Invoke generated lexer along with baseline lexer to compare results.

src/lexer/lexer-shell.cc

Index: src/lexer/lexer-shell.cc
diff --git a/src/lexer/lexer-shell.cc b/src/lexer/lexer-shell.cc
index 71ab3176cd7fd7bde6adb9582a70ba65460442cc..bdf8ac0540685f0e0c9d5edd94022507252bd2c7 100644
--- a/src/lexer/lexer-shell.cc
+++ b/src/lexer/lexer-shell.cc
@@ -42,6 +42,7 @@
 #include "scopeinfo.h"
 #include "string-stream.h"
 #include "scanner.h"
+#include "lexer.h"
 
 using namespace v8::internal;
 
@@ -84,12 +85,11 @@ class BaselineScanner {
     delete unicode_cache_;
   }
 
-  Token::Value Next() {
-    return scanner_->Next();
-  }
-
-  Scanner::Location Location() {
-    return scanner_->location();
+  Token::Value Next(int* beg_pos, int* end_pos) {
+    Token::Value res = scanner_->Next();
+    *beg_pos = scanner_->location().beg_pos;
+    *end_pos = scanner_->location().end_pos;
+    return res;
   }
 
  private:
@@ -99,14 +99,6 @@ class BaselineScanner {
 };
 
 
-class ExperimentalScanner {
-  explicit ExperimentalScanner(const char* fname);
-  ~ExperimentalScanner();
-  Token::Value Next();
-  Scanner::Location Location();
-};
-
-
 int main(int argc, char* argv[]) {
   v8::V8::InitializeICU();
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
@@ -121,13 +113,28 @@ int main(int argc, char* argv[]) {
       Isolate* isolate = Isolate::Current();
       HandleScope handle_scope(isolate);
       BaselineScanner baseline(argv[1], isolate);
-      Token::Value current;
-      while ((current = baseline.Next()) != Token::EOS) {
-        printf("%11s => (%d, %d)\n",
-               Token::Name(current),
-               baseline.Location().beg_pos,
-               baseline.Location().end_pos);
-      }
+      ExperimentalScanner experimental(argv[1]);
+      Token::Value expected_token, actual_token;
+      int expected_beg, expected_end, actual_beg, actual_end;
+      do {
+        expected_token = baseline.Next(&expected_beg, &expected_end);
+        actual_token = experimental.Next(&actual_beg, &actual_end);
+        printf("=> %11s at (%d, %d)\n",
+               Token::Name(actual_token),
+               actual_beg, actual_end);
+        if (expected_token != actual_token ||
+            expected_beg != actual_beg ||
+            expected_end != actual_end) {
+          printf("MISMATCH:\n");
+          printf("Expected: %s at (%d, %d)\n",
+                 Token::Name(expected_token),
+                 expected_beg, expected_end);
+          printf("Actual:   %s at (%d, %d)\n",
+                 Token::Name(actual_token),
+                 actual_beg, actual_end);
+          return 1;
+        }
+      } while (actual_token != Token::EOS);
     }
   }
   v8::V8::Dispose();