cmd/compile/internal/gc: preallocate slices in noder

The slice capacity is known for all these cases. Therefore, we can initialize them with the desired capacity. Change-Id: I1835b49108d157203d62e4aa119c2d7ab5e5e46f Reviewed-on: https://go-review.googlesource.com/c/go/+/200119 Run-TryBot: Matthew Dempsky <[email protected]> Reviewed-by: Brad Fitzpatrick <[email protected]> Reviewed-by: Matthew Dempsky <[email protected]> TryBot-Result: Gobot Gobot <[email protected]>
cloudflare · Oct 11, 2019 · 33fac9b · 33fac9b
1 parent 0e3e46f
commit 33fac9b
Showing 1 changed file with 9 additions and 9 deletions.
diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
@@ -25,7 +25,7 @@ import (
 // and its root represented by *Node is appended to xtop.
 // Returns the total count of parsed lines.
 func parseFiles(filenames []string) uint {
- var noders []*noder
+ noders := make([]*noder, 0, len(filenames))
  // Limit the number of simultaneously open files.
  sem := make(chan struct{}, runtime.GOMAXPROCS(0)+10)
 
@@ -398,7 +398,7 @@ func (p *noder) constDecl(decl *syntax.ConstDecl, cs *constState) []*Node {
  typ, values = cs.typ, cs.values
  }
 
- var nn []*Node
+ nn := make([]*Node, 0, len(names))
  for i, n := range names {
  if i >= len(values) {
  yyerror("missing value in const declaration")
@@ -453,7 +453,7 @@ func (p *noder) typeDecl(decl *syntax.TypeDecl) *Node {
 }
 
 func (p *noder) declNames(names []*syntax.Name) []*Node {
- var nodes []*Node
+ nodes := make([]*Node, 0, len(names))
  for _, name := range names {
  nodes = append(nodes, p.declName(name))
  }
@@ -540,7 +540,7 @@ func (p *noder) signature(recv *syntax.Field, typ *syntax.FuncType) *Node {
 }
 
 func (p *noder) params(params []*syntax.Field, dddOk bool) []*Node {
- var nodes []*Node
+ nodes := make([]*Node, 0, len(params))
  for i, param := range params {
  p.setlineno(param)
  nodes = append(nodes, p.param(param, dddOk, i+1 == len(params)))
@@ -590,7 +590,7 @@ func (p *noder) exprList(expr syntax.Expr) []*Node {
 }
 
 func (p *noder) exprs(exprs []syntax.Expr) []*Node {
- var nodes []*Node
+ nodes := make([]*Node, 0, len(exprs))
  for _, expr := range exprs {
  nodes = append(nodes, p.expr(expr))
  }
@@ -809,7 +809,7 @@ func (p *noder) chanDir(dir syntax.ChanDir) types.ChanDir {
 }
 
 func (p *noder) structType(expr *syntax.StructType) *Node {
- var l []*Node
+ l := make([]*Node, 0, len(expr.FieldList))
  for i, field := range expr.FieldList {
  p.setlineno(field)
  var n *Node
@@ -831,7 +831,7 @@ func (p *noder) structType(expr *syntax.StructType) *Node {
 }
 
 func (p *noder) interfaceType(expr *syntax.InterfaceType) *Node {
- var l []*Node
+ l := make([]*Node, 0, len(expr.MethodList))
  for _, method := range expr.MethodList {
  p.setlineno(method)
  var n *Node
@@ -1170,7 +1170,7 @@ func (p *noder) switchStmt(stmt *syntax.SwitchStmt) *Node {
 }
 
 func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *Node, rbrace syntax.Pos) []*Node {
- var nodes []*Node
+ nodes := make([]*Node, 0, len(clauses))
  for i, clause := range clauses {
  p.setlineno(clause)
  if i > 0 {
@@ -1226,7 +1226,7 @@ func (p *noder) selectStmt(stmt *syntax.SelectStmt) *Node {
 }
 
 func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []*Node {
- var nodes []*Node
+ nodes := make([]*Node, 0, len(clauses))
  for i, clause := range clauses {
  p.setlineno(clause)
  if i > 0 {