cmd/compile: directly construct Fields instead of ODCLFIELD nodes

Avoids some garbage allocations while loading import data. Seems to
especially benefit html/template for some reason, but significant
allocation improvements for other packages too.

name       old time/op     new time/op     delta
Template       345ms ± 6%      332ms ± 6%   -3.76%        (p=0.000 n=49+47)
Unicode        185ms ±10%      184ms ±12%     ~           (p=0.401 n=50+49)
GoTypes        1.04s ± 3%      1.04s ± 3%   -0.72%        (p=0.012 n=48+47)
Compiler       4.52s ± 7%      4.49s ± 9%     ~           (p=0.465 n=48+47)

name       old user-ns/op  new user-ns/op  delta
Template        532M ±17%       471M ±23%  -11.48%        (p=0.000 n=50+50)
Unicode         298M ±29%       311M ±28%     ~           (p=0.065 n=50+50)
GoTypes        1.52G ± 7%      1.54G ± 9%     ~           (p=0.062 n=49+50)
Compiler       6.37G ± 7%      6.42G ± 8%     ~           (p=0.157 n=49+48)

name       old alloc/op    new alloc/op    delta
Template      43.9MB ± 0%     42.3MB ± 0%   -3.51%        (p=0.000 n=48+48)
Unicode       34.3MB ± 0%     34.3MB ± 0%     ~           (p=0.945 n=50+50)
GoTypes        123MB ± 0%      122MB ± 0%   -0.82%        (p=0.000 n=50+50)
Compiler       522MB ± 0%      519MB ± 0%   -0.51%        (p=0.000 n=50+50)

name       old allocs/op   new allocs/op   delta
Template        414k ± 0%       397k ± 0%   -4.14%        (p=0.000 n=50+49)
Unicode         320k ± 0%       320k ± 0%     ~           (p=0.988 n=48+49)
GoTypes        1.18M ± 0%      1.17M ± 0%   -0.97%        (p=0.000 n=50+50)
Compiler       4.44M ± 0%      4.41M ± 0%   -0.66%        (p=0.000 n=50+50)

Passes toolstash.

Change-Id: I0f54c0fa420d4f4ed3584c47cec0dde100c70c03
Reviewed-on: https://go-review.googlesource.com/31670
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

src/cmd/compile/internal/gc/bimport.go

@@ -330,7 +330,7 @@ func (p *importer) obj(tag int) {
 		params := p.paramList()
 		result := p.paramList()
 
-		sig := functype(nil, params, result)
+		sig := functypefield(nil, params, result)
 		importsym(sym, ONAME)
 		if sym.Def != nil && sym.Def.Op == ONAME {
 			// function was imported before (via another import)
@@ -465,8 +465,15 @@ func (p *importer) typ() *Type {
 			result := p.paramList()
 			nointerface := p.bool()
 
-			n := methodname(newname(sym), recv[0].Right)
-			n.Type = functype(recv[0], params, result)
+			base := recv[0].Type
+			star := false
+			if base.IsPtr() {
+				base = base.Elem()
+				star = true
+			}
+
+			n := methodname0(sym, star, base.Sym)
+			n.Type = functypefield(recv[0], params, result)
 			checkwidth(n.Type)
 			addmethod(sym, n.Type, false, nointerface)
 			p.funcList = append(p.funcList, n)
@@ -506,7 +513,8 @@ func (p *importer) typ() *Type {
 
 	case structTag:
 		t = p.newtyp(TSTRUCT)
-		tostruct0(t, p.fieldList())
+		t.SetFields(p.fieldList())
+		checkwidth(t)
 
 	case pointerTag:
 		t = p.newtyp(Tptr)
@@ -516,14 +524,15 @@ func (p *importer) typ() *Type {
 		t = p.newtyp(TFUNC)
 		params := p.paramList()
 		result := p.paramList()
-		functype0(t, nil, params, result)
+		functypefield0(t, nil, params, result)
 
 	case interfaceTag:
 		t = p.newtyp(TINTER)
 		if p.int() != 0 {
 			formatErrorf("unexpected embedded interface")
 		}
-		tointerface0(t, p.methodList())
+		t.SetFields(p.methodList())
+		checkwidth(t)
 
 	case mapTag:
 		t = p.newtyp(TMAP)
@@ -555,9 +564,9 @@ func (p *importer) qualifiedName() *Sym {
 }
 
 // parser.go:hidden_structdcl_list
-func (p *importer) fieldList() (fields []*Node) {
+func (p *importer) fieldList() (fields []*Field) {
 	if n := p.int(); n > 0 {
-		fields = make([]*Node, n)
+		fields = make([]*Field, n)
 		for i := range fields {
 			fields[i] = p.field()
 		}
@@ -566,37 +575,35 @@ func (p *importer) fieldList() (fields []*Node) {
 }
 
 // parser.go:hidden_structdcl
-func (p *importer) field() *Node {
+func (p *importer) field() *Field {
 	p.pos()
 	sym := p.fieldName()
 	typ := p.typ()
 	note := p.string()
 
-	var n *Node
-	if sym.Name != "" {
-		n = nod(ODCLFIELD, newname(sym), typenod(typ))
-	} else {
+	f := newField()
+	if sym.Name == "" {
 		// anonymous field - typ must be T or *T and T must be a type name
 		s := typ.Sym
 		if s == nil && typ.IsPtr() {
 			s = typ.Elem().Sym // deref
 		}
-		pkg := importpkg
-		if sym != nil {
-			pkg = sym.Pkg
-		}
-		n = embedded(s, pkg)
-		n.Right = typenod(typ)
+		sym = sym.Pkg.Lookup(s.Name)
+		f.Embedded = 1
 	}
-	n.SetVal(Val{U: note})
 
-	return n
+	f.Sym = sym
+	f.Nname = newname(sym)
+	f.Type = typ
+	f.Note = note
+
+	return f
 }
 
 // parser.go:hidden_interfacedcl_list
-func (p *importer) methodList() (methods []*Node) {
+func (p *importer) methodList() (methods []*Field) {
 	if n := p.int(); n > 0 {
-		methods = make([]*Node, n)
+		methods = make([]*Field, n)
 		for i := range methods {
 			methods[i] = p.method()
 		}
@@ -605,12 +612,17 @@ func (p *importer) methodList() (methods []*Node) {
 }
 
 // parser.go:hidden_interfacedcl
-func (p *importer) method() *Node {
+func (p *importer) method() *Field {
 	p.pos()
 	sym := p.fieldName()
 	params := p.paramList()
 	result := p.paramList()
-	return nod(ODCLFIELD, newname(sym), typenod(functype(fakethis(), params, result)))
+
+	f := newField()
+	f.Sym = sym
+	f.Nname = newname(sym)
+	f.Type = functypefield(fakethisfield(), params, result)
+	return f
 }
 
 // parser.go:sym,hidden_importsym
@@ -632,7 +644,7 @@ func (p *importer) fieldName() *Sym {
 }
 
 // parser.go:ohidden_funarg_list
-func (p *importer) paramList() []*Node {
+func (p *importer) paramList() []*Field {
 	i := p.int()
 	if i == 0 {
 		return nil
@@ -644,27 +656,23 @@ func (p *importer) paramList() []*Node {
 		named = false
 	}
 	// i > 0
-	n := make([]*Node, i)
-	for i := range n {
-		n[i] = p.param(named)
+	fs := make([]*Field, i)
+	for i := range fs {
+		fs[i] = p.param(named)
 	}
-	return n
+	return fs
 }
 
 // parser.go:hidden_funarg
-func (p *importer) param(named bool) *Node {
-	typ := p.typ()
-
-	isddd := false
-	if typ.Etype == TDDDFIELD {
+func (p *importer) param(named bool) *Field {
+	f := newField()
+	f.Type = p.typ()
+	if f.Type.Etype == TDDDFIELD {
 		// TDDDFIELD indicates wrapped ... slice type
-		typ = typSlice(typ.DDDField())
-		isddd = true
+		f.Type = typSlice(f.Type.DDDField())
+		f.Isddd = true
 	}
 
-	n := nod(ODCLFIELD, nil, typenod(typ))
-	n.Isddd = isddd
-
 	if named {
 		name := p.string()
 		if name == "" {
@@ -676,14 +684,15 @@ func (p *importer) param(named bool) *Node {
 		if name != "_" {
 			pkg = p.pkg()
 		}
-		n.Left = newname(pkg.Lookup(name))
+		f.Sym = pkg.Lookup(name)
+		f.Nname = newname(f.Sym)
 	}
 
 	// TODO(gri) This is compiler-specific (escape info).
 	// Move into compiler-specific section eventually?
-	n.SetVal(Val{U: p.string()})
+	f.Note = p.string()
 
-	return n
+	return f
 }
 
 func (p *importer) value(typ *Type) (x Val) {

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

@@ -853,6 +853,22 @@ func tofunargs(l []*Node, funarg Funarg) *Type {
 	return t
 }
 
+func tofunargsfield(fields []*Field, funarg Funarg) *Type {
+	t := typ(TSTRUCT)
+	t.StructType().Funarg = funarg
+
+	for _, f := range fields {
+		f.Funarg = funarg
+
+		// esc.go needs to find f given a PPARAM to add the tag.
+		if f.Nname != nil && f.Nname.Class == PPARAM {
+			f.Nname.Name.Param.Field = f
+		}
+	}
+	t.SetFields(fields)
+	return t
+}
+
 func interfacefield(n *Node) *Field {
 	lno := lineno
 	lineno = n.Lineno
@@ -994,6 +1010,12 @@ func fakethis() *Node {
 	return n
 }
 
+func fakethisfield() *Field {
+	f := newField()
+	f.Type = ptrto(typ(TSTRUCT))
+	return f
+}
+
 // Is this field a method on an interface?
 // Those methods have an anonymous *struct{} as the receiver.
 // (See fakethis above.)
@@ -1048,6 +1070,30 @@ func functype0(t *Type, this *Node, in, out []*Node) {
 	}
 }
 
+func functypefield(this *Field, in, out []*Field) *Type {
+	t := typ(TFUNC)
+	functypefield0(t, this, in, out)
+	return t
+}
+
+func functypefield0(t *Type, this *Field, in, out []*Field) {
+	var rcvr []*Field
+	if this != nil {
+		rcvr = []*Field{this}
+	}
+	t.FuncType().Receiver = tofunargsfield(rcvr, FunargRcvr)
+	t.FuncType().Results = tofunargsfield(out, FunargRcvr)
+	t.FuncType().Params = tofunargsfield(in, FunargRcvr)
+
+	t.FuncType().Outnamed = false
+	if len(out) > 0 && out[0].Nname != nil && out[0].Nname.Orig != nil {
+		s := out[0].Nname.Orig.Sym
+		if s != nil && (s.Name[0] != '~' || s.Name[1] != 'r') { // ~r%d is the name invented for an unnamed result
+			t.FuncType().Outnamed = true
+		}
+	}
+}
+
 var methodsym_toppkg *Pkg
 
 func methodsym(nsym *Sym, t0 *Type, iface int) *Sym {
@@ -1119,30 +1165,34 @@ bad:
 }
 
 func methodname(n *Node, t *Node) *Node {
-	star := ""
+	star := false
 	if t.Op == OIND {
-		star = "*"
+		star = true
 		t = t.Left
 	}
 
-	if t.Sym == nil || isblank(n) {
-		return newfuncname(n.Sym)
+	return methodname0(n.Sym, star, t.Sym)
+}
+
+func methodname0(s *Sym, star bool, tsym *Sym) *Node {
+	if tsym == nil || isblanksym(s) {
+		return newfuncname(s)
 	}
 
 	var p string
-	if star != "" {
-		p = fmt.Sprintf("(%s%v).%v", star, t.Sym, n.Sym)
+	if star {
+		p = fmt.Sprintf("(*%v).%v", tsym, s)
 	} else {
-		p = fmt.Sprintf("%v.%v", t.Sym, n.Sym)
+		p = fmt.Sprintf("%v.%v", tsym, s)
 	}
 
-	if exportname(t.Sym.Name) {
-		n = newfuncname(lookup(p))
+	if exportname(tsym.Name) {
+		s = lookup(p)
 	} else {
-		n = newfuncname(Pkglookup(p, t.Sym.Pkg))
+		s = Pkglookup(p, tsym.Pkg)
 	}
 
-	return n
+	return newfuncname(s)
 }
 
 // Add a method, declared as a function.
@@ -1208,9 +1258,6 @@ func addmethod(msym *Sym, t *Type, local, nointerface bool) {
 		}
 	}
 
-	n := nod(ODCLFIELD, newname(msym), nil)
-	n.Type = t
-
 	for _, f := range mt.Methods().Slice() {
 		if msym.Name != f.Sym.Name {
 			continue
@@ -1223,7 +1270,10 @@ func addmethod(msym *Sym, t *Type, local, nointerface bool) {
 		return
 	}
 
-	f := structfield(n)
+	f := newField()
+	f.Sym = msym
+	f.Nname = newname(msym)
+	f.Type = t
 	f.Nointerface = nointerface
 
 	mt.Methods().Append(f)