commit a98fad02c421896bc75d97f49ccd245cdce7dd55
author Paul Wankadia <junyer@google.com> Tue Apr 09 06:23:02 2019 -0700
committer Paul Wankadia <junyer@google.com> Tue Apr 09 13:26:12 2019 +0000
tree 3fab6e601f251b0e7a31b6b7e20d40d53c810bd6
parent def664c3046d6c1f2e643e0d64baf43c432e25c6

Make the fuzzer check for large substrings as soon as possible.

Change-Id: I53377057e57658b60ea707af171dff234d5699bb
Reviewed-on: https://code-review.googlesource.com/c/re2/+/39750
Reviewed-by: Paul Wankadia <junyer@google.com>

re2/fuzzing/re2_fuzzer.cc

diff --git a/re2/fuzzing/re2_fuzzer.cc b/re2/fuzzing/re2_fuzzer.cc
index 2faebe0..061c418 100644
--- a/re2/fuzzing/re2_fuzzer.cc
+++ b/re2/fuzzing/re2_fuzzer.cc
@@ -22,25 +22,6 @@
   if (!re.ok())
     return;
 
-  // Don't waste time fuzzing high-size programs.
-  // They can cause bug reports due to fuzzer timeouts.
-  int size = re.ProgramSize();
-  if (size > 9999)
-    return;
-  int rsize = re.ReverseProgramSize();
-  if (rsize > 9999)
-    return;
-
-  // Don't waste time fuzzing high-fanout programs.
-  // They can cause bug reports due to fuzzer timeouts.
-  std::map<int, int> histogram;
-  int fanout = re.ProgramFanout(&histogram);
-  if (fanout > 9)
-    return;
-  int rfanout = re.ReverseProgramFanout(&histogram);
-  if (rfanout > 9)
-    return;
-
   // Don't waste time fuzzing programs with large substrings.
   // They can cause bug reports due to fuzzer timeouts when they
   // are repetitions (e.g. hundreds of NUL bytes) and matching is
@@ -63,6 +44,25 @@
     }
   }
 
+  // Don't waste time fuzzing high-size programs.
+  // They can cause bug reports due to fuzzer timeouts.
+  int size = re.ProgramSize();
+  if (size > 9999)
+    return;
+  int rsize = re.ReverseProgramSize();
+  if (rsize > 9999)
+    return;
+
+  // Don't waste time fuzzing high-fanout programs.
+  // They can cause bug reports due to fuzzer timeouts.
+  std::map<int, int> histogram;
+  int fanout = re.ProgramFanout(&histogram);
+  if (fanout > 9)
+    return;
+  int rfanout = re.ReverseProgramFanout(&histogram);
+  if (rfanout > 9)
+    return;
+
   if (re.NumberOfCapturingGroups() == 0) {
     // Avoid early return due to too many arguments.
     StringPiece sp = text;