[value-serializer] Ensure deserialized JSRegExp flags are valid

test/unittests/value-serializer-unittest.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/value-serializer.h"
 
 #include <algorithm>
 #include <string>
 
 #include "include/v8.h"
@@ skipping 1585 matching lines @@
   // RegExp containing a Latin-1 string.
   DecodeTest(
       {0xff, 0x0c, 0x52, 0x22, 0x06, 'Q', 'u', 0xe9, 'b', 'e', 'c', 0x02},
       [this](Local<Value> value) {
         ASSERT_TRUE(value->IsRegExp());
         EXPECT_TRUE(EvaluateScriptForResultBool(
             "result.toString() === '/Qu\\xe9bec/i'"));
       });
 }
 
+// Tests that invalid flags are not accepted by the deserializer. In particular,
+// the dotAll flag ('s') is only valid when the corresponding flag is enabled.
+TEST_F(ValueSerializerTest, DecodeRegExpDotAll) {
+  i::FLAG_harmony_regexp_dotall = false;
+  DecodeTest({0xff, 0x09, 0x3f, 0x00, 0x52, 0x03, 0x66, 0x6f, 0x6f, 0x1f},
+             [this](Local<Value> value) {
+               ASSERT_TRUE(value->IsRegExp());
+               EXPECT_TRUE(EvaluateScriptForResultBool(
+                   "Object.getPrototypeOf(result) === RegExp.prototype"));
+               EXPECT_TRUE(EvaluateScriptForResultBool(
+                   "result.toString() === '/foo/gimuy'"));
+             });
+  InvalidDecodeTest(
+      {0xff, 0x09, 0x3f, 0x00, 0x52, 0x03, 0x66, 0x6f, 0x6f, 0x3f});
+  InvalidDecodeTest(
+      {0xff, 0x09, 0x3f, 0x00, 0x52, 0x03, 0x66, 0x6f, 0x6f, 0x7f});
+
+  i::FLAG_harmony_regexp_dotall = true;
+  DecodeTest({0xff, 0x09, 0x3f, 0x00, 0x52, 0x03, 0x66, 0x6f, 0x6f, 0x1f},
+             [this](Local<Value> value) {
+               ASSERT_TRUE(value->IsRegExp());
+               EXPECT_TRUE(EvaluateScriptForResultBool(
+                   "Object.getPrototypeOf(result) === RegExp.prototype"));
+               EXPECT_TRUE(EvaluateScriptForResultBool(
+                   "result.toString() === '/foo/gimuy'"));
+             });
+  DecodeTest({0xff, 0x09, 0x3f, 0x00, 0x52, 0x03, 0x66, 0x6f, 0x6f, 0x3f},
+             [this](Local<Value> value) {
+               ASSERT_TRUE(value->IsRegExp());
+               EXPECT_TRUE(EvaluateScriptForResultBool(
+                   "Object.getPrototypeOf(result) === RegExp.prototype"));
+               EXPECT_TRUE(EvaluateScriptForResultBool(
+                   "result.toString() === '/foo/gimsuy'"));
+             });
+  InvalidDecodeTest(
+      {0xff, 0x09, 0x3f, 0x00, 0x52, 0x03, 0x66, 0x6f, 0x6f, 0x7f});
+}
+
 TEST_F(ValueSerializerTest, RoundTripMap) {
   RoundTripTest(
       "(() => { var m = new Map(); m.set(42, 'foo'); return m; })()",
       [this](Local<Value> value) {
         ASSERT_TRUE(value->IsMap());
         EXPECT_TRUE(EvaluateScriptForResultBool(
             "Object.getPrototypeOf(result) === Map.prototype"));
         EXPECT_TRUE(EvaluateScriptForResultBool("result.size === 1"));
         EXPECT_TRUE(EvaluateScriptForResultBool("result.get(42) === 'foo'"));
       });
@@ skipping 1386 matching lines @@
   InvalidDecodeTest(raw);
 }
 
 TEST_F(ValueSerializerTestWithWasm, DecodeWasmModuleWithInvalidDataLength) {
   InvalidDecodeTest({0xff, 0x09, 0x3f, 0x00, 0x57, 0x79, 0x7f, 0x00});
   InvalidDecodeTest({0xff, 0x09, 0x3f, 0x00, 0x57, 0x79, 0x00, 0x7f});
 }
 
 }  // namespace
 }  // namespace v8