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authorIan Lance Taylor <iant@google.com>2015-01-15 00:27:56 +0000
committerIan Lance Taylor <ian@gcc.gnu.org>2015-01-15 00:27:56 +0000
commitf8d9fa9e80b57f89e7877ce6cad8a3464879009b (patch)
tree58a1724fee16d2b03c65678c4dd9b50bb97137a9 /libgo/go/regexp/syntax/parse.go
parent6bd3f109d8d8fa58eeccd6b3504721b4f20c00c2 (diff)
libgo, compiler: Upgrade libgo to Go 1.4, except for runtime.
This upgrades all of libgo other than the runtime package to the Go 1.4 release. In Go 1.4 much of the runtime was rewritten into Go. Merging that code will take more time and will not change the API, so I'm putting it off for now. There are a few runtime changes anyhow, to accomodate other packages that rely on minor modifications to the runtime support. The compiler changes slightly to add a one-bit flag to each type descriptor kind that is stored directly in an interface, which for gccgo is currently only pointer types. Another one-bit flag (gcprog) is reserved because it is used by the gc compiler, but gccgo does not currently use it. There is another error check in the compiler since I ran across it during testing. gotools/: * Makefile.am (go_cmd_go_files): Sort entries. Add generate.go. * Makefile.in: Rebuild. From-SVN: r219627
Diffstat (limited to 'libgo/go/regexp/syntax/parse.go')
-rw-r--r--libgo/go/regexp/syntax/parse.go41
1 files changed, 40 insertions, 1 deletions
diff --git a/libgo/go/regexp/syntax/parse.go b/libgo/go/regexp/syntax/parse.go
index cb25dca3956..d579a4069b1 100644
--- a/libgo/go/regexp/syntax/parse.go
+++ b/libgo/go/regexp/syntax/parse.go
@@ -244,6 +244,7 @@ func (p *parser) repeat(op Op, min, max int, before, after, lastRepeat string) (
if sub.Op >= opPseudo {
return "", &Error{ErrMissingRepeatArgument, before[:len(before)-len(after)]}
}
+
re := p.newRegexp(op)
re.Min = min
re.Max = max
@@ -251,9 +252,47 @@ func (p *parser) repeat(op Op, min, max int, before, after, lastRepeat string) (
re.Sub = re.Sub0[:1]
re.Sub[0] = sub
p.stack[n-1] = re
+
+ if op == OpRepeat && (min >= 2 || max >= 2) && !repeatIsValid(re, 1000) {
+ return "", &Error{ErrInvalidRepeatSize, before[:len(before)-len(after)]}
+ }
+
return after, nil
}
+// repeatIsValid reports whether the repetition re is valid.
+// Valid means that the combination of the top-level repetition
+// and any inner repetitions does not exceed n copies of the
+// innermost thing.
+// This function rewalks the regexp tree and is called for every repetition,
+// so we have to worry about inducing quadratic behavior in the parser.
+// We avoid this by only calling repeatIsValid when min or max >= 2.
+// In that case the depth of any >= 2 nesting can only get to 9 without
+// triggering a parse error, so each subtree can only be rewalked 9 times.
+func repeatIsValid(re *Regexp, n int) bool {
+ if re.Op == OpRepeat {
+ m := re.Max
+ if m == 0 {
+ return true
+ }
+ if m < 0 {
+ m = re.Min
+ }
+ if m > n {
+ return false
+ }
+ if m > 0 {
+ n /= m
+ }
+ }
+ for _, sub := range re.Sub {
+ if !repeatIsValid(sub, n) {
+ return false
+ }
+ }
+ return true
+}
+
// concat replaces the top of the stack (above the topmost '|' or '(') with its concatenation.
func (p *parser) concat() *Regexp {
p.maybeConcat(-1, 0)
@@ -1639,7 +1678,7 @@ const (
// minimum and maximum runes involved in folding.
// checked during test.
minFold = 0x0041
- maxFold = 0x1044f
+ maxFold = 0x118df
)
// appendFoldedRange returns the result of appending the range lo-hi