cmd/compile/internal/syntax: replace inlined statement lists with syntax.BlockStmt

This simplifies the code and removes a premature optimization.
It increases the amount of allocated syntax.Node space by ~0.4%
for parsing all of std lib, which is negligible.

Before the change (best of 5 runs):

  $ go test -run StdLib -fast
  parsed 1517022 lines (3394 files) in 793.487886ms (1911840 lines/s)
  allocated 387.086Mb (267B/line, 487.828Mb/s)

After the change (best of 5 runs):

  $ go test -run StdLib -fast
  parsed 1516911 lines (3392 files) in 805.028655ms (1884294 lines/s)
  allocated 388.466Mb (268B/line, 482.549Mb/s)

Change-Id: Id19d6210fdc62393862ba3b04913352d95c599be
Reviewed-on: https://go-review.googlesource.com/38439
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

1 files changed, 12 insertions, 20 deletions

diff --git a/src/cmd/compile/internal/syntax/printer.go b/src/cmd/compile/internal/syntax/printer.go
index 43876a25c2..426921199e 100644
--- a/src/cmd/compile/internal/syntax/printer.go
+++ b/src/cmd/compile/internal/syntax/printer.go
@@ -349,8 +349,7 @@ func (p *printer) printRawNode(n Node) {
 		p.print(_Name, n.Value) // _Name requires actual value following immediately
 
 	case *FuncLit:
-		p.print(n.Type, blank)
-		p.printBody(n.Body)
+		p.print(n.Type, blank, n.Body)
 
 	case *CompositeLit:
 		if n.Type != nil {
@@ -524,15 +523,20 @@ func (p *printer) printRawNode(n Node) {
 		}
 
 	case *BlockStmt:
-		p.printBody(n.Body)
+		p.print(_Lbrace)
+		if len(n.List) > 0 {
+			p.print(newline, indent)
+			p.printStmtList(n.List, true)
+			p.print(outdent, newline)
+		}
+		p.print(_Rbrace)
 
 	case *IfStmt:
 		p.print(_If, blank)
 		if n.Init != nil {
 			p.print(n.Init, _Semi, blank)
 		}
-		p.print(n.Cond, blank)
-		p.printBody(n.Then)
+		p.print(n.Cond, blank, n.Then)
 		if n.Else != nil {
 			p.print(blank, _Else, blank, n.Else)
 		}
@@ -578,8 +582,7 @@ func (p *printer) printRawNode(n Node) {
 				p.print(n.Init)
 				// TODO(gri) clean this up
 				if _, ok := n.Init.(*RangeClause); ok {
-					p.print(blank)
-					p.printBody(n.Body)
+					p.print(blank, n.Body)
 					break
 				}
 			}
@@ -592,7 +595,7 @@ func (p *printer) printRawNode(n Node) {
 				p.print(n.Post, blank)
 			}
 		}
-		p.printBody(n.Body)
+		p.print(n.Body)
 
 	case *ImportDecl:
 		if n.Group == nil {
@@ -650,8 +653,7 @@ func (p *printer) printRawNode(n Node) {
 		p.print(n.Name)
 		p.printSignature(n.Type)
 		if n.Body != nil {
-			p.print(blank)
-			p.printBody(n.Body)
+			p.print(blank, n.Body)
 		}
 
 	case *printGroup:
@@ -882,16 +884,6 @@ func (p *printer) printStmtList(list []Stmt, braces bool) {
 	}
 }
 
-func (p *printer) printBody(list []Stmt) {
-	p.print(_Lbrace)
-	if len(list) > 0 {
-		p.print(newline, indent)
-		p.printStmtList(list, true)
-		p.print(outdent, newline)
-	}
-	p.print(_Rbrace)
-}
-
 func (p *printer) printSwitchBody(list []*CaseClause) {
 	p.print(_Lbrace)
 	if len(list) > 0 {