cmd/compile/internal/ir: add Func.DeclareParams

There's several copies of this function. We only need one.

While here, normalize so that we always declare parameters, and always
use the names ~pNN for params and ~rNN for results.

Change-Id: I49e90d3fd1820f3c07936227ed5cfefd75d49a1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/528415
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>

src/cmd/compile/internal/inline/inlheur/analyze_func_params.go

@@ -21,42 +21,12 @@ type paramsAnalyzer struct {
 	*condLevelTracker
 }
 
-// dclParams returns a slice containing the non-blank, named params
-// for the specific function (plus rcvr as well if applicable) in
-// declaration order.
-func dclParams(fn *ir.Func) []*ir.Name {
-	params := []*ir.Name{}
-	for _, n := range fn.Dcl {
-		if n.Op() != ir.ONAME {
-			continue
-		}
-		if n.Class != ir.PPARAM {
-			continue
-		}
-		params = append(params, n)
-	}
-	return params
-}
-
 // getParams returns an *ir.Name slice containing all params for the
-// function (plus rcvr as well if applicable). Note that this slice
-// includes entries for blanks; entries in the returned slice corresponding
-// to blanks or unnamed params will be nil.
+// function (plus rcvr as well if applicable).
 func getParams(fn *ir.Func) []*ir.Name {
-	dclparms := dclParams(fn)
-	dclidx := 0
-	recvrParms := fn.Type().RecvParams()
-	params := make([]*ir.Name, len(recvrParms))
-	for i := range recvrParms {
-		var v *ir.Name
-		if recvrParms[i].Sym != nil &&
-			!recvrParms[i].Sym.IsBlank() {
-			v = dclparms[dclidx]
-			dclidx++
-		}
-		params[i] = v
-	}
-	return params
+	sig := fn.Type()
+	numParams := sig.NumRecvs() + sig.NumParams()
+	return fn.Dcl[:numParams]
 }
 
 func makeParamsAnalyzer(fn *ir.Func) *paramsAnalyzer {

src/cmd/compile/internal/ir/func.go

@@ -65,9 +65,7 @@ type Func struct {
 	// include closurevars until transforming closures during walk.
 	// Names must be listed PPARAMs, PPARAMOUTs, then PAUTOs,
 	// with PPARAMs and PPARAMOUTs in order corresponding to the function signature.
-	// However, as anonymous or blank PPARAMs are not actually declared,
-	// they are omitted from Dcl.
-	// Anonymous and blank PPARAMOUTs are declared as ~rNN and ~bNN Names, respectively.
+	// Anonymous and blank params are declared as ~pNN (for PPARAMs) and ~rNN (for PPARAMOUTs).
 	Dcl []*Name
 
 	// ClosureVars lists the free variables that are used within a
@@ -455,3 +453,40 @@ func IsFuncPCIntrinsic(n *CallExpr) bool {
 	return (fn.Name == "FuncPCABI0" || fn.Name == "FuncPCABIInternal") &&
 		fn.Pkg.Path == "internal/abi"
 }
+
+// DeclareParams creates Names for all of the parameters in fn's
+// signature and adds them to fn.Dcl.
+//
+// If setNname is true, then it also sets types.Field.Nname for each
+// parameter.
+func (fn *Func) DeclareParams(setNname bool) {
+	if fn.Dcl != nil {
+		base.FatalfAt(fn.Pos(), "%v already has Dcl", fn)
+	}
+
+	declareParams := func(params []*types.Field, ctxt Class, prefix string, offset int) {
+		for i, param := range params {
+			sym := param.Sym
+			if sym == nil || sym.IsBlank() {
+				sym = fn.Sym().Pkg.LookupNum(prefix, i)
+			}
+
+			name := NewNameAt(param.Pos, sym, param.Type)
+			name.Class = ctxt
+			name.Curfn = fn
+			fn.Dcl[offset+i] = name
+
+			if setNname {
+				param.Nname = name
+			}
+		}
+	}
+
+	sig := fn.Type()
+	params := sig.RecvParams()
+	results := sig.Results()
+
+	fn.Dcl = make([]*Name, len(params)+len(results))
+	declareParams(params, PPARAM, "~p", 0)
+	declareParams(results, PPARAMOUT, "~r", len(params))
+}

src/cmd/compile/internal/ir/name.go

@@ -102,16 +102,13 @@ func NewBuiltin(sym *types.Sym, op Op) *Name {
 }
 
 // NewLocal returns a new function-local variable with the given name and type.
-func (fn *Func) NewLocal(pos src.XPos, sym *types.Sym, class Class, typ *types.Type) *Name {
-	switch class {
-	case PPARAM, PPARAMOUT, PAUTO:
-		// ok
-	default:
-		base.FatalfAt(pos, "NewLocal: unexpected class for %v: %v", sym, class)
+func (fn *Func) NewLocal(pos src.XPos, sym *types.Sym, typ *types.Type) *Name {
+	if fn.Dcl == nil {
+		base.FatalfAt(pos, "must call DeclParams on %v first", fn)
 	}
 
 	n := NewNameAt(pos, sym, typ)
-	n.Class = class
+	n.Class = PAUTO
 	n.Curfn = fn
 	fn.Dcl = append(fn.Dcl, n)
 	return n

src/cmd/compile/internal/ir/node.go

@@ -318,11 +318,18 @@ func (op Op) IsCmp() bool {
 	return false
 }
 
-// Nodes is a pointer to a slice of *Node.
-// For fields that are not used in most nodes, this is used instead of
-// a slice to save space.
+// Nodes is a slice of Node.
 type Nodes []Node
 
+// ToNodes returns s as a slice of Nodes.
+func ToNodes[T Node](s []T) Nodes {
+	res := make(Nodes, len(s))
+	for i, n := range s {
+		res[i] = n
+	}
+	return res
+}
+
 // Append appends entries to Nodes.
 func (n *Nodes) Append(a ...Node) {
 	if len(a) == 0 {

src/cmd/compile/internal/logopt/logopt_test.go

@@ -205,15 +205,15 @@ func s15a8(x *[15]int64) [15]int64 {
 			`"relatedInformation":[`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:    flow: y = z:"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from y := z (assign-pair)"},`+
-			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:    flow: ~R0 = y:"},`+
+			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:    flow: ~r0 = y:"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":4,"character":11},"end":{"line":4,"character":11}}},"message":"inlineLoc"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from y.b (dot of pointer)"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":4,"character":11},"end":{"line":4,"character":11}}},"message":"inlineLoc"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from \u0026y.b (address-of)"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":4,"character":9},"end":{"line":4,"character":9}}},"message":"inlineLoc"},`+
-			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from ~R0 = \u0026y.b (assign-pair)"},`+
-			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":3},"end":{"line":9,"character":3}}},"message":"escflow:    flow: ~r0 = ~R0:"},`+
-			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":3},"end":{"line":9,"character":3}}},"message":"escflow:      from return ~R0 (return)"}]}`)
+			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from ~r0 = \u0026y.b (assign-pair)"},`+
+			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":3},"end":{"line":9,"character":3}}},"message":"escflow:    flow: ~r0 = ~r0:"},`+
+			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":3},"end":{"line":9,"character":3}}},"message":"escflow:      from return ~r0 (return)"}]}`)
 	})
 }
 

src/cmd/compile/internal/noder/reader.go

@@ -107,6 +107,11 @@ type reader struct {
 	locals      []*ir.Name
 	closureVars []*ir.Name
 
+	// funarghack is used during inlining to suppress setting
+	// Field.Nname to the inlined copies of the parameters. This is
+	// necessary because we reuse the same types.Type as the original
+	// function, and most of the compiler still relies on field.Nname to
+	// find parameters/results.
 	funarghack bool
 
 	// methodSym is the name of method's name, if reading a method.
@@ -145,14 +150,6 @@ type reader struct {
 
 	// Label to return to.
 	retlabel *types.Sym
-
-	// inlvars is the list of variables that the inlinee's arguments are
-	// assigned to, one for each receiver and normal parameter, in order.
-	inlvars ir.Nodes
-
-	// retvars is the list of variables that the inlinee's results are
-	// assigned to, one for each result parameter, in order.
-	retvars ir.Nodes
 }
 
 // A readerDict represents an instantiated "compile-time dictionary,"
@@ -1237,7 +1234,7 @@ func (r *reader) funcBody(fn *ir.Func) {
 	}
 
 	ir.WithFunc(fn, func() {
-		r.funcargs(fn)
+		r.declareParams()
 
 		if r.syntheticBody(fn.Pos()) {
 			return
@@ -1294,7 +1291,7 @@ func (r *reader) callShaped(pos src.XPos) {
 		shapedFn = shapedMethodExpr(pos, shapedObj, r.methodSym)
 	}
 
-	recvs, params := r.syntheticArgs(pos)
+	params := r.syntheticArgs()
 
 	// Construct the arguments list: receiver (if any), then runtime
 	// dictionary, and finally normal parameters.
@@ -1306,7 +1303,10 @@ func (r *reader) callShaped(pos src.XPos) {
 	// putting the dictionary parameter after that is the least invasive
 	// solution at the moment.
 	var args ir.Nodes
-	args.Append(recvs...)
+	if r.methodSym != nil {
+		args.Append(params[0])
+		params = params[1:]
+	}
 	args.Append(typecheck.Expr(ir.NewAddrExpr(pos, r.p.dictNameOf(r.dict))))
 	args.Append(params...)
 
@@ -1315,44 +1315,9 @@ func (r *reader) callShaped(pos src.XPos) {
 
 // syntheticArgs returns the recvs and params arguments passed to the
 // current function.
-func (r *reader) syntheticArgs(pos src.XPos) (recvs, params ir.Nodes) {
+func (r *reader) syntheticArgs() ir.Nodes {
 	sig := r.curfn.Nname.Type()
-
-	inlVarIdx := 0
-	addParams := func(out *ir.Nodes, params []*types.Field) {
-		for _, param := range params {
-			var arg ir.Node
-			if param.Nname != nil {
-				name := param.Nname.(*ir.Name)
-				if !ir.IsBlank(name) {
-					if r.inlCall != nil {
-						// During inlining, we want the respective inlvar where we
-						// assigned the callee's arguments.
-						arg = r.inlvars[inlVarIdx]
-					} else {
-						// Otherwise, we can use the parameter itself directly.
-						base.AssertfAt(name.Curfn == r.curfn, name.Pos(), "%v has curfn %v, but want %v", name, name.Curfn, r.curfn)
-						arg = name
-					}
-				}
-			}
-
-			// For anonymous and blank parameters, we don't have an *ir.Name
-			// to use as the argument. However, since we know the shaped
-			// function won't use the value either, we can just pass the
-			// zero value.
-			if arg == nil {
-				arg = ir.NewZero(pos, param.Type)
-			}
-
-			out.Append(arg)
-			inlVarIdx++
-		}
-	}
-
-	addParams(&recvs, sig.Recvs())
-	addParams(&params, sig.Params())
-	return
+	return ir.ToNodes(r.curfn.Dcl[:sig.NumRecvs()+sig.NumParams()])
 }
 
 // syntheticTailCall emits a tail call to fn, passing the given
@@ -1489,105 +1454,32 @@ func (dict *readerDict) varType() *types.Type {
 	return types.NewArray(types.Types[types.TUINTPTR], dict.numWords())
 }
 
-func (r *reader) funcargs(fn *ir.Func) {
-	sig := fn.Nname.Type()
+func (r *reader) declareParams() {
+	r.curfn.DeclareParams(!r.funarghack)
 
-	if recv := sig.Recv(); recv != nil {
-		r.funcarg(recv, recv.Sym, ir.PPARAM)
-	}
-	for _, param := range sig.Params() {
-		r.funcarg(param, param.Sym, ir.PPARAM)
-	}
-
-	for i, param := range sig.Results() {
-		sym := param.Sym
-
-		if sym == nil || sym.IsBlank() {
-			prefix := "~r"
-			if r.inlCall != nil {
-				prefix = "~R"
-			} else if sym != nil {
-				prefix = "~b"
-			}
-			sym = typecheck.LookupNum(prefix, i)
+	for _, name := range r.curfn.Dcl {
+		if name.Sym().Name == dictParamName {
+			r.dictParam = name
+			continue
 		}
 
-		r.funcarg(param, sym, ir.PPARAMOUT)
+		r.addLocal(name)
 	}
 }
 
-func (r *reader) funcarg(param *types.Field, sym *types.Sym, ctxt ir.Class) {
-	if sym == nil {
-		assert(ctxt == ir.PPARAM)
-		if r.inlCall != nil {
-			r.inlvars.Append(ir.BlankNode)
-		}
-		return
-	}
-
-	name := r.addLocal(r.inlPos(param.Pos), sym, ctxt, param.Type)
-
-	if r.inlCall == nil {
-		if !r.funarghack {
-			param.Nname = name
-		}
-	} else {
-		if ctxt == ir.PPARAMOUT {
-			r.retvars.Append(name)
-		} else {
-			r.inlvars.Append(name)
-		}
-	}
-}
-
-func (r *reader) addLocal(pos src.XPos, sym *types.Sym, ctxt ir.Class, typ *types.Type) *ir.Name {
-	assert(ctxt == ir.PAUTO || ctxt == ir.PPARAM || ctxt == ir.PPARAMOUT)
-
-	name := ir.NewNameAt(pos, sym, typ)
-
-	if name.Sym().Name == dictParamName {
-		r.dictParam = name
-	} else {
-		if r.synthetic == nil {
-			r.Sync(pkgbits.SyncAddLocal)
-			if r.p.SyncMarkers() {
-				want := r.Int()
-				if have := len(r.locals); have != want {
-					base.FatalfAt(name.Pos(), "locals table has desynced")
-				}
+func (r *reader) addLocal(name *ir.Name) {
+	if r.synthetic == nil {
+		r.Sync(pkgbits.SyncAddLocal)
+		if r.p.SyncMarkers() {
+			want := r.Int()
+			if have := len(r.locals); have != want {
+				base.FatalfAt(name.Pos(), "locals table has desynced")
 			}
-			r.varDictIndex(name)
 		}
-
-		r.locals = append(r.locals, name)
+		r.varDictIndex(name)
 	}
 
-	name.SetUsed(true)
-
-	// TODO(mdempsky): Move earlier.
-	if ir.IsBlank(name) {
-		return name
-	}
-
-	if r.inlCall != nil {
-		if ctxt == ir.PAUTO {
-			name.SetInlLocal(true)
-		} else {
-			name.SetInlFormal(true)
-			ctxt = ir.PAUTO
-		}
-	}
-
-	name.Class = ctxt
-	name.Curfn = r.curfn
-
-	r.curfn.Dcl = append(r.curfn.Dcl, name)
-
-	if ctxt == ir.PAUTO {
-		name.SetFrameOffset(0)
-	}
-
-	return name
+	r.locals = append(r.locals, name)
 }
 
 func (r *reader) useLocal() *ir.Name {
@@ -1836,7 +1728,8 @@ func (r *reader) assign() (ir.Node, bool) {
 		_, sym := r.localIdent()
 		typ := r.typ()
 
-		name := r.addLocal(pos, sym, ir.PAUTO, typ)
+		name := r.curfn.NewLocal(pos, sym, typ)
+		r.addLocal(name)
 		return name, true
 
 	case assignExpr:
@@ -2076,10 +1969,8 @@ func (r *reader) switchStmt(label *types.Sym) ir.Node {
 		clause.RTypes = rtypes
 
 		if ident != nil {
-			pos := r.pos()
-			typ := r.typ()
-
-			name := r.addLocal(pos, ident.Sym(), ir.PAUTO, typ)
+			name := r.curfn.NewLocal(r.pos(), ident.Sym(), r.typ())
+			r.addLocal(name)
 			clause.Var = name
 			name.Defn = tag
 		}
@@ -2651,14 +2542,11 @@ func (r *reader) curry(origPos src.XPos, ifaceHack bool, fun ir.Node, arg0, arg1
 	typ := types.NewSignature(nil, params, results)
 
 	addBody := func(pos src.XPos, r *reader, captured []ir.Node) {
-		recvs, params := r.syntheticArgs(pos)
-		assert(len(recvs) == 0)
-
 		fun := captured[0]
 
 		var args ir.Nodes
 		args.Append(captured[1:]...)
-		args.Append(params...)
+		args.Append(r.syntheticArgs()...)
 
 		r.syntheticTailCall(pos, fun, args)
 	}
@@ -2689,10 +2577,8 @@ func (r *reader) methodExprWrap(origPos src.XPos, recv *types.Type, implicits []
 	typ := types.NewSignature(nil, params, results)
 
 	addBody := func(pos src.XPos, r *reader, captured []ir.Node) {
-		recvs, args := r.syntheticArgs(pos)
-		assert(len(recvs) == 0)
-
 		fn := captured[0]
+		args := r.syntheticArgs()
 
 		// Rewrite first argument based on implicits/deref/addr.
 		{
@@ -2805,17 +2691,13 @@ func syntheticSig(sig *types.Type) (params, results []*types.Field) {
 	clone := func(params []*types.Field) []*types.Field {
 		res := make([]*types.Field, len(params))
 		for i, param := range params {
-			sym := param.Sym
-			if sym == nil || sym.Name == "_" {
-				sym = typecheck.LookupNum(".anon", i)
-			}
 			// TODO(mdempsky): It would be nice to preserve the original
 			// parameter positions here instead, but at least
 			// typecheck.NewMethodType replaces them with base.Pos, making
 			// them useless. Worse, the positions copied from base.Pos may
 			// have inlining contexts, which we definitely don't want here
 			// (e.g., #54625).
-			res[i] = types.NewField(base.AutogeneratedPos, sym, param.Type)
+			res[i] = types.NewField(base.AutogeneratedPos, param.Sym, param.Type)
 			res[i].SetIsDDD(param.IsDDD())
 		}
 		return res
@@ -3492,6 +3374,7 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 	r.inlFunc = fn
 	r.inlTreeIndex = inlIndex
 	r.inlPosBases = make(map[*src.PosBase]*src.PosBase)
+	r.funarghack = true
 
 	r.closureVars = make([]*ir.Name, len(r.inlFunc.ClosureVars))
 	for i, cv := range r.inlFunc.ClosureVars {
@@ -3506,7 +3389,17 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 		r.dictParam = r.closureVars[len(r.closureVars)-1] // dictParam is last; see reader.funcLit
 	}
 
-	r.funcargs(fn)
+	r.declareParams()
+
+	var inlvars, retvars []*ir.Name
+	{
+		sig := r.curfn.Type()
+		endParams := sig.NumRecvs() + sig.NumParams()
+		endResults := endParams + sig.NumResults()
+
+		inlvars = r.curfn.Dcl[:endParams]
+		retvars = r.curfn.Dcl[endParams:endResults]
+	}
 
 	r.delayResults = fn.Inl.CanDelayResults
 
@@ -3529,15 +3422,14 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 	args.Append(call.Args...)
 
 	// Create assignment to declare and initialize inlvars.
-	as2 := ir.NewAssignListStmt(call.Pos(), ir.OAS2, r.inlvars, args)
+	as2 := ir.NewAssignListStmt(call.Pos(), ir.OAS2, ir.ToNodes(inlvars), args)
 	as2.Def = true
 	var as2init ir.Nodes
-	for _, name := range r.inlvars {
+	for _, name := range inlvars {
 		if ir.IsBlank(name) {
 			continue
 		}
 		// TODO(mdempsky): Use inlined position of name.Pos() instead?
-		name := name.(*ir.Name)
 		as2init.Append(ir.NewDecl(call.Pos(), ir.ODCL, name))
 		name.Defn = as2
 	}
@@ -3547,9 +3439,8 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 	if !r.delayResults {
 		// If not delaying retvars, declare and zero initialize the
 		// result variables now.
-		for _, name := range r.retvars {
+		for _, name := range retvars {
 			// TODO(mdempsky): Use inlined position of name.Pos() instead?
-			name := name.(*ir.Name)
 			init.Append(ir.NewDecl(call.Pos(), ir.ODCL, name))
 			ras := ir.NewAssignStmt(call.Pos(), name, nil)
 			init.Append(typecheck.Stmt(ras))
@@ -3582,7 +3473,7 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 		var edit func(ir.Node) ir.Node
 		edit = func(n ir.Node) ir.Node {
 			if ret, ok := n.(*ir.ReturnStmt); ok {
-				n = typecheck.Stmt(r.inlReturn(ret))
+				n = typecheck.Stmt(r.inlReturn(ret, retvars))
 			}
 			ir.EditChildren(n, edit)
 			return n
@@ -3595,17 +3486,20 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 	// Reparent any declarations into the caller function.
 	for _, name := range r.curfn.Dcl {
 		name.Curfn = callerfn
-		callerfn.Dcl = append(callerfn.Dcl, name)
 
-		if name.AutoTemp() {
-			name.SetEsc(ir.EscUnknown)
+		if name.Class != ir.PAUTO {
+			name.SetPos(r.inlPos(name.Pos()))
+			name.SetInlFormal(true)
+			name.Class = ir.PAUTO
+		} else {
 			name.SetInlLocal(true)
 		}
 	}
+	callerfn.Dcl = append(callerfn.Dcl, r.curfn.Dcl...)
 
 	body.Append(ir.NewLabelStmt(call.Pos(), r.retlabel))
 
-	res := ir.NewInlinedCallExpr(call.Pos(), body, append([]ir.Node(nil), r.retvars...))
+	res := ir.NewInlinedCallExpr(call.Pos(), body, ir.ToNodes(retvars))
 	res.SetInit(init)
 	res.SetType(call.Type())
 	res.SetTypecheck(1)
@@ -3618,20 +3512,19 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 
 // inlReturn returns a statement that can substitute for the given
 // return statement when inlining.
-func (r *reader) inlReturn(ret *ir.ReturnStmt) *ir.BlockStmt {
+func (r *reader) inlReturn(ret *ir.ReturnStmt, retvars []*ir.Name) *ir.BlockStmt {
 	pos := r.inlCall.Pos()
 
 	block := ir.TakeInit(ret)
 
 	if results := ret.Results; len(results) != 0 {
-		assert(len(r.retvars) == len(results))
+		assert(len(retvars) == len(results))
 
-		as2 := ir.NewAssignListStmt(pos, ir.OAS2, append([]ir.Node(nil), r.retvars...), ret.Results)
+		as2 := ir.NewAssignListStmt(pos, ir.OAS2, ir.ToNodes(retvars), ret.Results)
 
 		if r.delayResults {
-			for _, name := range r.retvars {
+			for _, name := range retvars {
 				// TODO(mdempsky): Use inlined position of name.Pos() instead?
-				name := name.(*ir.Name)
 				block.Append(ir.NewDecl(pos, ir.ODCL, name))
 				name.Defn = as2
 			}
@@ -3667,18 +3560,11 @@ func expandInline(fn *ir.Func, pri pkgReaderIndex) {
 		r.funcBody(tmpfn)
 	}
 
-	used := usedLocals(tmpfn.Body)
-
+	// Move tmpfn's params to fn.Inl.Dcl, and reparent under fn.
 	for _, name := range tmpfn.Dcl {
-		if name.Class != ir.PAUTO || used.Has(name) {
-			name.Curfn = fn
-			fn.Inl.Dcl = append(fn.Inl.Dcl, name)
-		} else {
-			// TODO(mdempsky): Simplify code after confident that this never
-			// happens anymore.
-			base.FatalfAt(name.Pos(), "unused auto: %v", name)
-		}
+		name.Curfn = fn
 	}
+	fn.Inl.Dcl = tmpfn.Dcl
 	fn.Inl.HaveDcl = true
 
 	// Double check that we didn't change fn.Dcl by accident.
@@ -3895,19 +3781,9 @@ func newWrapperFunc(pos src.XPos, sym *types.Sym, wrapper *types.Type, method *t
 	sig := newWrapperType(wrapper, method)
 
 	fn := ir.NewFunc(pos, pos, sym, sig)
+	fn.DeclareParams(true)
 	fn.SetDupok(true) // TODO(mdempsky): Leave unset for local, non-generic wrappers?
 
-	// TODO(mdempsky): De-duplicate with similar logic in funcargs.
-	defParams := func(class ir.Class, params []*types.Field) {
-		for _, param := range params {
-			param.Nname = fn.NewLocal(param.Pos, param.Sym, class, param.Type)
-		}
-	}
-
-	defParams(ir.PPARAM, sig.Recvs())
-	defParams(ir.PPARAM, sig.Params())
-	defParams(ir.PPARAMOUT, sig.Results())
-
 	return fn
 }
 
@@ -3946,11 +3822,7 @@ func newWrapperType(recvType *types.Type, method *types.Field) *types.Type {
 	clone := func(params []*types.Field) []*types.Field {
 		res := make([]*types.Field, len(params))
 		for i, param := range params {
-			sym := param.Sym
-			if sym == nil || sym.Name == "_" {
-				sym = typecheck.LookupNum(".anon", i)
-			}
-			res[i] = types.NewField(param.Pos, sym, param.Type)
+			res[i] = types.NewField(param.Pos, param.Sym, param.Type)
 			res[i].SetIsDDD(param.IsDDD())
 		}
 		return res
@@ -3960,7 +3832,7 @@ func newWrapperType(recvType *types.Type, method *types.Field) *types.Type {
 
 	var recv *types.Field
 	if recvType != nil {
-		recv = types.NewField(sig.Recv().Pos, typecheck.Lookup(".this"), recvType)
+		recv = types.NewField(sig.Recv().Pos, sig.Recv().Sym, recvType)
 	}
 	params := clone(sig.Params())
 	results := clone(sig.Results())

src/cmd/compile/internal/noder/writer.go

@@ -1114,7 +1114,7 @@ func (pw *pkgWriter) bodyIdx(sig *types2.Signature, block *syntax.BlockStmt, dic
 	w.sig = sig
 	w.dict = dict
 
-	w.funcargs(sig)
+	w.declareParams(sig)
 	if w.Bool(block != nil) {
 		w.stmts(block.List)
 		w.pos(block.Rbrace)
@@ -1123,24 +1123,18 @@ func (pw *pkgWriter) bodyIdx(sig *types2.Signature, block *syntax.BlockStmt, dic
 	return w.Flush(), w.closureVars
 }
 
-func (w *writer) funcargs(sig *types2.Signature) {
-	do := func(params *types2.Tuple, result bool) {
+func (w *writer) declareParams(sig *types2.Signature) {
+	addLocals := func(params *types2.Tuple) {
 		for i := 0; i < params.Len(); i++ {
-			w.funcarg(params.At(i), result)
+			w.addLocal(params.At(i))
 		}
 	}
 
 	if recv := sig.Recv(); recv != nil {
-		w.funcarg(recv, false)
-	}
-	do(sig.Params(), false)
-	do(sig.Results(), true)
-}
-
-func (w *writer) funcarg(param *types2.Var, result bool) {
-	if param.Name() != "" || result {
-		w.addLocal(param)
+		w.addLocal(recv)
 	}
+	addLocals(sig.Params())
+	addLocals(sig.Results())
 }
 
 // addLocal records the declaration of a new local variable.

src/cmd/compile/internal/reflectdata/alg.go

@@ -156,9 +156,9 @@ func hashFunc(t *types.Type) *ir.Func {
 	sym.Def = fn.Nname
 	fn.Pragma |= ir.Noinline // TODO(mdempsky): We need to emit this during the unified frontend instead, to allow inlining.
 
-	params, _ := typecheck.DeclFunc(fn)
-	np := params[0]
-	nh := params[1]
+	typecheck.DeclFunc(fn)
+	np := fn.Dcl[0]
+	nh := fn.Dcl[1]
 
 	switch t.Kind() {
 	case types.TARRAY:
@@ -382,10 +382,10 @@ func eqFunc(t *types.Type) *ir.Func {
 	sym.Def = fn.Nname
 	fn.Pragma |= ir.Noinline // TODO(mdempsky): We need to emit this during the unified frontend instead, to allow inlining.
 
-	params, results := typecheck.DeclFunc(fn)
-	np := params[0]
-	nq := params[1]
-	nr := results[0]
+	typecheck.DeclFunc(fn)
+	np := fn.Dcl[0]
+	nq := fn.Dcl[1]
+	nr := fn.Dcl[2]
 
 	// Label to jump to if an equality test fails.
 	neq := typecheck.AutoLabel(".neq")

src/cmd/compile/internal/ssa/export_test.go

@@ -55,16 +55,15 @@ type Conf struct {
 
 func (c *Conf) Frontend() Frontend {
 	if c.fe == nil {
-		f := ir.NewFunc(src.NoXPos, src.NoXPos, &types.Sym{
-			Pkg:  types.NewPkg("my/import/path", "path"),
-			Name: "function",
-		}, nil)
-		f.LSym = &obj.LSym{Name: "my/import/path.function"}
+		pkg := types.NewPkg("my/import/path", "path")
+		fn := ir.NewFunc(src.NoXPos, src.NoXPos, pkg.Lookup("function"), types.NewSignature(nil, nil, nil))
+		fn.DeclareParams(true)
+		fn.LSym = &obj.LSym{Name: "my/import/path.function"}
 
 		c.fe = TestFrontend{
 			t:    c.tb,
 			ctxt: c.config.ctxt,
-			f:    f,
+			f:    fn,
 		}
 	}
 	return c.fe

src/cmd/compile/internal/ssagen/abi.go

@@ -249,8 +249,8 @@ func makeABIWrapper(f *ir.Func, wrapperABI obj.ABI) {
 	// Reuse f's types.Sym to create a new ODCLFUNC/function.
 	// TODO(mdempsky): Means we can't set sym.Def in Declfunc, ugh.
 	fn := ir.NewFunc(pos, pos, f.Sym(), types.NewSignature(nil,
-		typecheck.NewFuncParams(ft.Params(), true),
-		typecheck.NewFuncParams(ft.Results(), false)))
+		typecheck.NewFuncParams(ft.Params()),
+		typecheck.NewFuncParams(ft.Results())))
 	fn.ABI = wrapperABI
 	typecheck.DeclFunc(fn)
 

src/cmd/compile/internal/ssagen/ssa.go

@@ -673,7 +673,7 @@ func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
 
 	// Declare variable to hold address.
 	sym := &types.Sym{Name: "&" + n.Sym().Name, Pkg: types.LocalPkg}
-	addr := s.curfn.NewLocal(pos, sym, ir.PAUTO, types.NewPtr(n.Type()))
+	addr := s.curfn.NewLocal(pos, sym, types.NewPtr(n.Type()))
 	addr.SetUsed(true)
 	types.CalcSize(addr.Type())
 
@@ -7928,7 +7928,7 @@ func (e *ssafn) SplitSlot(parent *ssa.LocalSlot, suffix string, offset int64, t
 	}
 
 	sym := &types.Sym{Name: node.Sym().Name + suffix, Pkg: types.LocalPkg}
-	n := e.curfn.NewLocal(parent.N.Pos(), sym, ir.PAUTO, t)
+	n := e.curfn.NewLocal(parent.N.Pos(), sym, t)
 	n.SetUsed(true)
 	n.SetEsc(ir.EscNever)
 	types.CalcSize(t)

src/cmd/compile/internal/typecheck/dcl.go

@@ -16,32 +16,18 @@ import (
 
 var funcStack []*ir.Func // stack of previous values of ir.CurFunc
 
-// DeclFunc creates and returns ONAMEs for the parameters and results
-// of the given function. It also sets ir.CurFunc, and adds fn to
+// DeclFunc declares the parameters for fn and adds it to
 // Target.Funcs.
 //
-// After the caller is done constructing fn, it must call
-// FinishFuncBody.
-func DeclFunc(fn *ir.Func) (params, results []*ir.Name) {
-	typ := fn.Type()
-
-	// Currently, DeclFunc is only used to create normal functions, not
-	// methods. If a use case for creating methods shows up, we can
-	// extend it to support those too.
-	if typ.Recv() != nil {
-		base.FatalfAt(fn.Pos(), "unexpected receiver parameter")
-	}
-
-	params = declareParams(fn, ir.PPARAM, typ.Params())
-	results = declareParams(fn, ir.PPARAMOUT, typ.Results())
-
-	funcStack = append(funcStack, ir.CurFunc)
-	ir.CurFunc = fn
-
+// Before returning, it sets CurFunc to fn. When the caller is done
+// constructing fn, it must call FinishFuncBody to restore CurFunc.
+func DeclFunc(fn *ir.Func) {
+	fn.DeclareParams(true)
 	fn.Nname.Defn = fn
 	Target.Funcs = append(Target.Funcs, fn)
 
-	return
+	funcStack = append(funcStack, ir.CurFunc)
+	ir.CurFunc = fn
 }
 
 // FinishFuncBody restores ir.CurFunc to its state before the last
@@ -56,65 +42,29 @@ func CheckFuncStack() {
 	}
 }
 
-func declareParams(fn *ir.Func, ctxt ir.Class, params []*types.Field) []*ir.Name {
-	names := make([]*ir.Name, len(params))
-	for i, param := range params {
-		names[i] = declareParam(fn, ctxt, i, param)
-	}
-	return names
-}
-
-func declareParam(fn *ir.Func, ctxt ir.Class, i int, param *types.Field) *ir.Name {
-	sym := param.Sym
-	if ctxt == ir.PPARAMOUT {
-		if sym == nil {
-			// Name so that escape analysis can track it. ~r stands for 'result'.
-			sym = LookupNum("~r", i)
-		} else if sym.IsBlank() {
-			// Give it a name so we can assign to it during return. ~b stands for 'blank'.
-			// The name must be different from ~r above because if you have
-			//	func f() (_ int)
-			//	func g() int
-			// f is allowed to use a plain 'return' with no arguments, while g is not.
-			// So the two cases must be distinguished.
-			sym = LookupNum("~b", i)
-		}
-	}
-
-	if sym == nil {
-		return nil
-	}
-
-	name := fn.NewLocal(param.Pos, sym, ctxt, param.Type)
-	param.Nname = name
-	return name
-}
-
 // make a new Node off the books.
-func TempAt(pos src.XPos, curfn *ir.Func, t *types.Type) *ir.Name {
+func TempAt(pos src.XPos, curfn *ir.Func, typ *types.Type) *ir.Name {
 	if curfn == nil {
-		base.Fatalf("no curfn for TempAt")
+		base.FatalfAt(pos, "no curfn for TempAt")
 	}
-	if t == nil {
-		base.Fatalf("TempAt called with nil type")
+	if typ == nil {
+		base.FatalfAt(pos, "TempAt called with nil type")
 	}
-	if t.Kind() == types.TFUNC && t.Recv() != nil {
-		base.Fatalf("misuse of method type: %v", t)
+	if typ.Kind() == types.TFUNC && typ.Recv() != nil {
+		base.FatalfAt(pos, "misuse of method type: %v", typ)
 	}
+	types.CalcSize(typ)
 
-	s := &types.Sym{
+	sym := &types.Sym{
 		Name: autotmpname(len(curfn.Dcl)),
 		Pkg:  types.LocalPkg,
 	}
-	n := curfn.NewLocal(pos, s, ir.PAUTO, t)
-	s.Def = n // TODO(mdempsky): Should be unnecessary.
-	n.SetEsc(ir.EscNever)
-	n.SetUsed(true)
-	n.SetAutoTemp(true)
+	name := curfn.NewLocal(pos, sym, typ)
+	name.SetEsc(ir.EscNever)
+	name.SetUsed(true)
+	name.SetAutoTemp(true)
 
-	types.CalcSize(t)
-
-	return n
+	return name
 }
 
 var (

src/cmd/compile/internal/typecheck/stmt.go

@@ -224,6 +224,7 @@ func tcGoDefer(n *ir.GoDeferStmt) {
 
 	// Create a new wrapper function without parameters or results.
 	wrapperFn := ir.NewClosureFunc(n.Pos(), n.Pos(), n.Op(), types.NewSignature(nil, nil, nil), ir.CurFunc, Target)
+	wrapperFn.DeclareParams(true)
 	wrapperFn.SetWrapper(true)
 
 	// argps collects the list of operands within the call expression

src/cmd/compile/internal/typecheck/subr.go

@@ -26,18 +26,10 @@ func LookupNum(prefix string, n int) *types.Sym {
 }
 
 // Given funarg struct list, return list of fn args.
-func NewFuncParams(origs []*types.Field, mustname bool) []*types.Field {
+func NewFuncParams(origs []*types.Field) []*types.Field {
 	res := make([]*types.Field, len(origs))
 	for i, orig := range origs {
-		s := orig.Sym
-		if mustname && (s == nil || s.Name == "_") {
-			// invent a name so that we can refer to it in the trampoline
-			s = LookupNum(".anon", i)
-		} else if s != nil && s.Pkg != types.LocalPkg {
-			// TODO(mdempsky): Preserve original position, name, and package.
-			s = Lookup(s.Name)
-		}
-		p := types.NewField(orig.Pos, s, orig.Type)
+		p := types.NewField(orig.Pos, orig.Sym, orig.Type)
 		p.SetIsDDD(orig.IsDDD())
 		res[i] = p
 	}

test/live_uintptrkeepalive.go

@@ -1,5 +1,6 @@
 // errorcheck -0 -m -live -std
 
+//go:build !windows && !js && !wasip1
 // +build !windows,!js,!wasip1
 
 // Copyright 2015 The Go Authors. All rights reserved.
@@ -22,7 +23,7 @@ import (
 	"unsafe"
 )
 
-func implicit(uintptr) // ERROR "assuming arg#1 is unsafe uintptr"
+func implicit(uintptr) // ERROR "assuming ~p0 is unsafe uintptr"
 
 //go:uintptrkeepalive
 //go:nosplit
@@ -47,13 +48,13 @@ func autotmpSyscall() { // ERROR "can inline autotmpSyscall"
 func localImplicit() { // ERROR "can inline localImplicit"
 	var t int
 	p := unsafe.Pointer(&t)
-	implicit(uintptr(p))           // ERROR "live at call to implicit: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
+	implicit(uintptr(p)) // ERROR "live at call to implicit: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
 }
 
 func localExplicit() { // ERROR "can inline localExplicit"
 	var t int
 	p := unsafe.Pointer(&t)
-	explicit(uintptr(p))           // ERROR "live at call to explicit: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
+	explicit(uintptr(p)) // ERROR "live at call to explicit: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
 }
 
 func localSyscall() { // ERROR "can inline localSyscall"