir.Node {
-	namedTypeSwitch := isNamedTypeSwitch(sw)
+func (r *importReader) caseList(switchExpr ir.Node) []ir.Node {
+	namedTypeSwitch := isNamedTypeSwitch(switchExpr)
 
 	cases := make([]ir.Node, r.uint64())
 	for i := range cases {
@@ -781,7 +781,7 @@ func (r *importReader) caseList(sw ir.Node) []ir.Node {
 			caseVar := ir.NewNameAt(cas.Pos(), r.ident())
 			Declare(caseVar, DeclContext)
 			cas.Vars = []ir.Node{caseVar}
-			caseVar.Defn = sw.(*ir.SwitchStmt).Tag
+			caseVar.Defn = switchExpr
 		}
 		cas.Body.Set(r.stmtList())
 		cases[i] = cas
@@ -821,7 +821,7 @@ func (r *importReader) node() ir.Node {
 		pos := r.pos()
 		typ := r.typ()
 
-		n := npos(pos, NodNil())
+		n := ir.NewNilExpr(pos)
 		n.SetType(typ)
 		return n
 
@@ -829,7 +829,7 @@ func (r *importReader) node() ir.Node {
 		pos := r.pos()
 		typ := r.typ()
 
-		n := npos(pos, ir.NewLiteral(r.value(typ)))
+		n := ir.NewBasicLit(pos, r.value(typ))
 		n.SetType(typ)
 		return n
 
@@ -864,26 +864,19 @@ func (r *importReader) node() ir.Node {
 	//	unreachable - mapped to case OADDR below by exporter
 
 	case ir.OSTRUCTLIT:
-		// TODO(mdempsky): Export position information for OSTRUCTKEY nodes.
-		savedlineno := base.Pos
-		base.Pos = r.pos()
-		n := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(r.typ()).(ir.Ntype), nil)
-		n.List.Set(r.elemList()) // special handling of field names
-		base.Pos = savedlineno
-		return n
+		pos := r.pos()
+		return ir.NewCompLitExpr(pos, ir.OCOMPLIT, ir.TypeNode(r.typ()).(ir.Ntype), r.elemList(pos))
 
 	// case OARRAYLIT, OSLICELIT, OMAPLIT:
 	// 	unreachable - mapped to case OCOMPLIT below by exporter
 
 	case ir.OCOMPLIT:
-		n := ir.NewCompLitExpr(r.pos(), ir.OCOMPLIT, ir.TypeNode(r.typ()).(ir.Ntype), nil)
-		n.List.Set(r.exprList())
-		return n
+		return ir.NewCompLitExpr(r.pos(), ir.OCOMPLIT, ir.TypeNode(r.typ()).(ir.Ntype), r.exprList())
 
 	case ir.OKEY:
 		pos := r.pos()
-		left, right := r.exprsOrNil()
-		return ir.NewKeyExpr(pos, left, right)
+		key, value := r.exprsOrNil()
+		return ir.NewKeyExpr(pos, key, value)
 
 	// case OSTRUCTKEY:
 	//	unreachable - handled in case OSTRUCTLIT by elemList
@@ -926,9 +919,9 @@ func (r *importReader) node() ir.Node {
 	// 	unreachable - mapped to OCONV case below by exporter
 
 	case ir.OCONV:
-		n := ir.NewConvExpr(r.pos(), ir.OCONV, nil, r.expr())
-		n.SetType(r.typ())
-		return n
+		pos := r.pos()
+		x := r.expr()
+		return ir.NewConvExpr(pos, ir.OCONV, r.typ(), x)
 
 	case ir.OCOPY, ir.OCOMPLEX, ir.OREAL, ir.OIMAG, ir.OAPPEND, ir.OCAP, ir.OCLOSE, ir.ODELETE, ir.OLEN, ir.OMAKE, ir.ONEW, ir.OPANIC, ir.ORECOVER, ir.OPRINT, ir.OPRINTN:
 		n := builtinCall(r.pos(), op)
@@ -942,10 +935,10 @@ func (r *importReader) node() ir.Node {
 	// 	unreachable - mapped to OCALL case below by exporter
 
 	case ir.OCALL:
-		n := ir.NewCallExpr(r.pos(), ir.OCALL, nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		n.X = r.expr()
-		n.Args.Set(r.exprList())
+		pos := r.pos()
+		init := r.stmtList()
+		n := ir.NewCallExpr(pos, ir.OCALL, r.expr(), r.exprList())
+		n.PtrInit().Set(init)
 		n.IsDDD = r.bool()
 		return n
 
@@ -979,7 +972,8 @@ func (r *importReader) node() ir.Node {
 	case ir.OADDSTR:
 		pos := r.pos()
 		list := r.exprList()
-		x := npos(pos, list[0])
+		x := list[0]
+		x.SetPos(pos) // TODO(mdempsky): Remove toolstash bandage.
 		for _, y := range list[1:] {
 			x = ir.NewBinaryExpr(pos, ir.OADD, x, y)
 		}
@@ -1006,9 +1000,7 @@ func (r *importReader) node() ir.Node {
 		return ir.NewAssignStmt(r.pos(), r.expr(), r.expr())
 
 	case ir.OASOP:
-		n := ir.NewAssignOpStmt(r.pos(), ir.OXXX, nil, nil)
-		n.AsOp = r.op()
-		n.X = r.expr()
+		n := ir.NewAssignOpStmt(r.pos(), r.op(), r.expr(), nil)
 		if !r.bool() {
 			n.Y = ir.NewInt(1)
 			n.IncDec = true
@@ -1021,15 +1013,10 @@ func (r *importReader) node() ir.Node {
 	// 	unreachable - mapped to OAS2 case below by exporter
 
 	case ir.OAS2:
-		n := ir.NewAssignListStmt(r.pos(), ir.OAS2, nil, nil)
-		n.Lhs.Set(r.exprList())
-		n.Rhs.Set(r.exprList())
-		return n
+		return ir.NewAssignListStmt(r.pos(), ir.OAS2, r.exprList(), r.exprList())
 
 	case ir.ORETURN:
-		n := ir.NewReturnStmt(r.pos(), nil)
-		n.Results.Set(r.exprList())
-		return n
+		return ir.NewReturnStmt(r.pos(), r.exprList())
 
 	// case ORETJMP:
 	// 	unreachable - generated by compiler for trampolin routines (not exported)
@@ -1038,57 +1025,47 @@ func (r *importReader) node() ir.Node {
 		return ir.NewGoDeferStmt(r.pos(), op, r.expr())
 
 	case ir.OIF:
-		n := ir.NewIfStmt(r.pos(), nil, nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		n.Cond = r.expr()
-		n.Body.Set(r.stmtList())
-		n.Else.Set(r.stmtList())
+		pos, init := r.pos(), r.stmtList()
+		n := ir.NewIfStmt(pos, r.expr(), r.stmtList(), r.stmtList())
+		n.PtrInit().Set(init)
 		return n
 
 	case ir.OFOR:
-		n := ir.NewForStmt(r.pos(), nil, nil, nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		left, right := r.exprsOrNil()
-		n.Cond = left
-		n.Post = right
-		n.Body.Set(r.stmtList())
-		return n
+		pos, init := r.pos(), r.stmtList()
+		cond, post := r.exprsOrNil()
+		return ir.NewForStmt(pos, init, cond, post, r.stmtList())
 
 	case ir.ORANGE:
-		n := ir.NewRangeStmt(r.pos(), nil, nil, nil)
-		n.Vars.Set(r.stmtList())
-		n.X = r.expr()
-		n.Body.Set(r.stmtList())
-		return n
+		return ir.NewRangeStmt(r.pos(), r.stmtList(), r.expr(), r.stmtList())
 
 	case ir.OSELECT:
-		n := ir.NewSelectStmt(r.pos(), nil)
-		n.PtrInit().Set(r.stmtList())
+		pos := r.pos()
+		init := r.stmtList()
 		r.exprsOrNil() // TODO(rsc): Delete (and fix exporter). These are always nil.
-		n.Cases.Set(r.caseList(n))
+		n := ir.NewSelectStmt(pos, r.caseList(nil))
+		n.PtrInit().Set(init)
 		return n
 
 	case ir.OSWITCH:
-		n := ir.NewSwitchStmt(r.pos(), nil, nil)
-		n.PtrInit().Set(r.stmtList())
-		left, _ := r.exprsOrNil()
-		n.Tag = left
-		n.Cases.Set(r.caseList(n))
+		pos := r.pos()
+		init := r.stmtList()
+		x, _ := r.exprsOrNil()
+		n := ir.NewSwitchStmt(pos, x, r.caseList(x))
+		n.PtrInit().Set(init)
 		return n
 
 	// case OCASE:
 	//	handled by caseList
 
 	case ir.OFALL:
-		n := ir.NewBranchStmt(r.pos(), ir.OFALL, nil)
-		return n
+		return ir.NewBranchStmt(r.pos(), ir.OFALL, nil)
 
 	// case OEMPTY:
 	// 	unreachable - not emitted by exporter
 
 	case ir.OBREAK, ir.OCONTINUE, ir.OGOTO:
-		var sym *types.Sym
 		pos := r.pos()
+		var sym *types.Sym
 		if label := r.string(); label != "" {
 			sym = Lookup(label)
 		}
@@ -1111,12 +1088,12 @@ func (r *importReader) op() ir.Op {
 	return ir.Op(r.uint64())
 }
 
-func (r *importReader) elemList() []ir.Node {
+func (r *importReader) elemList(pos src.XPos) []ir.Node {
 	c := r.uint64()
 	list := make([]ir.Node, c)
 	for i := range list {
-		s := r.ident()
-		list[i] = ir.NewStructKeyExpr(base.Pos, s, r.expr())
+		// TODO(mdempsky): Export position information for OSTRUCTKEY nodes.
+		list[i] = ir.NewStructKeyExpr(pos, r.ident(), r.expr())
 	}
 	return list
 }
@@ -1135,8 +1112,3 @@ func (r *importReader) exprsOrNil() (a, b ir.Node) {
 func builtinCall(pos src.XPos, op ir.Op) *ir.CallExpr {
 	return ir.NewCallExpr(pos, ir.OCALL, ir.NewIdent(base.Pos, types.BuiltinPkg.Lookup(ir.OpNames[op])), nil)
 }
-
-func npos(pos src.XPos, n ir.Node) ir.Node {
-	n.SetPos(pos)
-	return n
-}