Eagerly escape RegExp.source.

src/runtime/runtime-regexp.cc

Index: src/runtime/runtime-regexp.cc
diff --git a/src/runtime/runtime-regexp.cc b/src/runtime/runtime-regexp.cc
index 5846881f90ad5b68505a000753d8fd2f7324ce5f..d3212f464ff9839b13a8cb4ab107c8145561ecfa 100644
--- a/src/runtime/runtime-regexp.cc
+++ b/src/runtime/runtime-regexp.cc
@@ -844,6 +844,60 @@ static JSRegExp::Flags RegExpFlagsFromString(Handle<String> flags,
 }
 
 
+template <typename Char>
+inline int CountRequiredEscapes(Handle<String> source) {
+  DisallowHeapAllocation no_gc;
+  int escapes = 0;
+  Vector<const Char> src = source->GetCharVector<Char>();
+  for (int i = 0; i < src.length(); i++) {
+    if (src[i] == '/' && (i == 0 || src[i - 1] != '\\')) escapes++;
+  }
+  return escapes;
+}
+
+
+template <typename Char, typename StringType>
+inline Handle<StringType> WriteEscapedRegExpSource(Handle<String> source,
+                                                   Handle<StringType> result) {
+  DisallowHeapAllocation no_gc;
+  Vector<const Char> src = source->GetCharVector<Char>();
+  Vector<Char> dst(result->GetChars(), result->length());
+  int s = 0;
+  int d = 0;
+  while (s < src.length()) {
+    if (src[s] == '/' && (s == 0 || src[s - 1] != '\\')) dst[d++] = '\\';
+    dst[d++] = src[s++];
+  }
+  DCHECK_EQ(result->length(), d);
+  return result;
+}
+
+
+MaybeHandle<String> EscapeRegExpSource(Isolate* isolate,
+                                       Handle<String> source) {
+  String::Flatten(source);
+  if (source->length() == 0) return isolate->factory()->query_colon_string();
+  bool one_byte = source->IsOneByteRepresentationUnderneath();
+  int escapes = one_byte ? CountRequiredEscapes<uint8_t>(source)
+                         : CountRequiredEscapes<uc16>(source);
+  if (escapes == 0) return source;
+  int length = source->length() + escapes;
+  if (one_byte) {
+    Handle<SeqOneByteString> result;
+    ASSIGN_RETURN_ON_EXCEPTION(isolate, result,
+                               isolate->factory()->NewRawOneByteString(length),
+                               String);
+    return WriteEscapedRegExpSource<uint8_t>(source, result);
+  } else {
+    Handle<SeqTwoByteString> result;
+    ASSIGN_RETURN_ON_EXCEPTION(isolate, result,
+                               isolate->factory()->NewRawTwoByteString(length),
+                               String);
+    return WriteEscapedRegExpSource<uc16>(source, result);
+  }
+}
+
+
 RUNTIME_FUNCTION(Runtime_RegExpInitializeAndCompile) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 3);
@@ -865,6 +919,10 @@ RUNTIME_FUNCTION(Runtime_RegExpInitializeAndCompile) {
         isolate, NewSyntaxError("invalid_regexp_flags", args));
   }
 
+  Handle<String> escaped_source;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, escaped_source,
+                                     EscapeRegExpSource(isolate, source));
+
   Handle<Object> global = factory->ToBoolean(flags.is_global());
   Handle<Object> ignore_case = factory->ToBoolean(flags.is_ignore_case());
   Handle<Object> multiline = factory->ToBoolean(flags.is_multiline());
@@ -877,6 +935,7 @@ RUNTIME_FUNCTION(Runtime_RegExpInitializeAndCompile) {
       constructor->IsJSFunction() &&
       JSFunction::cast(constructor)->initial_map() == map) {
     // If we still have the original map, set in-object properties directly.
+    regexp->InObjectPropertyAtPut(JSRegExp::kSourceFieldIndex, *escaped_source);
     // Both true and false are immovable immortal objects so no need for write
     // barrier.
     regexp->InObjectPropertyAtPut(JSRegExp::kGlobalFieldIndex, *global,
@@ -898,6 +957,8 @@ RUNTIME_FUNCTION(Runtime_RegExpInitializeAndCompile) {
     PropertyAttributes writable =
         static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE);
     Handle<Object> zero(Smi::FromInt(0), isolate);
+    JSObject::SetOwnPropertyIgnoreAttributes(regexp, factory->source_string(),
+                                             escaped_source, final).Check();
     JSObject::SetOwnPropertyIgnoreAttributes(regexp, factory->global_string(),
                                              global, final).Check();
     JSObject::SetOwnPropertyIgnoreAttributes(