cmd/go: delay parsing the testmain template

The template is over a hundred lines and full of pipelines, and text/template isn't optimised to parse quickly, so it's no wonder that delaying the parsing to the first template use makes 'go env' much faster. Like in the previous patches to get rid of global regexp.MustCompile vars, use the newly introduced lazytemplate package. Close to two full milliseconds are shaved off of 'go env' runs. name old time/op new time/op delta ExecGoEnv-8 4.27ms ± 0% 2.63ms ± 1% -38.43% (p=0.002 n=6+6) Updates #29382. Change-Id: I4e2569e51ddf2afe1b46eb1a9e9e5845f7a3b0bd Reviewed-on: https://go-review.googlesource.com/c/155962 Run-TryBot: Daniel Martí <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Brad Fitzpatrick <[email protected]>
golang · Feb 28, 2019 · 6a72dd7 · 6a72dd7
1 parent 61170f8
commit 6a72dd7
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
@@ -15,10 +15,10 @@ import (
 	"go/doc"
 	"go/parser"
 	"go/token"
+	"internal/lazytemplate"
 	"path/filepath"
 	"sort"
 	"strings"
-	"text/template"
 	"unicode"
 	"unicode/utf8"
 )
@@ -556,7 +556,7 @@ func checkTestFunc(fn *ast.FuncDecl, arg string) error {
 	return nil
 }
 
-var testmainTmpl = template.Must(template.New("main").Parse(`
+var testmainTmpl = lazytemplate.New("main", `
 package main
 
 import (
@@ -657,4 +657,4 @@ func main() {
 {{end}}
 }
 
-`))
+`)