test/run: make errorcheck tests faster

Some of the errorcheck tests have many many identical regexps.
Use a map to avoid storing the compiled form many many times
in memory. Change the filterRe to a simple string to avoid
the expense of those regexps as well.

Cuts the time for run.go on index2.go by almost 50x.

Noticed during debugging of issue 7344.

LGTM=bradfitz
R=bradfitz, josharian
CC=golang-codereviews
https://golang.org/cl/74380043

diff --git a/test/run.go b/test/run.go
index c6775c01501ce150a7b9e46f5d7bcb7a5ff5ad13..c96e37dba00654ebbf6eadd92af7c7d9cdec7d25 100644 (file)
--- a/test/run.go
+++ b/test/run.go
@@ -760,7 +760,7 @@ func (t *test) errorCheck(outStr string, fullshort ...string) (err error) {
 
        for _, we := range want {
                var errmsgs []string
-               errmsgs, out = partitionStrings(we.filterRe, out)
+               errmsgs, out = partitionStrings(we.prefix, out)
                if len(errmsgs) == 0 {
                        errs = append(errs, fmt.Errorf("%s:%d: missing error %q", we.file, we.lineNum, we.reStr))
                        continue
@@ -802,9 +802,29 @@ func (t *test) errorCheck(outStr string, fullshort ...string) (err error) {
 
 }
 
-func partitionStrings(rx *regexp.Regexp, strs []string) (matched, unmatched []string) {
+// matchPrefix reports whether s is of the form ^(.*/)?prefix(:|[),
+// That is, it needs the file name prefix followed by a : or a [,
+// and possibly preceded by a directory name.
+func matchPrefix(s, prefix string) bool {
+       i := strings.Index(s, ":")
+       if i < 0 {
+               return false
+       }
+       j := strings.LastIndex(s[:i], "/")
+       s = s[j+1:]
+       if len(s) <= len(prefix) || s[:len(prefix)] != prefix {
+               return false
+       }
+       switch s[len(prefix)] {
+       case '[', ':':
+               return true
+       }
+       return false
+}
+
+func partitionStrings(prefix string, strs []string) (matched, unmatched []string) {
        for _, s := range strs {
-               if rx.MatchString(s) {
+               if matchPrefix(s, prefix) {
                        matched = append(matched, s)
                } else {
                        unmatched = append(unmatched, s)
@@ -818,7 +838,7 @@ type wantedError struct {
        re       *regexp.Regexp
        lineNum  int
        file     string
-       filterRe *regexp.Regexp // /^file:linenum\b/m
+       prefix string
 }
 
 var (
@@ -828,6 +848,8 @@ var (
 )
 
 func (t *test) wantedErrors(file, short string) (errs []wantedError) {
+       cache := make(map[string]*regexp.Regexp)
+
        src, _ := ioutil.ReadFile(file)
        for i, line := range strings.Split(string(src), "\n") {
                lineNum := i + 1
@@ -856,15 +878,20 @@ func (t *test) wantedErrors(file, short string) (errs []wantedError) {
                                }
                                return fmt.Sprintf("%s:%d", short, n)
                        })
-                       re, err := regexp.Compile(rx)
-                       if err != nil {
-                               log.Fatalf("%s:%d: invalid regexp in ERROR line: %v", t.goFileName(), lineNum, err)
+                       re := cache[rx]
+                       if re == nil {
+                               var err error
+                               re, err = regexp.Compile(rx)
+                               if err != nil {
+                                       log.Fatalf("%s:%d: invalid regexp in ERROR line: %v", t.goFileName(), lineNum, err)
+                               }
+                               cache[rx] = re
                        }
-                       filterPattern := fmt.Sprintf(`^(\w+/)?%s:%d[:[]`, regexp.QuoteMeta(short), lineNum)
+                       prefix := fmt.Sprintf("%s:%d", short, lineNum)
                        errs = append(errs, wantedError{
                                reStr:    rx,
                                re:       re,
-                               filterRe: regexp.MustCompile(filterPattern),
+                               prefix: prefix,
                                lineNum:  lineNum,
                                file:     short,
                        })